An IPM approach to Isopod control in no-till soybean

The benefits of no-till or reduced tillage practices have been well demonstrated. Unfortunately, significant changes in an agroecosystem may promote unanticipated pest problems. For example, moist microhabitats created by increased crop residue in no-till fields may provide the protection necessary for background organisms to reach pest status. In recent years, pillbugs and sowbugs (Malacostraca: Isopoda) have become a recurrent, early-season problem throughout reduced and no- till production soybean fields in south central Kansas. The succulent stem tissue below the cotyledons of germinating soybean seedlings is susceptible to isopod herbivory and this type of damage results in the compete destruction of the growing plant. Under intense isopod pressure, soybean growers must replant fields multiple times to establish a harvestable stand. Effective integrated pest management (IPM) strategies for isopod damage in soybean are not known. The objectives of this study were to evaluate potential control tactics for reducing isopod damage. In 2009 and 2010, several field experiments were conducted to determine the effects of various control strategies (i.e., residue destruction, planting date, insecticide rate, seeding rate) on the emergence of soybean in no-till production fields with a history of isopod damage near Lindsborg, KS. In both years and at multiple locations, residue removal was most effective at controlling isopod damage. Implications of our results to soybean growers as well as long-term impacts of select strategies in no-till systems will be discussed.