부산대학교 도서관

Local raw diatomaceous earth (Silica nano-particles) with or without a commercial pesticide (Challenger 36% SC) were tested against adults, 4th and 2nd nymphal instars of Alfalfa grasshopper, Heteracris littoralis (Rambur) (Orthopetra: Acrididae) under laboratory conditions. Obtained results showed that the mean duration of adults at all concentration levels of both treatments did not exceed 12.40 days compared to 31.40 days in the check. Also, revealed a highly significant difference between treatments and the check, while it was insignificant between both treatments at all tested concentrations. The Challenger/ Silica nano-particles formulation did not significantly enhance the rapid mortality as compared with the effect of Silica nano-particle alone at all tested concentrations. Morphological study using light and scanning- electron-microscopy (SEM) on adult mouthparts and alimentary tract revealed that, the Silica nano-particles induced great irregularity or malformation in the mouthparts and the mid-gut morphology causing shortening of adult longevity. It can be assumed that the killing action could be attributed to the reduction in food uptake and digestibility as a result of Silica treatments. Therefore, it could be concluded that Silica in any formulation could be applied as a safe pest control agent. [ABSTRACT FROM AUTHOR]