COMMON ARMYWORM ALERT - John Howell and Pam Westgate, UMass Extension

There are numerous reports of common armyworm in turf and hay crops, in many areas of the state. This insect also attacks corn and, occasionally, some other vegetables especially peppers. The mature caterpillar is about 1 1/2 inches long, greenish yellow to brown, with a dark stripe along each side. At this time it appears that the caterpillars are full size and will likely pupate soon. Therefore, damage from this generation should not continue much longer. These are heavy feeders on the leaves, in the whorl and in the ear. Damaged leaves appear to have been shredded and this is characteristic of both the common and fall armyworms. Larvae enter fruits of pepper and can cause extensive damage. Typically, damage begins near the edge of a field as the caterpillars move in from neighboring fields or grassy or weedy borders. This is likely to happen when they use up their food supply and move on to new areas. Be particularly watchful in fields that border hay. Available insecticides for corn include Warrior, Spin Tor, Larvin, Ambush and Lannate. Apply in 75 to 100 gallons of water per acre. Make two applications five to seven days apart when damage exceeds 15% in the whorl or pretassel stages. In peppers damage is more likely to occur from fall armyworm, but a second generation of common armyworm is possible. Orthene, Poounce, Spin Tor, Confirm and Lannate are labeled. Bacillus thuringiensis, while available and effective on small larvae, is ineffective on the large larvae that are causing the damage out there now. See the New England Vegetable Management Guide and the label for more information. Growers may want to apply a treatment to the edges of fields to intercept migrating caterpillars. (Source: Vegetable IPM Newsletter, JULY 5, 2001, Vol. 12, No. 8) [Editors Note: Please check http://www.umass.edu/umext/programs/agro/ and http://www.massdfa.org/ for detailed information on Common Armyworm. - SGS]

Crop Conditions and Pest Summary

Weather continues to drive many crop management activities. Frequent wetting periods generate optimal conditions for disease development. Strong storms with high winds and wind driven hail have plagued the state in many regions. Maintaining a good disease management program may be key, especially where plant tissue has been damaged by hail. Strawberry renovation is in progress. See last weeks Berry Notes for details on renovation procedures. As new leaves grow, check for feeding injury by Japanese Beetles and Strawberry Root Worm. More on this below. Also, make plans to collect leaf tissue samples for tissue analysis. This is the best way to check if your fertilization program is on target. Some growers are trying the new Annual (Plasticulture) system and are considering carrying their fields over for a second picking year. See Charlie O’Dell’s article on how to do this, below. Highbush Blueberries harvest is beginning on early sites and early varieties. I’ve had more calls about blueberry problems this year that about everything else combined. Concerns inlcude blossom and tip dieback resulting from freeze damage in May, poor vigor on certain varieties, off-color on new growth, root feeding by various grubs and weevil larvae, and small fruit. I’ve also had reports of terrific fruit-set, good size, and excellent flavor. It appears to be just one of those years where there is a wide variety of outcomes resulting from unusual weather conditions this year (really for the past 3-4 years). That’s New England! Summer raspberry harvest is in full swing. Disease pressure is high with repeated wetting periods. Check for Botrytis gray mold, cane diseases, sap beetle, two-spotted spider mite, Japanese beetle and potato leaf hopper. Fall raspberries are beginning to show flower clusters. Grapes clusters are developing and leaf pulling and cluster thinning are underway to help insure proper ripening of the fruit. Continue scouting for grape berry moth and mites. Japanese beetles are very active now. Maintain a good post bloom disease management program to avoid late season problems.

As foliage grows back after renovation, keep an eye out for feeding of strawberry rootworm (Paria fragariae). Strawberry leaves attacked by strawberry rootworm beetles are riddled with small holes. Some leaf damage occurs in May, but most occurs in August. Heavy infestations can reduce plant growth or kill plants. Although adults of the strawberry rootworm feed on the leaves of strawberry, root feeding by the larvae is more damaging to strawberry production. Adult strawberry rootworms are brown to black or copper-colored, shiny, oval-shaped beetles with four blotches on the shell-like wing covers. They are 1/8 inch long. The larvae are grubs that are 1/8 inch long, creamy white, with three pairs of legs. Adult strawberry rootworms overwinter in mulch and soil crevices, and become active in May and June. Adults feed primarily at night and hide in soil or mulch during the day. They chew small holes in leaves, and females lay eggs on older leaves near the soil surface. Larvae burrow into the ground to feed on strawberry roots from late spring to early summer. New adults begin emerging in mid-summer, and these beetles feed on strawberry foliage through early fall.

Scouting for the presence of adult beetles is best done after dark using a flashlight to examine plants. No threshold has been established for this insect, but a population of 10 to 20 beetles per square foot is considered high. As with all the root feeding insects, control of the root feeding stage is very difficult. Therefore, control measures for strawberry rootworm should be directed toward the adult stage. If feeding injury is observed in May or June, an insecticide spray at this time will reduce the number of egg laying females and, therefore, the number of grubs feeding during the summer. When the next generation of adults emerges in July or August, control measures may be needed again. Post-harvest foliar sprays of registered insecticides applied according to label directions provide control of adult strawberry rootworms.

"Show me the money" is what growers need from our strawberry research with hardy eastern U.S. varieties on plastic mulch for colder areas. Growers are rightfully concerned, unsure about risking the very expensive investments for equipment, plants, plastic mulch, drip irrigation, transplanter and frost control needed for 1-crop annual plantings for our strong consumer demand for locally grown, flavorful, vine-ripe berries in the mid-Atlantic region.

Our strawberry research is focused on developing a profitable recyclable production system for 3 cropping years per planting with hardy Eastern varieties. The challenge is to maintain adequate berry size and yields for second and third year crops from original plants in this hill system. Plants are maintained at original double-rowed spacing by the plastic mulch which prevents daughter runners from being able to root and destroy the evenly spaced hill configuration favoring easy harvest, clean berries and larger fruit plus in-row weed control.

Renovation practices after harvest plus management of second and third year plantings will be important to success, plus development of varieties more resistant to Anthracnose crown disease. At renovation, for example, after harvests and mowing of foliage, while crowns are highly visible, crown thinning/renewal may be necessary as with an asparagus knife. About one-half of each large crown is removed on such large crowned varieties as Chandler in warmer areas and Late Star in mid-Atlantic colder areas. Also vital for success will be September replacement by fertigation of nutrients depleted in the beds by the previous crop, based on late summer soil tests of the beds for nutrient inventory.

Another necessary carry over task in late winter is cleaning of beds to remove dead leaves and previous season runner growth. This abundant dead plant material has served us well in colder areas as a "home grown" winter mulch atop the beds to help protect crowns. It also serves as a huge source of latent, infectious spores of Botrytis Gray Mold fruit rot and other diseases that must be removed before occurrence of active new spring growth and fungicide applications during bloom. Such late winter plant cleaning is also vitally important in matted row production for best Gray Mold disease control, along with fungicide crop protectant sprays during bloom. In our carry over research plots we've removed this dead plant material by hand, a difficult, laborious, bend-over job. Research/Extension cooperating growers including the JP Via family and Hugh French and family also hand cleaned their carry over beds at a labor cost of $500 - $700 per acre. Small growers that don't have a late winter labor supply find hand cleaning beds to be an especially difficult task.

After seeing lawn mower blades modified to top-prune, lift and discharge woody nursery prunings in a large commercial nursery in Southeast Virginia, we decided to try this concept for mechanically cleaning strawberry beds. Credit for this idea goes to Mr. Johnny Patterson of Lancaster Farms, whose many talents include welding and metals fabrication. He welded flat steel to the back "lift" sides of 21" mower blades, a strip 3-1/2" long so that one-half inch of each steel strip protruded from the back side of the blade directly behind each 3-1/2" sharpened cutting edge. The 1/2" of extra steel protruding from the upper side at the ends of the blade creates amazing "airplane propeller" lift! After our research farm support technician, Mr. Romney Smith, welded and balanced, then reinstalled the blade we fired up the mower engine. Blade suction lifted gravel stones off the research farm shop gravel driveway and blew them out of the side discharge chute, look out folks! Only at near-idle speeds was the mower safe with the blade engaged on graveled areas.

The blade welding modification was completed in November, but we did not want to risk removing our home-grown crown mulch protection of dead runners and leaves atop the crowns and beds until late winter. The flying gravel stones showed us the concept works. Finally I could stand the suspense no longer. Just after the North American Strawberry Growers annual conference at Orlando, on Friday, Feb. 12, 1999 I tried this "suction mower" on a guard row of plastic mulched strawberries at our research farm. It worked! To keep from cutting the plastic mulch I had to adjust the blade/mower wheels until the blade was in its highest position 3" above the plastic mulch. The dead leaves and old runners are closer to the mulch, but are lifted and cut by the powerful wind/air suction of the blade. The wheels serve as height control as the 21" wide 5 horsepower hydrostatic drive mower moves easily on top of the bed at just above idle speed. To me the effect was similar to a relaxing stroll following and merely guiding the mower, while taking in the late winter sun and air in an upright position! Behind the mower appeared shiny black plastic mulch with 2 neat rows of original mother plants cleaned and neatly trimmed well above the crowns. Yes, Johnny Patterson can be proud, even Orville and Wilbur Wright might be proud to see their propeller "lift" idea used to reduce such back-tiring drudgery in the strawberry fields.

To clean bed sides, I also put the mower on an angle with 2 wheels running in the row middle and 2 wheels running on the bed top. Again, the mower cleaned off the dead runner growth just fine. Enterprising growers could weld or bolt such modified mower decks to a frame to go over each bed, one mower centered over the bed and two mowers trailing it, each on the bed sides, all secured to a frame-mounted 3-pt. Hydraulic tractor lift. One pass over each bed in late winter would clean the beds while the tractor driver gets some rest on the tractor seat. I believe we are another big step closer to showing you the money with carry over plastic mulched strawberries as a 3 crop production system reality for this colder region.

(Source: Commercial Horticulture Newsletter, January-February 1999 http://www.ext.vt.edu/departments/commhort/1999-02/1999-02-03.html )

Anthracnose and Alternaria: At this time fruit diseases can be controlled with applications of Captan. Typically a 10-day spray program should be maintained. Captan will not cure infections that occurred earlier in the season but would protect fruit from new infections. In tests with Aliette in 1998 activity was found against both Anthracnose and Alternaria. These tests show that Aliette can control fruit rots after infection has occurred and will not protect fruit. Therefore application of Aliette as close to harvest as possible will maximize the effectiveness of this material. The best timing for Aliette application is just prior to the second picking. This is still a relatively new material and it should be used with caution. Some fruit discoloration was seen last year, it was not severe but the material should be tested on small blocks using the spray equipment typical for a particular farm initially to determine its impact on quality.

We have seen anthracnose appear on damaged fruit (hail, herbicide or frost). These symptoms are an indication of the incidence of anthracnose in the field. Doing a keeping quality test can also test incidence. However, disease levels will probably remain low until the second picking. To test for keeping quality pints can be removed from the packing line and stored in either the packinghouse or office (i.e. at room temperature). They should be evaluated for the development of symptoms daily. When symptoms (fruit with orange spore masses) appear a count of the infected fruit should be initiated. The infected fruit should be carefully removed each day. Uninfected fruit can remain firm for up to 14 days under these conditions after which time they become soft and wrinkled. Having detailed records on incidence of anthracnose will be useful in upcoming years for planning disease control programs.

Alternaria can be a wound pathogen and will attack fruit that has split, is overripe or is damaged in various ways. The fungus forms airborne spores and is quite common this time of year. Use of spray mixtures that cause wounding (i.e. Captec with either Diazinon or Malathion) can increase the level of infection. In addition, if the period of time between picking is to long the fruit will become overripe and infection will increase. (Source: The Blueberry Bulletin, Vol. 17, No. 12, July 9, 2001)

Picnic Beetles

The picnic beetles belong to a family of beetles know as sap beetles, family Nitidulidae. Even though the name „picnic beetle‰ is not an officially accepted common name, it is commonly used in dealing with these two insects - Glischrochilus quadrisignatus and Glischrochilus fasciatus. The two species are treated together here because they are similar in size and appearance, and cause similar injury to brambles. The name picnic beetle seems appropriate since they are nuisance pests at picnics, being attracted to beer, potato salad, bread, and fruit salad. They have even been known to plunge without hesitation into a jar of pickles.

Damage: Picnic beetles bore into ripe and overripe fruit to feed and lay eggs. Their feeding makes fruit unmarketable, and the beetles themselves become contaminants in harvested fruits. They also introduce fruit-rotting fungi to berries. Late maturing raspberries are more vulnerable to picnic beetle damage than early berries because beetle populations are greatest in late summer and early fall.

Appearance: The picnic beetle is about 1/5 inch long, and black, with four yellow/orange spots on its back. It has knobbed antennae. Other related sap beetles are smaller and brown. The immature form of the picnic beetle is a larva that is white with a brown head; it reaches 1/4 to 3/8 inch long.

Life Cycle and Habits: The picnic beetles overwinter as adults in many types of plant cover near the soil surface. Once temperatures reach 60 to 65 degrees F in the spring, they become active and feed on fungi, pollen, or sap from many kinds of plants. They lay eggs in old corn ears or other decaying matter. Larvae develop in decomposing plant material, then pupate in the soil. New adults emerge in midsummer. There is one generation per year.

Cultural Control: Sanitation is the key to preventing sap beetle infestation. Keep berries off the ground, and practice frequent, complete picking. Remove overripe and damaged berries, and bury culled berries.

Mechanical Control: Use bait buckets filled with overripe fruit; place the buckets outside the fruit planting to trap picnic beetles.

Control by Insecticides: Because picnic beetles are attracted to overripe fruit, infestations usually build up after harvests are underway, and the use of insecticides is precluded by a combination of frequent picking and required preharvest intervals.

Scarab Beetles (order Coleoptera, family Scarabaeidae): Japanese Beetle (Popillia japonica),Rose Chafer (Macrodactylus subspinosus),Green June Beetle (Cotinis nitida)

Damage: Leaves are skeletonized during mid to late summer by Japanese beetles; leaves may also be fed upon in early summer by rose chafers. Ripe berries are destroyed by Japanese beetles and green June beetles. Flower buds are destroyed by rose chafers. Japanese beetle is most troublesome in the first two to three years after a planting is established. Rose chafer is most common in areas with light sandy soil. Green June beetles are most numerous in plantings near sites where manure or compost has been spread.

Appearance: The Japanese beetle is about 1/2 inch long and copper-colored, with metallic green markings and tufts of white hairs on the abdomen. The rose chafer is light brown, 1/2 inch long, and long legged. The green June beetle is 1 inch long, metallic green on top and brown on the sides. Larvae of all are soft white grubs with six legs and a brown head, usually found in a curled position.

Life Cycle and Habits: There is one generation per year of all three of these beetle species. Larvae (or grubs) of these scarab beetles develop in pastures, lawns, and other types of turf, where they live in the soil and feed on roots of grasses. The adults move to raspberry and blackberries to feed on flowers, leaves, and fruit. Rose chafers emerge in May and June; they feed most commonly on the white flowers and foliage of brambles, sometimes destroying flower buds and greatly reducing fruit production. Japanese beetles begin emerging in June and July; they feed on foliage but prefer ripe berries, especially those that are exposed to full sunlight. Green June beetles also emerge in July and they also feed on ripe fruit. Green June beetles are common where manure or compost has been spread, because such soils attract egglaying females and serve as ideal sites for larval development.

Cultural Control: Clean harvesting, which prevents an accumulation of overripe fruit, helps to prevent beetles from being attracted to plantings. Plowing or cultivation can destroy pupae in the soil.

Mechanical Control: For Japanese beetle and rose chafers, traps are available that use a sex attractant and/or feeding attractant to capture the beetles in a can or plastic bag, but such traps may not provide adequate control. Place traps near the planting, but not in the planting, because plants close to a trap may suffer increased localized damage from beetles that are attracted to the trap but not caught by it.

Control by Insecticides: Where immigrations of these beetles occur, insecticide application currently offers the only effective means of control. Preharvest restrictions must be obeyed.

Yellowjacket Damage: Yellowjackets feed on ripe and injured fruit. Their ability to sting and their aggressive behavior make them an annoyance and danger to pickers.

Appearance: There are several species of this group of wasps found in the North Central United States. Yellowjackets are yellow and black wasps that are about 1/2 to one inch long. Whitejackets and baldfaced hornets are close relatives that are black and white. Both are aggressive and nasty stingers.

Life Cycle and Habits: Depending on the species, the yellowjacket builds its nest underground or in old logs, or builds a large paper nest in trees or houses. The workers scavenge food such as caterpillars or other insects, pieces of flesh from dead animals, or ripe or injured fruit. Food is taken back to the nest to feed the larvae. Yellowjackets are attracted to ripe and injured fruit to feed on fluids and sugars, especially in late summer and during dry weather. Populations of yellowjackets peak in late summer.

Cultural Control: Yellowjackets can be discouraged by sanitation (regular and thorough picking of all berries as soon as they begin to ripen and frequent removal of overripe fruit and fruit debris). Do not allow pickers to bring sweet drinks, lunches, or other attractants into the planting.

Mechanical Control: Where yellowjackets are attracted to brambles despite good harvest practices, traps offer the only practical method for reducing problems. The key to trapping success is to get traps out early. Traps should be put up around the perimeter of the planting before the berries begin to ripen. Although commercial traps are marketed for some yellowjackets, these traps do not work for all species. For example, traps that contain heptyl butyrate to attract Vespula pensylvanica, the western yellowjacket, do not attract the German yellowjacket, Paravespula germanica, or several other common species in eastern North America. There are many yellowjacket traps on the market, and various baits such as fish, meat, jam, honey, beer, and yeast have been used with some success. Different baits and traps may have to be tried to determine which combination will work in a particular raspberry planting. Fish traps, made with a fish suspended over a tub of soapy water, can be effective against all species.

Control by Insecticides: Insecticides cannot be used effectively in bramble plantings for yellowjacket control.

Sources: (Ohio Fruit ICM News, Volume 5, No. 24 July 5, 2001)

Midwest Small Fruit Pest Management Handbook http://ohioline.ag.ohiostate.edu/b861/b861_34.html

Brambles-Production, Management, and Marketing http://www.ag.ohiostate.edu/~ohioline/b782/b782_21.html

Week of July 2: Warm weather has been ideal for grapevines. There seems to be plenty of growth this year due to adequate rain. Hedging is in full swing.

Pest Update: Japanese beetle and potato leafhopper populations are low to moderate. No reports of disease problems.

Cluster Thinning: With the season moving very quickly, the time for cluster thinning has arrived. Leaf pulling prior to cluster thinning helps workers see the cluster zone. Follow up frequently with workers to make sure thinning is proceeding as planned.

To thin to a desired yield/acre, you must have an average cluster weight in mind as well as the number of vines per acre. Take for example, a Chardonnay clone that averages 0.33 lbs. in a vineyard with 900 vines/acre with a target of 3 tons/acre.

· 6000 lbs./900 vines = 6.7 lbs./vine

· 6.7 lbs. per vine/0.33 lbs. per cluster = 20 clusters per vine on average

Twenty clusters would be the target number of clusters when thinning. This would be for a healthy vine that is filling the trellis. Undersized vines should not be expected to ripen a full crop unless unripe fruit is a goal. Of course crop is removed from newly planted vines. Resist the temptation to overcrop young vines. Young vines have a natural tendency to set large crops. Leaving an excessive crop on a young vine can set it back substantially particularly in a year with drought or stress from disease. Where this has been done in the research vineyard, crop in subsequent years has sometimes been light.

Large clustered Chardonnay clones at the research vineyard average 0.40-0.45 lbs./cluster. Smaller clustered clones range from 0.30-0.40 lbs./cluster. Merlot clones usually range from 0.30-0.42 while Cabernet Sauvignon clones usually range from 0.20-0.30. Admittedly, set in Cabernet has been problematic in this vineyard over the last few years. When estimating cluster weights, factor in the amount of set as well as berry size. For example, in 1999 where there was a fair amount of rain August-September, berries were on the large side, thus cluster weights were up.

At the research vineyard, we first go through and remove all clusters from shoots <18"; on 18-30" shoots, we leave one cluster; >30" and of sufficient diameter, we might leave two clusters. We never leave three clusters on a shoot. If our target cluster number has still not been met, we thin out crowded areas (for example, where two vines meet often there is a big mass of clusters), thin diseased or damaged clusters or clusters with poor set.

Thinning now is the best choice if the goal is to allow the vine to properly mature a specified crop load. Thinning at veraison can also be done though there are mixed opinions on whether quality improves substantially. Certainly if the vine is overcropped, quality will improve after a veraison thinning. Some feel that excess vine vigor can be tamed by delaying thinning until veraison. While this may help out, management of excessive vine vigor should be addressed via other vineyard management strategies. We thin at veraison if we made mistakes in our earlier thinning or if we see fruit struggling through veraison. This has happened with a few of the Pinot Noir clones as well as some of the late ripening varieties like Grenache. In cool years, thinning at veraison has been utilized quite a bit especially for late ripening red varieties. (Source: Long Island Fruit & Vegetable Update, No. 18, July 6, 2001)

It is approaching time to collect tissue samples for analysis of plant nutrient levels. Tissue analysis is a valuable and often underutilized tool in fruit nutrition programs. Results of nutrient analyses provide a means of accurately identifying nutritional problems that are difficult to diagnose by soil testing or observing plant appearance. More importantly, growers can identify and correct potential nutrient shortages before growth or yield is affected.

Start dividing the farm into uniform sampling units based on differences in soil types, past fertilization or management practices, or varieties. If these factors are generally uniform, designate sampling units of up to ten acres each. Although more samples will be required for farms on variable soils, more samples will provide a more accurate picture of the nutritional health over the farm. For routine monitoring, sample every two to four years. On larger farms, different blocks may be sampled during successive years on a two to four-year cycle.

To diagnose a suspected nutritional problem, two samples are often useful. Collect one from plants beginning to develop the problem and a second from nearby healthy plants.

The proper sampling time is between mid-July (southern Michigan) and mid-August (northern areas). For grapes, sampling should coincide with veraison. Samples from orchards and blueberry, raspberry and strawberry plantings should consist of 50 to 100 leaves collected from different plants throughout the sampling area. Collect full-sized leaves from the middle of current-season shoots, not spur leaves. If leaves do not detach readily when pulled in a downward direction, wait a week or two and try again. In raspberries, collect leaves only from primocanes (current season canes). For grapes, collect only the petioles (stems) of the most recently matured leaves. Concord leaves turn tan on the underside as they mature. Wash the tissues by swirling them in a dilute detergent solution for several seconds, then rinse briefly in tap water. Let samples air-dry on a table top for a day or two before sending them to the lab -- wet or moist leaves will rot during shipping.

Labs may offer analysis of single nutrients, such as nitrogen, but the cost of complete analyses is usually not that much more. The MSU Soil and Plant Nutrient Lab (517-355-0218) will analyze samples and provide an interpretive report for $23.00 (complete analysis), $10.00 (nitrogen only) or $16.00 (all nutrients except nitrogen). Send samples to the Soil and Plant Nutrient Lab, A84 PSSB, MSU, East Lansing, MI 48824. (Source: Fruit Crop Advisory Team Alert, Vol. 16, No. 14, July 10, 2001)

COMMON ARMYWORM ALERT - John Howell and Pam Westgate, UMass Extension

Crop Conditions and Pest Summary

Strawberry

Mechanically Cleaning Carry-over Strawberries – Charlie O'Dell, Virginia Tech

Highbush Blueberry

Disease Update from New Jersey – Peter Oudemans, Rutgers University

Brambles

Raspberry Fruit and Flower Pests – Ted W. Gastier, Ohio State University

Grapes

Long Island Grape Update – Alice Wise, Cornell University

General

Tissue Sampling for Nutrient Analysis– Eric Hanson, Michigan State Univ.

Meetings