Penetration of Sitophilus zeamais (Coleoptera: Curculionidae) through diatomaceous earth-treated bulk maize grain

International Journal of Tropical Insect Science - Tập 26 - Trang 28-34 - 2006
B. M. Mvumi1, T. E. Stathers2, P. Golob2, D. P. Giga3
1Department of Soil Science and Agricultural Engineering, University of Zimbabwe, Harare, Zimbabwe
2Natural Resources Institute, University of Greenwich, Kent, UK
3Bulawayo, Zimbabwe

Tóm tắt

The penetration of adult Sitophilus zeamais Motschulsky through maize grain bulks (0.75 m deep), treated with Protect-It®, a diatomaceous earth (DE) at 0, 0.05, 0.1 and 0.2% (w/w), was determined 12 weeks after weevils were released at the upper surface of the grain. Maize was stored in columns in polyvinyl chloride (PVC) pipes, under controlled conditions of 26 ± 2°C and 70 ± 10% RH. Grain samples were collected from various pre-determined depths and the numbers of S. zeamais adults counted. Differences in insect numbers between treatments and at different depths from which samples were collected were highly significant (P < 0.001). The bottom 2–3 layers (0.65–0.75 m deep) had significantly more insects than the upper layers for all the DE concentrations. No significant differences in total insect numbers (live + dead) were found between the DE concentrations. Dead S. zeamais weevils were found at the bottom of grain treated with Protect-It®, indicating that insects can penetrate through DE-treated grain 0.75 m deep but then subsequently die. There was no strong evidence that DEs admixed with bulk grain restrict S. zeamais movement within the grain.

Tài liệu tham khảo

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