Вплив Trichoderma Viride 017 на мікоценоз кореневої зони рослин огірків

Анотація

THE INFLUENCE OF TRICHODERMAVIRIDE 017 ON MYCOCENOSIS IN CUCUMBER ROOT ZONE

E. P. Kopilov, G. V. Tsekhmister

Introduction. Cucumber is a valuable, cost-effective and fast-growing agricultural crop. During the vegetation cucumber plants can be affected by various phytopathogenic microorganisms, particularly fungi leading to serious material damage to agriculture. Acremonium Link molds can also cause diseases of Cucurbitaceae plants. Usage of chemicals is the main effort method against pathogens. Pesticides may be accumulated in a time in food products and environment. The usage of biological method not only can improve soil phytosanitary state but contributes for yields increasing. Trichoderma molds are the promising bioagents of microbial remedies for crops protection from pathogens. The mentioned mold shave high antagonistic activity in relation to many phytopathogenic microorganisms. It caused by various mechanisms of action, in particular: hyperparasitism, competition and antibiosis. They are also able to synthesize phytohormonal substances which stimulate plant growth and development.

Purpose. Investigation of Trichoderma viride 017 influence on mycocenosis cucumber root zone with Acremonium sp. 502 artificial plants infection.

Methods. Molds biodiversity in rhizosphere, risoplane and histospheres of cucumber plants had been studied in field fine-grained experiment. Scheme of experiment: 1. Control (without the using microorganisms and chemical fungicide);2. Artificial infectious background (introduction the pathogen Acremonium sp. 502 into soil with cucumbers); 3. Artificial infectious background and inoculation of cucumber seeds with T. viride 017; 4. Artificial infectious background and soil spraying with chemical fungicide Previkur.

Samples were carried out in a flowering phase. Picking up, accounting and cultivation of molds were made according to generally accepted methods. The field experiment was made in three duplications. The statistical processing of the results was made according to Dospehov.

Results. Mycosenosis of cucumber root zone was represented by Acremonium Link, Alternaria Nees, Aspergillus Micheli, Chaetomium Kunze, Cladosporium Corda, Fusarium Link:Fr, Gliocladium Corda, Mortierella Coem, Mucor Micheli, Penicillium Link:Fr, Rhizopus Ehrenb, Trichoderma Hers and Dematiaceae. In control variant the maximum number of molds were found in rhizosphere. The number of molds in rhizosphere with an artificial infectious background significantly decreased. Here we found a significant number of molds that could be optional parasites (Fusarium, Dematiaceae and Acremonium).The inoculation of seeds with T. viride 017 caused an increase in the total number of molds. It was more than two times in comparison with artificial infectious background. Also the number of Fusarium, Acremonium and Dematiaceae decreased.

The largest number of molds were found on roots surface in control, the smallest one was in variant with fungicide Previkur application and in variant with artificial infectious back ground. The usage of T. viride 017 ensured enlargement the molds number in 1,4-1,9 times according to variants with artificial infectious background and fungicide. Artificial infectious background made by Acremonium sp. 502 caused to enlargement of these molds in soil. T. viride 017 and fungicide Previkur promoted for decrease the number of Acremonium molds.

The number of Fusarium was the most in variant with the chemical etchant. The usage of T. viride 017 ensured reduction of Fusarium in 1,2 times in comparison with the artificial infectious background. The number of Trichoderma molds was the most in variant with its inoculation. It can explained by optimal conditions for their development on cucumber plants roots.

Histospheres molds were mainly facultative parasites (Acremonium, Alternaria, Fusarium) and representatives of families Penicillium, Cladosporium, Trichoderma. In control variant and the artificial infectious background variant the total number of molds was the highest. In control variant Fusarium and Penicillium representatives were dominative. The artificial infectious background variant had another dominative form of molds, the representatives of Acremonium. The inoculation of T. viride 017 and fungicide usageled to decrease the total number of molds in histosphere. In variant with chemical fungicide Previkur mycocenosis is represented mainly by optional parasites Fusarium and Acremonium. In variant with T. viride017 inoculation the mold complex was formed by Penicillium, Alternaria and Trichoderma. The presence of Trichoderma molds in histosphere indicates their ability to form associations with cucumber plants.

Originality. For the first time cucumber mycocenosis with Acremonium sp. 502 usingas an artificial plants infection had been studied. The less number of pathogenic molds (Alternaria, Fusarium and Dematiaceae) were found in control variant and in samples of rhizosphere and risoplane without artificial infectious background. At the same time pathogenic molds were found much more with artificial infectious background. It can be explained that Acremonium sp. 502 not only affects the root system but also can attenuate plants immunity at seedling stage. Thus pathogens are able to colonize plants roots much easier.

Conclusion. The strain T. viride 017 is settling down in root zone enough well. It is able to reduce the number of pathogen molds and can be used for making up a biological preparation for cucumber plants protection in particular against Acremonium sp. 502.