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23RD
ANNUAL MARCH MESSAGE TO MASSACHUSETTS TREE FRUIT GROWERS (2001)
BY RONALD PROKOPY AND STARKER WRIGHT DEPARTMENT OF ENTOMOLOGY, UNIVERSITY OF MASSACHUSETTS KATHLEEN LEAHY, POLARIS ORCHARD MANAGEMENT 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 2001 PROBLEM PESTS: ACTIVITY, NEW FINDINGS AND TECHNOLOGIES TARNISHED PLANT BUG IPM MANUALS, SUPPLIES AND SERVICES PURCHASE OF 2001 PEST CONTROL GUIDES,
IPM MANUALS, ETC. GENERAL IPM TOPICS AND OPINION CHANGES IN ORCHARD CHEMICALS FOR 2001 As has been the case in recent years, some new types of pesticides have been labelled for use in orchards for the 2001 growing season. Some others may soon receive a label for the 2001 season. Still others have undergone some label modifications that will expand or contract past use patterns. Here's a summary of how things stand as of February 2001. A. NEWLY REGISTERED COMPOUNDS AVAUNT (indoxacarb) received full federal registration for use on apples and pears in the fall of 2000. This material represents a new class of compounds called oxadiazines. It has a novel mode of action and acts by inhibiting sodium ion entry into nerve cells, resulting in paralysis and death of a pest species. It is much more toxic when ingested by insects than by insect contact with a sprayed surface. Toxic effects are not immediate but gradual, sometimes requiring 3 or more days. Avaunt is registered for control of tarnished plant bug, plum curculio, codling moth, oriental fruit moth, lesser appleworm, leafrollers, leafhoppers and apple maggot. Recent trials in various states indicate it provides good to excellent control of tarnished plant bug, plum curculio, some leafrollers, codling moth and leafhoppers. Performance against apple maggot has been variable. Residual activity lasts 7-14 days depending on conditions. It's safe on most beneficials. INTREPID (methoxyfenozide) received full federal registration for use on apples in the fall of 2000. This material is a member of the diacylhydrazine class of insecticides. It has a novel mode of action that mimics the action of molting hormones of moth larvae. It must be ingested by larvae to be effective. Intrepid is registered for control of codling moth, lesser appleworm, leafrollers and leafminers. It is effective also against oriental fruit moth. It performs best in conjunction with an adjuvant to maximize deposition, redistribution and weatherability. It works best against internal feeders such as codling moth, oriental fruit moth and leafminers when application is just prior to egg hatch. It's very safe on all beneficials. It appears that Intrepid is intended by its manufacturer (Rohm and Haas) to replace Confirm. Intrepid has not yet been registered for use in MA. B. LABEL CHANGES LORSBAN (chlorpyrifos). Effective as of December 31, 2000, use of Lorsban 4E and Lorsban 50W on apples is restricted to pre-bloom application only. Keith Dorschner of the IR-4 program out of Rutgers is leading an effort to conduct field trials in 2001 on post-bloom trunk sprays of Lorsban against dogwood borers and other borers that are pests of apple trees. The research is intended to determine amounts of chlorpyrifos that appear in apples at harvest as a consequence of post-bloom use of chlorpyrifos as trunk sprays. Hopefully the findings will be favorable and allow resumption of post-bloom trunk sprays of Lorsban on apples beginning in 2002. For 2001, however, use of Lorsban on apples is restricted to pre-bloom, such as for control of San Jose scale, rosy apple aphid, and possibly also burr knot borers (see separate section on these borers). As far as we know, there have been no changes in use of Lorsban on peaches against borers, where 1 summer or post-harvest application per year to tree trunks or limbs (but not fruit or foliage) is still permitted. Whatever the intended use, effective as of February 1, 2001, Lorsban can now be purchased, mixed and applied only by a licensed applicator. PYRAMITE (pyridaben) has recently been registered for use on peaches and plums against European red mites. It is not effective, however, against two-spotted mites. C. MATERIALS THAT MAY YET RECEIVE A LABEL FOR USE IN 2001 Three new materials (ACTARA, CALYPSO and COMPLY) could receive registration for use on tree fruit in 2001 but none has yet been registered. We will keep you posted in our weekly newsletter Health Fruit if or when registration occurs. THIRD-LEVEL IPM: RATIONALE AND PROGRESS In 2000, we launched the second of two phases of research on third-level IPM practices in grower orchards. Third-level IPM aims at integration of all pest management practices with all horticultural practices. Why do we in Massachusetts devote a large amount of energy attempting to establish simple, effective and economical pest management practices under the concept of third-level IPM? We do so for 4 main reasons. First, new regulations under FQPA are restricting use of organophosphates and other familiar pesticides, thereby leaving a potentially serious gap in our ability to manage several key pests effectively. Third-level IPM offers promise of biologically based methods of control that could help fill this gap. Second, many other apple-growing regions of North America and many other apple-producing countries (especially in Europe) are in the process of developing advanced-level IPM practices that will permit their apples to be sold under some sort of "green label". Apples from Massachusetts intended for export that do not meet "green label" requirements may be excluded from some international marketplaces. Third, for Massachusetts growers who sell their apples at roadside stands, farmers' markets or as pick-your-own, it could be a distinct benefit to be recognized by customers as a grower who is highly conscious of the value of healthy fruit and a healthy environment. Fourth, federal grant funds are becoming increasingly restricted to supporting research and demonstration efforts that focus only on advanced forms of IPM. If we fail to obtain federal grant funds, Massachusetts will cease to have a viable IPM research and demonstration program for apples. Research on all levels of IPM will become severely restricted. The first phase of research on third-level IPM (1997-1999) focused on studying the influence of apple tree architecture (particularly tree size) on effectiveness of bio-based approaches to controlling key apple pests: plum curculio, flyspeck, apple maggot and mites. The second phase (2000-2003) aims at studying the influence of apple orchard architecture (particularly cultivar choice and arranagement and the nature of orchard border areas) on bio-based approaches to managing these same 4 key pests plus leafminers. Both tree architecture and orchard architecture are essential components of horticultural practice and both have a potentially powerful impact on the degree to which bio-based pest management techniques can be used. The 2000-2003 project involves studies in 48 plots of apple trees across 12 commercial orchards. The 4 plots within each orchard differ in management approach. Also, orchards differ in type of cultivar comprising perimeter rows of plots and in characteristics of outlying habitat. Below, we present 2000 findings (= the first year of this 4-year phase). We also present additional findings from 2000 research that complement findings in these 48 plots of trees. PROGRESS TOWARD DEVELOPING PLUM CURCULIO TRAPS Among key insect pests of pome and stone fruit, plum curculio (PC) is the only one for which there does not yet exist an effective monitoring trap. Here, we present a summary of findings from 3 principal lines of orchard research conducted in 2000. Full reports on each of these lines will appear in the 2000 issue of Fruit Notes. Commercial Orchard Trials of Traps for Monitoring PC. In the aforementioned 48 plots of trees in 12 commercial orchards, we evaluated 6 synthetic components of host fruit odor in combination with synthetic male-produced pheromone of PC (grandisoic acid) in association with 3 types of traps (pyramid, cylinder or Circle) placed under or within canopies of apple trees on perimeter rows. Traps were deployed at tight cluster or early pink and monitored every 3-4 days for 7 weeks for PC captures. Fruit in each plot were examined for PC injury on each monitoring date. Growers sprayed each plot 2-3 times with insecticide for PC control. Results showed that traps baited with pheromone alone captured no more PCs than unbaited traps. However, cylinder or Circle traps baited with pheromone plus benzaldehyde, ethyl isovalerate or limonene captured more than twice as many PCs as corresponding unbaited traps and in one case (cylinder traps with ethyl isovalerate plus pheromone) nearly 10 times as many as unbaited traps. The bottom line is how good trap captures are as indicators of the time or need to apply insecticide to control PC. Unfortunately, captures by even the best of the baited traps were no better than marginally related to optimal timing or the need to spray. So, despite the fact that for the very first time, we found odor-bait combinations that did a good job in attracting PCs to traps in commercial orchards, we still have a ways to go in developing an odor combination powerful and durable enough to truly reflect actual numbers of fruit-damaging PCs on perimeter trees at any given time of year. Other interesting findings were that trap captures and fruit injury levels were 3-4 times greater where Gala, Jonagold or Fuji trees comprised perimeter rows than where McIntosh or Empire trees comprised perimeter rows. Also, trap captures and fruit injury on perimeter rows directly facing 100 or more yards of open space were nearly as great as on perimeter rows directly facing woods 10 yards or less away. Both of these findings were surprising to us and suggest that we ought to be paying closer attention to cultivar arrangement and not ignoring open space in estimating probability of PC threat to fruit. Unsprayed Orchard Trials of Traps for Predicting PC Immigration. In a 4-acre block of non-commercial orchard trees at the Horticultural Research Center, we evaluated sticky-coated clear Plexiglas squares mounted on poles and pyramid traps for monitoring the progress of PC immigration from woods into the orchard. All traps were placed about a yard from the edge of woods foliage. They were baited with the same odor types tested in the 12 commercial orchards. Results showed that both sticky Plexiglas and pyramid traps baited with benzaldehyde plus pheromone captured about 6 times more PCs than corresponding unbaited traps. None of the other 5 synthetic fruit-odor components plus pheromone or pheromone alone performed very well. Traps baited with benzaldehyde plus pheromone were equally good at capturing the earliest immigrants (at pink) as well as late immigrants (around the time of fruit set). These are exciting results that for the very first time point the way toward placing baited traps at edges of habitat adjacent to annual "hot spots" of PC injury and using trap captures to determine when to begin and when to stop spraying against PC. Evaluation of Attractiveness of Different Host-Odor Compounds. To date, about 60 compounds have been identified as components of odor of plum or apple fruit at its most attractive stage to PC (2 weeks after bloom). Last year, we presented results of 1999 tests evaluating 30 of these compounds for attractiveness to PC. In 2000, we re-evaluated the 16 most attractive compounds of 1999 along with 6 additional host-odor compounds. Each compound was introduced into vials placed inside tops that capped boll weevil traps placed on the ground beneath apple trees in Massachusetts and Ohio. Each was evaluated at 3 different rates of odor release to create a very low, low, or medium dose of odor concentration in surrounding air. Over a 7-week period, more than 250 traps were deployed in Ohio and a similar number in Massachusetts. To measure attractiveness of a particular release rate of a compound, we created a Response Index (RI). If a baited trap was 2 times as attractive as an unbaited trap, then RI = 32. If 3 times, RI = 50. If 4 times, RI = 60. Results showed that 13 of the 22 compounds had RI values of 33 or greater at the most attractive release rate. In descending order of attractiveness, these were: 1-pentanol (71), S-limonene (65), phenylacetaldehyde (64), ocimene (56), hexyl acetate (50), Z-3-hexenyl acetate (50), benzaldehyde (45), 3-penten-2-ol (45), ethyl isovalerate (38), and geranyl propionate, isopropyl acetate, 2-propanol, and nonanal (each at 33). The continued attractiveness in 2000 of 8 compounds that proved attractive in 1999 tests (1-pentanol, limonene, phenylacetaldehyde, hexyl acetate,benzaldehyde, ethyl isovalerate, geranyl propionate and 2-propanol) gives us hope that one or more of these 8 compounds could be effective when used in other types of traps for capturing or monitoring PCs. In fact, as described here in a preceding section, benzaldehyde, limonene and ethyl isovalerate have already proven to be useful in combination with pheromone in attracting PCs in commercial orchards. Future Plans for PC. In 2001, we plan to again evaluate benzaldehyde, limonene and ethyl isovalerate in combination with pheromone in commercial and unsprayed orchards. By focusing on these 3 attractive fruit odor compounds plus pheromone in a more intensive way than in the past, we hope to gain enough replication and insight to begin to establish good relationship between trap captures and injury levels. We will also again evaluate (using boll weevil traps) the most promising 13 compounds found in 2000 tests to determine if attractiveness still holds. PROGRESS TOWARD CONTROLLING APPLE MAGGOT WITH TRAPS 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 previous years of research have shown that surrounding large blocks of medium-size apple trees with odor-baited sticky red spheres (5 meters apart) to intercept immigrating AMF can provide control nearly (but not quite) equal to control provided by 3 insecticide sprays. If traps are to become a feasible alternative to sprays for AMF control, we need to take into better account a range of factors that can affect trap performance and substitute something (e.g. pesticide-treated spheres) for sticky spheres as traps. We report here on progress made in 2000 toward these ends. Effect of Pattern of Trap Deployment on Control of AMF. In 2000 in the 12 commercial orchards, we compared 3 patterns of deployment of odor-baited sticky red spheres on perimeter-row apple trees for effectiveness in intercepting immigrating AMF. Each sphere was accompanied by a vial releasing a highly attractive 5-component blend of synthetic apple volatiles, including butyl hexanoate. The following treatments were applied to the 4 plots of perimeter-row trees in each orchard: (a) 5 baited spheres on the center tree of the perimeter row (total of 5 spheres), (b) 1 baited sphere every ~ 5 meters on the perimeter row (total of 5 spheres), (c) 1 baited sphere every ~ 10 meters on the perimeter row (total of 2-3 spheres), and (d) grower-applied insecticide (2-3 sprays) to the perimeter row. In addition, we placed 1 unbaited sticky sphere on each of 4 central trees in each plot to monitor degree of penetration of plot by immigrating AMF (few AMF originate within commercial orchards). Also, each of the other 3 sides of each plot (except insecticide-sprayed plots) received 1 baited sphere every ~10 meters to reduce penetration by AMF approaching from places other than woods, hedgerows, or open space opposite perimeter rows. Trapped plots received no insecticide sprays against AMF. Traps were deployed in June and remained through September. They were cleaned of all AMF and other insects every 2 weeks. Besides assessing responses of feral AMF to the above 4 treatments, we also released 32 color-marked male AMF ~10 meters away from perimeter trees (i.e. into woods, hedgerows or open space) and opposite each plot. Releases were made during July and August. Captured marked AMF were counted on spheres 4 days after release. Results showed little or no discernable difference among treatments in the degree to which feral AMF or marked and released males penetrated the perimeter row of apple trees. Injury to fruit by feral females was extremely low in all plots (due largely to poor overwintering survival of AMF pupae) and could not be taken with high confidence as indicative of treatment performance. Even so, combined data did suggest that all 3 deployment patterns of baited spheres and insecticide sprays performed about equally in preventing immigrating AMF from penetrating into plots. Results showed that substantially more feral and released AMF penetrated into plots of Gala, Jonagold or Fuji (considered susceptible to AMF) than into plots of McIntosh or Empire (considered somewhat tolerant of AMF). Also, results showed that more feral and released AMF penetrated into plots when woods were adjacent to plots than when hedgerow or open space was next to plots. Finally, results showed that penetration of feral AMF into plots of susceptible cultivars successively increased from each sampling period to the next (July to September), whereas in plots of tolerant cultivars, penetration successively decreased after a peak in early to mid-August. This pattern characterized plots having baited spheres and plots treated with insecticide. Together, our findings suggest that all 3 patterns of deploying baited spheres on perimeter-row apple trees worked about equally well in preventing feral or released AMF from penetrating into interiors of plots. However, penetration was considerably less into plots having tolerant cultivars on perimeter rows than plots having susceptible cultivars on perimeter rows, with penetration successively increasing toward harvest in plots of the latter. Overall, these results suggest that baited spheres may perform less well than insecticide sprays in preventing AMF penetration of orchards having susceptible cultivars on perimeter rows, especially as the season progresses. Effectiveness of Pesticide-Treated Spheres in Controlling AMF. In 2000 in 28 plots in 7 other commercial orchards (not the same orchards as the 12 above orchards), we compared the effectiveness of our newest versions of pesticide-treated spheres (PTS) against sticky spheres and insecticide sprays for controlling AMF. Odor-baited spheres were positioned ~5 meters apart on perimeter trees on all sides of each plot receiving spheres. Treatments per orchard were as follows: (a) wooden PTS having a top cap of compressed 85% sucrose: 15% paraffin wax as a vehicle for renewing sucrose on the sphere surface, (b) sugar/flour PTS received gratis from a private manufacturer (Fruit Sphere Inc.), (c) sticky-coated spheres, and (d) 2-3 insecticide sprays. Caps atop wooden PTS and sugar/flour PTS were replaced at mid-season (after 6 weeks) with fresh versions of each. Treatment effectiveness was measured by comparing numbers of AMF captured on interior unbaited monitoring traps (4 traps on central trees of each plot) and % injury to fruit in samples taken 5 times from July to September. Results showed that numbers of feral flies penetrating into plots surrounded by wooden PTS were no greater than numbers penetrating into plots receiving 2-3 insecticide sprays and were less than numbers penetrating into plots surrounded by sugar/flour PTS or sticky spheres. As before, damage by AMF was extremely low in all plots, although least in plots surrounded by wooden PTS and sticky spheres. Besides taking data on field performance of PTS, we returned individual PTS from each orchard to the lab after 6 weeks of field exposure and directly assessed toxicity to AMF by placing individual AMF on PTS and measuring mortality after 72 hours. Results showed that wooden PTS caused greater mortality to AMF than did sugar/flour PTS. Together, these results are the most encouraging yet obtained for using PTS (especially wooden PTS) in controlling AMF. On the down side, rodents such as mice, chipmunks and squirrels continued to eat away on sugar/flour PTS (as they have done in previous years), despite incorporation of 5% hot cayenne pepper into the spheres as a feeding deterrent. Thus, the future for sugar/flour PTS is not so bright. Progress Toward an Optimum Type of Wooden PTS Data from field and laboratory trials in 2000 strongly suggest that wooden PTS retain toxicity to AMF for at least 12 weeks, while sugar/flour PTS may begin to lose their toxic effects after as little as 6 weeks of field exposure. From direct observations of fly feeding on sugar/flour PTS and assessments of behavior post-exposure, it appears that some toxicant is lost along with surface sugar during rainfall. Given this, we now feel that further development of re-usable wooden PTS holds greater long-term promise for commercially viable behavioral control of AMF than do sugar/flour PTS. For nearly a decade, the major challenge we have faced in development of effective wooden PTS is continuously supplying the sphere surface with enough sugar to stimulate fly feeding, allowing PTS to achieve maximum toxicity to AMF with a minimal dose of insecticide. Since 1997, we have worked toward development of a wooden PTS system focusing on use of a sucrose-bearing top-cap affixed to each sphere which, under rainfall, releases a small amount of sucrose onto the sphere surface. Thus, as surface sugar is washed off by rain or heavy dew, it is replaced with sucrose from a source atop the PTS. In 1997 and 1998, we attempted to form these caps of nearly pure sucrose, finding quickly that the pure sugar caps were highly prone to breakdown under conditions of high humidity. In 1999, we formed and tested flat-topped, 1 ½” caps consisting of 85% sucrose bound in 15% paraffin (25 grams total mass). Although these caps worked for a short time in the field (~3 weeks), they ran out of sugar well before the close of the season. In 2000, we again tested caps consisting of 85% sucrose bound in 15% paraffin, but modified the caps in 3 major ways: 1) we increased the diameter to 2 inches; 2) we doubled the mass to 50 grams; and 3) we formed the caps using a hydraulic press that stamped 8 flutes into the top of each cap, ensuring even distribution of sucrose-bearing runoff. Upon lab testing, this style of cap was effective through 5 inches of accumulated rainfall (roughly equal to 5 weeks of field exposure). This was by far the best-performing wooden PTS to date, but we needed to address 2 major shortcomings: 1) further modification of caps to ensure effectiveness through at least mid-season (6-8 inches of rainfall), and 2) prevention of rodent damage to caps. In order to increase the duration of sucrose output from each cap, we attempted 3 modifications. First, we varied the paraffin content of caps, testing 50-gram caps of 10%, 15%, 20%, and 25% paraffin. Second, we increased the mass to 75 grams, while maintaining a diameter of 2 inches. Finally, we increased the cap diameter to 2 ½ inches. In short, none of these modifications improved the performance of caps atop wooden PTS. In fact, all modifications of cap height, diameter, and paraffin content were found to hinder cap performance; all modified caps were inferior to the 2000 field standard: a 2-inch cap of 50 grams, 85% sucrose:15% paraffin, with 8 pressed flutes. By applying artificial rainfall to wooden PTS bearing these caps, we found that although they could only provide an adequate supply of sucrose through 5-6 inches of rainfall, a substantial amount of sugar remained within the cap after even 8 inches of rain. Further, by direct observation of the movement of rainfall onto and off of these caps, we determined that a small amount of water actually moves through the slightly porous paraffin/sugar matrix. Therefore, we attempted to enhance the performance of caps by capitalizing on this phenomenon. To do this, we created a cap designed to hold a small amount of water in its matrix until the rainfall has stopped, at which point it releases highly concentrated sucrose onto the sphere surface. This percolation effect has 3 advantages: 1) the slow-developing sucrose-bearing runoff is highly concentrated to consistently stimulate fly feeding; 2) little sucrose runs off onto fruit and foliage beneath the traps, limiting fungal growth; and 3) the entire mass of sucrose in each cap is eventually used, dramatically increasing the endurance of each wooden PTS. To deter rodents from feeding on caps, we have integrated a wire guard into the outside layer of each cap, physically barring small mammals from damaging the caps atop wooden PTS. Tests against highly damaging, numerous, and extremely bold gray squirrels have shown that these caps can now endure great feeding pressure (far exceeding the pressure in a commercial orchard) with minimal damage. Although these caps are still under study, their performance has far exceeded any other style tested to date, and they hold the potential to markedly enhance the effectiveness and practicality of wooden PTS. We will carry forward in 2001 with field trials of wooden PTS equipped with the style of caps described above. However, for commercial use, we must wait for registrant and federal approval for use of imidacloprid (the best AMF toxicant to date) on wooden spheres. Given slim likelihood of rapid approval through this compound’s manufacturer, we may seek use of an alternative toxicant such as thiamethoxam for future commercial use. Future Plans for AMF. For 2001, we plan to continue to evaluate different patterns of sphere deployment in commercial orchards in hopes of finding an optimal deployment pattern, especially when cultivars susceptible to AMF comprise perimeter rows. Also, we plan to intensively evaluate our newest version of wooden PTS for AMF control in commercial orchards. PERFORMANCE OF RELEASED T. pyri MITE PREDATORS In 1997, we released Typhlodromus pyri mite predators in 24 blocks of apple trees in 8 commercial orchards. By 1999, there was excellent establishment and spread of T. pyri within blocks and excellent biocontrol of pest mites. In 2000, we released T. pyri in June on center trees of 2 plots in each of the 12 cooperating commercial orchards. One of the 2 plots per orchard also received cattail pollen as a potential alternate food source for the predators to enhance rapidity of population growth. Leaves in each plot were sampled 4 times from July to September and sent to cooperator Jan Nyrop at Geneva, NY for identification of mites and predators. Results showed that for the last sampling date (September), almost identical numbers of T. pyri were found on center (release) trees without pollen added as on those with pollen added and fewer were found on center trees in plots where no T. pyri were released. Evidently pollen supplied in June did not aid population growth of T. pyri, although it might have done so if releases and pollen application had been accomplished in May. We plan to track the spread of T. pyri within plots and contribution to mite biocontrol in 2001. STUDIES ON LEAFMINER SPECIES COMPOSITION AND PARASITISM In Massachusetts and throughout the Northeast, leafminers have been a consistent foliar pest of commercial apple plantings for 20 years or more. Although LM are detectable in all commercial orchards, some farms consistently experience above-threshold LM infestation, requiring regular chemical treatment. Over the past 5 years, infestations on many farms have elevated LM to annual consideration as a major damaging pest. Fortunately, a handful of new management tools (notably Provado and SpinTor) can provide excellent season-long control of threatening LM populations, obviating the need for older, more damaging pesticides (such as Vydate, Lannate, and pyrethroids). One might assume that adopting management tactics that rely on softer, more targeted treatments would enhance the effectiveness of natural enemies of LM. Indeed, in samples on unsprayed trees, LM are consistently well controlled by parasitoids alone. However, a general shift to use of these softer materials has sparked unexpected patterns in LM proliferation. On many farms, the current pattern is toward explosive population expansion from one generation to the next, particularly on second to third generation. For management within an IPM framework, these apparently contradictory trends demand a better understanding of the basic biology of the pest. In Massachusetts, the LM population consists of a blend of two major LM species: apple blotch leafminer (ABLM) and spotted tentiform leafminer (STLM). Until about a decade ago, ABLM was the dominant species present in commercial orchards in Massachusetts, while STLM was present principally in unmanaged trees in New England. In the past several years, many orchards have experienced a distinct and rapid shift in LM species composition, with exotic STLM displacing native ABLM. Although there is an apparent link between orchard-level shifts in species composition and orchard-level population density, we are unsure of the mechanisms causing these fluctuations in relative LM species abundance. One factor under study for several years has been the relative impact of two major LM parasitoids (Sympiesis marylandensis and Pholetesor ornigis, both parasitic wasps), which strongly affect LM population growth potential in commercial orchards. Both wasps are capable of offering effective biocontrol of LM in the absence of chemical sprays; in fact, in samples of unmanaged orchards taken in the past several years, mine density decreased 60% from first to third generation. Conversely, in Massachusetts commercial orchards in 2000, the overall mine density increased by 3600% (36 times) from first to third generation. This includes orchards that targeted first- or second-generation mines with chemical treatment. For many years, we have sampled leafminer density, species composition, and parasitism rates in orchards participating in our IPM studies. Through 1999, the focus of these projects was to determine whether trends in increasing LM populations followed shifts in LM species composition and to investigate potential links between orchard chemical selection and LM species composition. The ultimate goal of this project was to determine the reliability of current tools for LM monitoring and control for management of this highly variable pest complex. However, these studies of LM management within a first-level framework (treatment in accordance with trap-capture or sap-feeding mine density thresholds) have proven very difficult. It appears that the overall threat that LM pose to an orchard in any given year is shaped not only by first-generation adult density and weather factors (such as favorable egglaying conditions), but also by relative abundance of parasitoids and LM species complex, which are in turn impacted by both the composition and density of alternate hosts outside of the managed orchard and chemical selection within the orchard. In 2000 in the 12 commercial orchards involved in our third-level IPM program, we initiated an effort toward understanding the dynamics of LM population expansion in commercial orchards. The intent of the first year of this study was to establish a base-line profile of each orchard’s LM and parasitoid species composition. In following years, we hope to track these species profiles to determine whether trends toward problematic LM population densities can be linked to chemical orchard management or orchard architecture. As with other key pests, our focus in this study is at the orchard border, the interface between managed orchard trees and unmanaged alternate hosts. At the close of the 2000 growing season, we examined the influence of orchard perimeter composition (type and density of vegetation surrounding orchard blocks) on biological control of within-orchard LM populations. We sampled orchards at 3 critical periods of LM development (early June, early August, and early November), concurrent with development of each of 3 annual LM generations. During each of these sampling periods, we assessed density of mines in orchard trees, species composition of the LM population, and levels of parasitism by S. marylandensis and P. ornigis. In 2000, the density of first-generation mines across the 12 orchards varied from 0.0 to 9.0 mines per 100 leaves, with a project-wide mean of 2.7 mines per 100 leaves. Given generally low numbers of mines, 10 of the 12 growers in this study did not treat against first-generation LM (unlike 1999, when nearly all sampled orchards exceeded threshold levels). Along with overall mine density, parasitism rates were far lower than in 1999; samples of first-generation mines yielded a range of 4.0% to 23.1% parasitism, with a project-wide average of 16.3%. With few of the 12 growers applying insecticide targeting first-generation mines, coupled with modest parasitism, the project-wide second-generation mine density increased 7-fold, yielding 18.5 mines per 100 leaves. This increase is totally consistent with the historic 7-fold rate of increase between first- and second-generation LM in commercial orchards in Massachusetts. Along with increases in mine density, parasitism rates increased markedly, yielding a range from 35.0% to 68.7% and a project-wide average of 51.8%. No studied orchards developed a damaging third-generation mine density, averaging 97.2 mines per 100 leaves across blocks. This 5-fold rate of increase from second- to third-generation LM is somewhat higher than historical trends in Massachusetts commercial orchards, but not as alarming as increases seen in 1998 and 1999. For third-generation mines, there was a much broader range of parasitism (from 15.1% to 70.0%), with a project-wide average of 37.0%. Overall, trends in the species composition of orchards mirrored the trend of recent years, with data from this project strongly suggesting that STLM is rapidly becoming the dominant LM species in Massachusetts commercial apple orchards. In fact, in samples of third-generation LM (the most thorough samples taken), STLM were present in all 12 sampled orchards and constituted 71.5% of all LM sampled. Only 4 of the 12 studied orchards harbored a population of ABLM that represented 20% or more of the total LM density. Despite the momentum with which STLM are beginning to dominate these orchards, there remain a few orchards (3 in particular) with a dominant population of ABLM. Understanding the dynamics within these orchards may be the key to understanding the dynamics of the apparent species shifts. FIRE BLIGHT MANAGEMENT AND POSSIBLE ROLE OF POTATO LEAFHOPPERS As most growers are aware, New York and Michigan experienced extremely serious fire blight outbreaks last year. We heard of no major outbreaks of the disease in New England in 2000, but fire blight symptoms were seen in more orchards than has been the case for a long time in this region. Some trees in blocks which had fire blight as long as 6-8 years ago were symptomatic, presumably because of inoculum moving back into the orchard from adjacent wild hosts. Should we be concerned about fire blight in New England? In the past it has not been of major concern for most growers; our climate and cultivar mix have combined to keep fire blight problems to a sporadic minimum. But as growers shift to cultivars and rootstocks that are much more susceptible, it may be wise to assume that fire blight does have a potential for major concern. Even growers who have not yet seen any blight in their orchard should keep a vigilant eye; the bacteria can live on a variety of wild rosaceous hosts, and are thought to be transmitted by wind, insects, and even birds. The New England Apple Pest Management Guide has a good section on managing fire blight, so here we will simply outline some important practices for growers who did notice some fire blight in the orchard last year. Dormant pruning of infected tissue is the most critical practice. Cankers are an overwintering site for the bacteria, so all infected tissue should be removed. Dormant or early spring (before half-inch green) copper sprays are very helpful, because they suppress what might otherwise be extremely rapid reproduction of the bacteria on the woody surfaces of the tree, which would in turn provide the inoculum for any infections that occur during bloom and later. If infections occur during bloom, according to your own weather monitoring and/or reports from Extension, Streptomycin plus an “activator” should be applied, preferably about 24 hours pre-infection, and definitely by 24 hours post-infection. Strep should also be applied if there is a “trauma” during or after bloom, such as hail or very high winds. An important note: Strep should not be used against shoot infections after bloom in the absence of trauma conditions. It is ineffective at controlling shoot blight and indiscriminate use may speed up the development of resistance. The growth regulator Apogee also appears to have some inhibitory effect on the development of fire blight; most researchers report a 50% or higher level of suppression of fire blight in Apogee-treated trees compared to non-treated trees. Although this is not a sufficient level of control by itself, it appears that Apogee, applied in the correct manner for shoot growth suppression, may also turn out to be an important part of a fire blight management program. But be aware that the vegetative growth suppression effect of Apogee may be a negative for young trees that need to be growing rapidly! The role of insects in transmitting fire blight, and the need for insect control in fire blight management, are still largely open questions. It is clear that pollinating insects can carry the bacteria for short distances during bloom, which makes it all the more important to monitor the weather and promptly apply Strep if needed, since clearly we can’t and shouldn’t be trying to eliminate pollinating insects. After bloom is over, it is possible that some insects may carry small quantities of bacteria from tree to tree, or facilitate fire blight by creating wounds in the leaf tissue during feeding. Research has indicated that aphids have little or no importance in fire blight transmission, nor have white apple leafhoppers been shown to have any role. However, there is evidence that potato leafhoppers do facilitate fire blight transmission by wounding susceptible tissue and creating entry sites for the bacteria; it is not clear whether they also carry fire blight bacteria from tree to tree. It may be wise to control potato leafhoppers within a short distance of any active fire blight infections. PROBLEM PESTS: ACTIVITY, NEW FINDINGS AND TECHNOLOGIES 2000 Activity. For the 7th consecutive year in Massachusetts, TPB captures on monitoring traps and TPB injury to fruit in apple orchards were below levels experienced in the early 1990s. The same pattern was true in other New England states but not in Quebec, where TPB captures and fruit injury were well above normal. As pointed out in the 1999 March Message, such a long run of below-average TPB infestation in Massachusetts could be due to (1) a coinciding long run of unfavorable weather conditions for building of TPB adults during autumn or survival of adults over winter, (2) consistently poor weather for TPB activity during spring, (3) declining availability of favored flowering plants (especially alfalfa and other dairy-associated legumes) for building of TPB during summer and autumn, or (4) an increasing degree of region-wide biocontrol of TPB by parasitoids that were released in the early 1990s in Massachusetts and New Hampshire and have spread into other New England states but not yet as far north as Quebec. Increasingly, it appears that the third and fourth causes are the ones responsible for the continuous low levels of TPB seen in apple trees over recent years. New Findings. New findings on TPB involve trials of pesticide effectiveness in providing control. The information below comes from Dick Straub and associates in the Hudson Valley (HV) and Harvey Reissig and associates in western New York (WNY). They applied the following pesticides at pink and obtained the following results:
Combined results suggest that Danitol, Actara and Calypso performed better than Avaunt in controlling TPB and that each of the first three provided a level of TPB control better than that normally provided by Guthion or Imidan. Thus, if TPB begins to rise again, we should be able to count on Actara or Calypso as very effective alternatives to Guthion. Danitol might be less favored on account of its toxicity to predatory mites. 2000 Activity. Populations of EAS were somewhat below average in Massachusetts and most other New England states in 2000. Possibly the cool, rainy weather that occurred when many orchards were in bloom reduced egglaying activity of EAS. New Findings. New findings on EAS involve results of pesticide trials conducted by ourselves at the HRC and by Dick Straub and associates in the Hudson Valley (HV). Pesticides were applied at petal fall and first cover and yielded the following results:
Combined results suggest that all 5 pesticides tested in these trials performed well against EAS, although there was some variation in performance among trials. 2000 Activity. In Massachusetts and some other New England states, damage to fruit inflicted by PC progressed normally until about mid-June, never reaching a serious level. However, during the latter half of June many orchards experienced a very large amount of injury, sometimes reaching 30-40% damaged fruit on perimeter-row trees. The year was unusual in that nearly 60% of all overwintered PC immigrated into orchards during a hot spell in the first week of May (at the time of pink to early bloom). After that, several weeks of cool, wet weather saw only a small to moderate amount of additional immigration. The last wave of PCs immigrated during a warm spell in the last half of June. Growers who had stopped spraying for PC in late May were the ones who got hit the hardest in the latter half of June. New Findings. In recent years, a temperature-based model developed by Harvey Reissig and Jan Nyrop at Geneva, New York has been quite successful in predicting when a grower should stop spraying against PC. The model relies on accumulation of heat units to indicate that residual activity of a pesticide ought to extend through 325 degree days to ensure adequate season-long protection against PC. The model did not prove very effective in 2000, however, because with all the rain, not enough insecticide remained on sprayed trees to handle the flush of PCs that entered orchards in the latter half of June. This is where placing effective traps at edges of areas bordering orchards could be very useful in predicting the beginning and end of PC immigration (see earlier section on Progress Toward Developing Plum Curculio Traps). If trap captures show that PCs are immigrating in considerable numbers well after residual activity of insecticide has worn away, then another application could be made to give the needed protection. A symposium on PC was held at a joint national meeting of the Entomological Societies of America and Canada in Montreal in December of 2000. About a dozen talks were given, presenting latest findings from places as far west as Utah, as far south as Arkansas and as far north as Quebec. Because of its economic importance, PC has finally begun to stimulate widespread research attention. Other groups besides ourselves are working to develop good traps, though as yet no one else is studying host odor compounds as potential odor attractants. Perhaps the most striking news to come out of this symposium was the extreme devastation that PC caused to cherries in Michigan, where hundreds of thousands of dollars of crop were lost to PC because of infested loads of fruit being turned back at the marketplace. Researchers in Michigan are now working hard to come up with some solutions for the future. Several trials of pesticide effects on PC were conducted in 2000, principally by ourselves at HRC, Dick Straub and associates in the Hudson Valley (HV), Harvey Reissig and associates in Western New York (WNY), John Wise and associates in Michigan (MI), and Henry Hogmire and associates in West Virginia (WV). The information below involves 3 applications of each material against PC (petal fall, first cover and second cover).
Combined results suggest that Actara, Avaunt and Calypso performed about equally well in controlling PC and that in some cases (though not consistently) they exceeded or equalled Guthion or Imidan in controlling PC. Surround and Provado were less effective than these 5 materials. To be effective, Surround demands complete and constant coverage of existing and new growth, which was difficult to achieve in 2000 given all the rain. The bottom line from these studies is that if Imidan or Guthion were to be phased out, there exist 3 new materials (albeit expensive ones) that can provide very good control of PC. 2000 Activity. In Massachusetts, AMF populations in both unmanaged and commercial orchards were the lowest in memory. To illustrate, only 9 AMF-infested fruit were found among 15,200 fruit that we sampled at harvest across 18 commercial orchards. This is a remarkably low infestation rate, especially considering that the average orchard received only 2 sprays against AMF, one less than the normal 3 sprays. We don't know why AMF were so few but postulate that the very cold weather during the 3 weeks after Christmas in the absence of any snow cover may have caused mortality of overwintering pupae in the soil. In northern New England and Quebec, AMF actually were more abundant than normal, especially later in the season, causing greater than normal infestation of late cultivars. New Findings. A report in the June 2000 issue of Journal of Economic Entomology by Trimble and Vickers from Ontario gave 3 years of data on the effectiveness of perimeter-row sprays of Guthion or Imidan against AMF. Blocks of 10 acres in each of 6 orchards received an average of either 2.5 whole-block sprays or 2.5 perimeter-row sprays (directed at trees comprising the first 4 perimeter rows). Across 3 years for the 6 orchards, block-wide AMF injury averaged 0.15% for perimeter sprays versus 0.03% for whole-block sprays. These data are consistent with extensive studies we conducted in Massachusetts from 1988-1994 showing that Guthion or Imidan applied only to perimeter-row trees (in our case only 1 perimeter row rather than 4 in the Ontario study) can provide good control of AMF, though perhaps not quite as good as provided by whole-block sprays. In 2001, we will be initiating a study in commercial orchards in Massachusetts comparing effectiveness of Avaunt versus Guthion in perimeter-row versus whole-plot sprays for control of AMF. Several trials of pesticidal effects against AMF were conducted in 2000 by ourselves at HRC, Dick Straub and associates in the Hudson Valley (HV), and Harvey Reissig and associates in western New York (WNY). The information below involves 4 applications of each material against AMF during July and August.
Combined results suggest that Surround and Calypso performed about as well as Guthion in controlling AMF, whereas Avaunt and Actara were inferior to these materials. Therefore, even though Avaunt is a newly-labelled insecticide against AMF, we suggest that interested growers experiment with it only in a portion of the orchard rather than using it orchard-wide to see first-hand how well it performs. 2000 Activity. For the third consecutive year, SB injury was notable on apples sampled at harvest in commercial orchards in Massachusetts. Although damage overall averaged less than 0.5% in 18 monitored orchards, in one orchard damage averaged 5.5% of fruit at harvest. Unlike in 1999, SB damage in 2000 was not confined to areas vulnerable to SBs moving to apple trees from harvested peach trees. It was especially noticeable in orchards where weeds grew tall because of infrequent mowing. New Findings. Mark Brown of the USDA Fruit Research Lab in West Virginia caged SBs on apple branches near the end of August in 2000 to determine patterns of injury. He found that damage looks like cork spot when apples are cut open. When visible, surface injury appears as a small dark or blackish depression similar to an AMF egglaying sting. However, oftentimes the puncture made by an SB when inserting its beak was so small that it could not be detected, even though cork-spot-like injury was apparent when the apple was cut open. Brown found that SB injury was especially great on sun-exposed parts of fruit and on fruit that approached maturity. To repeat some information appearing in the 1999 March Message, observations in Washington State have shown that SB populations in orchards are greatest (a) where mullein (a favored host) is abundant near an orchard, (b) when dry weather causes SB hosts near orchards to dry up in mid-summer and stimulate SB movement into orchards, and (c) on perimeter rows of trees nearest areas of SB buildup in orchard borders. Possibly Actara and Calypso, which control tarnished plant bugs better than Guthion or Imidan, would provide effective control of SBs, which are fairly close relatives of tarnished plant bugs. 2000 Activity. Of the common moth pests, only leafrollers (LR) caused notable damage to apples sampled at harvest in 18 commercial orchards in Massachusetts in 2000. The average LR injury of 2.9% sampled apples was much greater than in 1999 and other recent years. Possible causes of this sudden rise in LR injury are unknown. Conversely, codling moth (CM) and lesser appleworm (LAW) caused less than 0.1% injury to harvest apples. Oriental fruit moth (OFM) also was lower on average than in 1999, but OFM larvae appeared in apples in about one-third of sampled orchards, an increase in the proportion of orchards experiencing OFM injury. Elsewhere in New England, fruit-feeding moth pests were at or below normal levels in sprayed orchards. But in western New York, Ontario, Pennsylvania and New Jersey, OFM continues to be a major concern in both peaches and apples. An extensive account of OFM biology, its increasing populations in orchards, and possible causes of increase were given in the 1999 March Message. New Findings. Research in the USA on fruit-feeding moth pests is greater than on all other orchard pests combined. The main reason is that most regions of the USA experience far more trouble from these moth pests than we do in Massachusetts or New England, due primarily to resistance of moth pests to several organophosphate insecticides. Much of the new research is focused on using dispensers of synthetic sex pheromone to disrupt mating of LR, CM, LAW and OFM. This is proving to be a very effective approach in several states but is rather expensive, both in terms of labor and materials. Unless one or more of these pest types becomes continuously more important in Massachusetts than in the past, the cost of using mating disruption for control cannot be justified by the expense. This assessment does not, however, apply to orchards using ecological or organic approaches to pest control. Here, moth pests of fruit could increase substantially under much-reduced pesticide programs. The recent study by Trimble and Vickers in Ontario cited in the section on apple maggot flies also involved assessment of perimeter-row versus whole-block sprays against CM and oblique-banded leafroller (OBLR). Average percent fruit injury at harvest for perimeter-row vs. whole block sprays was 0.19 vs. 0.04% for CM and 1.65 vs. 1.16% for OBLR. For both of these pests, results were similar to AMF results, indicating that pesticide treatments applied only to perimeter rows can provide good control of CM and OBLR, though not quite as good as whole-block sprays. Several trials of pesticidal effects against combined CM and OFM were conducted in 2000 by ourselves at HRC, Dick Straub and associates in the Hudson Valley (HV), Harvey Reissig in western New York (WNY), John Wise and associates in Michigan (MI) and Henry Hogmire and associates in West Virginia (WV). The information below is based on 6-7 applications of each material from first cover through the last spray in August.
Combined results suggest that Avaunt and Calypso (and possibly also Intrepid) were as good as Guthion or Imidan in controlling CM and OFM. Surround gave somewhat less control, and Actara gave poor control. Thus, if a problem with CM or OFM begins to arise, there should be a good replacement material (Avaunt, Calypso, and possibly Intrepid) should use of organophosphates be restricted. BORERS INFESTING BURR KNOTS ON APPLE TREES2000 Activities. Dogwood borers and apple bark borers have become frequent pests in some Massachusetts orchards in recent years and 2000 was no exception. Most orchards are free of these pests, possibly due to the nature of surrounding border areas. Orchards whose border areas contain dogwood or other wild hosts of borers are the most susceptible to attack. So are orchards where plastic mouse guards are used or where weeds next to tree trunks are mowed infrequently. Trees with many burr knots are the most susceptible, as these are the feeding sites of borer larvae. Burr-knot borers weaken trees and stunt tree growth. New Findings. Proven solutions to reducing burr knot borers include removal of plastic mouse guards from April through harvest, maintaining wire mouse guards free of debris and keeping lower parts of tree trunks free of weeds.Until now, many growers could rely on trunk sprays of Lorsban applied during July to control existing borer infestations. New regulations no longer allow post-bloom use of Lorsban. To address this problem, Dave Kain and associates of the Hudson Valley lab evaluated different times of Lorsban 50W applications in 2000. Here are the findings.
Results show that Lorsban 50W applied to tree trunks at 1.5 lbs/100 gal at petal fall controlled burr knot borers just as well as a mid-July application. If petal fall is an effective timing, might not pink application also be effective? Neither Thiodan nor Asana performed as well as Lorsban. For 2001, we suggest that growers who experienced burr-knot borers in 2000 consider applying Lorsban at pink to tree trunks and hope for the best. Problems with burr-knot borers are likely to be greatest for trees whose trunk diameter is 4 inches or less and greater for trees on perimeter rows within 100 yards or so of woods. LEAFHOPPERS2000 Activities. Both white apple leafhoppers (WALH) and rose leafhoppers (RLH) were more abundant in 2000 in Massachusetts and New England orchards than in the past couple of years. So also were potato leafhoppers (PLH), which descended in large numbers in late June and were particularly threatening to foliage of newly planted or young trees. It was commonplace to see yellowing and then browning of terminal growth on bearing trees caused by PLH. But no one has ever been able to show a negative effect on fruit quality or yield a result of this injury. In fact, it may even be beneficial in stunting excessive growth of terminals. The possible role of PLH in incidence of fire blight is a subject of current study (see above section under General IPM Topics and Opinion).New Findings. Relevant new findings involve insecticide trials conducted in 2000 against LH by Dick Straub and associates in the Hudson Valley (HV), John Wise and associates in Michigan (MI), and Henry Hogmire and associates in West Virginia (WV). The information below stems from mid-season or season-long applications of each material.
Combined results for WALH + RLH suggest that Provado, Avaunt and Calypso gave effective control, with the edge going to Provado, even at a very low rate (0.5 oz/100 gal) applied once (in early July). For PLH, the early-July, low-rate application of Provado proved as or more effective than any other material. We can conclude from these data that if abundant adults of WALH or RLH are observed on apple trees in early-mid June or yellowing of terminal foliage is observed on non-bearing trees in late June or early July, a single low-rate (0.5 oz/100 gal) application of Provado should provide excellent control of all 3 species. 2000 Activity. For Massachusetts, trap captures of first-generation LM in 1999 were the highest ever recorded in MA, inspiring most growers to treat 1st generation miners with Provado or SpinTor. Excellent control from these materials carried over to the 2000 growing season. Only 2 of 12 orchards monitored for LM in 2000 received an LM treatment. However, some of these monitored orchards saw a substantial number of third-generation mines this past October. So growers should be on the alert for rebounding LM populations in 2001. A fuller discussion of 2000 LM infestation levels and parasitism is given earlier in the section on General IPM Topics and Opinions. Elsewhere in New England, LM populations in 2000 were about normal. New Findings. With respect to timing of Provado for LM control, a grower in southeastern Massachusetts obtained excellent control in 2000 with a petal fall application but fair to poor control with an application 10 days later. This is consistent with grower observations in 1999, also suggesting that Provado applied at petal fall gave better LM control than when applied 10 days after petal fall.At a regional IPM meeting in Burlington, VT in October, Chris Maier gave a synopsis of his long experience with LM in Connecticut (CT). He indicated that in 1982, 8 of 9 commercial orchards sampled were dominated by apple blotch leafminers (ABLM). In 2000, 17 of 20 commercial orchards sampled were dominated by spotted tentiform leafminers (STLM), a dramatic change. A similar change is in progress in Massachusetts. The underlying causes of this change are uncertain, but could be related to changes in pesticide use patterns from Vydate, pyrethroids or Lannate to Provado, AgriMek or SpinTor for LM control and from 4 to 3 or fewer organophosphate (OP) sprays against apple maggot. LM are resistant to OPs but their parasitoids are not. Apparently in CT, current pesticides applied in May and June have a much more devastating effect on survival of parasitoid species that attack STLM than against parasitoid species that attack ABLM, probably due to timing of applications that permits parasitoids of ABLM to better escape effects of pesticides. A consequence of early-season escape of STLM from parasitism in CT is more rapid buildup of STLM than for ABLM. Also, STLM escapes parasitism better than does ABLM in the third generation in autumn. The process of STLM replacing ABLM is still unfolding in CT (as in MA). The net result may be greater difficulty in achieving effective LM suppression without resorting to annual or biennial pesticide applications. An article in a 2000 issue of Canadian Entomologist by Trimble and Tyndall shows that application of dispensers of synthetic STLM pheromone can achieve effective mating disruption and possibly effective control of this species. Eventually, this could be a useful approach (albeit an expensive one) to future LM management. Several trials of pesticide effects against LM were conducted in 2000 by Dick Straub and associates in the Hudson Valley (HV), Harvey Reissig and associates in western NY(WNY), John Wise and associates in Michigan (MI) and Henry Hogmire and associates in West Virginia (WV). The following information is based on 7 post-bloom applications of each material beginning at petal fall.
Combined results suggest that Calypso is a very effective material against LM. Actara appeared effective in some trials but not in others. Avaunt and Surround were not very effective in controlling LM. For the future, Calypso could be an addition to Provado, AgriMek and Spintor as effective insecticides against LM. MITES2000 Activities. For Massachusetts, European red mites (ERM) remained low in most commercial orchards throughout spring and summer of 2000. Contributing factors were low numbers of overwintering eggs, slow early-season development and generally cool, wet weather until August. Even with poor conditions for early-season oil applications (lots of wind and rain), troublesome populations of either ERM or TSM were few until late August. Some orchards in Massachusetts and other New England states, however, did experience ERM buildup in late August and early September, enough to give rise to troublesome numbers of overwintering ERM eggs and potential early-season problems for 2001. New Findings. Every year, the number of published articles on biology and control of pest mites of fruit trees exceeds that of any other pest type, including codling moth. For 2000, most published articles dealt with subtleties of interactions among mite predators, subtleties of effects of insecticides or fungicides on predator survival or reproduction, or new ways of measuring resistance of mites and predators to pesticides. No report struck us as being of particular relevance to mite control on fruit trees in Massachusetts. There was a verbal report by Dave Kollas of Connecticut made at a regional IPM meeting in Burlington VT in October, however, that is relevant. Kollas observed a kind of mite new to him that was causing foliage injury on apples in CT. Jan Nyrop of Geneva, NY verified the mite as being the yellow spider mite, Eotetranychus carpina borealis. They look like two-spotted mites (TSM) but are smaller with yellowish spots. Injury appears similar to TSM injury but is confined to the mid-rib area of leaves. It’s not the typical bronzing-type of mite injury. Yellow spider mites begin to appear about petal fall, much earlier than TSM normally appear. Fortunately, their reproductive capacity is only about one-sixth that of TSM. Yellow mites were observed in 2000 by Heather Faubert in Rhode Island and by other researchers in Quebec. Time will tell of their eventual importance. Trials of acaricidal effects against mites were conducted by Dick Straub and associates in the Hudson Valley (HV) and Henry Hogmire and associates in West Virginia (WV). The information below involves different times of applications of each tested material.
Results from WV suggest that Pyramite applied in early May did not provide effective season-long control of ERM but that application in late June did provide good control. Results from HV showed rather little lasting control of ERM or TSM by either Vendex, Kelthane or Pyramite applied in mid-August. However, both Kelthane and Pyramite were quite detrimental to predatory mites. These combined results suggest some uncertainty about the value of using Pyramite as a rescue material. Perhaps it can not always be counted on to do a truly effective job of controlling mites, and (as reported elsewhere) it harms predators. We advise some caution in relying solely on Pyramite to fix mite problems. A more sound IPM approach involves making 2 pre-bloom applications of oil and use of Apollo, Savey or AgriMek in cases where either spring weather makes 2 oil applications difficult or there is an exceptionally large overwntering population of ERM eggs. 2000 Activities. As in 1999, PP populations in 2000 were below normal, probably due in part to the cool weather that reduced the multiplication rate of PP. New Findings. Dick Straub and associates in the Hudson Valley evaluated several insecticides against PP in 2000. Because PP never reached even moderate numbers throughout the season, differences in performance among treatments were rather slight. A season-long program of Surround (8 sprays beginning at bud break) gave the best control. Excellent control was also given by a single spray of M-Pede or AgriMek at 8 days after petal fall, with a single spray of Pyramite at white bud or a single spray of Neem at 8 days after petal fall also doing a good job. Single sprays of Actara, Provado or Calypso at 8 days after petal fall were not as effective. 2000 Activities. We made no formal assessment of peach pests in Massachusetts in 2000. But reports on 2000 from New York indicated continuance of a recent trend toward increasing infestation of growing shoots and fruit by oriental fruit moth (OFM), tree trunks by peach tree borers (PTB), and tree trunks or limbs by lesser peach tree borers (LPTB). New Findings. In 2000, Art Agnello, Harvey Reissig and Dave Kain in New York evaluated effectiveness of different insecticides against OFM and the potential of using synthetic sex pheromones to disrupt mating and gain control of OFM, PTB and LPTB. Application times of insecticide against OFM were targeted at hatching time of first- or second-generation eggs (May and August, respectively). Each material was applied twice during the year: Asana, Lannate, Intrepid and Avaunt all gave very good control of OFM as judged by percent injury found at harvest, whereas Imidan and Calypso gave only fair control. As a first attempt at controlling OFM by mating disruption, 2000 results in New York were encouraging but need to be verified in future research. Mating disruption pheromone also showed much promise in its first year of use in New York against PTB and LPTB. If future research shows success of this behavioral approach to PTB and LPTB control in New York, we can look forward with confidence to using it in Massachusetts. IPM MANUALS, SUPPLIES AND SERVICES PURCHASE OF PEST CONTROL GUIDES, IPM MANUALS, ETC. For 2001, the monthly newsletters; weekly Healthy Fruit messages; the March Message; the Peach, Pear and Plum Guide; and the 2000-2001 New England Pest Management Guide will be available for a subscription of $50. Subscriptions may be ordered by sending a check for $50 made out to the University of Massachusetts to Wesley Autio, Department of Plant and Soil Sciences, Bowditch Hall, 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 2000-2001 New England Apple Pest Management Guide will be mailed to all who subscribe to the $50 package of information. The 2000-2001 NEAPMG was edited by Glen Koehler, Alan Eaton, Lorraine Los, Lorraine Berkett, Wes Autio, Jim Dill, Bill Lord, and Elena Garcia. The 1999-2000 Peach, Pear and Plum Guide includes updated pest biologies and control methods. The Peach, Pear and Plum Guide is edited by the UMass Tree Fruit Team.
Two fact sheets are available on biological control of mites and leafminers on apples. Costs:
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 UMass Extension Bookstore, Draper Hall, University of Massachusetts, Amherst, MA 01003. Please use the ID code (if provided) to specify the publication you are ordering. Fruit Notes of New England is a quarterly journal published by the UMass Plant and Soil Sciences Department and UMass Extension. It contains important new research findings on fruit growing in Massachusetts. The subscription price is $10 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. Healthy Fruit 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]. 2001 Tree Fruit Production Guide. 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. Penn State’s distribution center can also take telephone order (for credit card purchases) at (814) 865-4700. Updated New York Fact Sheets Among others, the Tree Fruit Fact Sheets set includes: 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, Apple Scab, Sooty Blotch and Flyspeck, European Apple Sawfly, Tarnished Plant Bug, Comstock Mealybug, and Phytophagous Mirid Bugs. The New York Fact Sheet series features excellent photographs, and a set of 30 can be purchased for $28.35. Individual sheets are also available for $2.00 each. These can be ordered from Media Services Resource Center-GP, 7 Research 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, and 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 VENDOR INFORMATIONA 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), which is also present 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, as shown by recent increases in Oriental fruit moth activity under reduced spray schedules. 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 in orchards dominated by ABLM. Orchards with mixed or unknown LM species composition may gain more reliable data from horizontal LM traps placed in the tree canopies. 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 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 and Great Lakes IPM. 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. Tangletrap (A Tanglefoot Co. product) Tangletrap (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. 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 Great Lakes IPM Many pest management supplies are also available from: OESCO, Inc. (Orchard Equipment) PEST MANAGEMENT SERVICES AVAILABLE IN 2001 IN MASSACHUSETTSIn 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, at http://www.umass.edu/umext/programs/agro/tree_fruit/. 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 [autio@pssci.umass.edu]. Two private consulting businesses will continue to offer IPM consulting, scouting, and other services in Massachusetts in 2001. Their addresses are: New England Fruit Consultants (NEFCON)
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