Degradation of the insecticide Hydramethylnon byPhanerochaete chrysosporium

The decomposition of the amidinohydrazone-type insecticide Hydramethylnon (HMN) by soil fungi has been investigated. A simple spectrophotometric method was developed for the estimation of HMN in soil and fungal culture media. HMN was found to be degraded in soil with a half life of 14 to 25 days.Degradation of HMN by the lignolytic fungus,Phanerochaete chrysosporium yielded two major breakdown products;p-(trifluoromethyl)-cinnamic acid (TFCA) andp-(trifluoromethyl)-benzoic acid (TFBA). TFCA was converted to TFBA which was subsequently metabolised via themeta-fission pathway. Fluoride release from HMN could not be detected.Abbreviations BzDAc benzene, dioxane, acetic acid (60: 36: 4) - DCM dichloroethane - DNPH 2,4-dinitro-phenylhydrazine - HMN Hydramethylnon - TDAc toluene, dioxane, acetic acid (90: 30: 1) - TFCA p-(trifluoromethyl)-cinnamic acid - TFBA p-(trifluoromethyl)-benzoic acid - TFP 1,5-bis(trifluoro-p-tolyl)-1,4-pentadien-3-one - VA veratryl alcohol