Insecticides effect against soil stink bugs (Scaptocoris castanea) Perty (Hemiptera: Cydnidae) e seu efeito no desenvolvimento e na produtividade da cultura do milho

Abstract

Due the lack of registered products for Scaptocoris castanea, new insecticides need to be developed in order to facilitate growing crops in these heavy soil pests’ areas. The aim of these studies were to evaluate the performance of insecticides applied at the sowing time (in furrow spray) and in seed treatment for soil brown stink bug control (S. castanea) and their effect over the plant development and productivity in corn crop in two locations in Goiás State. The treatments were: Untreated check, Durivo (chlorantraniliprole + thiamethoxam) at 100, 200 and 300 mL of comercial product/ha applied in furrow, Cruiser 350 FS (thiamethoxam) in seed treatment at 120 mL/ha + Durivo (chlorantraniliprole + thiamethoxam) 200 mL/ha in furrow spray and Cropstar (Imidacloprid + thiodicarb) in seed treatment at 300 mL/ha + Astro (clorpyryfos) in furrow spray at 1500 mL/ha (standard). The trials were carried out in Edéia and Rio Verde, in Goiás State (areas with heavy pressure of S. castanea). Trial design was randomized block with six treatments and four replicates. The plot size was five rows with 45 cm as row spacing by seven meters length. The results demonstrated that Durivo (chlorantraniliprole + thiamethoxam) at 300 mL/ha in furrow spray and the combination of Cruiser 350 FS (thiamethoxam) at 120 mL/ha + Durivo (chlorantraniliprole + thiamethoxam) at 200 mL/ha have been effective for the S. castanea control in both trials (Edéia and Rio Verde) showing average control around 71% at 14 days after emergence, and increments of 110% in stand, 56% in plant height, 70% in root dry matter contents, 52% in aereal part dry matter contents and around 71% of yield increase. The data has shown significant correlation (R2>0.8) for all parameter assessed in Edéia, where there was higher pest pressure. Durivo (Chlorantraniliprole + thiamethoxam) presents itself as an important tool, within S. castanea IPM concept due the effectiveness, low dose per hectare, favorable toxicological profile and it is registered for this pest control and application method.