This year, soybean aphids have the potential to reach population densities that exceed the economic threshold of 250 aphids per plant. It is likely that insecticides will be applied to many soybean fields to prevent yield loss.
Pyrethroid-Resistant Soybean Aphids
For the last two years, researchers in Minnesota have reported failures of insecticides with pyrethroid active ingredients for soybean aphid management. The areas where these pyrethroid resistant soybean aphids have been detected are not localized. Furthermore, pyrethroid resistant soybean aphids were observed in Northwest Iowa in 2016. Although we have no reported insecticide failures in South Dakota, there is the potential for this to occur.
Although pyrethroids offer the most economical form of management for the soybean aphid in terms of foliar insecticides, there are alternatives. These include insecticides that contain organophosphates, carbamates, or neonicotinoids as the active ingredient. These products can be found in the current edition of the South Dakota Pest Management Guide: Soybeans. In addition, two products that belong to the group butenolides (4D) have also been labeled for use against soybean aphids in soybean. The active ingredient for these products is flupyradifurone. Table 1 contains the information for these products and recommended rates for soybean aphid management.
Table 1. Addendum to 2017 Pest Management Guide: Soybean
|Product Name||Active Ingredient||Managed Pest||Rate||Pre-harvest Interval|
|Sivanto 200 SL||Flupyradifurone||Soybean aphid||7-10.5 fl oz/A||7 days|
|Sivanto Prime||Flupyradifurone||Soybean aphid||7-14 fl oz/A||7 days|