Efficacy of insecticides and crop critical stage for the management of chickpea pod borer (Helicoverpa armigera) in Central Zone of Tigray, Ethiopia

摘要

Chickpea pod borer (Helicoverpa armigera) is a major insect pest constraining chickpea production in Tigray, northern Ethiopia, as there is no recommended management option in the area. Therefore the present study was conducted to assess the efficacy of insecticides and to determine the critical growth stage of the crop for effective spray at Axum Agricultural Research Center. Results indicated that in laboratory profit 72% EC (profenofos), abema 3% EC (abamectin 20 g/L + emamectin benzoit 10 g/L), perfecto (imedachloprid + lambda-cyhalothrin) and hamectin (abamectin) reduced the number of larvae by 75, 55, 44 and 34%; 86, 82, 65, 56% and 83, 83, 66 and 83% at 24, 48 and 72 h after spray, respectively. Similarly abema 3%EC and profit (Profenofos) 72% EC were the most effective insecticides to give high mortality of pod borer on chickpea under field conditions. These insecticides reduced the number of larva per plant by 51 to 56.7% five days after spray. The number of damaged pods per plant was very low in both insecticides (0.91 and 1.05) but on the untreated check 3.05. The highest yield was also obtained from chickpea treated with abema 3%EC at podding stage (23.92 qt/ha). Comparatively the most effective insecticides against pod borer were abema and profit and the best application time were at podding stage of the crop. Thus chickpea growers in the area should prefer these insecticides for better pod borer management.