| Lasioderma serricorne is a worldwide pest of stored products, also a major pest of stored tobacco. This pest distribute widely and has strong reproduction capacity, also it has caused huge losses for tobacco industry. In this paper, we studied patterns of distribution and occurrence for Lasioderma serricorne in Linyi, and discussed the physical, chemical and biological control technology.Therefore we could provide theoretical basis for the prevention and treatment of the Lasioderma serricorne.The main results are as follows:1 By surveying the number of Lasioderma serricorne, we found that the population decreased and dropped greatly from 2008 to 2009 in Linyi tobacco recured factory.The average number of population was 37.4 per week per trap in 2008, and the number has dropped to 6.4 per weekper trap in 2009. At the same time, we surveyed the population density of Lasioderma serricorne and the loss of tobacco,and we found that the population density of the upper layer is bigger than that of the middle layer,and the population density of the middle layer is bigger than that of the lower layer. Lasioderma serricorne also caused the loss of tobacco, and the average loss was 4.2% and 1.18% in 2008 and 2009, separately.2 We also studied the occurrence pattern of Lasioderma serricorne in Linyi. It breeded three generations one year, and different generations overlap apparently. It survived the winter with older larvae in tobacco leaves.Overwintering larvae begun to move in mid-April, and the occurrence of the first generation reached peak in late June and early July.The third generation of adults occurred in early October.Overwintering generation started its activities later in 2009 compared with 2008. This was related to the lower temperature in April 2009. The duration of larvae was significantly greater than that of egg stage, the pupal stage and pre-spawning stage. The larval was the endanger state, and duration of adult was short.3 we studied effects of extreme temperatures to kill Lasioderma serricorne,and found that all the used temperatures all can kill every state of Lasioderma serricorne.The lower the temperature,the shorter the time needed (-20℃, 1h), (-15℃,5h), (-10℃,18h), (-5℃,7d), (0℃,13d), (5℃,28d).Also we found that the sensitivity of Lasioderma serricorne to low temperature was different at different growth stages. Egg stage was the most sensitive period to the low temperature; We also set seven high treatments (45℃,55℃,65℃,75℃,85℃,95℃,105℃) and found that constant exposure to high temperature also could kill Lasioderma serricorne. The mortality rate of pupae was 100% when they exposed at 85℃for 5 min, while larvae required higher temperature of 95℃for 100% mortality. The adults was more endurable to high temperature than eggs and larvae.The high temperature of tobacco-recured can meet the requirements of killing Lasioderma serricorne.4 We conducted experiments of three different pesticide(56% of aluminum phosphide,85% of the pirimiphos-methyl,2.5% of the deltamethrin) to control Lasioderma serricorne. The results showed that the mortality rate of pupae was 100% when the concentration of aluminum phosphide was 5.6 g/m3 and LC50 was 1.2169g/m3. Themortality rate reached 93.8% when the concentration of pirimiphos-methyl was 1200mg/L.With the increase of the concentration of deltamethrin, the control effect enchanced. Themortality rate was over 94% with 4 mg/m3 deltamethrin treatment,and LC50 was 27.827x 10-4μg per head.5 we studied the effects of Beauveria bassiana and Bacillus thuringiensis on Lasioderma serricorne. After inoculation with 1.46×109,1.46×108,1.46×107 spores per mL Beauveria bassiana, second instar larvae began to die from the fourth day. The Mortality rate was 100% at 14dpi,15dpi,18dpi, separately(dpi:day past inoculation).Eighteen Bacillus thuringiensis strains were isolated, and their control effects were different. Four of them can over 85% and one was over 96%. |
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