Studies On Biological Characteristics And Toxin Of Mycoparasite Of Cronartium Ribicola (Pestalotiopsis Sp.)

Armandii pine blister rust, caused by Cronartium ribicola,is a devastating stem rust. It mainly destroys middle and young stand, and leads to significantly declining in high growth, stem diameter and stem volume of armand pine Branches wither and eventually die, when the cankers circles the trunk circumference more than half. Chemical control has dominated over last decades, although some positive study results have been obtained, the disease has been spreading rapidly because there are still some difficulties on using some control methods. It will be a potentially high risk for Upper and Middle Protection Forests of Changjiang River and difficult to the recover the ecology. Mycoparasites, considered as important biological control agents for plant diseases, exit commonly in nature. One mycoparasite of Cronartium ribicola has been screened by member of the heading group about Research on mechanism of Acremonium eryuanensis infecting Cronartium ribicola. This isolate excreted toxin, and caused aeciospores necrosis. The research of MM011 biological characteristics and its toxin has important theoretical and practical significances to develop a new biological pesticide. The biological characteristics of MM011, the extraction and traits of its toxin, the parasitic mechanisms and the seperation and purification of active ingredient in toxin were systematically analysed and researched, and the controlling effect of mycelia and original toxin liquid of MM011 on infected (by Cronartium ribicola) Pinus armandii was evaluated in this paper. The main results were listed as the following:(1) Effect of nutrients on the mycelial growth of MM011: it was showed that polysaccharides were favorable for mycelial growth than monosaccharide or disaccharide. Significant differences of mycefial production existed among carbon sources. Solubility starch and maize flour were the most suitable carbon sources for mycelia growth of MM011, but it had practically no access to lactose. Organic nitrogen (protein peptone, yeast extracts, soy powder) and various amino acid (glutamic acid, glycine, aspartic acid) were well used by MM011, inorganic nitrogen in the ammonium and nitrate nitrogen could hardly be used. Inorganic salts Phosphate (sodium phosphate and potassium phosphate) of inorganic salts were more favorable for mycelial growth than other inorganic salts, and the optimum salt was sodium phosphate. Mycelial growth of MM011 existed certain differences in different growth factor, the facilitation wasn't obviously, and only the colony diameter of one which was added compound vitaminB was bigger than the control.