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Vegetables
Volume 59 Number 13 Date 07/31/2014 SQUASH BUG - Economic counts of 3-4 egg masses per plant were observed this week on squash in a Vernon County home garden, where a few plants had been killed by a combination of this insect and the striped cucumber beetle. Continued scouting of lower leaf surfaces for eggs is strongly recommended and controls should be implemented for flowering plants when a threshold of more than one egg mass per plant is detected. If not controlled at this time, plant damage and yield loss will result. Pyrethroid products are most effective against the small, newly-hatched nymphs while the larger adults are more difficult to control. GARDEN FLEAHOPPER - This common vegetable pest, which resembles flea beetles or black aphids, is reportedly yellowing lettuce and cucumber foliage in a Dane County garden. Counts are moderate at 2-3 per leaf, but even low numbers of adults and nymphs can cause stippling, and the deposition of black spots of fecal material on plants detracts from vegetable appearance and marketability. Extensive feeding may stunt plant growth and reduce yield. Suppression is easily accomplished with appropriate conventional or organic insecticides. Destruction of morning glory, quickweed, clover and other weedy hosts near cultivated areas will help eliminate sources of infestation. IMPORTED CABBAGEWORM - Moths are common around home gardens from Grant to Marathon County, indicating the potential for damaging larval populations next month. Egg deposition on cole crops is expected to intensify by early August. Scouting is advised through harvest. COLORADO POTATO BEETLE - Second generation larvae are appearing in potatoes in the southern and west-central areas. Late-season control of this pest may be warranted if defoliation exceeds 30% during tuber formation. Treatments should be applied when most of the population reaches the intermediate third instar stage, presuming this does not conflict with label recommendations or resistance management. Proper timing permits most eggs to hatch, but kills the larvae before they reach the destructive fourth instar. Potato producers are reminded to avoid consecutive use of the same insecticide product or use of different products with similar modes of action. STRIPED CUCUMBER BEETLE - Home gardeners in the southwest and west-central areas are reporting severe damage to cucurbits. Counts were high as 7-8 beetles per plant in a Vernon County garden this week. Treatment is justified for infestations of 4-5 beetles per 50 plants. CORN EARWORM - Counts have been very low at less than 19 per trap per week since migrants began arriving in pheromone traps three weeks ago. The primary migration has apparently not yet started. -- Krista Hamilton, DATCP Entomologist 
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