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The principles of good agricultural and horticultural practice, considering both environmental protection and high yielding of plants, require modern cultivation methods. In modern agriculture, it is possible to use biostimulants that protect the soil against degradation and plants against phytopathogens and stress. The purpose of 3-year field and laboratory studies was to determine the effect of Trichoderma harzianum T-22 and other biostimulants on the health status of scorzonera (Scorzonera hispanica L.) plants and microorganism populations in the rhizosphere of this plant. For this purpose, Biosept Active (a.s.—grapefruit extract), Timorex Gold 24 EC (based on tea tree oil), Trianum P (spores of Trichoderma harzianum Rifai T-22) and Zaprawa Nasienna T 75 DS/WS fungicide (a.s.—tiuram) were applied for the pre-sowing seed dressing of scorzonera cv. “Duplex”. The number of seedlings and the health status of scorzonera plants were determined during three growing seasons. In each year of the study, mycological analysis of seedling roots and roots after scorzonera harvest was conducted to establish the quantitative and qualitative composition of fungi colonizing these parts. Moreover, microbiological analyses of scorzonera rhzisphere soil were conducted and served as the basis to determine the total population of fungi and bacteria (including Pseudomonas sp. and Bacillus sp.). Antagonistic activity of rhizosphere bacteria Pseudomonas sp., Bacillus sp. and fungi was determined based on laboratory tests on selected scorzonera soil-borne fungal pathogens (Alternaria scorzonerae, Fusarium culmorum, Fusarium oxysporum, and Rhizoctonia solani). The experiments showed that Trianum P most effectively protected the roots of scorzonera against infection by Alternaria alternata, A. scorzonerae, Neocosmospora solani, Fusarium spp., Sclerotinia sclerotiorum, Rhizoctonia solani, and Botrytis cinerea. The rhizosphere population of Bacillus sp. and Pseudomonas sp. in the treatments with Trianum P or Zaprawa Nasienna T 75 DS/WS was larger than in the other experimental treatments. A reverse relationship was observed in the population of rhizosphere fungi. The application of grapefruit extract, tea tree oil and Trichoderma harzianum T-22 increased antagonistic activity of Pseudomonas sp., Bacillus sp. and selected saprotrophic fungi against soil-borne fungal pathogens, especially Alternaria sp., Rhizoctonia sp., and Fusarium sp. In summary, Biosept Active, Timorex Gold 24 EC and Trianum P can be recommended as plant biostimulants in Scorzonera hispanica cultivation. Full article

The principles of good agricultural and horticultural practice, which consider both giving environmental protection and high yielding of plants, require modern cultivation methods. Modern cultivation of horticultural plants uses, for example, cover crops, living mulches, plant growth-promoting microorganisms (PGPMs), plant growth regulators (PGRs) and other biostimulants protecting the soil against degradation and plants against phytopathogens and stress. The purpose of field and laboratory studies was to determine the effect of Trianum P (containing Trichoderma harzianum Rifai T-22 spores), Beta-Chikol (a.s.—chitosan), Timorex Gold 24 EC (based on tea tree oil) and fungicide Zaprawa Nasienna T 75 DS/WS (a.s.—tiuram 75%) on the health of carrot (Daucus carota L.) plants and the microorganism population in the rhizosphere of this plant. Moreover, the antagonistic effect of rhizosphere fungi on selected carrot fungal pathogens was determined. Laboratory mycological analysis allowed one to determine the qualitative and quantitative composition of fungi colonizing the underground parts of carrot plants. In addition, the total population of fungi and bacteria was determined (including Bacillus sp. and Pseudomonas sp.) based on the microbiological analysis of the rhizosphere soil. The application of the plant growth-promoting fungus (Trichoderma harzianum T-22), chitosan and tea tree oil positively influenced the growth, development and health status of carrot plants. T. harzianum T-22, chitosan and fungicide most effectively protected carrots against infection by soil-borne fungi from the genus Alternaria, Fusarium, Haematonectria, Sclerotinia and Rhizoctonia. The rhizosphere population of Bacillus sp. and Pseudomonas sp. in the treatments with Trianum P or Zaprawa Nasienna T 75 DS/WS was bigger than in the other experimental treatments. A reverse relationship was observed in the population of rhizosphere fungi. T. harzianum T-22, chitosan and tea tree oil promoted the growth of antagonistic fungi (Albifimbria sp., Clonostachys sp., Penicillium sp., Talaromyces sp. and Trichoderma sp.) in the carrot rhizosphere. Antagonistic activity of these fungi towards Alternaria dauci, Alternaria radicina, Sclerotiniasclerotiorum and Rhizoctonia solani was higher after the application of the preparations compared to control. Consequently, Trianum P, Beta-Chikol and Timorex Gold 24 EC can be recommended as plant biostimulants in ecological agricultural production, including Daucus carota cultivation. Full article

Downy mildew caused by the oomycete Bremia lactucae Regel is a serious disease of lettuce in field and greenhouse production. Here we report on the antifungal activity of essential Australian tea tree oil (TTO) derived from Melaleuca alternifolia against downy mildew in lettuce. Preventive treatments with Timorex Gold (STK Ltd., Petach Tikva, Israel), fungicide containing TTO, suppressed the development of B. lactucae on cotyledons and young lettuce plants. Epifluorescence microscopy showed that TTO had a moderate inhibitory effect on spore germination of the pathogen but a strong inhibitory effect on sporophore emergence and hence on sporulation. Timorex Gold (22.3 EC W/V) was as effective as copper hydroxide in controlling the disease in organic field plots. It was as effective as the fungicides Bellis (Boscalid + Pyraclostrobin; BASF, Germany) and Commet (pyraclostrobin; BASF, Germany) in conventional production. The results demonstrate that Timorex Gold effectively suppresses the development of downy mildew in lettuce in growth chambers as well as in the field, and thus suitable biopesticide for its control. Full article

Timorex Gold based on the essential tea tree oil (TTO) derived from the Australian tea tree oil (Melaleuca alternifolia) plant has demonstrated high efficacy and a strong curative activity against black Sigatoka in banana and controlled it in stages 1, 2, 3, and 4 of disease development. Transmission electron microscope (TEM) examination of infected leaf sections treated with Timorex Gold revealed disruption of the fungal cell membrane and destruction of the fungal cell wall in disease development stages 4 and 5. Mineral oil and the fungicide difenoconazole, when applied alone, had no curative effect and did not disrupt the fungal cell wall or membrane, similar to the untreated control tissue. A single spray of Timorex Gold effectively controlled and suppressed powdery mildew in cucumber by causing the disappearance of 99% of established colonies recorded 1 or 2 days after the application and was effective for up to 8 days after application. Scanning electron microscope (SEM) examination of infected and Timorex Gold-treated leaves indicated strong shrinkage and disruption of fungal hyphae and conidial cells. The curative and suppressive modes of action of the Timorex Gold may explain its success in controlling both diseases. Full article