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ARS Home » Research » Publications at this Location » Publication #76939
Title: DEGRADATION OF FENAMIPHOS IN AGRICULTURAL PRODUCTION SOILS.

Author
item Johnson, Alva

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Erratic control of nematodes often follows the application of nematicides. The efficacy of fenamiphos was determined in a sweet corn-sweet potato- vetch cropping system for six years. The nematicide was applied at 6.7 kg a.i./ha immediately before planting each crop, and untreated plots served as controls. Based on numbers of root-knot nematodes in the soil at monthly intervals, root-gall indices, and yield of crops, the efficacy of the nematicide diminished during the third year. The accelerated degradation of fenamiphos appears to be biologically mediated. Therefore, the nematicide applied immediately before planting crops in intensive produciton systems should not exceed three years. After three years, the crop rotation and (or) the nematicide should be changed.

Technical Abstract: Nematicides are used to control a wide variety of nematodes on many crops. Erratic control often follows the application of nematicides. These results are not always predictable and have been associated with degradation of nematicides. These compounds may be degraded in soil through chemical, physical, and biological mechanisms. The accelerated degradation of nematicides appears to be biologically mediated and is an agricultural problem that has been observed in crop monocultures and in other crop production systems where biodegradable compounds are repeatedly applied to the same soil. The problem can occur in any microbiologically active soil, and it is not unique to any single nematicide or class of nematicides. As indicated by the numbers of root-knot nematodes (Meloidogyne incognita) in the soil in a 6-year sweet corn-sweet potato- vetch rotation, the efficacy of a nematicide diminished during the third year. Therefore, the nematicide applied immediately before planting sweet corn, sweet potato, and vetch should not exceed 3 years. After 3 years, the crop rotation and (or) the nematicide should be changed.