The evaluation of the bioactivity of powders from 18 plant species on Acanthoscelides obtectus (Say) was performed considering the effect of these materials on the insect behavior and survival. The proportion of 0.3 g of powder per 10 g of bean grains was used in all experiments. The repellent activity of each powder was evaluated by using arenas with five circular plastic boxes, being the central box linked to the others with plastic tubes, in the diagonal disposition where adult insects could choose boxes containing treated or not treated grains. The number of insects in each recipient was counted after 24h. Insecticidal activity was determined by maintaining 1-day old adults in plastic boxes containing bean grains mixed with powder from each plant. Boxes containing only beans were used as control. Five days after infestation, the number of dead insects and the number of total and fertile eggs were determined. The most efficient treatment was the powder from the aerial part of Chenopodium ambrosioides d. (derivation) 2 that caused repellence, total adult mortality and no oviposition, followed by rinds of fruits of Citrus sinensis (cv. Pera) and leaves of Lafoensia glyptocarpa. Leaves of Coriandrum sativum were non repellent but caused total adult mortality and no oviposition. Powders from aerial part of C. ambrosioides d.1, from leaves of Eucalyptus citriodora, Mentha pulegium, Ocimum basilicum, O. minimum and Ruta graveolens, from rinds of fruits of Citrus reticulata (cv. Murcote) and from fruits of Melia azedarach and L. glyptocarpa were repellent too.
Insect; Phaseolus vulgaris; insecticide plant; bean weevil
