Efficacy of diatomaceous earth in controlling major store product pests: Plodia interpunctella, Tribolium confusum and Acanthosclides obtectus

Diatomaceous earth (DE) is an inert dust formed from fossilized skeletal remains of diatoms. Insecticidal activity is a result of desiccation that occurs after DE particles destroy lipid layers of insect cuticule. Efficacy depends on chemical composition, particle size and geographic origin. This work assessed contact efficacy of DE originating from Kolubara open-pit mine (Serbia), in comparison to SilicoSec®, against P. interpunctella, T. confusum and A. obtectus. DEs were applied at rates: 5, 10, 15 and 20 mg-2. Mortality was recorded after 24, 48, 72 h and seven days. Significant mortality of P. interpunctella larvae was recorded after seven days of exposure at two higher rates of SilicoSec® (48.0 and 54%, respectively) and Kolubara DE (45.6 and 58.5%, respectively). Higher rates of SilicoSec® and Kolubara DE caused significant mortality of T. confusum after seven days (54.1, 84.3%, 49.2, 78.2%, respectively). High mortality of A. obtectus was recorded after 48 and 72 h in SilicoSec® (61.5, 82.1%, respectively) and in Kolubara DE (58.0, 78.5%, respectively) when applied at 20 mg-2.