Abstract Factors affecting the susceptibility of adults of 13 and larvae of 2 species of stored product beetles to entanglement by Trogoderma larval hastisetae were studied. The length, diameter, shape, density, and angle of the test insects' setae probably affected susceptibility. The setae on the hindwings of Trogoderma adults were susceptible to permanent hastisetal attachment which prevented normal closure of elytra over the hindwings. Sitophilus oryzae (L) and Cryptolestes pusillus (Schönherr) were susceptible, with 93 and 83% mortality, respectively, at the end of 72 hr exposure. Tribolium castaneum (Herbst), T. confusum (duVal), Gibbium psylloides (Czenpinski), and Tenebroides mauritanicus (L.) resisted hastisetal attachment. Scanning electron micrographs revealed the attachments of heads of hastisetae to setae of several beetles exposed to larval Trogoderma.