Study On Pathogens Of Slash Pine Damping-off In Hubei Province And Biocontrol Bacteria

Slash pint(Pinus elliottii) is an important tree species for foresting in the south China, and the turpeniue produced by slash pine is the important chemical raw material, but damping off occurring during the period of cultivating seedlings reduce its yield and qulity severly. The data both here and abroad indicated that the slash pine damping-off is caused by many fungi including Rizoctonia sp., Pythium sp., Fusarium sp., Aternria sp., Botrytis sp., Pestalotia sp. and so on, and the pathogens in the different area are not the same. In the past the infection and spreading of these pathogens were prevented by physical and chemical methods.The object of the research is slash pine damping-off in Hubei province and the step of research is as follow:l)Surveying the distributing rules of bacteria and fungi at the part of roots afterr the seedlings transplanted to definitive place.2)separating the pathogens of slash pine damping-off in Hubei province, indentifing the primary pathogens and studying on the biological chracteristics.3)screening the bacteria which have antagonistic effects on the pathogens of slash pine damping-off and indentifying them with sequencing their 16S rDNA.4)measuring the antagonistic ability of C23 gained by my screening and the bacteria, including Q2-87, 2-79, Pf-5, 1M1-96, Q37-87, HT5-1, MVP1-4 and FF1R8 afforded by the lab of roots diseases biocontrol department of agriculture USA on the plate,and studying on their colonization ability on the roots of slash pine.Researches demonstrate that: 1)during the several month of transplanting the seedlings to definitive place, the amounts of the microbes in the rhizospere increase and the amounts of the bateria are much more than that of the fungi. 2)the slash pine disease in the hubei province is caused by the complex infection of many pathogens predominated by Rhizoctonia sp., Fusarium sp.and Alternaria sp. Of all the ones with the strongest pathogenicity are Rhizoctonia sp; the most ones are Fusarium sp., and a majority of Fusarium sp. have stronger pathogenicity on the slash pine seedlings; Alternaria sp. have the weakest pathogencity.3) 7 isolates of the bioncontrol ones gained by screening and having the potential of control the slash pine damping off are Burkholderia cepacia; 2 isolates are Bacillus subtilis; one is unknown species.4)C23 isolated...