Studies Of Resistance And The Physiological And Biochemical Effect On Cumber Leaves Of Isaria Fumosorosea Pf9606

Currently, Isaria fumosorosea, one of important entomopathogenic fungi,had been registered for pest control in North America and Europe.In this experiment,taking Isaria fumosorsea Pf9606and cucumber leaves as materials,studing the effect by stress of high temperature and ultraviolet on the spore germination and appressorium formation of Isaria fumosorosea Pf9606was studied in this experiment, the compatibility of Pf9606with ultraviolet protectants and fungicides,the physiological and biochemical effects pesticides on cucumber leaves was studied additionally.The results were as follows:1.Under the laboratory condition,the efffect on the conidial germination and appressorium formation was studied under high temperature.The results showed that the treatment of sustained high temperature had a great influence on the conidial germination of Isaria fumosorosea,the germination rate was less than10%between36℃～45℃;it decreased significantly with temperature rising,the spore germination rate was still up51.91%at36℃,and appressorium formation rate of4.44%in7h, the germination rate dropped to8.73%and appressorium formation rate of0at42℃;,they were significantly different under the same temperature, the conidial germination rate was56.81%at42℃but appressorium formation rate of1.2%in3h,they were both0after7h. When exposured to36℃,39℃,42℃,45℃, the Lt50were8.12h、6.95h、3.72h、3.03h。2. The UV irradiation ability of Isaria fumosorosea Pf9606was mesured through UV mutagenesis.it turned out that the conidial germination rate decreased significantly with the time increasing by UV,it reduced from55.33%to0when the time was extended from50s to180s by UV.The Lt50was52.94%when it exposured to UV.3. The compatibility of Isaria fumosorosea Pf9606with UV protectants was studied by pendant-drop method.The results showed that Isaria fumosorosea could be protected by Ascorbic acid and sodium to a certain extent,but not Congo red and zinc oxide.The ideal concentration of ascorbic acid was0.2mg/mL, and0.9mg/mL of sodium fluorescein.4. The compatibility of Isaria fumosorosea Pf9606with fungicides was studied. There was almost no inhibition on the conidial germination rate of Isaria fumosorosea by fungicides with normal concentration,but there were differences between them.The conidial germination rate was less than7%by Streptomycin, metiram,metalaxylmancozeb and13.72%of fiumorph-mancozeb. 5.The effect on MDA and protein content in cucumber leaves by pesticides was studied with foliar spray.Results showed that MDA content increased inordinately by different pesticides.It had no significant differences by Isaria fumosorosea compared with the control but significantly higher by the other three chemical pesticides. The MDA content by deltamethrin was1.7times much than the control in6th day; the protein content was significantly lower than the control by three kinds of chemical pesticides,it was the loweset by deltamethrin in10th day and significantly lower than the control.6. The effects on antioxidant enzyme activity in cucumber leaves by pesticides was studied under laboratory condition,the SOD activity in cucumber leaves rised and then fell within10d.It had no significant differences by Isaria fumosorosea compared with the control and increased significantly by three oher kinds of chemical pesticides,compared10d to2d,the SOD activity increased by41.2%,48.9%by acetamiprid and deltamethrin.7. The activity of peroxidase rised and fell by different pesticides and had no significant differences by Isaria fumosorosea compared with the control. It was1.22times than the control in6th day by deltamethrin and significantly higher in8th day by acetamiprid and imidacloprid,they had no significant difference commpard with the control in10th day. The trend of CAT was similar to POD.