ECOTOXICOLOGY OF PESTICIDES IN THE TROPICAL PADDY FIELD ECOSYSTEM

In tropical countries rice has been identified as one of the crops tha t is particularly susceptible to the negative impacts of pesticide use . In addition to the physicochemical nature of the pesticide, tropical climatic conditions and agricultural practices play important roles i n determining the fate and distribution of pesticides in the tropical paddy held ecosystem. The assessment of ecotoxicological effects of pe sticides in the tropical paddy field ecosystem has been based primaril y on acute lethality tests conducted on fish species commonly found in paddy fields. The effects of pesticides in the paddy field ecosystem on other nontarget organisms ranging from microalgae and cyanobacteria to paddy field crabs have also been investigated, although such studi es are limited. As a means to promote a more judicious use of pesticid es in the paddy field, the adoption of integrated pest management stra tegies have resulted in varying degrees of success. The most widely ac cepted form of control measure is the integration of multiresistant cu ltivars with reduced use of pesticides. Effective training of the padd y farmer has been identified as the key to successful implementation o f integrated pest management strategies.