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Looking Ahead
Volume 61 Number 13 Date 07/28/2016 WESTERN BEAN CUTWORM - Moth counts have peaked at most southern and central monitoring sites. The cumulative state total as of July 27 is 1,185 moths in 75 pheromone traps, which is an increase from last year's count of 644 moths but still low in comparison to the numbers documented from 2007-2012, when flights of 2,200-10,800 moths were recorded. Preliminary results of the 2016 annual trapping survey are summarized in the map on page 91. SOYBEAN APHID - Monitoring efforts should be increased in all areas of the state as more fields enter the pod-setting stages. DATCP surveys indicate average densities are low at fewer than 35 aphids per plant, though individual fields could develop economic populations early next month. Foliar treatment is not recommended until soybean fields have been thoroughly sampled to determine if the established threshold of 250 aphids per plant on 80% of the plants has been exceeded. SPOTTED WING DROSOPHILA - Emergence has surged since mid-July and is expected to intensify in August. Inspecting fruits for larvae, installing exclusion netting, and maintaining protective insecticide coverage are all important measures for protecting berry crops from SWD at this time. Chemical spray programs, alternating at least three different materials (different modes of action), should be initiated as fruit begins to color and continue every 4-5 days through harvest, with consideration of pre-harvest and reentry intervals. Chilling berries immediately after harvest to 34°-36° F is recommended to slow development of larvae and eggs in fruits that may be infested. CORN EARWORM - Migrants arrived in very low numbers for the third week. Although the monthly total count of only 20 moths at 18 pheromone trap locations signals a low risk of earworm infestation as of late July, scouting of silking cornfields should be increased. Monitoring network participants are reminded to replace lures on a weekly basis. JAPANESE BEETLE - Reports suggest that these beetles are more abundant than in the previous 6-7 years, and significant damage is occurring in some apple orchards, nurseries and vineyards. Continued weekly scouting is advised in August for apples, corn, grapes, soybeans, and all other susceptible crops as long as beetles are present. EUROPEAN CORN BORER - The treatment window for second-generation larvae has opened across southern and central Wisconsin with the accumulation of 1,550 degree days (modified base 50°F). Susceptible corn should be inspected next week for egg masses and small larvae. Chemical control directed against early-instar corn borers will remain an option until 2,100 degree days have been surpassed, or for approximately 2-3 weeks under normal August temperatures. -- Krista Hamilton, DATCP Entomologist 
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