Effects Of Soil In Different Regions And Temperature On The Persistence Of Lecanicillium Lecanii

As an important entomogenous fungus,Lecanicillium lecanii plays an important role in the integrated pest control.Clarifying the persistence of Lecanicillium lecanii in different regions has important guiding significance for the prevention and control of pests in farmland.The results of this study are as follows:1.Difference in the persistence of Lecanicillium lecanii in different regions.The results showed that the Lecanicillium lecanii(whose powder passed through 20 mesh sieve)was applied to soil in autumn and winter of 2018,and the initial concentration of 10~7/g of Lecanicillium lecanii was applied in Beijing City,Langfang City of Hebei Province and Penglai City of Shandong Province for one month:the CFU(colony forming unit)was the highest in Penglai City,and that was the lowest in Beijing City;the initial concentration of 10~7/g of Lecanicillium lecanii was applied in Beijing City,Langfang City of Hebei Province,Kaifeng City in Henan Province and Zhangjiakou City of Hebei Province for three months:the CFU was the highest in Kaifeng City,that was similar in Beijing City and Langfang City,and that was the lowest in Zhangjiakou City;for the initial concentration of 10~6/g of Lecanicillium lecanii,the CFU was similar in Beijing City,Penglai City in Shandong Province,Kaifeng City in Henan Province and Zhangjiakou City in Hebei Province,and that was the lowest in Langfang City in Hebei Province.In 2018,Lecanicillium lecanii was applied in Beijing City,Langfang City of Hebei Province,Penglai City of Shandong Province,Kaifeng City of Henan Province and Zhangjiakou City of Hebei Province,the CFU dropped to 10~3 after 8-11 months.In 2019,the persistence of Lecanicillium lecanii(whose powder passed through 50 mesh sieve)was in these regions again.When the initial concentration of 10~7/g and 10~6/g of Lecanicillium lecanii was applied for one month,the CFU was the highest in Beijing City and the lowest in Langfang City;for 3-4 months,the CFU in Beijing City,Langfang City,Penglai City and Kaifeng City all dropped to 10~3,but the CFU in Zhangjiakou City was at the level of 10~4 after 5 months.2.Differences in persistence of Lecanicillium lecanii in soil in laboratory.Paddy soil and red soil from Dongfeng Town,Jian'ou City,Fujian Province,farmland soil from Weishi County,Kaifeng City,Henan Province,soil from beichenghuang Island,Penglai City,Shandong Province,soil from Bashang and Baxia,Zhangjiakou City,Hebei Province,soil from experimental base of Chinese Academy of Agricultural Sciences,Langfang City,Hebei Province,soil from Zhongguancun experimental base in Beijing,soil from Mohe Town,Heilongjiang Province,and soil from Southwest University in Chongqing.The 10 samples were air-dried and prepared to 15%soil moisture,and the experiments on the persistence of Lecanicillium lecanii(whose powder passed through 50 mesh sieve)was carried out in the incubator at 25?,15?,4?and 0?.The results showed that at the same temperature,the CFU of Lecanicillium lecanii in Fujian soil was the highest than that in other regions;and the higher initial concentration of Lecanicillium lecanii fell faster.At the temperature of 25?,the CFU was lowest than that of 15?,4?and 0?in soil of all regions;at the temperature of 4?,the CFU was highest than that of 25?,15?and 0?in soil of all regions.