Bioactivity of the mexican-tea, Chenopodium ambrosioides L., towards Sitophilus zeamais Mots. (Coleoptera: Curculionidae)

This work deals with the influence of the powder and aqueous extracts of Chenopodium ambrosioides L. on behaviour and survival of the maize weevil, Sitophilus zeamais Mots. The powders tested were obtained from leaves, branches, fruits and the whole plant (with fruits), when the plant was in the fructification period. The insects were obtained from a population reared on wheat grains. The effect of the powders from the different vegetal structures and from the whole plant (with fruits) was evaluated concerning the insect behavior (attractiveness and/or repellence) and insecticide activity on the adult phase. The insecticide activity of the aqueous extract from the different structures and from the whole plant (with fruits) was evaluated on immature and adult S. zeamais. The results were as follows: a) powders from fruits, branches and leaves of C. ambrosioides were not repellent to S. zeamais adults; b) powders from fruits and whole plant (with fruits) presented insecticide activity against S. zeamais adults; c) the aqueous extracts from these structures did not affect survival and adult emergence in S. zeamais.

Insecta; maize weevil; Chenopodiaceae; botanical insecticide