Ação do insecticida tiametoxame aplicado às sementes na emergência e vigor de plântulas de Vigna unguiculata (L.) Walp

Abstract

The aim of this study was to evaluate the effects of thiamethoxam on the emergence and vigor of cowpea seedlings. The cowpea seeds, cv. ‘Nova era’, were treated with the active ingredient thiamethoxam at dosages of 0.07; 0.14; 0.21; 0.28 e 0.35 g a.i. L‑1. The experimental design used was a randomized block in factorial 2 × 2 × 6, where the first factor were lots of seasons 2013/2014 and 2014/2015, the second factor the two sowing seasons, summer and winter, and the third factor the doses of thiamethoxam. The parameters evaluated were: Percentage emergency, emergency speed index, shoot length and seedling root, and dry weight of shoot and seedling root. There was interaction between the lots and the sowing for the dry mass variable of shoot and root and between doses and the time of planting to emergence and emergence speed index. The insecticide thiamethoxam stimulates the physiological performance of cowpea seeds, occurring positive effects on growth and assimilation of dry matter by the roots, and better initial performance and uniform establishment of seedlings in the winter.