Rhizoctonia Solani Toxin Pathogenic Mechanism And Six Fungicides Measured The Virulence Of Rhizoctonia Solani

Pellicularia sasakii is one of the serious disease of the world, it deduced productions and threatened food safe。Recently, it occurred frequently and has blocked the rice high-production. With wide using of chemical pesticide, pesticide resistance becoming the focus.The result has showed that Crude toxin of Rhizoctorzia solani was harm to sheath and cell membrane of leaves. It changed the preciousness of cell membrane and leakaged the substances. With 5-10 times toxin dilution, damage probability of the cell membrane was above 80% and trended to up with prolonging handling time. Besides, it restrained plants chlorophyll contents. With 10 times dilution, chlorophyll contents were less 85% than control samples and the contents were lower with higher of toxin contents and longer of dealing. Crude toxin of Rhizoctorzia solani could promote the activity of Ache, esterase, GST etc in sheathes and leaves of rice. When the toxin dilution reAched between 20 and 200times, Ache, esterase and GST activity were higher than control samples, but when the dilution magnification was bigger, those activities were no obviously change. Moreover, there was a relative relationship between enzyme activities and handling time. Generally, enzyme activities increased with prolonging toxin handling time. After 2-3 days of toxin handling, enzyme activities reAched the top, and then decreased.Five bactericides was used to take biologicall test of Rhizoctorzia solani indoor, the test showed that EC50 of Hexaconazole was lowest, but its bacteriostasis was the best, the worstest was Thiram. Thiram is a protective bacteriacide and can't be absorpted and translocated. Hexaconazole can be absorpted and has a good precaution and treatment effects. Its action mechanism is to stop biosynthesizing germs phytosterols non-ergot-derived, destroy forming germs cell membrane and finally put germs into dealth.