Estimation of avoidable yield losses in Indian mustard (Brassica juncea L.) due to mustard aphid, Lipaphis erysimi (Kaltenbach) in Rewari district, Haryana, India

Abstract

The Indian mustard (Brassica juncea L.) is a significant oilseed crop in India. The sap-sucking pest, mustard aphid (Lipaphis erysimi) emerged as a major threat to this crop, which can harshly reduce yield. The research experiment was carried out during the Rabi seasons, 2019-20 and 2020-21 at Rewari, Haryana to comprehend the influence of L. erysimi infestation on different yield parameters of B. juncea in the field. The two cultivars of B. juncea namely, RH 725 and RB 50 were raised in a paired plot design with two different sets viz., protected and unprotected and thirteen replications each set were kept. The protected set was sprayed with insecticide Dimethoate 30 EC @ 625 ml ha-1 one time only, whereas unprotected set was kept free from insecticidal application for natural infestation of the pest. The present investigation revealed that under unprotected conditions, the yield parameters viz., weight of 100 siliquae, 100 siliquae husk, 10 main apical shoots (10 cm) and 1000 seeds, as well as seed yield, were significantly (P<0.01) affected by the L. erysimi infestation, while parameter, seed germination percentage influenced non-significantly (P>0.01). The maximum seed yield losses were registered in genotype RH 725 (26.25 %) when compared with RB 50 (25.92 %). All other yield parameters exhibited the same pattern except for three parameters i.e. weight of 100 siliquae, 100 siliquae husk and 10 main apical shoots (10 cm). In conclusion, this research highlights the colossal yield losses inflicted by L. erysimi infestation in B. juncea in unprotected conditions and the utility of insecticidal application in the enhancement of crop yield by management of this insect pest in protected conditions.