Study On Insecticidal Activity Of Crude Extract Of Metabolic Protein Of Isaria Fumosorosea IF-1106

Isaria fumosorosea is an important entomogenous fungus that can be used for biological control.Toxic substances produced in the process of growth and metabolism are one of the main factors causing insect diseases or death.The isolation,extraction and activity of the strain are helpful to elucidate the pathogenic mechanism of the strain to insects.It is also the basis for expanding its medicinal value.In this study,crude protein was extracted from the culture medium of Isaria fumosorosea IF-1106.Their insecticidal activities against Myzus persicae were determined by three biological methods,and the changes of blood cell numbers in the blood cells of the Myzus persicae were observed.The results showed that the molecular weight of crude protein extracted from Isaria fumosorosea IF1106 of medium was40~70 k Da.The insecticidal activity of blood injection method and artificial feeding method was significantly higher than that of surface contact method.After the blood cavity injection,the Myzus persicae darkened,some of its chest and abdomen darkened,some of its chest darkened,and then died.The cumulative corrected mortality reached(81.85±13.45)%,when injected high concentration crude protein extract about 132 h.The cumulative corrected mortality reached(85.45±11.88)%,After feeding high concentration crude protein extract about 144 h.After feeding and injecting the crude protein extract,the proportion of plasma hemocytes and granulosa cells in the adult of Myzus persicae increased and then decreased.On the 3rd day after injection,the percentage of plasma hemocytes of Myzus persicae increased significantly to(28.58±3.08)%.After feeding crude protein was reached(33.75±2.14)% at the 3rd day.After feeding and injection for 2 days,The proportion of plasma cells on the 2nd day of the treatment of Myzus persicae was significantly increased,reached(22.17±2.28)%.The proportion of granulocytes in the feeding treatment was(18.56±1.74)%.The above studies showed that the crude extract of Isaria fumosorosea IF-1106 has high injection and feeding toxicity to adult Myzus persicae,and it is a kind of active metabolite with research value.This study not only helps to elucidate the pathogenic and toxic mechanism of this strain on insects,but also provides theoretical support for the screening of highly virulent strains and the development of highlyeffective fungal insecticides.It has certain significance for the commercialization and industrialization of Isaria fumosorosea strains.