Tuberculosis of ash trees in Western Podillya of Ukraine: etiology, symptomatology and pathogenesis

Abstract

It is emphasized that in recent years epiphytotic dieback of many forest tree species has been observed in Ukraine and in other countries. It is dynamic and has a tendency to increase. In the deep pathology of this phenomenon out of attention remained phytopathogenic bacteria, which have high reproductive energy and can penetrate into the plant both from the outside, and cause the pathological process as a vital obligates. It is established that the most common and harmful illness of ash-tree is tuberculosis. The causative agent of the disease is the phytopathogenic bacterium Pseudomonas syringae pv. savastanoi - infects trunks, branches and shoots, and inflorescences of ash. From tuberculous pathology as a concomitant myco- and microbiota isolated bacteria Pseudomonas sp., P. fluorescens, P. syringae, Erwinia herbicola, E. horticola, Xanthomonas sp. and micromycetes Cladosporium cladosporiodes, Ulocladium botrytis, Mycelia sterilia (dark), Mycelia sterilia (orange), Fusarium heterosporum, Fusarium sp., Acremonium strictum, Cylindrocarpon didymum etc. It has been stated that Xanthomonas sp. showed in the experiment variable pathogenic properties, indicating the expansion of its specialization and indicates the need for further study of bacterial pathology of forest tree plants. In the pathogenesis of the disease five stages (phases) of its development are identified and the main symptomatic characteristics of lesions are given, which allows timely recognition of the affected tree for each age group of plantings. The methods for bacterial diseases of the ash diagnosing are improved. The species composition of the damaging entomologic fauna as a vector of infectious (tuberculosis) pathology is established. Hydrothermal stress is shown to be a catalytic factor in epiphytotic dieback of ash-tree. The emphasis is on the promising and expedient use of antagonistic properties of myco- and microorganisms and biologics on their basis for the prevention and protection stands of ash from pathogens of bacteriosis. It has been shown that pathology of ash tree is a multi-faceted phenomenon with interconnected processes of infectious and non-infectious cause. The study results indicate the need to differentiate the etiology and pathogenesis of this negative phenomenon, that is, not to confuse the factors that lead to weakening of the ash-tree (causative factors of the disease) and factors that cause epiphytotic dieback.

Keywords

• pathogenic myco- and t microflora
• infectious diseases
• harmful entomologic fauna
• symptoms
• system interaction
• pathogenicity
• antagonism
• prevalence of diseases