SEASONAL INCIDENCE AND MANAGEMENT OF MAJOR INSECT PESTS OF CABBAGE (Brassica oleracea var. capitata L.)
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Date
2023
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Birsa Agricultural University, Ranchi
Abstract
Cabbage, Brassica oleracea var. capitata (L.) is most commonly grown cole crop in Jharkhand. Cabbage, like other cole crops, is attacked by wide range of pests right from germination to harvest; among them the diamondback moth, aphid and cabbage semilooper, are responsible for appreciable losses of cabbage. The current study, "Seasonal incidence and management of major insect pests of cabbage (Brassica oleracea var. capitata L.)," was carried out at the Vegetable Research Area of the Department of Horticulture, Birsa Agricultural University, Ranchi, Jharkhand, during Rabi, 2021-22, to observe the diversity of insect pests and natural enemies, seasonal incidence of major pests in relation to important weather parameters, and to assess the bio-efficacy of some safer synthetic insecticides against major pests of cabbage. Based on the findings, ten species of insect pests and four species of natural enemies were observed on cabbage (Var. "Golden Acre") during the experiment period. The diversity study at different growth stages of cabbage indicated that the highest species richness of insect pests was recorded during the seedling stage, while the highest diversity and evenness were found during the heading stage. In the case of natural enemies, the seedling stage recorded the highest species richness, while diversity was highest during the pre-heading stage and evenness was highest during the heading stage.The incidence of cabbage aphid, diamondback moth and cabbage semilooper started in the first week of December (48th SMW) which gradually increased and reached its peak population in the 2nd, 7th and 6th SMW, respectively. The correlation analysis revealed that the aphid population had significant negative correlation with maximum temperatures and sunshine hour, and significant positive correlation with rainfall whereas the populations of diamondback moth and cabbage semilooper had significant negative correlation with maximum temperature. The bio-efficacy of synthetic insecticides such as Chlorantraniliprole 18.5%SC, Difenthiuron 50%WP, Emamectin benzoate 5%SG, Fipronil 5%SC, Flubendiamide 39.35%SC, Pyridalyl (10% EC), and Spinosd (45% SC) against major insect pests of cabbage revealed thatDifenthiuron 50%WP and Fipronil 5%SC wererecorded the most effective insecticides in reducing the aphid populations whereas, the application of Pyridalyl (10% EC) and Spinosd (45% SC) recorded the most effective insecticides against the larval populations of diamondback moth and cabbage semilooper. The treatment Pyridalyl 10%EC also recorded the highest yield (224.71 q ha-1), highest increase in yield over control (42.15 %) and highest benefit-cost ratio (19.2:1).