ACTIVIDAD INSECTICIDA DEL ACEITE ESENCIAL DEL PAICO Chenopodium ambrosioides L. SOBRE Sitophilus zeamais Motschulsky

Sitophilus zeamais is one of the major pests of stored cereals worldwide and its control is based on the use of synthetic insecticides, but their irrational use has caused environmental pollution and resistance. Essential oils have shown contact and fumigant insecticidal effect and could be an alternative to synthetic compounds. Hence, the insecticidal properties of essential oil of Chenopodium ambrosioides L. were assessed under laboratory conditions against adults of Sitophilus. zeamais. The variables studied were contact and fumigant toxicity, and antifeedant and repellent activity. Mortality by contact toxicity did not exceed 30% in all the treatments evaluated. The highest F1 reduction was observed in the treatment of 4.0% with 41.3% of emergence (58.7% of inhibition). Grain weight loss 283 Aros, J. et al. Aceite esencial de Chenopodium ambrosioides sobre Sitophilus zeamais was lower than 9.0% and maize germination was not affected. All treatments exhibited fumigant activity, while concentrations equal to or lower than 0.5% showed repellent and feeding deterrent effect. It can be concluded that essential oil of Ch. ambrosioides has potential for S. zeamais control.