Search

We evaluated the relative population growth of two stored-product insect species in the genus Trogoderma, the khapra beetle, Trogoderma granariumEverts (Coleoptera: Dermestidae), and the warehouse beetle, Trogoderma variabileBallion (Coleoptera: Dermestidae). Ten adults of each species were placed in vials containing wheat or paddy rice. These tests were performed at 27 and 32°C and the number of adults in the vials were counted after 35 and 70 days. For all the time intervals and temperatures of both species on wheat, the resulting larval abundances were similar, with the exception of 27°C at 70 days where more T. variabilelarvae developed. At the higher temperature, both species had similar population growth on rice. However, the success was mixed at 27°C with T. granariumhaving a greater abundance after 35 days, while T. variabiledominated after 70 days. Frass production in both commodities was usually similar for the two species, but greater frass production occurred by T. variabileon wheat after 70 days at 27°C, while T. granariumproduced more frass on rice after 35 days at 32°C. Both species nearly always caused equivalent commodity damage. Our research suggests that under ideal conditions these two closely, but very differently treated species in commerce from the genus Trogodermahave comparable population growth, and cause similar damage on wheat and rice.

In the present work, a series of tests were performed to examine the effect of previously captured adults in floor traps, on the captures of Τrogoderma granariumEverts and T. variabileBallion, in single species releases. In a first series of tests, a single trap with kairomone oil and dead adults of single or both species was placed in a plastic container, which was used as the release arena. Subsequently, adults of both species were separately released in the arena, and the adult capture was recorded 24 h later. In a second series of trials, two traps were placed in the same arena, containing different numbers of prior seeded adults, and adult capture was similarly recorded. For T. granarium, in all cases, more adults were found inside the trap than under the trap or on the trap walls. In contrast, for T. variabile, most adults were recorded on the trap walls. In general, T. variabilehad a stronger response to the traps than T. granarium.This work illustrates that previous captures of either species do not negatively affect captures of new live adults and may tend to enhance captures in some cases. This has important implications for the use of traps for the biosureveillance of these two important dermestid species.