Bioefficacy of Emamectin Benzoate against American Bollworm, Helicoverpa armigera Under Field Conditions. الفعالية الحيوية لمبيد إيمامکتين بنزوات ضد دودة اللوز الأمريکية بمحصول القطن تحت الظروف الحقلية

Abstract

American bollworm, Helicoverpa armigera is the foremost insect that negatively affected cotton crops around the world. A field experiment was conducted at the Sedi-Salem area, Kafr El-Sheikh Governorate,Egypt to assess the bioefficacy of emamectin benzoate 5 SG(EB)on cotton against H. armigera.The tested pesticides were used as a foliar application under field conditions at the2019-2020season.The experiment was designed in plots of 5 m × 5 m size using a randomized block design (RBD) with seven different treatments.A pneumatic knapsack sprayer was used for foliar application of tested pesticides. Three doses of EB @ 7, 11, and 15 g a.i./ha were evaluated against the pest under study. Furthermore, endosulfan 35 EC, Proclaim®, Spinosad 45 SC, and an untreated blank were also included in the field experiment. The findings concluded that 11 g a.i./ha of EB was the active dose for controlling the larval population of H. armigera.This dose caused a 64.75% reduction of boll damageover an untreated check at the end of observation in the field experiment.The yield ranged from 16.00 to 19.66 q/ha in all treatments.EB at 15 g a.i./ha was a very effective dose which was on par with the final results of 11 g a.i./ha.Entirely EB treatments augmented seed cotton yield under field conditions as compared to the control plot. The study demonstrates the potentiality of EB as an eco-friendly bioinsecticide against the American bollworm.The effective doses of EB @ 11and 15 g a.i./ha should be used in the cotton field to manage the infestation of H. armigera.