Research On Occurrence Feature And Prevention Measure Of Potato Fusarium Wilt

The potato fusarium wilt (Fusarium oxysporum) was a kind of important diseases, in recently years, the incidence of potato blight became more serious every day in some replant plots with the continuous increasing of potato planting, which threated to the potato production already and affected the yield and quality of potato seriously, led to the economic decline directly. So the study which occurrence regularity and prevention measure of potato fusurium wilt was stablished the rationale to research this plant disease. The finding of the study as follow:1. The results of the potting experiment show that the rate of plant wilting, diseased plant and tuber which the soil inoculated bacteria respectively was36.7%,58.3%and71.3%, the rate of plant wilting, diseased plant and tuber which seeding with diseases potato seed respectively was11.7%,18.0%,21.4%, so the primary infection source is soil inoculated bacteria, seeding with diseases potato seed is also higher.2. The results of plant disease occurrence in the field with different fertilizer types and cultivation ways show that, rational fertilization can postpone the morbidity of plant disease, the rate of plant wilting and tuber which applied urea plant respectively was13.3%and47.1%. It was markedly lower than CK and other treatments and the production reached the highest, which is2202kg/667m2; Secondly, the treatment with the potato special fertilizer and bicarbonate showed that the rate of plant wilting rate lower than CK, and the yield somewhat increase. Using the cultivation with membrane and ridging could effectively reduce the disease rate of tuber.3. From the collection of crop rhizosphere soil sample by separating, screening had better antagonistic effect various of106strains, among them, fungi,1; actinomycetes,43; bacteria,62; mainly including Bacillus type bacteria. The strong and stable antibacterial effects were two strains of bacteria H-12and W-5, the bacteriostasis belt width were5.5mm and7.0mm respectively.4. Through the control efficience of indoor, the determinations of strains H-12and W-5to the prevention effects of potato blight, which have reached more than80.0%, respectively82.8%and81.5%.5. In the test of rhizosphere colonization show that, their biomasses represented were different downturn in a period, but they both were stable in fine, respectively was 2.3×105cfu/g and6.1×105cfu/g, could be better fixed in plant rhizosphere soil; while the colonization test in the potato root show the biomasses of strains H-12and W-5were downturn constantly and were lower than biomasses in the soil, which colonization time were short, respectively only were77cfu/g and16cfu/g after20days.6. Through researching on the morphological and physiological and biochemical reaction of the Bio-controlling strains H-12and W-5, combined with16S rDNA sequence analysis, the strain W-5was identified as a Bacillus subtilis; but strain H-12could not be accurately determined its taxonomic status, so being identified as Bacillus (Bacillus sp.) temporaryly.