Movement of Cryptolestes ferrugineus out of wheat kernels and their mortalities under elevated temperatures.

Arlene-Christina, G.D., Jayas, D.S., Fields, P.G., Jian, F., White, N.D.G., and Alagusundaram, K. (2014). "Movement of Cryptolestes ferrugineus out of wheat kernels and their mortalities under elevated temperatures.", Journal of Stored Products Research, 59, pp. 292-298. doi : 10.1016/j.jspr.2014.09.003  Access to full text

Abstract

The rusty grain beetle, Cryptolestes ferrugineus (Coleoptera: Laemophloeidae), is a common pest in stored grain. The present study examined the time taken for larvae of C. ferrugineus to exit wheat kernels at 40–55 °C, stage-specific mortality at 40–60 °C, and whether a combination of heat and shaking could be used to control this pest. The average time larvae took to leave wheat kernels ranged from 130 min at 40 °C to 6 min at 55 °C. At 55 °C and 6 min exposure, 81 ± 2% of larvae exited the kernels, 10 ± 1% of larvae were alive inside kernels and 9 ± 2% were dead inside kernels. Under constant temperature of 55 °C, less than 5% of the larvae escaped in 2 min, but under the rising temperature of 40, 45, 50 and then to 55 °C, over 50% of the larvae escaped in 2 min at 55 °C. The time taken to reach 50 and 95% mortality was similar for all stages. Higher temperatures resulted in higher mortality in a shorter exposure time. The longest LT95 for pupae was 6480, 293, 50 and 3.7 min at 45, 50, 55 and 60 °C, respectively. At 55 °C for 88 min, combined with shaking gave 88% control in a 100-g wheat bulk. Time needed to kill eggs and pupae were much longer than the time needed to force larvae out of kernels. Therefore, the combination of heat and shaking would only provide partial disinfestation of C. ferrugineus.

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