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Community Education > Insect Management in PeppersBy Ruth Hazzard Introduction Peppers are grown for fresh market and processing in Massachusetts. Whatever the market, pepper fruit must be free of insect damage or infestation. The three key insect pests of peppers in Massachusetts are green peach aphid, pepper maggot fly and European corn borer. European corn borer is the most widespread and most damaging of these. This fact sheet reviews identification, monitoring and management methods for these three pests. Aphids Aphids fly into peppers in June and July. The most common species is green peach aphid, which is light green, yellow green, or pink, with no distinctive marks. Wingless females feed on the underside of leaves, and give birth to tiny nymphs which look just like them. Most of the time, predators such as ladybeetles and lacewings, and aphid parasites, keep aphid numbers under control in peppers. Aphids may build up after broad-spectrum insecticides are used for pepper maggot or European corn borer. In some cases, aphids can vector viruses such as cucumber mosaic virus. Insecticides are not effective in controlling this because the transmission occurs rapidly at low population numbers. Reflective mulches can be used to reduce virus transmission. The silver surface deters aphids from landing on pepper. Monitoring: examine the underside of four leaves per plant on 25 plants. Count aphids found. Calculate the average aphids per leaf (divide total by 100). Threshold: 10 per leaf. See New England Vegetable Management Guide for recommended materials. Pepper Maggot Fly This small fly, which is closely related to the apple maggot fly, has one generation per year. Adults emerge in mid to late July and are active for several weeks. Pepper maggot flies are bright yellow with three yellow stripes on the thorax, green eyes, and clear wings with a distinct banding pattern (see drawing). Females insert their eggs directly into the pepper fruit. The legless white maggots feed and tunnel inside the fruit, especially in the placenta. When they are ready to pupate, they usually exit at the blossom end, leaving tiny round exit holes. These holes allow for the entry of pathogens in to the fruit. Sometimes the oval brown pupae can be found inside the fruit. Often damage is detected only because of premature ripening or decay of the fruit. Monitoring: Yellow apple maggot sticky traps baited with a vial of strong ammonia are the most effective traps. Placement is important. The best capture rate occurs when traps are placed up in trees near the field; a more practical but less effective site is in on a 4-foot stake at the field border. Threshold: If one fly is captured, begin a series of 2 treatments, about 2 weeks apart, with a material labeled for pepper maggot (such as Dimethoate™ or Thiodan™). Neem (Neemix ™) is currently being evaluated at the University of Connecticut as an alternative to broad-spectrum materials. This material is derived from the tropical neem tree and acts as an oviposition deterrent as well as a toxin. Pepper maggot fly is particularly active in some regions and on some farms in the state. Many farms never have a problem with this pest. If a given farm has a history of pepper maggot activity, and pepper maggot fly has been captured in the region, then it is recommended that an insecticide be applied on that farm. However, farms that have never had a problem with this pest generally do not need to be concerned. European corn borer Only the second generation of European corn borer damages pepper fruit. In Massachusetts, this flight generally begins the last week of July. Moths lay flat, white egg masses on the underside of leaves. Eggs hatch in 4-9 days, depending on temperature. European corn borer caterpillars (larvae) are whitish or gray with a pattern of dark spots and a black or dark brown head. This dark head capsule distinguishes them from pepper maggots, which are completely white. Larvae usually enter the fruit by tunneling under the cap. They leave a pile of light brown frass on the surface. Often this is the only indication that a pepper is infested until two or three weeks after the borer enters, when bacterial soft rot causes the fruit to decay. After harvest, growers often know that fruit is infested because it sinks in the wash tub. Monitoring: Flight is detected by placing two white nylon mesh Heliothis Scentry ™ traps, with the base at weed height, in weedy areas near pepper fields. Traps should be placed 50-100 feet apart. One is baited with a lure for the Iowa strain (Z I) and the other with a lure for the New York strain (E II) of ECB. Both of the these strains exist throughout Massachusetts. Check traps weekly or twice a week from the third week of July on. Threshold: Insecticide applications should begin one week after trap counts reach 7 per week (or one per night). The actual risk of borers entering fruit begins after eggs have been laid and begin to hatch, which takes at least a week after flight begins. During the time that ECB moths are active (the second flight usually lasts through August), a regular schedule of insecticide applications should be maintained. When trap captures drop below 20 per week, insecticides should no longer be needed. The intervals recommended for insecticide applications depend on the material used. Acephate (Othene™, 7 dh) can be used at 10-day intervals; synthetic pyrethroids (Asana™, 7 dh or Ambush™ or Pounce™, 3 dh) at 7-day intervals; and Bt products (Mattch ™, Cutlass™, Javelin™, 0 dh) twice weekly. Days to harvest restrictions often dictate choice of material. Some pepper varieties, especially hot varieties, appear to have some resistance to ECB. Research is currently underway at UMass. to learn more about the importance of fruit shape, cuticle thickness and capsaicin content (hotness) for ECB damage. We are also evaluating a biointensive IPM system that includes use of Bt sprays and release of Trichogramma ostriniae, wasps that parasitize ECB egg masses. University of Massachusetts Extension Selected IPM Articles: |
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