Breeding preferences of Anopheles culicifacies in the rice agro-ecosystem in Kheda district, Gujarat.

Breeding preferences of Anopheles culicifacies, a principle malaria vector, in the plains of India was studied in the rice agro-ecosystem of Kheda district in central Gujarat. Extensive breeding of this species was found in the rice field channels (20.83 per cent) and in rice fields (5.32 per cent). However, rice nurseries (0.91 per cent) and post-harvested rice fields (2.51 per cent) were less preferred. The species was found in abundance in newly transplanted rice fields and during early months of rice cultivation with a peak prevalence in the non-monsoon (Rabi) season. The breeding of An. culicifacies was inversely proportional and negatively correlated (r = -0.868; p < 0.05) with the height of the plants, whereas it showed a positive correlation (r = 0.779; p < 0.05) with the distance between plants. Rice fields near the villages supported maximum breeding of An. culicifacies (48 per cent) followed by the rice fields, 0.5 to one km away from the human habitation. Co-efficient of association (C8 index) revealed a positive association of the species with An. annularis, An. pallidus, An. subpictus and Cx. quinquefasciatus. However, it was negatively associated with An. nigerrimus, Cx. tritaeniorhynchus and Cx. vishnui sub groups.