Action of Different Exposures of Chilled Atmospheric Treatments on the Mortality of Granary Weevil and Embryo Viability of the Treated Wheat

Abstract

The granary weevil, Sitophilus granarius (L.), is considered a serious pest in stored grain worldwide. As residual-based protection possibilities become scarcer, the development of eco-friendly control technologies that can be implemented in practice is becoming urgent. In this spirit, our objective was to assess the effectiveness of different levels of atmospheric cooling against S. granarius under laboratory conditions. We also analysed the effects of cooling on progeny generation and the viability of treated wheat. Thus, we investigated the consequences of atmospheric exposures to temperatures of −5, −10, −15, −20, and −25 °C for 60, 75, and 90 min on these factors, and also explored the effects of nearby ranges using extrapolation. The viability of the treated wheat embryo was analysed using a TTC test. Our results showed that the highest efficacy was observed at an atmospheric cooling temperature of −25 °C (with a parallel recorded temperature of −10.5 °C in the stored grains zone), with a 90 min exposure at suboptimal relative humidity (40%). At 60% relative humidity, the mortality averages were more dispersed, and the expected efficiencies above 95% occurred at longer exposures. The post-suppressive effect of cooling can be confirmed in all three exposures. The different cooling temperatures of the tested exposure times did not produce any appreciable changes in the viability of treated wheat embryos. In conclusion, our results show that the use of atmospheric cooling can be an effective solution for stored product protection.

Keywords

• atmospheric cooling
• control method
• mortality
• relative humidity
• <i>Sitophilus granarius</i>
• stored product