ISHS Acta Horticulturae 422: International Conference on Integrated Fruit Production
THE EPIPHYTIC MICROFLORA OF THE APPLE PHYLLOPLANE AND ITS ROLE IN BIOLOGICAL SCAB CONTROL. |
| Authors: | F.S. Kalenich, L.I. Padalko |
| Abstract:
It was established that the seasonal dynamics of the number of the apple phylloplane epiphytic microorganisms generally and microepiphytes showing a high antagonistic activity towards the scab excitant particularly was different in the gradient of the contrasting disease resistance of the host plant and depending on the presence or absence of pesticide treatments of plantings as well. It was found that under conditions of the pure culture microorganisms of different taxonomic groups which were studied displayed antagonistic features against the conidial stage of the scab excitant. Under both in vitro and in vivo conditions, the most active strains were isolated among micellar fungi and bacterial microepiphytes. Pedoclimatic conditions of the southern zone of the Ukraine permit to grow high yields of many fruit cultures spread here. The main fruit culture in this zone, as in all the republic, is the apple tree occupying 63% of the total orchard area and providing 60-80% of the gross yield of large and small fruits. Among many apple diseases, one of the most widespread and harmful is scab causing up to 40% of total losses inflicted on this culture by the complex of harmful organisms. Despite droughty conditions, scab practically every year inflicts a discernible damage on orchards in the south of the Ukraine. It is especially dangerous in years with rainy weather during spring and at the beginning of summer when under non-taking protective measures the disease often spreads and develops so intensively that trees of severely affected apple varieties shed a mass of leaves already in June-July, which leads to a sharp decrease of the plant productivity. The forming yield is, as a rule, of poor market quality. In recent years, the probability of arising scab epiphytoties in commercial apple plantings of the southern zone of the Ukraine significantly increased owing to the tendency towards narrow spacing orchards, enlarging the areas of irrigated plantings and growing both aboriginal and introduced disease-nonresistant varieties on large land areas. At present in the Ukraine, fruit culture disease protection including apple scab protection is based on taking a complex of measures among which chemical treatments occupy the main place. But, owing to the complication of the ecologic situation including by widely using plant protection chemicals in orchards, increasingly greater attention is given to the development of a biological method for apple scab protection in recent years. Main attention is given to searching for natural antagonists of the apple scab excitant among representatives of the microflora of different ecological niches. Strains of the most active antagonists can be used as agents of biological preparations against scab and other plant diseases. In our opinion, searching for natural antagonists of the scab excitant among representatives of the epiphytic microflora of the apple phylloplane is promising since just here, on leaves, fruits, | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
