Degradation of Alachlor by Rhizoctonia solani¹

Abstract

The direct effects of herbicides on fungi are reported to include: inhibition, stimulation, or no effect as determinated by growth, sporulation, spore germination, and pathogenicity. Also, certain fungi have been found to rapidly degrade herbicides present in the ecosystem. Research was conducted to determine the influence of 2‐chloro‐2′,2′‐diethyl‐N‐(methoxymethyl)acetanilide (alachlor) on the growth and development of Rhizoctonia solani Kuehn, and to quantify the rate of alachlor degradation by R. solani in nutrient media containing differing concentrations of sucrose. Alachlor did not influence sugar utilization or growth of R. solani. Fungal growth and degree of alachlor degradation were proportional to the amount of sugar in the media. Apparently R. solani does not utilize alachlor as a sole carbon source and degradation of this herbicide is dependent on the presence of some other source of carbon.

Temperature Influences on Uptake, Translocation, and Metabolism of Alachlor in Snap Beans (Phaseolus vulgaris)

“…Alachlor is metabolized rapidly in both resistant and sus ceptible plants as well as in soil and water ecosystems (1, 2, 7,11,12,13). Alachlor is metabolized in yellow nutsedge to a water soluble product within 2 days of application (1).…”

Weed Control by Alachlor and Residues in Sweet Potato (Ipomoea batatas) and Soil

“…At 16 weeks after application, less than 2% of the alachlor applied to the soil remained. The rapid loss of this herbicide from soil has been attributed primarily to microbial degradation (1,2,8,9,12,13). Loss is secondarily attributed to volatilization, leaching, photodecomposition, and chemical decomposition (1,4).…”

Environment Behavior and Fate of a New Pyrimidynyloxybenzoic Herbicide ZJ0273 in Aerobic Soil

“…S 3 , 28.1% in S 2 , and 17.5% in S 1 , which were far lower than the 70% as described as the nonaccumulative criteria in the directive by CEC (1997). The formation of soil-bound residues for many pesticides has been reported to be mediated by the activities of soil microorganisms (Smith & Philips, 1975;Haider, 1983;Krause et al, 1985). During the entire incubation, ANOVA analysis showed that there was no significant difference in BR formation between the two 14 C labels (p ≥ 0.05), which implies that formation of BR in soils involved parent compound and/or metabolites with both pyrimidine and benzyl rings, rather than metabolites with a single ring.…”