No abstract

The analysis was conducted on the general biogenicity and phylogenetic structure of fungi in the soil microbiome of greenhouse cucumbers grown as a monoculture and after the precursors of pepper and lettuce. The relationship between the following indicators has been proved: the total biological activity of the soil, the species composition of micromycetes, the development of Fusarium root rot, and yield. The effect of biological preparations based on strains of Trichoderma viride and Gliocladium virens antagonistic fungi on the development of Fusarium root rot, nematodes and yield of cucumbers was studied. The results of the experiment show that when cucumbers are grown after the precursor pepper and lettuce, the development of Fusarium root rot and nematodes does not exceed critical values.The introduction of Trichoderma and Gliocladium fungi into the soil in the form of a dry preparation with a titre 2.0 x 10 10 conidia/g when transplanting plants to a permanent place at a consumption rate of 40 kg/ha increases the yield of greenhouse cucumbers by 20-23%. The experiment is part of the study of the "soil exhaustion" syndrome and the possibilities of overcoming it. The obtained results will serve as bioindicators that can be used for preliminary diagnostics of the sanitary condition of degraded soils, selection of agrotechnical, breeding and protective measures of plants.

The possibilities of using the biological products “Trichodermine” (Trichoderma viride Pers ex Fr.), “Gliocladine” (Gliocladium virens Miller et al.) and the mycorrhizal activator “Rhizo VAM Basic” (Glomus intraradices Schenck&Smith) for control of fungal diseases in garden pea and and their impact on the biometric indicators of young plants were studied. Biological preparations based on antagonistic fungi Trichoderma viride and Gliocladium virens improve the phytosanitary condition of the plants, the mycorrhizal fungus Glomus intraradices stimulates the formation of the root system and tuber formation, but has a weak fungicidal effect against Fusarium wilt in this culture. The experiment was performed on an artificial infectious background by Fusarium oxysporum Schlecht. f. sp. pisi (Hal.) Raillo, isolated from diseased plants. The effect of application of the biological products“Trichodermine” and “Gliocladine” is 34-68%, from “Rhizo VAM Basic” - 8% compared to the infected control. The combined application of biological preparations with fungicidal and mycorrhizal action significantly protects the crop from infection with the causative agent of Fusarium wilt of garden pea.

The main diseases of snap bean (Phaseolus vulgaris L.) for organic production and the possibilities for control have been studied. The strategic directions of the experimental work included: monitoring of diseases; study of pathogens’ variability; the field resistance of the Bulgarian bean varieties “Evros” and “Tangra” to the diseases in organic farming; optimization of the phytosanitary state of the crop through the authorized plant protection products. It has been established that seed-borne diseases are of predominant importance for organically grown garden beans. These are bacterial blight Xantomonas axanopodis pv. phaseoli, halo blight Pseudomonas syringae pv. phaseolicola and anthracnose Colletotrichum lindemuthianum. The screening of Bulgarian bean varieties for disease resistance showed that the “Evros” variety is relatively resistant to bacterial blight and anthracnose, which makes it suitable for growing by biological technologies. The development of bacterial blight and anthracnose after five treatments with the fungicide Bordeaux Mix 20VP (Bordeaux mixture 200 g/kg Cu +) with an interval of 10-14 days, starting from the flowering phase, is in the range up to 12.5%.

The article presents studies on the influence of the microbiological product “Trichodermine”, bio-organic fertilizers and growth regulators based on humic acids „Nagro”, „Stimix”, „BioLife” and mineral fertilizers (NPK) on the biological activity of the soil, the degree of disease, caused by Alternaria capsici-annui Savul & Sandu and pepper yield in field production. It has been found that the differences in the "Soil Biological Activity" indicator depends on the number of micro-organisms, the composition (species diversity) and the percentage of major Micromycetes. Organic products help optimize soil health and reduce the total content of fungal colonies, and in the Micromycetes composition the fungus Trichoderma sp. is more common. When mineral fertilizers are introduced, the number of fungal pathogens and toxin producers increases. A higher total yield was obtained in variants with biological treatment. The increase in yield is between 9% and 29%.