A Survey Of Pests Species In Stored Cassava Chips And Control Researches On Its Main Pest:Araecerus Fasciculatus(De Geer)

Through to storage in dry cassava slices pests survey in the main producing areas of the country by the Guangdong and Guangxi provinces of cassava and the customs intercepted documents identity their pest species of56species belonging to three orders,21families, eight kinds of pests, including Araecerus fasciculatus (De Geer) is a major species, because borer hazards seriously affect the value of dry cassava chip. Araecerus fasciculatus (De Geer), belonging to Coleoptera, Anthribidae, is a storage pests of tropics zone. Araecerus fasciculatus (De Geer) not only can harm beans like dried cassava slices, but also harm cocoa, coffee, corn, vegetable herbs, garlic and many other stores. The insect is native to India and have occurred among various provinces.This dissertation from the high and low temperature, carbon dioxide atmosphere and ethyl fumigation three areas to prevente Araecerus fasciculatus, the findings provide a theoretical basis and reference for actual production prevention and control of Araecerus fasciculatus. The main conclusions of this pilot study were as follows:High temperature treatment is relatively strong lethal effect on Araecerus fasciculatus, increase the process temperature, prolong the treatment time, the mortality of Araecerus fasciculatus all3instars adults, pupae and larvae increase correspondly.3h dealing under50℃the mortality rate of all3instars below22%.3h at60℃and2h or long time at65℃the mortality rate of all3instars reached100%, prevention effect is good.2.5h heat treatment under60℃, adults and pupae mortality reaches100%, the larvae can reach98.3%. It showed, under60℃and65℃dealing with relative short period of time have good prevention effect on the Araecerus fasciculatus.Low-temperature have a greater impact on Araecerus fasciculatus. Decrease the dealing temperature, and prolong treatment time, the mortality of Araecerus fasciculatus all3instars adults, pupae and larvae increase correspondly. Dealing with-15℃and-20℃for4h or-25℃for2h can perfectly kill all three instars of Araecerus fasciculatus.-5℃and0℃completely kill the three insects states a longer dealing time256h was needed. This shows that at a certain low temperature conditions appropriate to extend the processing time, low temperature will have a good control effect on Araecerus fasciculatus. The carbon dioxide concentration of atmosphere is also a prevention of Araecerus fasciculatus, while increase the concentration of carbon dioxide, and prolong the dealing time, the mortality ofAraecerus fasciculatus adult and larval increased. The test shows that the larvae is not so sensitivity compare with adult to the concentration of carbon dioxide in the ambient temperature25℃, under conditions of humidity around70%. With40%%65%、80%of the carbon dioxide atmosphere were treated Araecerus fasciculatus adult5d,4d,3d, the mortality can reach100%. Use80%of the carbon dioxide concentration in the processing of coffee beans as larvae5d, the mortality rate is less than90%;80%of the carbon dioxide treatment using beans as6d, the mortality rate was100%.Ethyl formate is another recommend prevention for Araecerus fasciculatus, with increasing the dosage of Ethyl formate, and prolong the exposure time, the mortality of adults, pupae and larvae of Araecerus fasciculatus will rise. Treatment at a concentration of ethyl30μ1/1of60h, Araecerus fasciculatus adults and larvae mortality was100%and pupae mortality88.3%;60h fumigation under Ethyl concentration of35μ1/1the pupae mortality more than90%. Compare to adults and larvae, pupae require higher concentrations of ethyl or longer exposure time to death.