BY
RONALD
PROKOPY AND STARKER
WRIGHT
DEPARTMENT OF ENTOMOLOGY, UNIVERSITY OF
MASSACHUSETTS
GLEN MORIN AND ROBIN SPITKO
NEW ENGLAND FRUIT CONSULTANTS
GLEN
KOEHLER
UNIVERSITY OF MAINE, ORONO, MAINE
INTRODUCTION Since its inception, the intent of the March Message has been to summarize new information and offer thoughts related to the management of insect and mite pests in Massachusetts. The March Message is not considered to be a publication, thus allowing the expression of opinion that might be withheld from a formal publication.
GENERAL IPM TOPICS AND OPINION
CHANGES IN ORCHARD CHEMICALS FOR 1999
UPDATE ON THIRD-LEVEL IPM STUDIES IN COMMERCIAL ORCHARDS
UPDATE ON DEVELOPMENT OF PLUM CURCULIO TRAPS
UPDATE ON DEVELOPMENT OF BAITED SPHERES FOR APPLE MAGGOT CONTROL
PROGRESS TOWARD ESTABLISHMENT OF T. PYRI MITE PREDATORS IN ORCHARDS
FOOD QUALITY PROTECTION ACT: AN UPDATE AND IMPLICATIONS FOR THE TREE FRUIT INDUSTRY
RESIDUES OF AZINPHOSMETHYL ON APPLES
COMPUTER-BASED RESOURCES: APPLE INFORMATION MANAGER AND ORCHARD RADAR
PROBLEM PESTS: 1998 ACTIVITY, NEW FINDINGS AND TECHNOLOGIES:
TARNISHED PLANT BUG
PLUM CURCULIO
APPLE MAGGOT
LEAFMINERS
APHIDS
LEAFHOPPERS
MITES
PEAR PSYLLA
PEACH PESTS
IPM MANUALS, SUPPLIES AND SERVICES:
PURCHASE OF 1999 PEST CONTROL GUIDES, IPM MANUALS, ETC
MONITORING AIDS: TYPES AND VENDOR INFORMATION
PEST MANAGEMENT SERVICES AVAILABLE IN 1999
GENERAL IPM TOPICS AND OPINION
CHANGES IN ORCHARD CHEMICALS IN 1999
As reported in last year’s March Message, progress toward registration of new agricultural chemicals by EPA has slowed considerably, as focus has shifted toward interpretation and implementation of FQPA. Even so, a handful of chemicals has made progress toward reaching the market.
SpinTor 2 SC (spinosad, 22.8%) received a federal label in 1998 for use against lepidopteran pests. SpinTor is a new actinomycete microorganism derivative (a mixture of spinosyn A and spinosyn D = spinosad), labeled for use on apple against leafroller and tentiform leafminer. It’s chemistry is highly target-specific, minimizing impact on natural predators. Early trials have indicated effective control of leafroller, but information regarding efficacy and timing against leafminer is not well established. A maximum of 3 applications can be used in a season, though to avoid development of resistance, it is not recommended for use against consecutive generations. Preliminary field trials suggest that this material may have some potential for future use against apple maggot, and it is expected to receive a label for use in Massachusetts early in 1999.
Confirm (tebufenozide) is currently labeled for use against lepidopteran pests of walnuts and pecans; the manufacturer expects to receive federal registration for use on apples in the spring of 1999. This material controls development of a wide range of lepidopteran pests of apple (including codling moth, leafroller and lesser appleworm) by inducing premature molting, killing the target insect. The principal mode of action is through ingestion. Thus the larvae must feed for a short time on the crop surface before the chemical will take effect, though activity through contact has been observed in some insects. Confirm is considered to be highly pest-specific (only known to be active against lepidopteran larvae), and is very soft on beneficials.
Comply (fenoxycarb), which has been in a registration holding pattern for several years, is unlikely to receive federal approval. The Section 18 emergency exemption, under which this material was available in the Northwest, was not granted for the 1998 growing season, and is not expected for 1999. Its chemical classification (as a carbamate) severely reduces its chances for registration.
Pyriproxyfen is currently labeled for use on cotton (Knack), and it is available in the Pacific Northwest for use on tree fruit under a Section 18 exemption. This product is classified as an insect growth regulator, and is being fast-tracked toward full EPA registration for use on apples and pears, under the name of Esteem. A full label is expected late in the 1999 growing season; it is intended for use against psylla on pear and codling moth, leafroller, leafminer, and San Jose scale on apples. It is reportedly offers good control of psylla and excellent control of San Jose scale, and is relatively inexpensive.
Pennstyl (cyhexatin) is continuing its progress toward re-registration. Formerly sold as Plictran, it is well known as an effective summer-rescue mite control material, and is particularly soft on beneficials. This would be a welcome summer alternative, and EPA has recently named Pennstyl as one of its priorities for registration in order to better manage resistance development. However, it is likely that this material will only be labeled for use on ornamentals during the 1999 growing season; selected food crops are to be added to the label in 2000.
Last season, there were several reports that Vendex was being voluntarily pulled by its manufacturer. However, the label (formerly held exclusively by DuPont) was shifted into a joint venture with Griffin. In short, Vendex is still available for use against mites on apples, peaches, pears, plums and nectarines.
UPDATE ON THIRD-LEVEL IPM STUDIES IN COMMERCIAL ORCHARDS
Twenty years of research and extension work in Massachusetts prepared us to embark on a new level of IPM in apples in 1997: third-level IPM. In order to make the leap from second-level IPM (integration across all relevant disciplines, promoting biologically-based control approaches) to third-level IPM (integration of all pest management practices with all horticultural practices), in 1997 we embarked on the first phase of our third-level applied research program, which will span 1997-1999.
Our field experiments of 1998 were modeled after those of 1997 and centered around performance comparisons of bio-based versus pesticide-based tactics for managing plum curculio, mites, apple maggot and flyspeck on large (M.7) versus medium (M.26) versus small (M.9) apple trees. The composition of New England apple orchards is in transition from large to semi-dwarf to dwarf trees, and neither we nor anyone else in the world has knowledge of whether bio-based tactics perform as well on small trees compared with larger trees, upon which virtually all New England IPM studies had been conducted prior to the 1997 field season.
As in 1997, the 1998 third-level IPM experiment was conducted in a total of 48 blocks across 8 commercial orchards. Each of the 48 blocks was square, 7 rows across, averaging 49 trees per block. Of the 48 blocks, 16 were comprised of large trees, 16 of medium trees and 16 of small trees. All trees were mature and bore fruit. Of the 16 blocks of each tree size, 8 were under bio-based management to the maximum extent possible; the remaining 8 blocks were under grower-based first-level IPM management. The following sections discuss results obtained on plum curculio, apple maggot and mites as managed using bio-based versus first-level IPM practices in our experiment.
PROGRESS TOWARD DEVELOPMENT OF PLUM CURCULIO TRAPS
Among key insect pests that attack pome and stone fruit in North America, plum curculio (PC) is the only one for which there does not yet exist an effective monitoring trap. In 1995, we began in earnest to conduct research aimed at developing such a trap. Since then, we have conducted as intensive a research effort on PC as funds have permitted. Here, we present a brief summary of our 1998 findings, which stemmed from 4 principal lines of investigation. Full reports on each of the aspects described here are given in the Summer 1998 issue of Fruit Notes.
Commercial-Orchard Trial of Unbaited Traps for Monitoring PCs. In 1997, we evaluated the performance of unbaited trunk-mimicking black pyramid traps placed next to tree trunks in 48 blocks of commercial-orchard trees (16 blocks each of small, medium-size and large trees). In 1998, we repeated this study in the same blocks of trees and expanded it to include evaluation of unbaited twig-mimicking vertical black cylinder traps placed within tree canopies. Traps were unbaited because at the beginning of the 1998 PC season, no odor attractive to PC was available. Twice weekly from petal fall until 5 weeks afterward, traps were examined and fruit in each block were monitored for incidence of PC damage. All blocks received 2 or 3 sprays of Guthion or Imidan at 9-14 day intervals beginning at petal fall.
Results showed that PC injury was very slight in all blocks prior to the first spray. It increased sharply between the first and second spray and increased still further between the second and third spray. Captures of PCs by pyramid traps at tree trunks were greatest prior to the first spray, were fewer between the first and second spray, and were extremely few between the second and third spray. Captures by cylinder traps in tree canopies were about half the total captures by pyramid traps. They were slightly greater between the first and second spray than prior to the first spray, but dropped to near zero between the second and third spray. These same patterns held true for blocks of all tree sizes. Overall, results of 1998 confirmed results of 1997 and indicated that captures of PCs by unbaited pyramid (or cylinder) traps are not accurate indicators of the need for or timing of insecticide application against PC.
Comparison of Six Different Types of Unbaited Traps for Monitoring PCs. In 1998, we evaluated 6 different types of unbaited traps for monitoring PCs in each of 2 small unsprayed and 2 small sprayed orchard blocks. Traps were: (1) clear Plexiglas squares (2 x 2 feet) placed 6 feet from edges of foliage of woods bordering each block and intended to intercept PCs exiting from overwintering sites; (2), (3) and (4) clear Plexiglas squares (2 x 2 feet), green wooden squares (2 x 2 feet), or black wooden rectangles (1 x 4 feet) placed 18 inches from edges of canopies of orchard trees and facing woods, intended to intercept PCs flying toward apple tree canopies, (5) black pyramids (2 x 4 feet) placed next to apple tree trunks, intended to capture PCs entering trees via climbing up tree trunks, and (6) black cylinders (3 x 12 inches) placed in apple tree canopies, intended to capture PCs crawling up branches or twigs. Each trap of types 1-4 was fastened vertically to a wooden pole at 4 feet (center of trap) above ground and received a coating of Tangletrap on the side facing the woods. Twice weekly from petal fall until 8 weeks afterward, the traps were examined and fruit in each block were monitored for incidence of PC damage. Sprayed blocks received 2 applications of Imidan to control PC.
Results showed that black pyramid traps captured more total PCs than any other trap type in unsprayed blocks, with no difference in PC captures among trap types in sprayed blocks. In unsprayed blocks (though not in sprayed blocks), increases in captures by sticky clear and sticky green traps at edges of apple tree canopies, but not increases in captures by any other trap types, were significantly positively correlated with increases in fruit damage caused by PCs during the monitoring period. This finding is similar to 1997 findings in a single unsprayed orchard block and suggests that a more user-friendly form of a sticky trap placed at the edge of an apple tree canopy to capture PCs flying into apple trees might hold promise as an effective monitoring trap. However, to be truly effective, a monitoring trap will require addition of attractive odor.
Evaluation of Various Unbaited Twig-Mimicking Traps for Attractiveness to PCs. In 1998, we evaluated 4 different colors and 9 different sizes of vertical cylindrical twig-mimicking traps for attractiveness to PCs. When foraging within tree canopies, PCs find host fruit for feeding and egglaying almost exclusively by walking on fruit-bearing branches and twigs and not by flying. The cylindrical traps tested here were intended to mimic vertical branches and twigs and to capture PCs that ascended the trap surface and entered a boll weevil trap top that capped the cylinder. All traps were emplaced in small unsprayed orchards at petal fall and remained for 7 weeks.
Results suggested that black cylinders (3 x 12 inches and approximating twig color) were more attractive than same-size green, yellow, or white cylinders, that black cylinders 3 inches in diameter were more attractive than 1 or 6 inch diameter black cylinders, and that black cylinders 24 inches tall were more attractive than black cylinders 6 or 12 inches tall. Together, these results suggest that twig mimics that are black in color, 3 inches in diameter, and 24 inches tall could be potentially effective traps within tree canopies if accompanied by attractive odor. This experiment will be repeated in 1999 to confirm 1998 results.
Evaluation of Compounds from Plum Odor for Attractiveness to PCs. Cooperating chemist P. L. Phelan of Wooster, Ohio has identified 19 compounds from odor of plum fruit as being present in detectable amounts using gas chromatography. In 1998, we evaluated 18 of these compounds (all purchased in synthetic form from a chemical supply house) at different concentrations in laboratory assays and at 1 concentration in field assays for attractiveness to PCs. Lab assays were conducted using still-air Petri dish chambers. Field assays were conducted using boll weevil traps placed on the ground beneath unsprayed apple trees.
Results showed that 2 compounds were significantly more attractive than controls at the lowest concentration tested in lab assays and also in field assays: ethyl isovalerate and limonene. A repeat experiment in the field confirmed PC attractiveness to these 2 compounds. None of the other 16 compounds tested was attractive in the field, and none led to significantly more captures than controls in lab assays. These results are the first anywhere to show that PCs are attracted to specific compounds present in host fruit odor.
Future Plans on PC. In 1999, we plan to evaluate combinations of ethyl isovalerate and limonene at various concentrations and in conjunction with synthetic male sex pheromone (unavailable in 1998, but available in 1999) as lures for attracting PCs to the most promising types of visual traps tested in 1998.
UPDATE ON USE OF STICKY SPHERES AND DEVELOPMENT OF PESTICIDE-TREATED SPHERES FOR CONTROLLING APPLE MAGGOT
Apple maggot flies (AMF) build to high populations on millions of unmanaged wild apple and hawthorn trees, from which they invade orchards in July, August and September. Several years of field research and commercial orchard trials have shown that surrounding small or large blocks of medium-sized apple trees with odor-baited sticky red sphere traps (5 yards apart) to intercept immigrating AMF can provide effective control without need for insecticide application. In 1998, we continued to evaluate the ability of sticky red spheres to control AMF in blocks of commercial orchard trees, we continued to develop and evaluate non-sticky pesticide-treated spheres as a substitute for sticky spheres, and we initiated studies on patterns of sphere deployment in orchards.
Evaluation of Sticky Spheres for AMF Control. As in 1997, in 1998 we placed 1 red sticky sphere baited with butyl hexanoate (synthetic attractive fruit odor) on each perimeter tree (26 trees) in each of the 8 third-level IPM blocks of each of the 3 sizes of trees mentioned earlier. Traps were emplaced in early July and removed in October. To preserve trap-capturing power, traps were cleaned of AMF and other insects every 3 weeks (a labor-intensive procedure).
In all, more than 59,000 AMF (a very large number) were captured in the 24 blocks that received sticky spheres for AMF control. Damage to fruit by AMF averaged slightly less in third-level (0.76%) than grower-sprayed first-level (0.84%) blocks of small trees, slightly less in third-level (0.14%) than first-level (0.16%) blocks of medium-sized trees, and slightly greater in third-level (0.38%) than first-level (0.24%) blocks of large trees. These 1998 data patterns are very similar to those found in 1997 using the same experimental approach in the same 48 blocks of trees. They show that in blocks of small (M.9) and medium-size (M.26) trees, AMF control by baited sticky spheres is just as good as control by 3 insecticide sprays. In blocks of large trees (M.7 or standard), control using sticky red spheres may not be quite as good as use of 3 insecticide sprays. This portends well for use of spheres to control AMF in blocks of dwarf trees that will dominate orchards of the future.
Development and Evaluation of Pesticide-Treated Spheres for AMF Control. Our ultimate goal is to develop effective, durable, inexpensive and easy-to-deploy pesticide-treated spheres (PTS) as substitutes for sticky-coated spheres for direct control of AMF. In concept, a PTS would be coated with a mixture of insecticide, fly feeding stimulant and residue-extending agent. A fly alighting on such a sphere would feed, ingest insecticide and die before laying eggs. The need to use Tangletrap or other sticky as fly killing agent would be eliminated. In 1998, we evaluated 5 candidate insecticides at different doses, new approaches to preserving the residual activity of feeding stimulant and sphere integrity, and new approaches to preventing negative effects of fungi and rodents on PTS.
We evaluated 5 types of insecticides, each at several doses: imidacloprid (our standard), avermectin, spinosad (all 3 recently labeled for apple orchard use), fipronil and sugar-ester (the latter 2 are safe materials not yet labeled for orchard use). Each material was mixed into Glidden red gloss latex paint (our standard effective residue-extending agent for insecticide). Laboratory trials showed little or no insecticidal effect of paint-incorporated avermectin, spinosad or sugar-ester. Results with imidacloprid and fipronil were promising. Paint-coated spheres containing each of these 2 materials at 2, 4, 8, or 16% active ingredient (a.i.) were placed in apple trees in late July and evaluated for toxicity to apple maggot flies in September and October. Results showed that even at the highest dose tested (16% a.i.), neither imidacloprid nor fipronil killed more than 15% of alighting AMF in the absence of sugar following 12 weeks of exposure to outdoor weather. However, 12-weeks-exposed PTS that received a spray of sugar just before AMF alighted on them caused high AMF mortality: greater than 70% death among AMF that alighted on PTS having either 2% a.i. of imidacloprid or 8% a.i. of fipronil. We conclude that even a very small dose of imidacloprid (2% a.i. in a mixture of paint, sucrose and water) is sufficient to provide season-long kill of alighting AMF provided that sugar is present on the sphere surface.
To preserve residual activity of feeding stimulant (sucrose), we took 2 approaches. First, for wooden PTS, we attempted to augment sucrose washed away from the paint (into which it was originally incorporated at a concentration of 20%) by seating a 1 1/4 inch diameter plastic petri dish on top of a wooden sphere and filling the dish with a mixture containing sucrose, liquid fructose and water which was heated and became hard after drying. It was intended that during rainfall, some of the mixture would disperse onto the sphere surface and replace lost sugar. Second, for sugar/flour PTS, we added stabilizing ingredients to the composition of the sucrose/flour mixture comprising the body of the sphere with the intent that the sphere body (overlaid with paint and insecticide) would not degrade as readily under rainfall as it did in 1997. After drying, such a sphere emitted a continuous supply of sucrose to the surface, irrespective of rainfall amount.
To prevent fungal growth on the sphere surface, we experimented with several fungicides and found that incorporating 1% sorbic acid into the body of the sphere was the most effective approach. To prevent rodents from consuming sugar/flour spheres (as they did in 1997), we evaluated several doses and formulations of capsaicin (red pepper) and found that 5% powdered capsaicin incorporated into the sucrose/flour mixture was the most effective approach.
Finally, we compared in commercial orchards the effectiveness of our new-version wooden PTS and our new-version sugar/flour PTS (both coated with 2.0% a.i. imidacloprid in latex paint) with sticky-coated spheres for direct season-long control of AMF. In all, we used 8 orchards, each having 4 blocks of medium-sized trees (49 trees/block). These were not the same blocks used in the third-level IPM experiment. Each block receiving spheres was surrounded by 26 same-type spheres 5 yards apart, each baited with butyl hexanoate. Spheres were deployed in early July and remained until September.
The results showed that sugar/flour PTS performed about as well (0.77% injured fruit) as sticky spheres (0.70% injured fruit) and nearly as well as 3 insecticide sprays (0.59% injured fruit) in controlling AMF. However, wooden PTS did not perform as well (2.93% injured fruit), probably because the caramelized sugar atop the wooden PTS was lost through rainfall at midseason, leaving wooden PTS devoid of sucrose from midseason onward. Fly pressure was exceptionally high in 1998. We are very encouraged by results using flour/sugar PTS, but less encouraged by results using wooden PTS.
Studies on Trap Deployment Patterns to Control AMF. If odor-baited spheres are ultimately to replace insecticides for control of AMF, sphere deployment patterns must be optimized so that the fewest possible spheres are used for control. Presently, we surround orchard blocks with spheres 5 yards apart on perimeter apple trees. In 1998, graduate student Juan Rull continued his studies on optimizing sphere deployment. By hanging sticky spheres in each of 8 same-cultivar trees for each of 9 cultivars in each of 2 commercial orchards and examining spheres for AMF weekly, Juan was able to show distinct differences in peak periods of fly captures according to cultivar type. By color-marking and releasing thousands of male flies in woods at edges of orchard blocks, he was able to show that (a) perimeter traps on small and medium-size trees were better able to prevent fly penetration into blocks than were perimeter traps on large trees, and (b) grouping 8 traps into a single perimeter tree is as or more effective in capturing released flies than spacing traps singly among 8 perimeter trees. These findings should help us to optimize trap deployment patterns according to tree cultivar and tree size.
Future Plans on AMF. In 1999, we plan to continue our efforts to improve the quality and durability of both wooden PTS and sugar/flour PTS for AMF control, and continue to evaluate optimal patterns for trap deployment to achieve consistently high AMF control under a wide range of orchard conditions. Also for 1999, 2 private companies have put in a bid to begin manufacturing sugar/flour PTS for grower use, and a facilitator in the EPA is working with Bayer Corporation (the manufacturer of imidacloprid) to officially label imidacloprid for use on PTS against AMF.
PROGRESS TOWARD ESTABLISHMENT OF T. PYRI MITE PREDATORS IN COMMERCIAL ORCHARDS
Pest mites are usually completely controlled by predatory mites on unmanaged apple trees that receive no insecticide or fungicide. Some commonly-used orchard pesticides such as synthetic pyrethroids and EBDC fungicides kill or otherwise harm predatory mites, leading to pest mite outbreaks and need for miticide application. As discussed in previous issues of the March Message and Fruit Notes, about 90% of Massachusetts orchards harbor populations of the predator Amblyseius fallacis. Unfortunately, populations of A. fallacis do not generally build to numbers sufficient for providing mite biocontrol until late July at the earliest, too late for early and mid-season biocontrol of pest mites. Hence, in cooperation with Jan Nyrop of the Geneva lab of Cornell University, we embarked on a program of seeding third-level blocks with the predatory mite Typhlodromus pyri. This predator can provide effective pest mite biocontrol during early and mid-season, provided certain harmful pesticides (e.g. pyrethroid and carbamate insecticides and EBDC fungicides) are not used. Until 1995, when we seeded it in some second-level IPM blocks, it was present in less than 10% of Massachusetts orchards.
In May of 1997, each of the aforementioned 24 third-level IPM blocks received 100 blossom clusters containing T. pyri predatory mites. The clusters were sent to us by Jan Nyrop. All 100 clusters were fastened to the centermost tree of each 49-tree third-level block. No T. pyri were released in the first-level IPM blocks. Every 2 weeks during July and August, we sampled leaves from the center tree, the 2 outermost trees in the center row and the center trees in the 2 outermost rows to determine degree of establishment and rate of spread of T. pyri in each third-level block. Comparable samples were taken from each first-level block. In all, nearly 13,000 leaves were sampled in 1997 and more than 17,000 were sampled in 1998. All samples were sent to Jan Nyrop for identification and recording of numbers of pest and predatory mites in each sample. Identification of predatory mites to species requires highly specialized expertise not currently available at the UMass.
Results for 1997 showed substantial numbers of T. pyri present on center trees on which they were released in blocks containing small, medium or large trees. At their peak, populations of T. pyri averaged about 1 per leaf on center (release) trees. Essentially no T. pyri were found on other sampled trees in blocks in which T. pyri were released or on any trees in blocks in which T. pyri were not released.
Results for 1998 showed that even though T. pyri averaged at least 0.5 per leaf on center trees of each block size in late August 1997, they averaged only about 0.1 per leaf on the same trees in early July 1998. Causes for this decline in density are not yet fully understood. However, in August 1998, densities of T. pyri on center trees reached 0.5-0.8 per leaf. Importantly, by August 1998, T. pyri had spread to outer trees in the same row (the 3rd trees on each side of the center tree) in substantial numbers in blocks of small trees (whose foliage within rows was contiguous) and in detectable numbers in blocks of medium and large trees (whose foliage within rows was not contiguous). There was little evidence of spread of T. pyri to other rows of trees in our blocks. Interestingly, Amblyseius fallacis was rather equally abundant on all sampled trees in all blocks and IPM-level types, except in third-level blocks of small trees, where it was virtually absent (these blocks had the greatest of all populations of T. pyri). Trends in populations of pest European red mites on sampled trees were similar for third- and first-level blocks of each tree size. Importantly, abundance of T. pyri on release trees in August of 1998 averaged 7 times greater in blocks that received only oil, Apollo or Savey in 1997 or 1998 than in blocks that received Agri-Mek in 1998. These data tend to confirm findings of others showing that Agri-Mek is moderately if not rather highly toxic to T. pyri.
In sum, data trends for 1997 and 1998 suggest solid establishment of T. pyri on trees on which they were released (provided these trees did not receive Agri-Mek) and substantial spread to other same-row trees in blocks of small trees when within-row foliage was contiguous. As of August 1998, no impact of T. pyri on pest mites could yet be detected, but we expect this to occur in 1999.
FOOD QUALITY PROTECTION ACT: AN UPDATE AND IMPLICATIONS FOR THE TREE FRUIT INDUSTRY
Overview. Since the passage of the Food Quality Protection Act (FQPA) in August 1996 as part of the 1996 Farm Bill, volumes of literature have been written on the pros and cons of the Act’s eventual implementation. FQPA includes major revisions in both the Federal Food, Drug, and Cosmetics Act (FFDCA) as related to food safety, as well as to pesticide registration and use provisions in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The law states that EPA should give priority consideration to reassessment of tolerances which appear to pose the greatest threat to human health. The complex issues involved with implementing this law are rising to the surface as EPA struggles to interpret and subsequently enforce the guidelines of this statute. As the law states, EPA must reassess 33% of all food tolerances by August 1999. To date, of the 9,728 tolerances subject to reassessment, EPA has reassessed 2,308 tolerances, of which 999, or about 43% are organophosphates, carbamates, organochlorines, and carcinogenic pesticides. According to the law, EPA must reevaluate pesticides in order of their perceived greatest risk, which is why the organophosphate pesticides are being evaluated first.
Tolerance Reassessment Advisory Committee. As part of the FQPA implementation process, EPA and USDA formed the Tolerance Reassessment Advisory Committee (TRAC), an advisory panel of 52 key persons representing diverse agricultural interests. The committee was formed partly as a result of a directive from Vice-President Al Gore to proceed in an informed and cautious manner with regard to FQPA implementation. The TRAC is jointly chaired by Peter Robinson, Acting Deputy Administrator of EPA and Richard Rominger, Deputy Secretary, USDA. Administrative and regulatory officials of both USDA and EPA are well represented in the TRAC sessions. Since the TRAC began meeting in May of 1998, more than 6 meetings of the TRAC and TRAC workgroups have occurred, and many hundreds of Washington D.C. hours have been put in by TRAC members. Nine key science policies which will affect tolerance reassessments have been developed, debated, and are now available for public comment. Once these policies have been established, EPA will move promptly to implement these policies in it’s risk assessments. Some examples of key policies being debated are:
Once EPA has these policies in place, it will implement them in deciding new use patterns and in setting new tolerance limits under FQPA reevaluation of pesticide registration.
The Organophosphate Insecticides. Organophosphates, (OPs) are the first group of agricultural chemicals to be evaluated under the new FQPA guidelines. This class of insecticides is used on approximately 75% of fruit, vegetable and grain crops produced in the U.S. Organophosphates act as nerve poisons to insects through action on acetylcholinesterase, an enzyme also possessed by mammals, including humans. Concerns regarding the actual neurotoxicity of OPs to humans were actively debated by TRAC members. The OPs have been used as important components of Integrated Pest Management programs, which have been developed in the past 25 years, due to limited persistence in the field and tolerance to OPs by many biological control agents. So far, 28 preliminary risk assessments of organophosphate pesticides have been released for public comment. The remaining 15 preliminary risk assessments will be released for comment before May 1999. A public comment period on risk management for the first of the organophosphate pesticides will begin in spring or summer of 1999. Risk mitigation measures and alternative pest control strategies will be an extremely important part of this process. At this point, EPA will be working closely with USDA to come up with use patterns for pest control that will not cause undue disruption of food production systems due to lack of pest control materials. EPA expects to complete tolerance reassessment for all the organophosphates by the end of 2000.
What can fruit growers expect in 1999?
American agriculture is facing challenges of a magnitude that it has not experienced in the recent past. Producers are struggling with economic forces which are stretching their capacity to remain in farming to the limit. Increased international competition will be a given in the next millenium; significant price increases are difficult to envision as communication and shipping capacity increases globally. At the same time, increased production costs are eating up any small profit margins which do exist. This is true for most other agricultural commodities as well as tree fruits.
There is no doubt that implementation of FQPA will cause increased complications in crop production due to increased pre-harvest intervals and other types of use pattern changes. However, there are many good aspects of FQPA which should be considered, in addition to the increased environmental/consumer protection that the law hopes to provide. Never before have EPA and USDA opened up the registration procedure to so much input from groups affected by their rulings. Because of the difficulties of implementing these policies, regulatory officials have had to learn vastly more about agricultural production than they have in the past. They are coming head-to-head with the difficulties growers face in growing agricultural crops. USDA is planning to set up regional pest management centers to help growers with crop production problems. Regulatory officials are also becoming more aware of the financial situation of most growers as they go through this process. Improvements such as IPM crop insurance and even price-support systems for fruit and vegetable growers are being actively debated and investigated. The difficulties of FQPA implementation can help focus attention on the pressing needs of U.S. agricultural production in general. Growers must be willing to voice their concerns and make their needs known. It is important to face the coming challenges with an open attitude and use the coming changes our advantage instead of mourning the loss of "the old days."
RESIDUES OF AZINPHOSMETHYL ON APPLES
As reported in full in the Spring 1998 issue of Fruit Notes, we sampled apples at harvest from third-level and first-level IPM blocks in 5 Massachusetts commercial orchards in 1997 and submitted them to cooperating toxicologist John Clark of UMass for detection of azinphosmethyl (AZ). Limit of sensitivity for detecting AZ was 40 ppb (parts per billion). Results showed that no AZ was detected on apples in any of the third-level IPM blocks that received an average of 3 sprays of AZ against plum curculio in May and June but no sprays of AZ thereafter (apple maggot was controlled by red sphere traps). In first-level IPM blocks that received an average of 2.4 sprays of AZ to control apple maggot in July and August, AZ residue on fruit at harvest averaged 96 ppb. The good news is that 96 ppb is only 5% of the currently tolerated amount of AZ on fresh apples in the marketplace. The bad news is that AZ was in fact present on harvested fruit in a detectable amount in orchards where AZ was used to control apple maggot. More good news is that AZ used in 3 sprays to control plum curculio was not present in detectable amount at harvest.
Interestingly, in a newsletter distributed by Glen Koehler of Maine on June 1 of 1998, Glen presented results from a USDA Pesticide Data Program (PDP) 1996 summary report showing that for 530 samples of fresh apples of domestic origin taken from supermarkets in 19 states, 55% of the samples had a detectable level of AZ, with the average amount of AZ being 92 ppb. This is nearly identical to the 96 ppb found in our study on apples from first-level IPM blocks in Massachusetts.
In a certain sense, it is very comforting to know that apples from Massachusetts and other states have an average amount of AZ at harvest that is only 5% of the currently allowable amount. Unfortunately, even this very low amount of AZ may contribute too much to the future FQPA risk cup allowed for this insecticide. We should know much more about allowable future use of AZ on apples before the end of 1999. Quite possibly, the days to harvest interval will be increased to 60 days or so following the last application. This would be good news for continued use of AZ against plum curculio but not so good for its continued use against apple maggot.
COMPUTER-BASED RESOURCES: APPLE INFORMATION MANAGER AND ORCHARD RADAR
The Apple Information Manager, or AIM, is a source of information for New England apple growers. It is located on the Internet, and is a cooperative effort of the New England Land Grant Universities and Extension. As a result, it brings together the resources of six university systems in one location. AIM features the following resources:
To find AIM on the Web, go to http://orchard.uvm.edu/aim/
Orchard Radar is the flashy name for a simple concept: using desktop computers and the internet to receive commercially available weather data, use the data as input for apple pest management and horticulture models, and then use the Internet again to distribute the model estimates to growers. The term "Radar" is used because it implies the appropriate way to view these products as tools that help you gauge the relative nearness (in time) or size (severity) of an oncoming object, such as pest risk or horticultural stage. These products are only like radar in this conceptual sense; there is no direct use of radar technology in making the estimates.
Growers are familiar with relationships between weather variables such as temperature and rainfall and the orchard events. Some of these relationships are simple, like knowing that warm weather leads to earlier bloom. Others are more detailed, such as the effects of temperature, rain, and leaf wetness on apple scab infection potential. Many such relationships have been formally quantified and published in scientific literature. Others are used as more or less reliable, informal rules. The models that make up Orchard Radar consist of both formal and informal relationships.
The relationships have been around for years, but the logistical difficulties in collecting and processing weather data on individual grower computers has prevented full use of the available information by orchard decision makers. The emergence of the Internet into mainstream use has provided a path by which a single computer can handle the large volume of weather data for multiple sites; process those data; and then quickly, inexpensively, and automatically broadcast estimates to growers.
The Radar model estimates are supplementary tools for IPM decision making, though the best and most useful tool is the experience and knowledge of the grower. As with any decision-making aid, common sense is required to use the Orchard Radar tools effectively. Neither the distributor of the weather data nor Cooperative Extension can guarantee the validity of each model for each location and situation. These are experimental tools still undergoing development. Thus, grower feedback is very important. The intent in providing Orchard Radar is not to have a machine attempting to make orchard management decisions; it is only to improve the consistency of the information base upon which growers make decisions. As with any other source of information, you should look at these estimates as another piece of the large puzzle.
Orchard Radar is available at http://pmo.umext.maine.edu/apple/allmodels/RadarIntro.htm
Both AIM and Orchard Radar are computer-based, so you need to have a computer (or access to a computer) in order to take advantage of the tools. The programs needed to navigate the Internet are readily available, and generally very easy to learn and use.
PROBLEM PESTS: 1998 ACTIVITY, NEW FINDINGS AND TECHNOLOGIES
1998 Activity In 1998, as has been true since 1995, TPB trap captures and fruit injury were below 1990-1994 levels in Massachusetts. Most growers were able to go without a prebloom spray against TPB and experienced a comparatively low amount of injury on harvested fruit. The same was true throughout most of the Northeast. The fact that TPB populations and injury levels have been below normal for 4 consecutive years makes one wonder if TPB parasites (Peristenus digoneutis) that were released in Mid-Atlantic states, New York and New England a few years ago aren’t beginning to take hold in an increasingly substantial way. Let’s hope this is the case, as TPB have been the main reason for prebloom use of Guthion and Imidan, which aren’t needed for prebloom control of any other pest on apples.
New Findings. Unfortunately, there is no new information to report on effects of pesticides on TPB or on other aspects of TPB biology or management appropriate to New England apple orchards.
Guthion, Imidan and Lorsban remain the pesticides of choice, although Digon may be preferable in hot-spot blocks if applied before half-inch green (to avoid toxicity to bees). Pyrethroids (Asana, Ambush, Pounce) usually are more effective than Guthion, Imidan or Lorsban and are cheaper to buy, but often prove to be more expensive in the long run because of the devastating effects of pyrethroids on mite predators.
Thresholds for Treatment. For the past 3 years (1996-1998), we have placed 8 sticky white rectangle traps in 8-acre blocks in each of 12 commercial orchards and monitored TPB captures as well as TPB injury to fruit. This has been done in an attempt to refine our threshold levels for treatment against TPB and to determine optimal numbers of traps per 8-acre block needed to provide a reliable TPB population estimate. Blocks receiving insecticide against TPB are eliminated from analysis because of insecticide interference with relationships between trap captures and fruit injury. It will therefore take us another year or two more to complete the data set. In the meantime, we will stay with our present thresholds. White sticky traps should be placed in the orchard at silver tip. Traps should be hung at knee level, clear of waving branches and tall grass. Thresholds are as follows:
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Wholesale (mainly fancy and extra fancy) |
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Retail |
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1998 Activity. In 1998 in Massachusetts, fruit injury by PC was somewhat greater than in recent years owing in part to lack of fruit on wild apple and plum trees. Areas of prebloom cold injury and lousy weather during pollination resulted in precious few fruit on unmanaged fruit trees. With nowhere else to go to feed and lay eggs, overwintered PCs moved in above-average numbers into commercial orchards, especially into blocks not far from abandoned trees that bore fruit in 1997 and gave rise to the PCs that appeared in 1998. Because of the dearth of unmanaged fruit in which they could develop in May and June of 1998, PCs are expected to appear in 1999 in numbers well below normal.
New Findings. In an earlier section of this March Message, we reported results of our 1998 research aimed at developing an effective trap for PC. Other than this, new findings involve tests of various insecticides against PC.
Dick Straub of the Hudson Valley lab evaluated Guthion 35WP at 12oz./100 vs. Imidan 50WP at 20 oz./100, each applied every 14 or 21 days against PC in 1998. PC damage was as follows: untreated control = 23.5%; Imidan at 14- and 21-day intervals = 3.3 and 0.9%, respectively; Guthion at 14- and 21-day intervals = 0.5 and 0.0%, respectively. In this test, Guthion performed better than Imidan at each timing. Strangely, 21-day intervals were superior to 14-day intervals, a result which Straub attributed to a particular 21-day interval spray that coincided with peak PC immigration into orchards. General consensus at a meeting of eastern tree fruit researchers in Vermont in October of 1998 was that Guthion and Imidan are equally effective against PC, but Imidan has a shorter residual effect and requires perhaps 3-4 annual treatments to assure good control compared with 2-3 treatments using Guthion. Lorsban has an even shorter residual activity against PC than does Imidan.
Harvey Reissig of Geneva, New York compared the spraying of border rows only (i.e. the outer 2 rows) with spraying all rows in a block, using Guthion at 14-day intervals beginning at petal fall for each setup. For border-row treatment plots, PC injury to fruit on border rows vs. internal rows averaged 0.3 and 1.2%, respectively. For all-row treatment plots, PC injury to fruit on border rows vs. interior rows averaged 0.9 and 0.2%, respectively. Although PC distribution among plots receiving the same treatment type was quite variable, results suggest that a season-long program consisting only of border-row sprays is not as effective as one or more sprays applied to the entire orchard in preventing PC injury. Our experience in Massachusetts and the experience of Charles Vincent and Gerald Chouinard in Quebec suggests that border row sprays against PC can provide excellent PC control for at least part of the PC season, but in Massachusetts and evidently also in New York, not for the entire PC season. At least 1 whole-orchard spray against PC is needed.
At Geneva, New York, garlic was applied in a formulation called "Guardian" (along with the adjuvant Sylgard) in 3 sprays at 2-week intervals beginning at petal fall against PC. It provided no control of PC, however. So it seems that garlic-flavored apples will not be on the shelf in the near future. There may be some hope on the horizon for those who wish to grow "organic" apples and still control PC without using a synthetic insecticide. A material called kaolin, which consists of refined clay particles from Georgia soils, plus an additive, has been shown in preliminary tests in West Virginia and Maryland to suppress PCs when applied in sprays to apple trees. Kaolin is a harmless material used commercially in cosmetics, paint pigments, electrical conductors, and paper production. The biggest constraints seem to be the large amount needed to achieve PC suppression (50 pounds or so per acre per application) and the frequency of application (every 7 days or so). The trees turn white or gray temporarily but this disappears after rainfall and produces no adverse effects on foliar or fruit quality. Quite the contrary, fruit size and red color are enhanced. We will look into use of kaolin against PC in 1999 and report more on its effectiveness in the next March Message.
Thresholds for Treatment. No change here from 1998 recommendations. The best guide to determining when to start spraying for PC is to examine fruit as high as can be reached on early-blooming trees of perimeter rows (or on nearby unsprayed trees) in traditional hot spots and spray as soon as you see a fresh egglaying scar. Don’t wait until fruit begins to size up before spraying, as PC can damage a fruitlet as soon as petals fall from it. When to stop spraying against PC? Consider using the day degree (DD) model developed by Harvey Reissig and colleagues in New York and reported in full in a 1998 issue of Environmental Entomology. Calculate the number of DD above 50°F (as a base) beginning at petal fall. The timing for the last spray should be such that active insecticide is in place until 340 DD are accumulated. Day degrees for a single day are calculated by subtracting 50°F from the average temperature for that day (i.e. the average of the maximum and minimum). This model has performed very well in tests in Massachusetts in 1997 and 1998, with no new PC injury occurring after the 340 DD prediction where residual spray material was present.
1998 Activity. AMF populations were highly variable in Massachusetts orchards in 1998. In some locales where thunderstorms moistened the soil at least occasionally during summer, AMF immigrated into orchards throughout summer in exceptionally high numbers and caused well-above-normal fruit injury. As with plum curculio, the main factor contributing to such a large amount of immigration was near total absence of fruit on wild apple trees owing to very poor weather before and during bloom. In other locales, the soil remained very dry from mid-July to harvest and few AMF were seen after an early flush of immigrants. This same spotty appearance of mid- and late-season AMF was characteristic of other New England states and New York in 1998. It highlighted the value of red sphere traps for determining whether one did or did not have a population requiring treatment. The general dearth of wild fruit in which AMF larvae could develop in 1998 suggests that AMF will not be much of a problem in Massachusetts commercial orchards in 1999.
New Findings. If organophosphates are withdrawn from permissible use on apples or pre-harvest intervals are extended to 60 days or more, what current materials labeled for orchard use could serve as a substitute for AMF control? None of the carbamates will serve this purpose well. Nor will Provado, Agri-Mek or Confirm. These materials either are inherently ineffective against AMF, are absorbed into the leaf surface rapidly and hence removed from contact with AMF, or have very short residual activity. What about SpinTor (spinosad)? A communication from Brian Olson, an informed representative of Novartis (= manufacturer of SpinTor), suggests that SpinTor can control AMF pretty effectively if applied every 7 days. It breaks down under UV light and thus is unlikely to last more than a week or so. If it comes down to SpinTor and no other insecticidal choice, growers may want to look into using pesticide-treated spheres to control AMF (see section on this subject under General IPM Topics and Opinions).
Thresholds and Treatment. We continue to recommend hanging unbaited sticky-coated red spheres to monitor AMF and spraying when an average of 2 AMF per trap has been reached. Traps should be hung in early July. Continue monitoring in late-ripening cultivars into September.
1998 Activity. Three species of leafminer are active in commercial orchards in Massachusetts and other New England states: apple blotch leafminer (ABLM), spotted tentiform leafminers (STLM) and apple leafminer (ALM). Populations of ABLM/STLM were highly variable among Massachusetts commercial orchards in 1998. Some orchards experienced very high numbers right from the start (before bloom), while most orchards saw relatively few numbers through July. But some of the latter experienced a veritable explosion of ABLM/STLM in August or September, causing much concern about the possible impact on fruit drop, especially where ReTain was not used. The explosive pattern was especially characteristic of blocks treated with Agri-Mek after petal fall. We really don’t understand why there was such an explosion from the second to the third generation, though the same thing occurred in other New England states, New York and Ontario. Perhaps parasitoids that normally do a good job of attacking second-generation ABLM/STLM were comparatively few in 1998 owing to the very dry weather in July and August or to some adverse effect of Agri-Mek or Provado on them. This was definitely the case in Ontario, where parasitoids attacking second-generation STLM were sharply down from recent years. Whichever, growers should be on guard for large populations of adult ABLM/STLM emerging this spring. ALM was very abundant in several Hudson Valley orchards and in a few New England orchards in 1998. ALM is not known to cause premature fruit drop but may have other adverse effects on crop yield or quality. Having 5-6 generations per year (rather than the 3 generations per year typical of ABLM/STLM), ALM can build to very large numbers by harvest, with miners almost obliterating the green surface area of young leaves, particularly on watersprouts.
New Findings. In 1998, Glen Morin of NEFCON evaluated SpinTor (spinosad) at 4 oz./acre and Provado at 6 oz./acre, each applied twice (July 2 and July 15) against 2nd generation sap-feeding miners of ABLM/STLM. By July 29 (last date on which miners were sampled), SpinTor reduced sap- and tissue-feeding miners by 45 and 90%, respectively, compared with 55 and 95% reduction, respectively, achieved by Provado. Thus, 2 applications of either material against second-generation miners (an expensive approach) achieved good results. A report from New Hampshire by Alan Eaton indicated that SpinTor did not work very well as a single application against first-generation ABLM/STLM. Also, Dick Straub in the Hudson Valley reported that SpinTor did not control ALM to any substantial degree. Charles Vincent in Quebec has found that shredding fallen apple leaves after leaf drop in late October or in spring, before LM adult emergence, kills the great majority of LM pupae. Bill MacHardy of New Hampshire shreds apple leaves after leaf drop to control apple scab. Thus, there may be a 2-fold benefit to engaging in leaf shredding: reducing scab inoculum and physically or otherwise destroying LM pupae.
Beginning in 1996, we have been involved in an extensive study in 12 commercial orchards in Massachusetts aimed at determining how many sticky red trunk traps are needed per 10-acre block of trees to accurately monitor populations of first-generation ABLM/STLM adults. Because any insecticide used against first-generation LM disrupts the association between trap captures and larval mines, we have been forced to eliminate more data than we can save for determining trap vs. mine relationships. So it will take more years of work to come to any firm conclusions.
During the course of this study, we have sampled mines at harvest to determine the composition of LM species in each orchard. These data show some rather dramatic trends. Statewide, the poulations of ABLM and STLM are nearly identical. However, individual orchards each have unique combinations of the two species: ranging from 100% ABLM to 100% STLM. If the species composition of an orchard is not known, leafminer management can be quite difficult, as the two species respond to different types of traps and exhibit slightly different timing of growth stages through the season. Our interest in studying species composition stems not only from a management perspective, but also from a need to determine the mechanism responsible for shifts in species composition.
Until about 15 years ago, ABLM was thought to be the only species of leafminer present in Massachusetts orchards. Since that time, many orchards (with no apparent geographical relationship) have experienced a substantial shift toward dominance by STLM. In fact, several orchards in this study have shifted entirely from ABLM to STLM in as little as 5 years. What is responsible for this marked shift in species composition? There is strong evidence that chemical use patterns at least partially determine which species dominates an orchard. It appears that as use of harsh chemicals has declined for the last 20 years, natural enemies of ABLM have built up to some extent, offering partial control of this species in many orchards. Unfortunately, a lack of ABLM seems to open the door for infestation by STLM, which (as a much more recent arrival) apparently does not have the parasitoid complex in place as yet to offer effective biological control.
A much more intensive sampling effort is needed to pinpoint the mechanisms responsible for the shifts in species composition occurring in Massachusetts commercial orchards. Such an effort (scheduled to start during the 1999 growing season) will focus on pheromone and unbaited trap captures, species density and composition, parasitoid density and distribution, whole-orchard chemical use patterns, and impacts on fruit yield and quality.
Threshold for Treatment. Our thresholds are the same as given in the 1998 March Message, with the caution that trap capture thresholds apply to ABLM and not to STLM and that they may be unreliable if fewer than 4 traps are used per 8-acre block. For Massachusetts, we suggest the following:
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1998 Activity. Among the 4 kinds of aphids (rosy, green apple, spirea, woolly) that colonize apple trees in Massachusetts and other New England states, only woolly aphids appeared in above-average numbers in commercial orchards in 1998. For this species, populations reached damaging levels in a few orchards in July and subsided to a lower level by August. During recent years, widespread use of carbaryl as a thinner and Provado or Agri-Mek to control leafminers has had a beneficial side effect in reducing aphid populations, especially apple and spirea aphids.
New Findings. Because aphids are of lesser importance than several other apple pests, there are few new findings relevant to their management on New England apple trees. Two findings are considered here.
First, it seems that captan used to control the summer diseases flyspeck and sooty blotch is also a very helpful in preventing buildup of sooty mold fungus on fruit covered with honeydew excreted primarily by woolly aphids but also by apple and spirea aphids. This is a general observation that we have made in commercial orchards ever since more growers switched to captan for summer use a couple of years ago. It suggests that insecticides directed specifically at controlling woolly aphids can be relaxed without threat of fruit damage, provided captan is used as a summer fungicide. That’s good news.
As has been true for many years now, apple and spirea aphids (though not woolly aphids) are controlled well in most orchards by aphid predators, particularly larvae of syrphid flies and larvae of Aphidoletes aphidimyza flies. Over the past 2-3 years, we have seen a massive buildup of Asian lady beetles, which have begun to replace other species of lady beetles and perhaps also the above types of fly predators as biocontrol agents of aphids in orchards.
A study by Brown and Miller published in a 1998 issue of Entomological News shows that in West Virginia, the seven-spotted lady beetle was the dominant species of lady beetle in commercial orchards from 1989 to 1994. Beginning in 1995, however, the recently introduced Asian lady beetle has become the dominant species. It has replaced most other species of lady beetles in commercial orchards and has provided a very high and consistent degree of biocontrol of apple and spirea aphids, though not woolly aphids (which are protected from most predators by the waxy fluff they secrete).
Asian lady beetles were originally released in the East in 1978 by the USDA as biocontrol agents, but the first overwintering beetles were not recorded until 1993. Since then, their populations have built into such enormous numbers that they are now considered pests by many homeowners. On a particular mid-October weekend in Massachusetts in 1998, so many Asian lady beetles alighted on brightly-colored houses and barns that it was hard to see the paint. By the thousands, millions, and billions, these alighting beetles eventually made their way into buildings to find protection during winter. In Asia, the adults annually migrate (after feeding on aphids) to high cliffs and mountains, where they overwinter in huge populations. By aggregating, there is less chance that any one beetle will be consumed by a predator such as a bird. The bright shinny surface of a chalk cliff or mountain face (analogous to a brightly-painted building) is the major cue that the beetles use to hone in on a site for aggregation. Even though homeowners might consider Asian lady beetles as pests, they certainly are very helpful in boosting biocontrol of apple and spirea aphids to a higher level.
Thresholds and Treatment. No change from recent March Messages
Apple Aphids/Spirea Aphids. In most orchards, apple aphids and spirea aphids rarely require treatment. If more than 50% of vegetative terminals are infested and predators are present on less than 10% of infested terminals, a half-rate of Thiodan (1/2 lb./100 gal) may be applied for control.
Rosy Apple Aphids. To monitor for rosy aphids from green tip through petal fall or first cover, examine 10 interior fruit clusters on each of 10 trees and treat when 1% or more of clusters are infested. Researchers in New York recommend choosing clusters for examination that show evidence of possible aphid infestation. In addition, you may want to focus on trees of more highly susceptible varieties (for example, Cortland, Idared, or Golden Delicious). If these thresholds are reached by tight cluster, Lorsban provides good control, as does Provado at petal fall.
Woolly Apple Aphids. Our traditional (tentative) threshold for WAA has been 50% of pruning cuts infested, using Thiodan at 1/2 lb./100 gals if threshold is exceeded. There is some question as to the accuracy of this threshold, given the lack of direct correlation between foliar and root populations of WAA. High populations of canopy WAA on untypical feeding sites may be one sign of a destructive root population. There are currently no proven insecticide treatments available in Massachusetts against below-ground populations.
1998 Activity. Leafhoppers, particularly white apple leafhoppers, reached some of the highest population levels by harvest that we have seen in Massachusetts in recent years. This was not the case in some other New England states, however. The probable underlying reason for the leafhopper problem in Massachusetts was the light apple crop, which resulted in comparatively little use of Sevin as a thinner. Also, only a minority of Massachusetts growers used Provado for leafminer control in 1998. Hence, first-generation leafhoppers were relatively free from pesticidal effects and could build into larger than normal second-generation numbers in summer and third-generation numbers toward harvest. Although we can’t say for sure, overwintering leafhopper eggs are probably abundant and could set the stage for a fast start for leafhoppers in 1999.
New Findings. The principal new finding on leafhoppers comes from a study by Straub, Stower, and Jentsch in the Hudson Valley published in a late 1997 issue of the Journal of Economic Entomology. Application of Sevin at 1/2 lb. a.i. per acre, Sevin at 1 lb. a.i. per acre or Provado at field-recommended rate 1 week after petal fall in 1995 resulted in 93, 97, and 100% reduction, respectively, in white apple leafhopper adults by mid-June and 50, 85, and 96% reduction, respectively, in white apple leafhopper adults by mid-September compared with populations in untreated control plots. When this experiment was partially repeated in 1996, Sevin at 1 lb. a.i. per acre applied 20 days after petal fall or Provado applied at petal fall achieved about 95 and 80% reduction, respectively, of rose leafhopper adults by late June (no data were taken on population at harvest). These findings suggest that Sevin at 1 lb. a.i. per acre as well as Provado at recommended rate applied within 2-3 weeks of petal fall can have a strong impact on populations of both white apple and rose leafhoppers. In some years, the beneficial effects may carry all the way to harvest. But in years of large overwintering leafhoppers egg populations or a heavy rainfall shortly after application (in the case of Sevin), a single treatment of either of these materials may not be enough to provide control through harvest. As mentioned in the 1997 March Message, our own research on rose leafhoppers shows that removal or herbiciding of rosebushes within 100 yards or so of an orchard can cut down on within-orchard populations by 60-70%.
Thresholds and Treatment. No change from recent March Messages. For preventing injury caused by feeding of first-generation WALH or RLH nymphs in June: 3 nymphs per leaf. For growers annually experiencing troublesome LH populations at harvest, we recommend a provisional threshold of 25 WALH and/or RLH nymphs per 100 leaves in June.
1998 Activity. Populations of European red mites (ERM) developed in fits and starts in 1998 in most of New England. The cool damp weather of late April and early May was not conducive to rapid ERM reproduction after egg hatch at pink. But the warm, dry period over the last 3 weeks of May stimulated rapid ERM population growth, only to be slowed to a near standstill by the cool wet weather of June. The warm, dry weather of July and August stimulated rapid building of ERM once again, accompanied by building of two-spotted mites (TSM) in several orchards. Orchards using only a double-oil program maintained mite control until mid or late July, but in many cases, an application of summer miticide was needed to hold populations down after that. Most growers who used a pink or petal fall application of Apollo, Savey or Agri-Mek made it through early August in good shape. But in several cases, populations of ERM or TSM flared to an unacceptable level after that and required a summer miticide.
New Findings. Biocontrol by predators. The most important factor in maintaining ERM below damaging levels is presence of sufficient predatory mites to promote effective biocontrol. Unsprayed apple trees do not have problems with pest mites. The main reason: presence of a complex of predators that achieves biocontrol. We get into trouble in commercial orchards when we use insecticides, fungicides or miticides that disrupt predators, either by killing predators outright or negatively affecting some aspect of predator physiology, such as reproductive capability.
A predator is a predator is a predator. As a renowned poet once wrote, this may be true in the case of roses, but a 1998 publication by Lester, Thistlewood and Harmsen of Ontario in the Journal of Applied Ecology indicates that all species of mite predators on apple trees are not equal in value. These workers manipulated the size and number of predator refuges from pyrethroid sprays on apple trees by placing polyethylene sheeting over parts of apple trees before spraying with permethrin. The most abundant predators on the trees before spraying were Typhlodromus caudiglans (a very close relative of Typhlodromus pyri, which we and others have been releasing in Massachusetts apple orchards since 1993) and Zetzellia mali (commonly known as yellow mites, and perhaps the most conspicuous and frequently seen mite predators in Massachusetts apple orchards). Before spraying, the authors estimated there to be about 470 individuals of T. caudiglans and 560 individuals of Z. mali per tree. The pyrethroid spray essentially wiped out all T. caudiglans predators but had virtually no effect on Z. mali predators. The resiliency of Z. mali was also observed in blocks of apple trees in Massachusetts treated with both Pyramite and Carzol. One might imagine the high survival of Z. mali to be a good thing. Not so in this case. As shown by earlier work by Santos and Laing and confirmed by Lester and co-authors, it takes a whole lot of Z. mali (an average of well more than 1 per leaf) to make even a slight dent in a population of European red mites. Rarely do we see populations of Z. mali this large. In fact, Lester and co-authors found that moderate and even low populations of Z. mali were detrimental to recolonization of sprayed leaves by T. caudiglans and thus beneficial to pest mites, because T. caudiglans and Amblyseius fallacis (in another study) were much less able to build to effective numbers in the presence than in the absence of Z. mali. It takes fewer A. fallacis and Typhlodromus predators per leaf to achieve effective biocontrol compared with Z. mali. A major part of the negative effect of Z. mali on more effective species of predators, according to Stone and Croft in a 1998 publication in Environmental Entomology, stems from Z. mali consuming eggs of other predatory mites. The main message from the 1998 publication by Lester and co-workers is that even though a pyrethroid spray may not be harmful to all species of predatory mites, it can be extremely harmful to those species of predators that offer the best hope for providing biocontrol of red mites. The presence of certain species of predators such as Z. mali shortly after a pyrethroid spray should not lull us into thinking that no harm was done by the spray.
As we have pointed out in recent issues of the March Message, the species of mite predator second in abundance to Z. mali in Massachusetts commercial apple orchards is A. fallacis. In a 1998 book chapter, Nyrop, English-Loeb and Roda of Geneva, New York reiterate that A. fallacis is a much more effective predator on low herbaceous plants (such as strawberries) than on trees. They propose that the higher relative humidity associated with growth habits of herbaceous plants is one of the main reasons why A. fallacis has such a strong natural tendency to inhabit ground cover plants compared with trees. Unless prey are more abundant in trees than in ground cover, A. fallacis are not inclined to move into trees. Thus, we can count on A. fallacis as being effective predator of pest mites on apple trees only when pest mite populations reach fairly substantial levels and relative humidity in the tree canopy is high, such as from mid-July until harvest.
The fact that we can not count on A. fallacis to provide biocontrol of pest mites in apple trees until mid-July has been the driving force behind a program initiated by Jan Nyrop of the Geneva lab to seed orchards with the predatory mite T. pyri, which we have found to occur naturally in fewer than 10% of Massachusetts commercial apple orchards. In 1996, Nyrop coordinated a program of seeding T. pyri in at least 4 commercial orchards in every New England state. Samples of leaves taken in 1998 and sent to Nyrop for identification and counting of predatory mites clearly show that T. pyri has gained a firm foothold in nearly every orchard where it was seeded and that it built into substantially higher numbers in 1998 compared with population levels in 1997. This is exciting news. There is a long history of studies in Europe and other continents showing that if T. pyri can become established in apple orchards and not be subjected to certain pesticides that affect it negatively, it can provide essentially permanent and effective biocontrol of pest mites on apple trees. It thrives much better than does A. fallacis under conditions of moderate or low humidity and few available prey, conditions typical for apple trees in May and June.
Growers interested in seeding T. pyri into their orchards should obtain a 4-page Fact Sheet entitled "Achieving Biological Control of European Red Mite in Northeast Apples: an implementation guide for growers" by Breth, Nyrop and Kovach (Cornell IPM Bulletin 215). This excellent 1998 publication is illustrated with colored pictures on how to introduce T. pyri into an orchard and is available for $5.00 form Deborah Breth, Box 150, Albion, NY 14411.
It does little or no good to seed T. pyri if it will be undone by use of certain pesticides. Several new publications appeared in 1998 on studies done on several continents showing strong adverse effects of certain pesticides on T. pyri as well as on A. fallacis.
Regarding A. fallacis, Bostanian and colleagues in Canada reported that the fungicides dodine and mancozeb but not fungicides captan, metiram and myclobutonil reduced egg hatch of A. fallacis significantly, with dodine also toxic to nymphs. None of these fungicides affected longevity or fecundity of female A. fallacis.
Regarding T. pyri, your attention is directed to the following table, which is an insert into the aforementioned 1998 publication by Breth, Nyrop and Kovach and gives relative toxicities of common orchard pesticides to this predator. One note of caution: new information obtained in 1998 suggests that Agri-Mek may be more toxic to T. pyri than indicated in this table:
Materials with a low toxicity can be used when needed. Pesticide with moderate toxicity should be used sparingly. Those with high toxicity must be avoided. Refer to your State Extension Pesticide Recommendations for ratings of relative efficacy and application timing for specific target pests.
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Apple scab |
Nova, Rubigan, or Procure in combination with captan |
mancozeb or metiram (EBDC fungicides) before bloom |
mancozeb or metiram (EBDC fungicides), or Ziram after bloom |
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Powdery mildew |
Nova, Rubigan, Procure, Bayleton, sulfur |
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Fire blight |
fixed copper, streptomycin |
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Black rot |
captan, benomyl, or Topsin M |
mancozeb or metiram before bloom |
mancozeb or metiram after bloom |
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Sooty blotch and flyspeck |
benomyl, Topsin M, captan |
Lorsban |
mancozeb, metiram or Ziram after bloom |
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Rust disease |
Nova, Rubigan, Procure, or Bayleton |
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mancozeb or metiram after bloom |
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Rosy apple aphid |
Thiodan or Provado |
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Lannate, Vydate, dimethoate |
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Tarnished plant bug |
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pyrethroids |
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Spotted tentiform leafminer |
Provado |
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pyrethroids, Vydate, Lannate |
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Codling moth |
azinphosmethyl, Imidan, Penncap M, B.t. |
Lorsban |
Lannate, dimethoate |
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Green fruitworm |
Thiodan |
Lorsban |
pyrethroids, Lannate |
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Obliquebanded leafroller |
B.t., Confirm, spinosad, Penncap M |
Lorsban |
Lannate, pyrethroids |
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Plum curculio |
azinphosmethyl, Imidan, Penncap M, carbaryl |
Lorsban |
pyrethroids |
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Leafhoppers |
Provado, Thiodan, carbaryl |
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Lannate, dimethoate, Carzol, Vydate |
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Apple aphids, spirea aphids |
Provado, Thiodan |
Lorsban |
dimethoate, Lannate, Vydate |
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Apple maggot |
azinphosmethyl, Imidan, Penncap M |
Lorsban |
Lannate, dimethoate |
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European red mites |
prebloom oil, Savey, Apollo, Pyramite, Vendex |
Agri-Mek, summer oil, Kelthane |
Carzol |
For an updated version of this insert, contact Deborah I. Breth, CCE, PO Box 150, Albion, NY 14441
New Findings. Control by Miticides. Since 1995, 4 new miticides have been registered since 1995 for use on apples: Apollo, Savey, Agri-Mek and Pyramite. The first 3 in this group are intended for use just before or just after bloom, whereas Pyramite is intended as a rescue material for use in July and August. Here, we will focus on results of 1998 miticide trials conducted by ourselves and by NEFCON in Massachusetts, by Art Agnello and Harvey Reissig in New York, and by Henry Hogmire in West Virginia. These are the sources of new information available to us at the time of this writing (February 2, 1999).
In a study at the Horticultural Research Center in Belchertown, we found that a single application of Apollo at 2 oz./100 controlled ERM very well until July 24, irrespective of whether application was made at tight cluster, pink, or petal fall. Oil applied at tight cluster followed by Apollo at petal fall gave no better control than Apollo alone at petal fall. Regardless of time of application, Apollo ceased to control ERM effectively by August 14. In contrast, a single application of oil at 2 gal/100 provided effective ERM control only through July 10, with ERM building to levels by July 31 that were twice as great as the highest population found on any Apollo treatments on August 14. Thus, Apollo offered about 3-4 weeks longer effective control of ERM than a single application of oil at tight cluster. In another study in Massachusetts, Glen Morin of NEFCON observed that at low rates, Pyramite kills ERM nymphs best, adults moderately and eggs least. It has rather little effect on two-spotted mites (this is an expected result; for use against TSM, Pyramite must be used at a higher rate).
In New York, Apollo alone at tight cluster or at petal fall performed as well against ERM as Apollo plus oil at tight cluster but not quite as well as Savey alone at petal fall. Other experiments aimed at determining the effect on mites of a single application of the pyrethroid Asana or the organophosphate Guthion at tight cluster or petal fall in the blocks treated with either Apollo or Agri-Mek. Results showed that under conditions of low to moderate ERM pressure, both Apollo and Agri-Mek provided acceptable ERM control into August, regardless of whether it was used in combination with Asana or Guthion. However, under slightly higher ERM pressure, use of Asana (but not Guthion) compromised the effectiveness of Apollo and Agri-Mek and led to need for treatment with Pyramite by mid-July to knock down rapidly building ERM populations. Pyramite could not, however, handle the high populations of apple rust mites that resulted from use of Asana. The bottom line from the 1998 New York studies: Apollo or Savey controlled ERM effectively for the entire season under conditions of low initial ERM populations but where initial ERM population were slightly above moderate, Apollo and Savey failed to control ERM beyond mid-July in cases where Asana was used.
In West Virginia, oil and Apollo together at tight cluster as well as oil at tight cluster followed by Apollo at petal fall provided very good control of ERM and moderate control of apple rust mites through the end of June. Both of these treatment types performed better against ERM than Apollo alone at either timing, but were not better than Pyramite alone at petal fall. Pyramite at petal fall was better than any Apollo treatment against pest mites. In a second test, Agri-Mek at petal fall was as good as Pyramite at petal fall against both ERM and rust mites.
These 1998 findings from Massachusetts, New York, and West Virginia are not entirely consistent with findings from these same and other states in 1997, as reported in the 1998 March Message. The major difference involved optimal timing of Apollo (better at petal fall than at tight cluster or pink in 1997 tests) and use of oil in conjunction with Apollo (the combination was better than Apollo alone in 1997 but not in Massachusetts and New York in 1998). As with most field research, several years of trials are needed to draw firm conclusions.
Although no data are available, it has been observed in Rhode Island and other states that Silwet applied at 13oz./100 will kill most ERM if applied at 200-300 gal. of water per acre at petal fall but not if applied at 100 gal. or less. A note of caution on Silwet is that it has little or no residual activity and would require very frequent applications to achieve sustained ERM control.
As a final note, virtually all investigators who have worked on control of mites on apples would place highest priority on biological control of mites via predators as the best long-term solution to mite management. Many growers who have constructed their pesticide-choice programs so as to maximize the potential for mite predator buildup find they no longer need to use any miticide except for pre-bloom oil sprays. If it appears from early-season sampling or from previous years’ experience that some miticide in addition to pre-bloom oil will be needed, then combined 1996, 1997 and 1998 information suggest that Apollo plus oil at tight cluster, Savey with or without oil at tight cluster or pink, and Agri-Mek with oil (or some other adjuvant) at petal fall or a week after petal fall are the choices that will consistently provide best mite control. Both Apollo and Savey are as easy as oil on predators, whereas Agri-Mek can kill 50% or more of T. pyri. Pyramite ought to be considered only as a rescue material for use in late June, July or August. As strongly emphasized by Art Agnello of New York, growers should do everything in their power to reduce the likelihood of resistance to these new materials. Resistance has been shown to occur in some orchards after only 3 consecutive years of using Apollo or Savey (reports from other continents) and after only 4 consecutive years of using Pyramite (reports from Asia). Apollo and Savey are very similar in their mode of action. If a grower plans to use early-season miticides in a preventative-type program, then as suggested by Art Agnello, year 1 could involve Apollo or Savey, year 2 Agri-Mek, year 3 Apollo or Savey, year 4 Agri-Mek and so on. If this sort of program is adopted, building of T. pyri may be very slow, however, owing to the apparent adverse effects of Agri-Mek.
Thresholds for Treatment. As pointed out by Art Agnello of New York, the miticides we used to use (for example, Omite and Plictran) were usually applied in response to a threshold population detected by timely sampling. Thus, thresholds were very useful for determining need for application. In contrast, Apollo and Savey must be used so early in the season that it is simply not possible to determine beforehand whether a given orchard will ultimately need intervention against mites. This shift away from a scouting-based (responsive) to a calendar-based (preventative) management approach does not bode well for implementation of good IPM practice. In addition, such a preventative approach increases the likelihood of early development of resistance. Apollo and Savey were originally intended for use as rescue materials in summer and work well for this purpose. Concern with residue on fruit has constrained their use to pre-bloom, thereby negating their use within a traditional IPM approach.
What to do? As indicated in the 1998 March Message, we have no answer, except to continue to offer up thresholds developed in New York and intended for decisions on application of materials beginning at petal fall, which would involve potential use of Agri-Mek, Vendex, Kelthane, Pyramite and perhaps in the near future, Pennstyl (cyhexatin).
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1998 Activity. Like 1997, the 1998 growing season held few surprises as far as psylla management was concerned. In most cases, prebloom oil programs slowed development of the first generation, allowing many growers to hold off until mid-June for the first insecticide application.
New Findings. Over the past 4 years, the pool of chemicals available for use against pear psylla has become much stronger. Mid-way through the 1997 growing season another tool emerged; Pyramite received a label for use on pears against psylla, red mite and pear rust mite. Because it was registered during the season, growers were only able to apply Pyramite against late-season build-up of psylla, on which it had apparently little effect. It was thought, given the high rate of material necessary for use against psylla and its limited knock-down power, that the cost of the material might be prohibitive to use on pears.
The 1998 growing season offered the first full-season analysis of use of this material, with promising results. In a field trial performed by NEFCON, a single treatment with Pyramite (10 oz./acre, applied in mid-June) offered excellent control of psylla through August. In this trial, 1 application of Pyramite far outperformed 2 applications (2 qts./acre) of Mitac, with preliminary evidence of ovicidal activity enhancing effectiveness. Given these results, an application of Pyramite may be considered as a good alternative to Agri-Mek soon after petal fall, as both materials also offer control of European red mites on pears.
An approach of alternating between treatments is highly recommended in pear psylla management, as this pest is notorious for generating chemical resistance rapidly. Resistance management is central to the psylla research being done in Washington. Currently, the focus is on development of insect growth regulators, such as fenoxycarb (Comply) and pyriproxyfen (Knack), to which resistance develops much less rapidly. Comply, which has been awaiting EPA registration since 1996, has been classified as a carbamate (subject to tight regulation under FQPA) and will not likely be labeled anytime soon. Knack, on the other hand, is being tested in the Northwest and will likely receive full registration.
Encouraging biological control of psylla through habitat management is also gaining attention in the Northwest. Researchers believe that manipulation of groundcover, particularly through modified mowing practices, may allow for build-up of psylla predators. Trials of mowing practices and predator seeding will be ongoing over the next several seasons.
Thresholds for Treatment. As reported last year, attempts to correlate captures of psylla adults on sticky panel traps with the potential for damage have been unsuccessful thus far. Because of the continued lack of an effective trap for monitoring buildup of pear psylla, inspection of terminals remains as the most effective monitoring practice. Fruit set is the time to make an initial judgment as to whether an early treatment is warranted. If 10% (or more) of terminals are infested, then there are several options for treatment: data from New York suggest that an application of Provado at petal fall (20 oz./acre) followed by a second application within 2-4 weeks will offer control of low to moderate populations; Agri-Mek in conjunction with horticultural oil or similar adjuvant applied 1-2 weeks after petal fall provides 4-6 weeks of protection under normal conditions; and back-to-back sprays of Mitac have shown an acceptable level of control, with the first application 2 weeks after petal fall and the second 7-10 days later. Pyramite (10-13.2 oz./acre) can also be considered as an option (with timing similar to Agri-Mek), targeting application against early to mid-instar nymphs, before hardshells begin to form. A maximum of 2 applications of Pyramite can be used, which must be more than 30 days apart.
New Findings. In a 1998 survey of commercial peach growers in Massachusetts, plant bugs and stink bugs ranked first and second as pests causing substantial injury to harvested fruit, warranting attention and treatment. These results placed catfacing insects well ahead of plum curculio and lepidopteran pests—especially surprising given the lack of plant bug activity on apple in the past 4 years. The following, written by Karen Hauschild and adapted from the 1997 March Message, is a description of each group of catfacing insects, followed by ways to manage these pests.
Plant Bugs. The most commonly encountered plant bug on peaches is the tarnished plant bug, Lygus lineolaris. This insect is especially problematic because it is such a diverse feeder. However, according to the literature, TPBs do not live on peaches at all, but rather prefer to live and reproduce in weedy groundcover or in hedgerows or fields that are adjacent to peach orchards. Adult plant bugs fly up into trees early in the growing season. Plant bugs in the genus Lycocoris have also been reported to feed on peaches, which may offer a partial explanation of widespread plant bug activity on peaches in the absence of activity on apples. The white oak plant bug, hickory plant bug and other species within Lycocoris are normally found on forest trees, but can move to peaches in the absence of their preferred hosts.
Stink Bugs. The other group of true bugs that attacks peaches (rated second in importance by commercial growers among all insect pests) is the pentatomids, or stink bugs. Three species in particular are usually associated with catfacing injury. These are the brown stink bug (Euschistus servus), the dusky stink bug (E. tristigmus) and the green stink bug (Acrosternum hilare). These insects are all highly mobile, and usually remain in the orchard for only a short period of time, creating a difficult situation for chemical control of adults. Stink bugs, unlike the plant bugs previously mentioned, do reproduce on the trees, frequently laying eggs on the lower surface of peach leaves. These eggs are easily identified: barrel-shaped, shiny, and usually in clusters of about 7 eggs. After the eggs hatch, the young nymphs move down into the groundcover within a short period of time, doing little or no feeding on peaches.
Between the plant bugs and stink bugs, there appears to be a fairly clear delineation of which group is causing which damage. The literature indicates that tarnished plant bugs are the first to appear in peach orchards, feeding on swelling buds which can cause bud abscission. Plant bugs are also generally responsible for fruit bud damage, which is most severe between petal fall and 3/4 inch fruit. If fruit damaged at this time does not fall from the tree, at maturity it is heavily scarred (catfaced). Populations of brown and dusky stink bugs normally are greatest within a month of shuck fall, while numbers of green stink bugs tend to increase throughout the growing season. Damage from plant bugs and stink bugs later in the season is less pronounced on the fruit, appearing as small holes with gummy exudate or dry corky areas just below the fruit surface.
Approaches to Treatment. A recurring theme in effective control of plant bugs and stink bugs in peach orchards is meticulous groundcover management. As reported last year, understory plants such as clover and broadleaf weeds are well known to harbor large populations of plant bugs, while tightly cropped, dense grasses discourage pests from taking up residence in the groundcover.
When scouting for stink bugs and plant bugs on peaches, shuck fall is the best time to look for signs of attack, as feeding by both groups is likely to be occurring as the fruit begins to size. Research indicates that Guthion or Imidan alone will give marginal control: they are about 50% effective in preventing plant bug or stink bug injury. Therefore, we continue to recommend use of a full rate of Guthion or Imidan in conjunction with a 1/3 rate of Asana, Ambush or Pounce. A 1/3 rate of pyrethroid offers a good compromise, extending the residual effectiveness of Guthion or Imidan while limiting the destructive effects against mite predators.
IPM MANUALS, SUPPLIES AND SERVICES
PURCHASE OF 1999 PEST CONTROL GUIDES, IPM MANUALS, ETC.
For 1999, the monthly newsletters; weekly Healthy Fruit messages; the March Message; the Peach, Pear and Plum Guide; and the 1998-1999 New England Pest Management Guide (with accompanying 1999 update) will be available for a subscription of $45. Subscriptions may be ordered by sending a check for $45 made out to the University of Massachusetts to Karen Hauschild, UMass Extension, West Experiment Station, University of Massachusetts, Amherst, MA 01003. Single copies of the March Message are also available for $5, and may be useful to out-of-state growers as an alternative to the entire Massachusetts subscription. Copies of the following publications may be ordered individually from the UMass Extension Bulletin Center:
The 1998-1999 New England Apple Pest Management Guide and 1999 NEAPMG Update will be mailed to all who subscribe to the $40 package of information. The 1998-1999 NEAPMG was edited by Glen Koehler, Lorraine Los, Dan Cooley, Jim Dill, Bill Lord and Jim Schupp. The 1999 NEAPMG Update was edited by Glen Koehler, Dan Cooley, Alan Eaton, Bill Lord, and Ron Prokopy.
There will be a new version of the Peach, Pear and Plum Guide for the 1999-2000 growing seasons, which will include updated pest biologies and control methods. The Peach, Pear and Plum Guide is edited by the UMass Tree Fruit Team.
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Tree fruit management guides should only be used during the growing season(s) for which they were written. Information obtained from old guides may be outdated and may result in illegal pesticide application, or growers may miss new information about phytotoxicity or effectiveness. We highly recommend that growers discard old pest management guides in favor of the updated versions. |
Two fact sheets are available on biological control of mites and leafminers on apples.
Costs:
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1999-2000 New England Apple Pest Management Guide |
$15.00 |
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1999-2000 Peach, Pear and Plum Guide |
$** |
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Opportunities for Increased Use of
Biological Control in Massachusetts |
$7.00 |
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Biological Control Fact Sheets: |
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Apple Blotch Leafminer |
ID Code: IPMA 000L 594A |
$2.95 |
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Spider Mites in Apples |
ID Code: IPMA 000L 595A |
$2.95 |
The costs above include production, handling and mailing expenses. Checks should be made out to the University of Massachusetts and sent together with your order to the Bulletin Center, Draper Hall, University of Massachusetts, Amherst, MA 01003. Please use the ID code (if provided) to specify the publication you are ordering.
Fruit Notes, a quarterly journal published by the UMass Plant and Soil Sciences Department and UMass Extension, contains important new research findings on fruit growing in Massachusetts. The subscription price is $10.00 per year ($12 US funds for foreign subscriptions), and checks should be made out to the University of Massachusetts and sent to Wesley Autio, Department of Plant and Soil Sciences, Bowditch Hall, University of Massachusetts, Amherst, MA 01003.
The Healthy Fruit newsletter is published weekly from early April through early August, and contains timely information regarding pest management, such as insect and disease phenologies and management options; and crop management strategies, such as thinning and fruit maturity. It is provided to all package subscribers via e-mail or first-class mail, or can be faxed for an additional $20 fee. Subscription requests, e-mail distribution requests, and fax copy requests should be sent to Wes Autio [autio@pssci.umass.edu].
Tree Fruit Production Guide 1998-1999. Penn State University. Price $13.00. Make checks payable to Penn State and send with your name, address and the title of the publication you are requesting to Publications Distribution Center, College of Agricultural Sciences, Penn State University, 112 Ag Administration Building, University Park, PA 16802.
"New York Fact Sheets" Tree Fruit Fact Sheets include:
Pear Psylla Codling Moth
Plum Curculio Green Fruitworm
Obliquebanded Leafroller Peachtree Borer
Apple Maggot Fly Spotted Tentiform Leafminer
European Red Mite Predatory Mites
Rosy Apple Aphid San Jose Scale
White Apple Leafhopper Dogwood Borer
Woolly Apple Aphid Oriental Fruit Moth
Beneficial Insects Redbanded Leafroller
Brown Rot Fire Blight
Powdery Mildew Cedar Apple Rust
The New York Fact Sheet series features excellent photographs, and a set of 30 can be purchased for $18.55. Prices range from $1.00-$1.50 for most single fact sheets. These can be ordered from Resource Center-GP, 7 Business and Technology Park, Cornell University, Ithaca, NY 14850.
"Pest Management Fact Sheets" Cooperative Extension Service, University of New Hampshire, Durham, NH 03824. Free of charge. Fact sheets are available on:
Tarnished Plant Bug Codling Moth
Redbanded Leafroller Apple Maggot Fly
Plum Curculio European Red Mite
Two Spotted Spider Mite Aphids
Scale Insects Fire Blight
Apple Scab
Common Tree Fruit Pests, published in 1994. A comprehensive guide to identification and control of more than 50 arthropod pests of tree fruits. Written by entomologist Angus Howitt of Michgan State University. Contains many excellent color pictures and straightforward information on most pests encountered in the field. Available in hardcover ($37.50) or laminated ($30.00) from: Bulletin Office-TFP, Michigan State University, 10B Agricultural Hall, East Lansing, MI 48824-1034. The publication number is NCR-63 (Common Tree Fruit Pests). Checks should be made out to Michigan State University.
Mid-Atlantic Orchard Monitoring Guide. Published in 1995 by the Northeast Regional Agricultural Engineering Service, under the guidance of West Virginia University and with input from fruit researchers throughout the Mid-Atlantic region. Contains thorough and current information on pest and disease biology, monitoring and treatment, as well as nutrition, irrigation and fruit evaluation. Many color photographs. Available for $75.00 from Northeast Regional Agricultural Engineering Service, Cooperative Extension, 152 Riley-Robb Hall, Ithaca, NY 14853-5701. Checks should be made payable to NRAES.
MONITORING AIDS: TYPES AND PURCHASING
A variety of pheromone and visual traps is commercially available to growers as pest monitoring aids. We have had considerable experience with the following traps as part of our IPM research and extension efforts over the past years.
1. Pheromone Traps
Leafminers – Pheromone traps for spotted tentiform leafminer (STLM) adults have been used in Massachusetts, but they are of uncertain effectiveness in attracting apple blotch leafminers (ABLM), the predominant leafminer species in most commercial orchards in Massachusetts.Codling Moth (CM), Obliquebanded Leafroller (OBLR), Oriental Fruit Moth (OFM), Redbanded Leafroller (RBLR), Variegated Leafroller (VLR), Lesser Appleworm (LAW), Sparganothis Fruitworm – Although traps have been used in the Massachusetts IPM program, these pests are not usually much of a problem and so we have rarely used trap capture data for management decisions. As part of our ongoing extension efforts, we plan to continue to monitor these pests closely, as these pests may have the potential to develop resistance to commonly used organophosphate compounds. Monitoring for these pests will be more important with a very low spray schedule.
Lesser Peachtree Borer, Peachtree Borer, Dogwood Borer – Pheromone traps are available for determining appearance and abundance of adults.
Tufted Apple Bud Moth, Green Fruit Worm – Generally these pests have not been a problem in Massachusetts orchards and we have not used pheromone traps for them in our IPM program. Green fruitworm was a major problem in a few western Massachusetts orchards in the early 1980’s but numbers have declined in subsequent years.
2. Visual Traps
Tarnished Plant Bug (TPB) - We continue to experience good results with the sticky white rectangle traps for TPB. These traps should be set out at silver tip (no later), with pesticide application need and timing based on cumulative captures from silver tip to tight cluster or pink.Leafminers - Sticky red visual traps, stapled to tree trunks at silver tip, continue to prove useful in indicating adult emergence and in predicting need for treatment pre-bloom or at petal fall.
European Apple Sawfly (EAS) - EAS adults are highly attracted to sticky white rectangle traps that mimic apple blossoms. Traps should be placed at pink; the need for pesticide application is based on cumulative captures from pink to petal fall.
Apple Maggot Fly (AMF) - Sticky red spheres that mimic ripe Delicious apples are an excellent aid in monitoring AMF abundance. They are especially helpful in June and July for determining first arrival of flies in early variety blocks and in August and September for determining arrival of late season flies immigrating into blocks of Delicious and other late season varieties. Traps should be positioned in late June for early-developing and mid-season varieties and in early July for late developing varieties. Sticky red spheres baited with synthetic apple volatiles developed in New York are 2-4 times more effective in capturing AMF than unbaited sticky spheres alone. Traps should be cleaned of insects and debris regularly, preferably once every 2 weeks, as capturing effectiveness will decrease with the accumulation of dead insects. Several variations of sticky red spheres, including lightweight plastic molded traps, are available from the IPM products division of Gempler’s.
Pear Psylla - Sticky yellow traps can be placed 1-2 m from the ground in the south quadrant of the tree to monitor adult activity in spring.
Pear Thrips - Sticky yellow traps should be set three feet high. We use a tomato stake and a metal shelf bracket to mount the trap in the correct position. Traps should be checked at least weekly from ground thaw until fruit bloom. Current recommendations call for a minimum of four traps per ten acre block. Monitoring for thrips populations in nearby overwintering areas (e.g. sugar bushes) can help to determine the potential for thrips immigration.
3. Tangle-Trap (A Tanglefoot Co. product)
Tangle-Trap (Bird Tanglefoot) is a clear, odorless, non-drying adhesive that is used to coat the reusable red sphere traps. Tree Tanglefoot is also a non-drying adhesive, but it should not be used with the red sphere traps since it is not clear or odorless.
4. Metos Apple Scab Monitoring Computer
This computer will determine if an infection period has occurred for apple scab. In addition, it can be used to calculate degree day accumulations in order to monitor insect development.
5. Bird Control Balloons
Scare-Eye bird control balloons have given good to excellent results in reducing bird injury to Cortlands and other susceptible varieties. One balloon is effective over a radius of approximately 20 yards.
Suppliers:
Pheromone traps, synthetic apple volatiles, visual traps, bird repelling balloons, Tangletrap, and magnification equipment for use in sampling are available from:
Gempler’s
211 Blue Mounds Road
P.O. Box 270
Mt. Horeb, WI 53572-0270
(800) 382-8473 (Orders)
(800) 332-6744 (Customer Service)
Many pest management supplies are also available from:
OESCO, Inc. (Orchard Equipment)
Rt. 116
Conway, MA 01341
(413) 369-4335
Great Lakes IPM
10220 Church Road
Vestaberg, MI 48891
(517) 268-5693
PEST MANAGEMENT SERVICES AVAILABLE IN 1999 IN MASSACHUSETTS
In addition to the weekly monitoring and other information provided through University of Massachusetts Extension IPM, growers are strongly urged to monitor their own orchards, or hire private consultants to do so.
The UMass Tree Fruit Advisor is available on the World Wide Web. This site includes Tree Fruit Team contact information; current issues of Fruit Notes, the March Message and Healthy Fruit; and links to other resources, such as Orchard Radar, chemical labels, the NEAPMG, and nutrient management information. Questions about the system should be referred to Wes Autio.
Two private consulting businesses will continue to offer IPM consulting, scouting, and other services in Massachusetts in 1999. Their addresses are:
New England Fruit Consultants (NEFCON)
56 Taylor Hill Road
Montague, MA 01351
(413) 367-9578
(413) 367-0313 (FAX)
Polaris Orchard Management
364 Wilson Hill Road
Colrain, MA 01340
(413) 624-5104