Enhanced biodegradation of insecticides

Felsot, A.S., Enhanced biodegradation of insecticides in soil Implications for agroecosystems, Annu. Rev. Entomol., 34,453,1989. 

Enhanced Biodegradation of Insecticides in Midwestern Corn Soils... 

Dzantor, E.K. and A.S. Felsot. Effects of Conditioning, Cross-Conditioning, and Microbial Growth on Development of Enhanced Biodegradation of Insecticides in Soil, J. Environ. Sci. Health, B24(6) 569-597 (1989). 

Enhanced biodegradation of pesticides has received considerable attention in recent years since it was first described by Audus (1) for the herbicide 2,4-D. Diphenamid, a soil applied herbicide, is also subject to enhanced biodegradation by soil microorganisms (2.31. Fungicides (4.51 and insecticides (6-91 are also subject to enhanced degradation by soil microorganisms. The carbamothioate herbicides are readily degraded by microbes (10.Ill and especially after repeated applications (12-191. ... 

Evaluation of Some Methods for Coping with Enhanced Biodegradation of Soil Insecticides... 

Following the confirmation of enhanced biodegradation of EPTC, over three thousand compounds were screened as extenders in an attempt to restore EPTC activity. Fonofos, an organophosphorus insecticide, (O-ethyl... 

Of the three insecticides studied, enhanced biodegradation has been definitively associated with repeated applications of carbofuran ( ). In our studies, the chemical assay data from 1987 only weakly suggested the development of enhanced biodegradation, and the data from 1988 indicated that biodegradation rate was not affected by multi-year carbofuran treatments. Since a severe drought occurred in 1988, a lack of soil moisture may have slowed the rate of carbofuran degradation. 

Resistance mechanisms associated with changes in toxicokinetics are predominately cases of enhanced metabolic detoxication. With readily biodegradable insecticides such as pyrethroids and carbamates, enhanced detoxication by P450-based monooxygenase is a common resistance mechanism (see Table 4.3). 

Organophosphates (Fig. 10, Table 3) are more toxic than chlorinated hydrocarbons, in particular to humans,but they exhibit lower persistence in soils and do not seem to accumulate in soil fauna or concentrate in birds and fish [74]. This behavior is also related to an enhanced water solubility and lower vapor pressure of organophosphates. Malathion and Parathion (Fig. 10, Table 3) insecticides are known to be chemically hydrolyzed and biodegraded by micro-... 

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