Using planting date to manage bean pod mottle virus in soybean

Delayed planting has been suggested to reduce density of the bean leaf beetle (Cerotoma trifurcata (Forster)), the principal vector of Bean pod mottle virus. Therefore, planting date was explored to determine if it might impact damage caused by the virus. Four planting dates, ranging from mid-March to mid-June, and two soybean (Glycine max (L.)) cultivars were examined for their effect on the relative damage caused by the virus in central Iowa for the years 2000-2002. Damage was assessed in terms of seed coat mottling, pod number, and yield loss. In 2000, the third planting date resulted in improved yield and seed quality compared to the other three dates. In 2001 and 2002, however, planting date had minimal impact. Therefore, the practice of delayed planting, under the conditions of these experiments, is not a consistently effective management tactic for controlling disease caused by this virus. The data also demonstrated that seed coat mottling, which can result in financial penalties to producers, was unreliable for predicting relative amounts of virus in seed.