Mosquito breeding in relation to aquatic vegetation and some physico-chemical parameters in rice fields of central Gujarat.
In weekly surveys of 27 rice fields in 9 villages of Kheda district in central Gujarat, India, conducted in a 2-year period beginning in June 1988, a total of 14 anopheline and 15 culicine species were encountered in close association with different types of aquatic vegetation (which included algae and cyanobacteria, Azolla pinnata, Ceratophyllum demersum, Eichhornia crassipes, Cynodon dactylon, Hydrilla verticillata, Ipomoea aquatica, Lemna minor and Marsilea spp.). Among anophelines, Anopheles annularis, A. nigerrimus, A. subpictus and A. tessellatus were of general distribution and were found associated with each type of aquatic vegetation. A. culicifacies showed poor association with most of the aquatic weeds. Maximum number of anophelines were found associated with algae (e.g. Spirogyra pratensis) and cyanobacteria. The Culex vishnui sub-group predominated among culicines and showed frequent association with Ceratophyllum demersum, H. verticillata and algae. The effects of physico-chemical parameters on mosquito larval populations are discussed.