Impact of Short-Term Atmospheric Heat Transfer on the Survival of Granary Weevil in Stored Winter Wheat

Abstract

The granary weevil Sitophilus granarius L. is a pest causing substantial damage to stored wheat worldwide, against which the elaboration of sustainable control methods has recently been gaining importance. Our objective was to assess the efficacy of a rapid atmospheric convection heat transfer method against S. granarius under laboratory conditions. We examined the changes in adult mortality and progeny survival triggered by heat and the effect of this on the quality parameters of treated wheat items. The insecticidal efficacy, achieved by the treatment of infested grains, was also analyzed at 37, 47, 67, 87, and 107 °C for 5, 6, and 7 min under 40% and 60% rh exposure to atmospheric heating with the progeny production assessed 45 days after the treatment. The quality parameters of the treated wheat were analyzed by a germination test and NIR grain analysis. Our findings showed that adequate eradication of S. granarius was obtained at 107 °C for 5 min of exposure under suboptimal (40% rh) relative humidity values. At 60% relative humidity, mortality averages were more dispersed, and efficacies above the expected 95% occurred over longer exposures. The progeny-suppression effect from short-term heating was affirmed. The atmospheric convection heat transfer method, under the applied temperature and exposure time combinations, did not induce detectable changes in the quality parameters or the germination ability of the treated wheat. Overall, our findings indicated that the use of short-term heating for the post-harvest protection of cereals is feasible, which may contribute to the realization of residuum-free pest management and provide an effective and sustainable technique in integrated pest management.

Keywords

• mortality
• protection method
• qualitative parameters of winter wheat
• relative humidity
• <i>Sitophilus granarius</i>
• short-term heating