In Summary:
1. Cobalt is still an effective pesticide against spider mites and provides adequate control in South Dakota;
2. Continuous use of the same pesticides increases the rate of resistance development, and rotating modes of action of pesticides used in soybeans is important in integrated pest management and insect resistance management.

Given the growing concern over spider mite resistance to chemicals that have been used in soybeans intensively, it is important for producers to know which pesticides from different classes are still effective. There are new pesticides with a long residual activity and high effectiveness that may be available to producers in the future and we already have data confirming their efficacy in South Dakota.

As with all field research, data collected over a one-year study is limited in scope, and we are continuing this work this year, with the support of the South Dakota Soybean Council funding, as well as other funding sources. At the completion of this multi-year project, we will be able to provide soybean producers in South Dakota with research-based recommendations for managing spider mites on soybeans supported by data collected in the state. Fuller Objectives

Insecticide efficacy trials for soybean insect pests:
In the summer of 2012, the Fuller program planted an aphid foliar insecticide trial designed to test 16 different product/rate combinations. Because of extremely low aphid levels last summer, plots did not reach a point where they could be treated. Instead, for the rest of the funding period the Fuller program provided support and assistance for the other objectives in the project. In spring and early summer the program prepared and planted a new field trial for the summer of 2013. This trial is to test a number of seed treatment and foliar products against both early season soybean pests, and later season pests. The results will be published in an outreach-friendly format as iGrow bulletins.