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Effect of phosphine dose on sorption in wheat

Daglish, G.J. and Pavic, H. (2008) Effect of phosphine dose on sorption in wheat. Pest Management Science, 64 (5). pp. 513-518.

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Article Link(s): http://dx.doi.org/10.1002/ps.1531

Publisher URL: http://www3.interscience.wiley.com/cgi-bin/home

Abstract

BACKGROUND: In spite of the extensive use of phosphine fumigation around the world to control insects in stored grain, and the knowledge that grain sorbs phosphine, the effect of concentration on sorption has not been quantified. A laboratory study was undertaken, therefore, to investigate the effect of phosphine dose on sorption in wheat. Wheat was added to glass flasks to achieve filling ratios of 0.25-0.95, and the flasks were sealed and injected with phosphine at 0.1-1.5 mg L-1 based on flask volume. Phosphine concentration was monitored for 8 days at 25°C and 55% RH.

RESULTS: When sorption occurred, phosphine concentration declined with time and was approximately first order, i.e. the data fitted an exponential decay equation. Percentage sorption per day was directly proportional to filling ratio, and was negatively correlated with dose for any given filling ratio. Based on the results, a tenfold increase in dose would result in a halving of the sorption constant and the percentage daily loss. Wheat was less sorptive if it was fumigated for a second time.

CONCLUSIONS: The results have implications for the use of phosphine for control of insects in stored wheat. This study shows that dose is a factor that must be considered when trying to understand the impact of sorption on phosphine concentration, and that there appears to be a limit to the capacity of wheat to sorb phosphine.

Item Type:Article
Business groups:Agri-Science, Crop and Food Science
Additional Information:© Society of Chemical Industry.
Keywords:Dose; fumigation; phosphine; sorption; wheat.
Subjects:Plant pests and diseases > Individual or types of plants or trees > Wheat
Plant culture > Harvesting, curing, storage
Plant pests and diseases > Pest control and treatment of diseases. Plant protection > Pesticides
Deposited On:21 Jan 2009 05:02
Last Modified:27 Oct 2011 00:58

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