Enhanced biodegradation reduces the capacity of metham sodium to control soil pests

Abstract

Enhanced biodegradation of methyl isothiocyanate (MITC), the toxin produced by the broad-spectrum biocide metham sodium, substantially reduced its toxicity to whitefringed weevil, Naupactus leucoloma (Boheman), in laboratory tests using metham sodium-treated field soils. A level of enhanced biodegradation in a highly degrading soil that reduced MITC production and persistence to approximately 10% of that in a mildly degrading soil caused a doubling of the LC 90 . Given the very high acute toxicity of MITC, this superficially limited effect in reality demonstrates the dramatic impact that severe levels of enhanced biodegradation can have in reducing the efficacy of metham sodium for control of soil-borne pests and diseases.

Glucosinolates and biofumigation: fate of glucosinolates and their hydrolysis products in soil

“…In sterile soil there is typically a fast reaction taking place within an hour which reduces the extractable concentration of isothiocyanate in soil to 60-80% of that applied, thereafter the concentration is reduced slowly (Rumberger and Marschner 2003;Matthiessen et al 2004a;Gimsing et al 2008). This fast reaction is most likely due to sorption to the organic matter, as the reduction is larger the more organic matter the soil contains, but volatilization also plays a role (Fig.…”

A review of isothiocyanates biofumigation activity on plant parasitic nematodes

“…Additionally, the bacterial community composition was significantly affected by adding pure 2-propenyl glucosinolate, the effect being more pronounced than in treatments with myrosinase added to the GLS (Hanschen et al 2015). Interestingly, enhanced biodegradation of ITCs has been observed for soils frequently grown with Brassicas probably due to microorganisms favored in these conditions (Warton et al 2003;Gimsing et al 2009aGimsing et al , b, 2007Matthiessen et al 2004;Matthiessen and Kirkegaard 2006).…”

Sustainable sweetpotato farming systems to improve soil health and reduce losses caused by root-knot nematode

“…Most sweetpotato growers currently rely on nematicides for nematode control, with two soil fumigants (metham sodium and 1, 3 dichloropropene) and two non-volatile chemicals (oxamyl and fluensulfone) currently approved for use by the Australian Pesticides and Veterinary Medicines Authority. However, all nematicides are expensive, many have off-site environmental impacts, some lose their efficacy due to enhanced biodegradation, and broad-spectrum fumigants such as metham sodium destroy beneficial organisms as well as the target pest (Thomason 1987;Stirling et al 1992;Warton et al 2001;Matthiessen et al 2004: Sánchez-Bayo 2011Blaesing 2014).…”