Exposition of Pecan Black Aphid (<i>Melanocallis caryaefoliae</i>) to Creseote Bush (<i>Larrea tridentata</i>) Extracts

Abstract

Creseote bush-based (Larrea tridentata Cov.) botanical insecticides have not been evaluated on pecan black aphid (Melanocallis caryaefoliae D.), the purpose of this research was to test the insecticide and/or repellent effect of the creseote-bush raw extracts on this insect. Ethyl acetate, methanol and water as solvents, the stem and leaf organs were tested at concentrations of 0.5%, 1%, and 2%, as well as their witnesses and the interactions of each. Extract application was made by immersion during 10 s and the incubation was made in a wet chamber, making observations at 24, 48 and 72 hours after the treatment was applied. Mortality was evaluated by touching the aphid and seeing it did not move, while for repellence the insects found outside of the leaf were taken into account. A higher mortality effect was observed at a 1% concentration for the three solvents on the leaf extracts, being the methanol one the most efficient, on the other hand the stem extracts had the same behavior, presenting the higher mortality in the ethyl acetate extracts at 0.5% and 2% both at 72 hours. On the other hand the higher repellent effect presented at 24 hours in stem extracts, with a variation in the leaf extracts.