Determination of Crop Losses, Economic Threshold Level and Management of Spotted Pod Borer, Maruca vitrata (Fabricius) in Pigeonpea
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Date
2017
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Punjab Agricultural University, Ludhiana
Abstract
Field studies were conducted during kharif 2016 to determine the crop losses, to establish economic threshold level (ETL) and to evaluate the efficacy of some novel insecticides for the management of Maruca vitrata in pigeonpea. Using insect density method for estimating the avoidable yield losses due to M. vitrata in pigeonpea var. PAU 881, highest avoidable yield loss of 79.05 per cent was recorded in the treatment with eight larvae per plant as compared to the uninfested control. The correlation coefficients for the larval infestation level and the pod damage as well as seed damage were significantly positive. However, significantly negative correlation was observed between larval infestation level per plant and seed yield as well as with 100 seed weight. On the basis of chemical protection method, avoidable losses due to M. vitrata in two indeterminate varieties (PAU 881 and AL 201) and two determinate varieties (AL 15 and MN-1) of pigeonpea varied from 39.55-84.68 per cent, with the determinate var. MN-1 registering the highest (84.68%) avoidable loss and the lowest (39.55%) in the indeterminate var. PAU 881. On the basis of regression analysis and gain threshold, the EIL and ETL were computed to be 5.58 and 4.19 webs per plant, respectively. Among the different novel insecticides evaluated for their bio-efficacy against M. vitrata in pigeonpea, the treatment comprising chlorantraniliprole 18.5 SC @ 30 g a.i ha-1 was found to be significantly superior over all other treatments as well as untreated control. Results of the study revealed that significantly lowest pod damage (7.22%), highest seed yield (1278 kg ha-1) and maximum net monetary returns over control (Rs. 22,020 ha-1) were obtained in the treatment chlorantraniliprole 18.5 SC @ 30 g a.i ha-1. The next best treatments were indoxacarb 14.5 SC @ 73 g a.i ha-1 and flubendamide 480 SC @ 48 g a.i ha-1. Studies also revealed that all the insecticidal treatments were relatively safer to the natural enemies at their respective dosage.
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