Incidence of pests in jute (Corchorus olitorius L.) ecosystem and pest–weather relationships in West Bengal, India

Abstract

Experiment on jute crop was conducted during pre-kharif to kharif seasons (April to August) at Bidhan Chandra Krishi Viswavidyalaya (BCKV), West Bengal, India in a view to record the pest incidence on olitorius jute and to determine the weather parameters impacting on pest population in jute under West Bengal conditions. Seventeen different species of pests belonging to insects, mites and nematodes were found feeding on jute. Among them, jute semilooper (Anomis sabulifera Guen.), Bihar hairy caterpillar (Spilarctia obliqua Wlk.), grey weevil (Myllocerus discolor Bohemus), yellow mite (Polyphagotarsonemus latus Banks), stem weevil (Apion corchori Marshall), and root knot nematode, Meloidogyne incognita are causing economic damage to the crop and other pests were considered as minor pests. Correlation studies with weather parameters showed that incidence of semilooper was negatively correlated (r = −0.795 to −0.725) with the maximum temperature but had positive significant association with minimum temperature (r = 0.528–0.715), morning relative humidity (RH) (r = 0.579–0.857) and afternoon RH (r = 0.876). Bihar hairy caterpillar incidence also exhibited positive significant relationship with morning RH (r = 0.577) and afternoon RH (r = 0.545). Morning and afternoon RH and rainfall also had significant positive correlation with the incidence of M. discolor with r = 0.535, 0.570, and 0.700, respectively. None of the meteorological parameters had any significant influence on the incidence of A. corchori. Yellow mite incidence showed positive association with morning RH (r = 0.563–0.679) and afternoon RH (r = 0.526–0.618). Rainfall was found favourable for proliferation and incidence of M. discolor only but had a negative effect on the incidence of stem weevil and yellow mite. Thus climatic factors particularly temperature, relative humidity and rainfall played a pivotal role on occurrence and existence of different pests on jute crop.