The relation between phosphine sorption and terminal gas concentrations in successful fumigation of food commodities.

Vanitha Reddy, P. and Rajashekar, Y. and Begum, Khamrunissa and Leelaja, B. C. and Rajendran, S. (2007) The relation between phosphine sorption and terminal gas concentrations in successful fumigation of food commodities. Pest Management Science, 63 (1). pp. 96-103. ISSN 1526-498X

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Abstract

Owing to increased tolerance and the development of resistance in stored product insects to the fumigant phosphine, in recent years there has been a shift in the target terminal concentration from 100 ppm (100 mL m(-3)) to a higher level of 1000 ppm to achieve 100% insect mortality in 7 day commodity treatments. Therefore, there is a need to investigate whether the revised target concentration could be achieved for food commodities fumigated with phosphine at the standard dose of 2 g m(-3) for 7 days under airtight conditions at > or = 25 degrees C. When different types of food commodity (total 74) were fumigated (300 g per replicate) with phosphine at 2 g m(-3) for 7 days, the terminal gas concentrations in the free space of the commodities varied from 0 to > 2000 ppm. In chambers containing no substrate, a 1417 ppm concentration was recorded. Paddy rice, most of the oilseeds, shelled tree nuts, butter beans, cardamom, green gram splits, coriander powder, rice bran and cocoa powder were more sorptive (> or =60%), such that the target concentration of 1000 ppm was not achieved at the end of 7 days. For these commodities, increased doses of 3-6 g m(-3) were required to attain 1000 ppm. In-shell almonds, green cardamom, in-shell peanuts, leaf tea, tamarind pulp and sunflower seeds were exceptionally sorptive (>90%), so that 0, 41, 112, 168, 203 and 217 ppm respectively were noted at the end of 7 days; the dose must exceed 6 g m(-3) for effective fumigation of these commodities.

Item Type:	Article
Uncontrolled Keywords:	phosphine; food commodities; sorption; target concentration; effective dose
Subjects:	600 Technology > 03 Agriculture > 05 Insect/Pest Control
Divisions:	Food Protectants and Infestation Control
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	07 Aug 2008 07:14
Last Modified:	30 Apr 2012 10:12
URI:	http://ir.cftri.res.in/id/eprint/1906

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