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Soybeans
Volume 57 Number 12 Date 06/28/2012 SOYBEAN APHID - Colonies have become slightly more common in soybeans, but densities remain extremely low. Surveys this week found populations of only 1-3 aphids per infested plant in 11 of 60 (18%) fields examined. All soybean fields should be checked for aphids next week and consistently throughout July and August. JAPANESE BEETLE - Minor defoliation was encountered in soybeans in Dane, Monroe, Richland and Vernon counties. The incidence of leaf feeding is increasing as more beetles emerge, but severity is low. Densities of beetles can vary greatly between the field interior and border rows, emphasizing the importance of thorough inspection of all areas of corn and soybean fields before making control decisions. In most instances, soybeans can tolerate substantial defoliation without reduction in yield potential, although a rescue treatment may be warranted if defoliation levels exceed 30% prior to bloom and 20% between bloom and pod fill. TWO-SPOTTED SPIDER MITE - Symptoms are appearing in a few fields in the southern and central areas, indicating that growers should begin monitoring soybeans at 4- to 5-day intervals for the characteristic bronzing and stippling associated with early mite infestation. Soybean fields in the abnormally dry southern half of the state are particularly susceptible to infestation this season. Mite populations could explode during bloom if the dryness continues. --Krista Hamilton, DATCP Entomologist 
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