Effectiveness of two diatomaceous earths (FossilShield® and SilicoSec®) against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) infesting two maize varieties (CLH103 and SHABA) at storage
By: Fotso Tagne Gabriel, Tofel Haman Katamssadan, Nukenine Elias Nchiwan, Adler Cornel
Key Words: Sitophilus zeamais, Diatomaceous earths, Malathion, Maize variety, exposure periods.
Int. J. Agr. Agri. Res. 8(5), 1-13, May 2016.
Influence of maize varieties CLH103 and SHABA on the effectiveness of FossilShield® and SilicoSec® against Sitophilus zeamais was evaluated in laboratory. Each product was used at 0, 0.5, 1, 1.5 and 2 g/kg and four exposure periods (1, 3, 7 and 14 days) for adult mortality and F1 progeny production. Damaged and germinated seeds were also assessed. Malathion (positive control) was used at the recommended dosage (0.5 g/kg). Probit analysis showed that FossilShield® and SilicoSec® were more toxic to weevils on CLH103 than SHABA from 3 days post-infestation, while within 1 day post-infestation, the two products were rather more toxic on SHABA than CLH103. Student t-test showed significant difference between the two maize varieties treated with FossilShield® in the reduction of adult emergence at 1 g/kg while with SilicoSec® this difference was observed for all concentrations. Malathion as positive control completely inhibited the development of insects on the two maize varieties. Like Malathion at the single dosage (0.5 g/kg), the number of emerged insects was completely reduced by each diatomaceous earth (DE) at 2 g/kg. FossilShield® (from 1.5 g/kg) reduced completely grain damages in the CLH103 variety, while FossilShield® (2 g/kg) almost reduced grain damages (1.0%). SilicoSec® achieved complete reduction on CLH103 variety, while, on SHABA variety, the reduction of grain damage was significantly different (7.4%). Seed germination was not affect by the DEs. In this study, the results showed that utilization of FossilShield® and SilicoSec® could be favorably considered as alternative solution to Malathion against Sitophilus zeamais.