Seasonal incidence and efficacy of botanical insecticides against Painted bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) in Indian mustard (Brassica juncea genotype RH 725)

Abstract

Bagrada hilaris (Burmeister) is a serious pest of Brassica crops in the North-Western region of India, inflicting crop yield losses. Therefore, the present study was conducted on seasonal incidence and management of B. hilaris in Brassica juncea genotype RH 725 at farmer’s field, Kolana village, Aravalli Hills Region, Rewari, Haryana, India during Rabi, 2019-20 and 2020-21. This study laid out the trial in a randomized block design with three replications and six treatments viz., Neem Seed Kernel Extract (NSKE) @ 7%, Nimbecidine @ 0.03%, Neem oil @ 5%, NSKE @ 5%, Neem oil @ 7% and control (unsprayed). Observations on the incidence of B. hilaris showed that it appeared from 5^th Standard Meteorological Week (SMW) (0.34 bugs plant^-1) and attained peak during 10^th SMW with 5.77 bugs plant^-1. The incidence of B. hilaris exhibited significant positive correlation with maximum (r=0.852, p<0.05) and minimum (r=0.900, p<0.05) temperature, rainfall (r=0.763, p<0.05) and wind velocity (r=0.959, p<0.05). Spray of Neem oil @ 7% (83.01 %) was the most effective in reducing the B. hilaris population over control followed by NSKE @ 7% (81.48 %), while NSKE @ 5% (68.85 %) confirmed least effective. Seed yield in different treatments varied from 1440.5 kg ha^-1 (NSKE @ 5%) to 1590 kg ha^-1 (Neem oil @ 7%) against 1216 kg ha^-1 in control. The highest incremental cost-benefit ratio was registered with NSKE @ 7% (1: 7.70) followed by Nimbecidine @ 0.03% (1: 7.41) and NSKE @ 5% (1: 6.25). The present investigation signified that the study on the seasonal incidence of B. hilaris in relation to weather parameters could provide information for planning pest control and management strategies. The botanicals could be used as eco-friendly and economical substitutes for chemical insecticides at farmer’s fields against this insect pest.