Persistence and effects of fenamiphos on native algal populations and enzymatic activities in soil

Fenamiphos is a commonly and widely used nematicide and insecticide in agri culture but information on its effects on microorganisms in soil is scarce. The microbial role in the persistence of fenamiphos in soil was determined by comparing the relative rate of its degradation in autoclaved and unauto claved soil. Nearly 80% of added fenamiphos disappeared in unautoclaved soi l during a 20-day incubation. In autoclaved soil incubated under similar co nditions the recovery of fenamiphos was about 91%, This indicates the invol vement of microorganisms in the degradation of this compound. Fenamiphos in general was not toxic to the soil algal community and soil enzymes (dehydr ogenase, phosphatase and beta-glucosidase). Therefore fenamiphos at field a pplication rates may not endanger non-target microorganisms and their activ ities in soil. (C) 1999 Elsevier Science Ltd. All rights reserved.