Corn Stand and Yield Loss from Seedling Injury by Southern Corn Rootworm (Coleoptera: Chrysomelidae)

ABSTRACT Southern corn rootworm, Diabrotica undecimpunctata howardi Barber, can cause severe stand loss in reduced tillage corn after a vetch cover crop. Trials conducted over 3 yr found that clothianidin and thiamethoxam neonicotinoid seed treatments and conventional granular insecticides applied in-furrow or as a T-band were very effective against southern corn rootworm. Treatments were categorized as no control (untreated), partial control, and full control based on the extent of seedling injury. In 2 yr, damaged plants were individually marked and their survival, tiller (i.e., secondary stem) production, and ear and grain weight measured. About one-half of plants injured by larvae produced a tiller, with most plants producing tillers within 30 d after planting. All dead-hearted plants not producing a tiller died and were not evident by mid-season. In no control plots with severe damage, healthy plants produced more ears per plant and secondarily more grain weight per plant than healthy plants in full ...