Study On The Effect Of Capsaicin In Pests Preventing For Grain Storage Of South-central China

Grain is susceptibly damaged by pests, microbe, mice and other biologic hazards during storage time, resulting in the decline in grain weight and quality. While the chemicals which used to protect the grain currently have many shortcomings, so it is very important to research new grain storage insecticide that is safe and environmental friendly. Capsaicin which is no harm to human and the environment has strong spicy. So it is a great development potential botanical insecticide substance. This paper studied the toxicity of capsaicin systematically on the seven kinds of important stored grain pests (Sitophilus zeamais, Tribolium castaneum, Rhizopertha dominica, etc.) in fumigation effect, repellency and population suppression of biological activity. Recode of capsaicin on the hazards of stored grain pests, and the protective effect of the weight and quality of grain, to determine the significance of role of capsaicin in grain storage. Therefore, it provides scientific basis to develop new stored grain protections which are no harm to human and the environment.The test results show that:1. Capsaicin can repel the pests: Sitophilus zeamais, Tribolium castaneum, Rhizopertha dominica, booklice, Cryptolestes pusillus, Cryptolestes ferrugineus.50g/L of capsaicin concentrations can repel more than half the number of the pests (booklice, Tribolium castaneum, Cryptolestes pusillus, Cryptolestes ferrugineus) to control side.2. Respecting the low-grade fumigation effect of capsaicin to pests, author doesn't do much more work about fumigation with sealed triangular flasks. The Contact toxicity of capsaicin is low-grade, too.3. With2%capsaicin ethanol solution sprayed on cargo rice evenly, the effect was studied of capsaicin in Sitophilus zeamais and Tribolium castaneum preventing for grain storage. The results showed that according to the ratio of capsaicin to cargo rice2g/kg and4g/kg, Sitophilus zeamais and Tribolium castaneum appeared distinctly refusing feed effect. The damage rate of cargo rice in30days caused by Sitophilus zeamais were only35.4%and26.4%to that of blank controls, similarly Tribolium castaneum caused damage rate only30.6%and24.8%to that of blank controls. The reproduction number caused by Sitophilus zeamais and Tribolium castaneum was only9.23%and26.1%of blank control, according to0.5g capsaicin per1000g cargo rice. When adding capsaicin2g per1000g cargo rice, Sitophilus zeamais lived only one and Tribolium castaneum zero survived. The result showed that capsaicin had obvious reproduction effect on tested pests.