The Research Of The Movement Behavior Of Stored Grain Pests Under Different Temperature

The influence of temperature on diffusion rate of Tribolium castaneum, Sitophilus oryzae,Sitophilus zeamais, Rhyzopertha dominica, Oryzaephilus surinamensis was researched underthe condition of different temperature and situations. The diffusion rate was monitored onsurface of solid and wheat bulk in a perspex groove, wheat seed column that temperature wascontrolled in uniformity and in gradient with the grain bulk. Influence of temperature on flightinitiation of Tribolium castaneum and Rhyzopertha dominica was observed.Crawling speed of stored grain pests on solid surface were influenced by temperaturesignificantly. The minimum temperature to crawl were15℃,11℃,10℃,12℃,12℃both onsolid surface and wheat bulk for Tribolium castaneum, Sitophilus oryzae, Sitophilus zeamais,Rhyzopertha dominica and Oryzaephilus surinamensis. Crawling speed of stored grain pestswas grow up in a line from the critical temperature to30℃. Crawling speed of Triboliumcastaneum and Rhyzopertha dominica were declined slightly from30℃to35℃. Triboliumcastaneum crawl speed in the grain surface was exponential growth. Other insects were lineargrowth.Stored grain pests showed active crawling behavior in the12~30℃wheat seed columnexcept Rhyzopertha dominica. In the wheat seed column Sitophilus oryzae, Sitophiluszeamais and Oryzaephilus surinamensis showed a certain climbing habit, but migration rate:the level> up> down. Rhyzopertha dominica was gathered in the grain, crawl rate is notsignificantly affected by temperature.Using the trapping method to determine Tribolium castaneum, Sitophilus oryzae,Sitophilus zeamais and Oryzaephilus surinamensis is valid from12℃to35℃. Crawlingspeed of Tribolium castaneum is the lowest under the same temperature. We can calculate thetrapping time according to the craw time Tribolium castaneum needed from the bottom of thegranary to the grain surface. By this time and the level of Tribolium castaneum crawlingspeed, calculate horizontal range the trap can be detected.Stored grain pests showed significant trend warm behavior in the wheat seed columnwith temperature gradient. The favorite temperature zone is25～35℃. At the beginning, crawling speed increased gradually when pests craw to the warm end. Then crawling speeddecreased when the temperature became higher. The number of insects distributed in therange22~25℃and25~28℃were similar because Sitophilus oryzae, Sitophilus zeamaishave climbing habit. In the optimum temperature28~31℃, the crawling speeds:Oryzaephilus surinamensis> Sitophilus zeamais> Sitophilus oryzae> Tribolium castaneum.We should focus on the parts of the grain temperature above22℃when using trappingmethod.More Tribolium castaneum and Rhyzopertha dominica fly under the condition withlight.For Tribolium castaneum, the take-off rate is about1.09to1.38times higher thancondition without light. For Rhyzopertha dominica, the take-off rate is about1.24~8.30times higher than condition without light. The best take-off temperature for Triboliumcastaneum is28±1℃at150±5Lux light conditions. After24h71.67%Triboliumcastaneum flied out. Under the same condition, the best take-off temperature is30.0℃forRhyzopertha dominica and21.57%pests flied out within the experimental period.