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

Authors: GOURGOUTA, MARINA - University Of Thessaly; ATHANASSIOU, CHRISTOS - University Of Thessaly; ARTHUR, FRANK - Retired ARS Employee; Morrison Iii, William; Scully, Erin

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sorghum serves as a staple food crop for millions of people, particularly in arid and semi-arid regions due to its drought tolerance. While traditionally used for animal feed in developed countries, its role in human consumption is growing due to its health benefits and richness in nutrients and fiber, especially for gluten-free diets. Stored product insects cause significant post-harvest losses through feeding damage, contamination, and weight loss, yet very little is known about the susceptibility of different sorghum varieties to stored product insects. In this study, we evaluated the impact of temperature (26 and 32 C) on the susceptibility of four different sorghum varieties (Waxy Burgundy, Non-Waxy Burgundy, Whole White, and Sumac) to feeding by two common stored product insects, sawtoothed-grain beetle and warehouse beetle. Sumac and Waxy Burgundy were the most susceptible to both insects regardless of temperature. Furthermore, population levels for sawtoothed-grain beetle were significantly higher overall at 32 C, particularly on the Sumac and Waxy Burgundy varieties, while warehouse beetle showed only a slight increase in population at this temperature. 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.

Technical Abstract: 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 and Trogoderma variabile, two common stored-product pests. Four sorghum varieties (Waxy Burgundy, Non-Waxy Burgundy, Whole White, and Sumac) and a wheat control were tested at two temperatures (26 °C and 32 °C). The study revealed that certain sorghum varieties, such as Sumac and Waxy Burgundy, were more susceptible to pest damage, suggesting that varietal selection plays a key role in pest resistance. Furthermore, results showed that O. surinamensis exhibited significantly higher population growth and damage at 32 °C, particularly on the Sumac and Waxy Burgundy varieties, while T. variabile showed a slight increase in population at 32 °C but with less pronounced effects. Both species caused greater weight loss and kernel damage at elevated temperatures, with frass production higher at 32 °C, though they 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.