CHEMICAL CONTROL OF Diabrotica spp. LARVAE DAMAGING MAIZE UNDER NO-TILLAGE SYSTEM

Abstract

The objective of this study was to evaluate the efficacy of insecticides applicationto control the corn rootworm, Diabrotica spp., on no-till corn. Field trials were conducted ateight locations in Ponta Grossa, PR, during two years. The treatments used in plots weredifferent insecticides and application methods. The experimental design was a randomizedcomplete block replicated four times. To evaluate the effect of insecticides, soil samples of20 x 20 x 20 cm were taken around the corn plants and examined to recover rootworm larvae.Root systems were evaluated for rootworm damage using a 1-6 visual scale. Also, wereevaluated stand, percentage of plants with symptoms and grain yield. The insecticideschlorpyrifos 10 G, terbufos 50 G, tebupirimfos 20 G, fipronil 20 G, and chlorpyrifos 450 SCe 480 EC applied in furrow provided the best larvae control. Seed treatment with thiodicarb,fipronil, imidacloprid, furathiocarb and fipronil+thiodicarb showed low efficiency to larval control.Insecticides application prevented root damage and yield loss (54%).

Keywords

• insecta
• insecticide
• soil insect
• corn rootworm
• Zea mays