Efficacy of a synthetic zeolite against five species of stored-product insects on concrete and wheat

Zeolites are alkaline aluminum silicates that are widely used in agriculture, and possess properties similar to many inert dusts. A synthetic zeolite (Odor-Z-Way; sodium aluminum silicate) used for odor adsorption was tested for its ability to control adults of stored-product insects on concrete surfaces and on hard red winter wheat. Insect species tested included adults of the lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); maize weevil, Sitophilus zeamais (Motschuslky); sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and red flour beetle, Tribolium castaneum (Herbst).  Concrete-poured arenas in 9-cm diameter Petri dishes were sprinkled with the synthetic zeolite to provide deposits of 0 (control), 5 and 10 g/m². Mortality was assessed at 1, 3, 9, 12, 20, and 24 h post-introduction. All adults of R. dominica were killed after 1 h exposure at 10 g/m² whereas S. oryzae and S. zeamais required 3 and 9 h exposure at 5 g/m².  All O. surinamensis adults were dead at 12 h at 10 g/m² while 24 h were required at 10 g/m² for T. castaneum adults.   On wheat complete mortality of both S. oryzae and S. zeamais adults after 7 d of exposure occurred at an application rate of 0.5 g/kg of grain.  All O. surinamensis adults died when exposed to 0.25 g/kg and all T. castaneum adults died at 0.75 g/kg. Adults of R. dominica were the most difficult to control, and even at a high rate of 2 g/kg the mortality after 7 d was about 73%.  Our results suggest that the synthetic zeolite has potential in controlling stored-product insects on stored wheat, and additional laboratory and field evaluations are planned to determine its persistence and efficacy on wheat.

Keywords: Synthetic zeolite, inert dust, residual application, wheat, pest managament