Susceptibility of sorghum to infestation by Oryzaephilus surinamensis (Coleoptera: Silvanidae) and Trogoderma variabile (Coleoptera: Dermestidae): influence of variety and temperature

This study evaluated the effects of sorghum variety and temperature on the population growth, frass production, kernel damage, and weight loss caused by Oryzaephilus surinamensis (L.) and Trogoderma variabile, Ballion, two common stored-product pests. Four sorghum varieties (Waxy Burgundy, Non-Waxy Burgundy, Whole White, and Sumac) were evaluated at two temperatures, 26 and 32 °C, with wheat serving as the control. The study revealed that certain sorghum varieties, such as Sumac and Waxy Burgundy, were more susceptible to pest damage, suggesting that varietal selection significantly influences population growth potential. Furthermore, results showed that O. surinamensis exhibited significantly higher population growth and damage at 32 °C, reaching approximately a mean of 43 individuals/per vial in the control and 37 individuals/per vial in Waxy Burgundy, while T. variabile showed a slight increase in population at 32 °C but with less pronounced effects. Weight loss, kernel damage, and frass production were significantly higher at 32 °C for both species. Notably, T. variabile caused up to 15% kernel damage at this elevated temperature. However, frass production did not differ significantly between sorghum varieties. The study highlights the role of temperature in enhancing pest activity and underscores the importance of selecting resistant sorghum varieties for integrated pest management in post-harvest storage.