Volume 63 Number 6 Date 06/07/2018
SOYBEAN APHID - Surveys of VC-V2 soybeans found aphids in six of 25 (24%) fields sampled during the reporting period ending June 5. Densities ranged from 1-2 aphids per infested plant on 1-8% of plants, based on 100 plants examined per field. Specific counties where the aphids were detected were Grant, Iowa, Lafayette and La Crosse. These observations confirm that aphids are dispersing to soybeans.
BEAN LEAF BEETLE - Light defoliation was observed at 60% of sites surveyed in the south-central and southwest counties. Fewer than 15% of the plants were affected in most fields and beetle counts were very low. Chemical control of this pest during the soybean vegetative stages should be considered only if field-wide defoliation levels exceed 40% or if populations of 39 or more beetles per foot of row are observed. Economic soybean damage directly resulting from bean leaf beetle feeding is rare in Wisconsin.
ROSE CHAFER - This defoliator was noted on field crops and in gardens in the past week. The larval stages of the rose chafer are white grubs that feed on the roots of grasses and weeds. Adult emergence and defoliation are expected to increase next week and peak by late June, particularly in areas of the state with sandy soils.
-- Krista Hamilton, DATCP Entomologist