|
|
|
Soybeans
Volume 57 Number 20 Date 08/30/2012 SOYBEAN APHID - The annual survey documented the lowest densities in the history of soybean aphid in Wisconsin. Examination of 161 soybean fields once in July and again in August found an exceptionally low state average of only three aphids per plant during the July portion of the survey and a count of seven per plant this month. The previous lowest state average was 11 aphids per plant in 2004. Probable explanations for the scarcity of aphids this year include intense heat and extensive chemical treatment of fields for two-spotted spider mites, which also reduced aphid numbers. WHITEFLIES - Populations remain unusually high in west-central fields. Counts of 5-53 per leaf were noted in the Alma area of Buffalo County and at a few sites in Monroe and Trempealeau counties. This common pest of greenhouse plants and commercial vegetables has been abundant in western Wisconsin soybeans this summer. Levels elsewhere in the state generally have been low. GREEN CLOVERWORM - Larval counts have increased to moderate levels in a small number of fields since early August, but are low in most areas. Many soybean fields are beyond the point where yield loss is likely. JAPANESE BEETLE - Adults continue to be active and fairly common in soybeans. Defoliation has not exceeded economic thresholds and control has been unjustified for most fields this season. The heaviest infestations of the year in soybeans were noted in Chippewa and Eau Claire counties earlier this month. --Krista Hamilton, DATCP Entomologist 
|
|