Anopheles breeding in relation to aquatic vegetation and certain physico-chemical parameters in rice fields of Purnia district

Anopheles breeding in relation to aquatic vegetation and certain physico-chemical parameters was studied in rice fields of Purnia district. Association of larvae with different types of aquatic vegetation in different proportions was observed. Maximum Anopheles larvae were found associated with green and blue green algae. It indicates that algae encountered mosquito breeding by providing food and shelter followed by Ipomea, Hydrilla and water hyacinth. Among physico-chemical parameters pH, temperature, turbidity, electrical conductivity, DO, nitrate, carbonate and phosphate showed positive correlation while chloride and bicarbonate showed negative correlation. It can be concluded that aquatic vegetation usually growing in rice fields influences Anopheles breeding and their abundance varies with the occurrence and intensity of each aquatic plant. Physico-chemical factors also exert impact on larval survival and emergence. Thus, such factors should be considered when designing an integrated vector control program. However, a detailed study on the role of other interrelated factors such as predator-parasitie relationship, cultivation practices, emergence rate etc is needed for full understanding of the subject. Although the specific soil type was not analyzed in this survey, other reports indicated that there is variation in development of Anopheles larva among the different soil types