VOLATILE COMPOUNDS DERIVED FROM PLANTS WITH FUMIGANT EFFECT ON Sitophilus zeamais.

Abstract

Corn is one of the most consumed cereals in the world. In Brazil, it is widespread and cultivated for its wide use and the possibility of storage for long periods, without causing damage to grain quality. This quality can be affected by insect pests, being Sitophilus zeamais one of the main ones. Since they have a high degree of reproduction, they complete their grain development cycle, reduce the weight and quality of maize and can attack other crops. The control of this pest is made by synthetic insecticides, which cause resistant insect populations and intoxication of applicators and grains. Natural insecticides from plants emerge as a possibility for pest control such as S. zeamais. The objective of this work was to analyze the fumigation toxicity of compounds derived from plants. The compounds used were: dodecanal, dodecanol, α-Pinene and β-Pinene base compounds found in plants. For the fumigation toxicity bioassays, plastic containers were used, where filter paper discs were placed on the inner side of the lid of each pot (diameter: 2.5 cm, height: 5.5 cm, volume: 24 ml). Then dilutions of the stock solution of each compound were prepared in ethanol and 20 µl of the test solutions were added to the filter paper. After evaporation of the solvent, the lid was firmly placed in the pot, to which 20 insects were added, forming a sealed chamber. Mortality of these insects was evaluated after 7 days. The assays were performed in quadruplicate. Dodecanal and β-Pinene were more efficient, as the mortality rates were: 2,500 ppm (30.4% and 18.9%), 5,000 ppm (70.3% and 55.8%) and 10,000 ppm (92.1% and 76.7%) respectively. In conclusion, the tested compounds are presented asnatural alternatives for S. zeamais control due to their fumigation toxicity.