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Effect of diet on phosphine toxicity, rate of development and reproduction of the rice weevil Sitophilus oryzae (Linnaeus)

Nguyen, Tam T. and Kaur, Ramandeep and Schlipalius, David I. and Collins, Patrick J. and Ebert, Paul R. (2016) Effect of diet on phosphine toxicity, rate of development and reproduction of the rice weevil Sitophilus oryzae (Linnaeus). Journal of Stored Products Research, 69 . pp. 221-226. ISSN 0022-474X

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Article Link(s): http://dx.doi.org/10.1016/j.jspr.2016.08.012

Publisher URL: http://www.sciencedirect.com/science/article/pii/S0022474X16301722

Abstract

One of the loci responsible for strong phosphine resistance encodes dihydrolipoamide dehydrogenase (DLD). The strong co-incidence of enzyme complexes that contain DLD, and enzymes that require thiamine as a cofactor, motivated us to test whether the thiamine deficiency of polished white rice could influence the efficacy of phosphine fumigation against insect pests of stored grain. Three strains of Sitophilus oryzae (susceptible, weak and strong resistance) were cultured on white rice (thiamine deficient), brown rice or whole wheat. As thiamine is an essential nutrient, we firstly evaluated the effect of white rice on developmental rate and fecundity and found that both were detrimentally affected by this diet. The mean time to reach adult stage for the three strains ranged from 40 to 43 days on brown rice and 50–52 days on white rice. The mean number of offspring for the three strains ranged from 7.7 to 10.3 per female over a three day period on brown rice and 2.1 to 2.6 on white rice. Growth and reproduction on wheat was similar to that on brown rice except that the strongly resistant strain showed a tendency toward reduced fecundity on wheat. The susceptible strain exhibited a modest increase in tolerance to phosphine on white rice as expected if thiamine deficiency could mimic the effect of the dld resistance mutation at the rph2 locus. The strongly resistant strain did not respond to thiamine deficiency, but this was expected as these insects are already strongly resistant. We failed, however, to observe the expected synergistic increase in resistance due to combining thiamine deficiency with the weakly resistant strain. The lack of interaction between thiamine content of the diet and the resistance genotype in determining the phosphine resistance phenotype suggests that the mode of inhibition of the complexes is a critical determinant of resistance.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Thiamine deficiency Dihydrolipoamide dehydrogenase rph2 Phosphine Fumigation
Subjects:Science > Entomology
Plant culture > Field crops > Rice
Plant culture > Field crops > Wheat
Plant pests and diseases > Pest control and treatment of diseases. Plant protection
Deposited On:25 Sep 2016 23:15
Last Modified:25 Sep 2016 23:15

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