Beet army worm, Spodoptera exigua (Hubner): An emerging pest of chickpea in Western Maharashtra

Abstract

Effect of different sowing dates of chickpea on the incidence of Beet army worm, Spodoptera exigua (Hubner) and its grain yield was studied under Pulses Improvement Project, Mahatma Phule Krishi Vidyapeeth, Rahuri during rabi 2014- 15 and 2015-16. Chickpea varieties (ICCL 86111, ICCV 10, ICC 3137 and Digvijay) were sown on nine sowing dates (at 15 days interval) viz., 15th September, 1st October, 16th October, 31st October, 16th November, 30th November, 15th December, 30th December and 15th January. Larvae feed on the seedling and vegetative stages of chickpea. The insect pest appeared in the field 15 to 20 days after sowing of the crop i.e. at seedling stage and remain it prevailed up to 25 to 30 days after germination. Thereafter, the infestation was negligible from flowering to maturity of the crop. Correlation study revealed that during 2014-15, there was positive and significant correlation with maximum and minimum temperature when the crop was sown on 15th September. However, during 30th November sown crop, there was significant negative correlation of maximum temperature with higher incidence on the variety Digvijay. Same trend was observed during 2015-16 and all the varieties showed positive and significant correlation with maximum temperature when crop was sown on 1st October. Relative humidity had no significantly association with S. exigua almost all the sowing date except at 30th November sown crop during 2014-15. However, during 2015-16, morning relative humidity showed positive for significant association with S. exigua at 15th September sown crop for all varieties, while Digvijay at 30th November sown crop. The association of rainfall pattern and the incidence of both the pest at different sowing dates was non significant. It could be concluded from the present study that early and late sowing of chickpea resulted in higher infestation of S. exigua than that of optimum sown crop.