Biological Characters, Sensitivity To Fungicide And ITS Sequence Analysis Of The Pathogens Caused Anthracnose From Rubber Trees

Colletotrichum gloeosporioides (Penz.) Sacc proves to be an important plant Pathogenic Fungi, which is classified as Fungi, Eumycota, Deuteromycotina, Coelomycetes, Melanconiales, Colletotrichum Corda. On the rubber trees, it can lead to anthracnose that will result severe defoliation and reduce the production of latex.Generally, Colletotrichum gloeosporioides (Penz.) Sacc starts to endanger the rubber trees in young leaf period and high-moisture situation. But in 2004, we observed that some aging rubber leaves also occurred harmful disease whose symptom was just like the anthracnose, in some farms of Yunnan Banna district in drought condition, we named it as OLAR, comparatively the disease happened in young leaf period called YLAR. Up until now, whether OLAR and YLAR had essential difference or the same pathogeny had not been studied clearly. If we can answer these questions exactly, these would have a directed significance on the effective prevention of Colletotrichum gloeosporioides (Penz.) Sacc. This research aimed at these problems, and carried on the contrast analysis on OLAR and YLAR. The contents and results consisted of the following four aspects:1 A contrast analysis on biological characters of the pathogens.The results indicated that: The variety scope of the mycelial growth rates, colony pattern, conidial size of all the experimental fungal strains were slightly. The best temperature for growth was proved to be 24~28℃,pH 5.0~7.0, as a whole, the growth rate of YLAR's mycelium was a little quickly than that of OLAR's.2 Contrast analysis on pathogenicity.Inoculated OLAR and YLAR to stabbing and unstabbing young rubber tree vane respectively, then checked the severity degree after 30h, 48h and 72h. When dealing with the 72h, the changing scope of OLAR on stabbing leaf was 28.30%~88.30%, while YLAR was 55.83%~74.17%, which indicated that OLAR's pathogenicity range was notably higher than that of YLAR; the scope of OLAR in unstabbing was 9.50%~31.7%,YLAR's was 17.08% ~50.00%, the range of OLAR was less than that of YLAR. All in all, under the stabbing situation, the pathogenic ability of OLAR was higher than YLAR, while unstabbing the result was opposite.