Dr. L Rajesh Chowdary

Crop protection always aims to avoid or prevent crop losses or to reduce them to economically acceptable level but losses due to pests had been enormously increased. Insect pest problems in agriculture have shown a considerable shift during first decade of twenty-first century due to ecosystem and technological changes. The incidences of several insect pests like mealy bugs, particularly Phenacoccus solenopsis on cotton; sugarcane woolly aphid, Ceratovacuna lanigera on sugarcane; and tobacco caterpillar, Spodoptera litura, on several crops, has shown an increasing trend. There was a decline in the pest status of bollworm (Helicoverpa armigera) whereas the sap feeders, viz. aphids, jassids, mirids and mealy bugs are emerging as serious pests. Recently, the occurrence of resistance in Bt cotton to Helicoverpa armigera in different regions had been reported. The global losses due to insect pests have declined from 13.6 per cent in post-green revolution era to 10.8 per cent towards the beginning of this century. In India, the crop losses have declined from 23.3 per cent in post-green revolution era to 17.5 per cent at present. In terms of monetary value, the Indian agriculture currently suffers an annual loss of about Rs 8,63,884 million due to insect pests. The climate change will also affect the pests distribution and they range from expansion in the geographical range, increased risk of invasion in new area, change in overwintering patterns, change in crop pest synchrony; change in pest complexes on spatial and temporal bases and finally pests management strategy. The impacts of climate change can be positive, negative or neutral, since these changes can decrease, increase or have no impact on insect pests and diseases, depending on specific agro climatic location of each region or period.

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