Pesticide Resistance and Management

Resistance of organisms to biocides has been an important practical problem since bacterial resistance to antibiotics emerged. Insecticide resistance was first reported in 1952 when mosquitoes transmitting malaria and other vector diseases were found to be resistant to DDT. Resistance in a number of household, veterinary and stored product pests followed from the mid 1950’s to 1960’s. Resistance to DDT and endrin in field crop pests such as tobacco caterpillar, diamond back moth and various species of aphids was identified between late 1960’s and the 1970’s. In 1987, farmers in important growing regions of coastal Andhra Pradesh faced same problems in controlling the unprecedented outbreaks of cotton boll worm, Helicoverpa armigera with certain insecticides including synthetic pyrethroids.

Fungicide resistance has assumed menacing proportions after 1970. During the last decade, various cases of failure of disease control with different groups of systemic fungicides have been reported causing serious problems when alternative substitutes were not available. In India, development of resistance by Venturia inaequalis to the most widely used fungicides carbendazim and mancozeb, Phytophthora infestans and Plasmopara viticola to metalaxyl, Pyricularia oryzae to IBP, Pythium aphanidermatum to fosetyl Al, Rhizoctonia batalicola to carbendazim and Xanthomonas campestris pv. oryzae to plantomycin have been well documented. Development of resistance in fungi against ergosterol biosynthesis inhibitors was also reported from different parts of the world. Considerable crop losses have been reported due to development of resistance to systemic fungicides.

The various strategies to cope up with resistance to pesticides include i) use of mixtures ii) limitation of use, iii) rotation of pesticides and iv) integrated resistance management. Monitoring is a major component of integrated resistance management. On account of the increasing problems of resistance towards pesticides, monitoring programmes establish themselves a special importance. The pesticide resistance problems, monitoring programmes to defect pesticide resistance and management strategies to cope up with pesticide resistance are discussed in this paper.