Investigation of chestnut cancer causing phytopathogenic fungus Cryphonectria Parasitica’s (Murrill) antagonist microscopic fungi in the Sachkhere region of Georgia.

Author: Qetevan Benashvili
Keywords: chestnut blight, antagonist micromycetes, vegetative compatibility.
Annotation:

The massive devastation of Chestnut (Castanea sativa Mill.) forests, caused by the pathogenic fungus from ascomycetes - Cryphonectria parasitica (Murr.) Barr, is a worldwide problem today. This botanical catastrophe of the century significantly touched Georgia as well. No effective method has been found yet against this pathogen. The only approach used widely is a biological control of a disease. Since, a biocontrol method that means application of hypovirulent strains is not suitable for Georgia because of existence of a great variety of vegetatively compatible groups of C.parasitica. Revealing and testing of antagonists agains to the pathogen microorganism is more and more worldwide accepted experience. The aim of the research was to isolate strains of C.parasitica from Imereti region (west Georgia)) villages: Darka, Eto, and Chala, and to assess antagonistic effect of the aboriginal microscopic fungi. Several strains of C. parsitica were isolated and identified from the necrotic cankers of the bark, near the sick trees, as well as some strains of different soil micromycetes were isolated from the same locations. Antagonistic effect of each strain against C. parasitica was studed. Vegetative compatibility within C.parasitica strains has been investigated. Studed strains of C. patasitica did not reveal any vegetative compatibility, which shows the high genetic diversity of C.parasitica in Georgia. Totally 50 isolates of microscopic fungi have been obtained from studied soils, identified and their collection has been created. Among the investigated micromycets only genera: Penicillium, Trichoderma and Aspergillus proved their antagonistic effect. No information existed about Aspergillus antagonistic effect before. In our study Aspergillus spp. strains appeared to be especially effective against the pathogenic fungus. Two species of Aspergillus - A. Niger and A. Flavus have revealed the full dominance on C.parasitica. Experimental results have both theoretical and practical importance. The collection of antagonists of C. parasitica may serve as the base for management and localization of chestnut blight cancer, since it seems possible to create and test in situ the antinecrotic bio-preparation.