Tribolium castaneum (Coleoptera: Curculionidae) sensitivity to repetitive applications of lethal doses of imidacloprid and extracts of Clausena anisata (Rutaceae) and Plectranthus glandulosus (Lamiaceae)

  • A Goudoum
  • LS Ngamo
  • MB Ngassoum
  • LN Tatsadjieu
  • CM Mbofung

Abstract

Nowadays, chemical control strategies in crop protection are mostly based on biopesticides or on low persistence synthetic molecules. These tools are alternatives of some products exhibiting adverse effects on consumers and polluting environment. Biopesticides made of essential oils of aromatic plants are more and more advised as user and environmental friendly crop protectants. Few works reviewed consequences of their repetitive use on the capability of the pest to resist to their insecticidal efficiency. The present work was carried out to compare the variation in the efficiency of a synthetic insecticide, imidacloprid and essential oils of Clausena anisata (Rutaceae) and Plectranthus glandulosus (Lamiaceae) against the flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae), during 4 generations (F4). The lethal dose of these insecticides that causes 80% of mortality (LD80) at the first generation killed at the 3rd generation, 60% of pest for the two essential oils and 25% for imidacloprid. At the 4th generation, 25% of the pest populations were killed by the essential oils and 5% by imidacloprid applications. Egg and post-ovum development time differed among generations (P < 0.001). However, the fecundity of sensitive females was greater than that of resistant ones treated with essential oils. Insects treated with imidacloprid exhibited important fecundity in advanced generations. The LD50 level of the F4 treated with imidacloprid is 10 times that of the parental generation; however, the increase doubled from the parent to the F4 while treated with the essential oils. This work showed that T. castaneum could acquire resistance to imidacloprid faster than to 2 tested essential oils. © 2010 International Formulae Group. All rights reserved.

Keywords: Chemical control, Essential oils, Imidacloprid, Susceptibility, Stored products, Tribolium castaneum.

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