RESUMO
Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of many agricultural and ornamental crops in tropical and subtropical regions causing damages that result in important economic losses. Insecticides are commonly used in greenhouses or fields to control B. tabaci populations leading to rapid evolution of resistance that render treatments inefficient. Therefore, and for environmental and human health concerns, other approaches must be developed for this pest management. In the present study, we compare, using the leaf dip method, the toxicity of three essential oils (Cymbopogon citratus, Ocimum americanum, and Hyptis spicigera) and three seed oils (Lannea microcarpa, Lannea acida, and Carapa procera) with three chemical insecticides (acetamiprid, deltamethrin, and chlorpyrifos-ethyl) on adults. Two B. tabaci biotypes (MED-Q1 and MED-Q3) belonging to the Mediterranean species and collected in Burkina Faso were used. Essential oils were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. We showed that these two biotypes have different levels of resistance to the three insecticides, MED-Q3 being more sensitive than MED-Q1. Moreover, they differ in the frequency of resistance alleles to insecticides, especially for organophosphates, as these alleles are almost fixed in MED-Q1. On the other hand, the two biotypes prove to be more susceptible to the plant extracts than to insecticides except for chlorpyrifos-ethyl, with essential oils that showed the highest insecticidal activities. Monoterpenes content were the most abundant and showed the highest insecticidal activities. Our results indicated that essential oils, but also seed oils, have the potential to constitute an alternative strategy of pest management.
