Assessment of avoidable yield losses in crop brassicas by insect-pests

Abstract

A five years’ field study was carried out to assess the avoidable yield losses in Brassica juncea and B. rapa due to insect-pests from 2011-12 to 2015-16 crop seasons at the Oilseeds Research Farm of Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, India. The experiment was laid out in a randomized block design with three replications and two sets viz. protected and unprotected. The protected set was sprayed with thiamethoxam 25 WG @ 100 g ha-1 and dichlorvos 85 SL @ 500 ml ha-1 against mustard aphid and cabbage caterpillar, respectively. Data on the insect-pests were recorded at weekly intervals while yield data were recorded at harvest. The loss in seed yield due to mustard aphid and cabbage caterpillar infestation varied from 18.3 to 24.5 per cent. The two B. juncea varieties NRCDR 2 and PBR 91 suffered about 24 per cent yield loss and harboured significantly higher mustard aphid and cabbage caterpillar population than B. rapa BSH 1 which suffered 18.3 per cent yield loss.