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Soybeans
Volume 57 Number 9 Date 06/07/2012 SOYBEAN APHID - Extremely low numbers of aphids were detected in 3 of 21 soybean fields (VC-V2 stages) sampled in the past week. In Columbia and La Crosse counties, 1-2% of the plants had very low densities of 1-3 aphids per infested plant. Eighteen other fields sampled in Columbia, Green, Jackson, Monroe and Trempealeau counties had no detectable population. BEAN LEAF BEETLE - Defoliation is evident in the southern and west-central counties. Less than 12% of soybean plants were affected in Columbia, Jackson, La Crosse, Monroe and Trempealeau County fields and surveys yielded no more than 1-2 adults per 50 feet of row. Two fields in Green County 25% plants with minor leaf injury. Treatment is justifiable at about 40% defoliation or 39 beetles per foot of row during the vegetative stages. ROSE CHAFER - Light defoliation caused by this insect was observed this week in soybeans in Juneau, La Crosse and Monroe counties. Currently the damage involves fewer than 10% of plants. Beetles have also been noted on a variety of ornamental and garden plants in Adams, La Crosse and Sauk counties since late May. Activity and leaf skeletonization should increase over the next 2-3 weeks, especially in the sandier areas of the state. GREEN CLOVERWORM - Larvae of various maturities were collected at the rate of 1-7 per 10 sweeps in Columbia and La Crosse counties this week. The presence of relatively high numbers in alfalfa may be an indicator of potential problems for soybeans later this season. --Krista Hamilton, DATCP Entomologist 
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