Studies on seasonal incidence and effective management of Helicoverpa armigera (Hubner) on Chickpea

Abstract

An investigation was carried out to study the seasonal incidence and effective management of Helecoverpa armigera (Hubner) on chickpea in randomizes block design with three replications during Rabi, 2014-15 and 2015-16 at Crop Research Center of Sardar Vallabhbhai Patel University of Agriculture & Technology Meerut. The population of H. armigera was recorded during entire crop season from 1st and 52nd standard meteorological weeks (0.46 and 0.40 larvae/m row) to 14th standard week (1.40 and 1.06 larvae/m row) during 2014-15 and 2015-16, respectively. The highest larval population (10.13 and 8.26 larva/m row) was observed in 11th and 12th standard week during 2014-15 and 2015-16, respectively. During this period the mean atmospheric temperature and relative humidity were 20.10 and 21.24 oC and 70.64 and 80.72 per cent, respectively. Population dynamics of H. armigera was significantly positive correlated to temperature (r= 0.692 and r= 0.501) and rainfall (0.202 and 0.680) while negative with relative humidity (r=-0.186 and r= -0.173) during both years. During 2014-15, the grain threshold against H. armigera ranged from 60.00 (neem oil) to 110.76 kg/ha (spinosad). The corresponding values of economic injury level ranged from as low as 0.85 (neem oil) to 1.50 larvae/m row (spinosad). During 2015-16 the grain threshold ranged from 57.35 (neem oil) to 105.88 kg/ha (spinosad). The economic injury level ranged from 0.70 (neem oil) to 1.29 larvae/m row (spinosad). The value of ETL for different treatments viz. flubendiamide, rynaxypyr, neem oil, spinosad and emamectin benzoate were 0.99, 1.20, 0.75, 1.40 and 1.22 larvae/m row, respectively during 2014-15, while the value of ETL for different treatments during 2015-16 were 0.81, 0.99, 0.61, 1.20 and 1.00 larvae/m row, respectively. The crop sown on 30 December, fetched maximum mean larval population (5.76 and 6.06 larvae/m row), which was significantly higher than those in 20th December (5.19 and 5.50 larvae/m row), 10th December (4.74 and 4.01 larvae/m row), 30th November (4.14 and 3.84 larvae/m row) and 20th November (3.56 and 2.91 larvae/m row), respectively. The late sown crops received higher pod borer damage than early sown crops during both the years. The efficacy of different insecticides viz., rynaxypyr, emamectin benzoate, flubendiamide, profenophos, spinosad, lufenuron, HaNPV, Beauveria bassiana and neemarin (neem oil) against H. armigera revealed that rynaxypyr 20 SC @ 150 ml/ha was found most effective in reducing the infestation of H. armigera followed by flubendiamide 48 SC @ 75 ml/ha. The neemarin 5 % @ 3 lit/ha was recorded less effective. Among bio-pesticides, spinosad 45 SC @ 150 ml/ha was found more effective as compare to other. The highest grain yield was recorded from rynaxypyr 20 SC @ 150 ml/ha during both years. Whereas the highest cost: benefit ratio obtained from profenophos 50 EC @ 1000 ml/ha.