Abstract

Termites are most pestiferous insects causing damage to crop and buildings. Their control still relies mainly on harmful chemical pesticides to the detriment of eco-friendly pesticides. The aim of this study was to evaluate the effect of three plant extracts on the survival rate of termite species, Macrotermes subhyalinus Smeathman and Trinervitermes geminatus Wasmann, known to cause damage to crops, vegetation and buildings in Togo. Cissus quadrangularis (Vitaceae), Pennisetum purpureum Schumach (Poaceae) and Vetiveria zizanoides Nash (Poaceae) extracts were examined for their termiticidal activity against these termites. Three formulations including acetone and hexane extracts and powder were prepared for each plant species at five different concentrations. Six replicas were made for each tested concentration with 30 workers per replica in the laboratory conditions. All the tested plants showed termiticidal activities by reducing the rate of survival duration of tested termites. The powder of V. zizanoides was very effective on M. subhyalinus; its lowest concentration (5 mg/cm²) reduced the survival rate of this termite by up to 87%. Among the extracts, acetone extract of P. purpureum caused the highest reduction of M. subhyalinus survival rate at higher concentration. Both acetone and hexane extracts of V. zizanoides were very effective on T. geminatus, reducing by more than 90% survival rate of this termite. Although these plants extract seem to bear potential termiticidal activity, however, further studies need to be carried out in order to determine their respective components.

Key words: Botanical insecticides, Cissus quadrangularis, Pennisetum purpureum, Vetivera zizanoides, termite species.