Influence of commodity type and temperature on the population growth of Trogoderma granarium Everts and Trogoderma variabile Ballion (Coleoptera: Dermestidae)

Authors: BALIOTA, GEORGIA - University Of Thessaly; Morrison Iii, William; DOMINGUE, MICHAEL - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; ATHANASSIOU, CHRISTOS - University Of Thessaly

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2025
Publication Date: 9/11/2025
Citation: Baliota, G.V., Morrison III, W.R., Domingue, M.J., Athanassiou, C.G. 2025. Influence of commodity type and temperature on the population growth of Trogoderma granarium Everts and Trogoderma variabile Ballion (Coleoptera: Dermestidae). Journal of Stored Products Research. Volume 115, January 2026, 102804. https://doi.org/10.1016/j.jspr.2025.102804.
DOI: https://doi.org/10.1016/j.jspr.2025.102804

Interpretive Summary: With the increase in global trade, grain infested with stored product insects is constantly being moved into new environments, highlighting a need to understand the role that temperature plays in population growth. Among these, the khapra beetle and the warehouse beetle are economically significant pests of stored grains worldwide, with khapra beetle considered a quarantine pest throughout the world. However, the impact of temperature on population growth of these two insects on stored grain commodities that are commonly shipped around the world remains limited. The aim of this study was to compare offspring production of khapra beetle and warehouse beetle when infesting wheat and rice kernels under a wide range of temperatures (25–40°C). We observed that both species performed better when infesting wheat compared to rice, while khapra beetle had greater offspring production than warehouse beetle in wheat, regardless of the temperature tested. Both species produced more offspring between 30 to 35°C while temperatures above 37 °C suppressed offspring production and damage to both wheat and rice. Overall, this research shows that high temperatures suppress population growth and feeding damage by khapra beetle and warehouse beetle to multiple grain commodities, supporting the development of sustainable storage and quarantine practices.

Technical Abstract: The growth of global trade, alongside climate change, has increased interceptions of quarantined stored product insects, and highlights a need to understand the thermal ecology of these pests. Among these, the khapra beetle, Trogoderma granarium Everts and the warehouse beetle, T. variabile Ballion (Coleoptera: Dermestidae) are economically significant pests of stored grains worldwide. However, knowledge about their population dynamics in direct comparison under different conditions remains limited. The aim of this study was to determine, in parallel, the progeny production of T. granarium and T. variabile when infesting whole soft wheat and paddy rice kernels under a wide range of temperatures (25–40oC). We observed that both species performed better when infesting wheat compared to rice, while T. granarium had greater progeny production than T. variabile in wheat, regardless of the temperature tested. Both species developed and reproduced better at a range between 30 to 35oC while temepratures above 37 oC suppressed progeny production and damage on the commodities. Overall, this research contributes to a deeper understanding of pest behavior in relation to commodity and environmental factors, supporting the development of sustainable storage and quarantine practices.