The Sitophilus zeamais species is a major pest of stored maize in Brazil. The control is made, usually, using measures of hygiene and cleanliness, synthetic insecticides and fumigant protectors. The search for less toxic products, biodegradable and safe from an ecological point of view is very well accepted by society. the objective of this study was to test the toxicity by contact and ingestion and fumigant of essential oils and eugenol natural organic compound for adults of S. zeamais. The values of LC50 in oil from leaves of Piper hispidinervum, Eugenia uniflora, Cinnamomum zeylanicum, P. marginatum, Schinus terebinthifolius, Melaleuca leucadendron, green fruits of S. terebinthifolius and eugenol compound in tests of contact and ingestion were estimated at 1.0; 11.6, 14.2, 21.1, 57.7, 75.8, 98.8 and 14.8 L/40 g maize, respectively. The toxicity ratios (TR) ranged from 1.3 to 98.8. In the fumigation of adults, the lethal concentrations ranged from 0.53 to 94.7 L/L air, in the following order of toxicity: P. hispidinervum > P. aduncum > S. terebinthifolius > green fruits of S. terebinthifolius > P. marginatum > eugenol, and the TR ranged from 2.0 to 178.7.
Weevil maize; bioactivity; plant insecticides; lethal concentrations
