Abstract
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.
Highlights
Carrot (Daucus carota L.) belongs to the family Apiaceae
The purpose of the study was to determine the effect of Trichoderma harzianum T-22, chitosan and tea tree oil on the health status of carrot plants and microorganism population in the rhizosphere
The experiments showed that plant density in the experimental plots grown from the seeds dressed with the fungicide Zaprawa Nasienna T 75 DS/WS was similar to the number of plants obtained after the application of biostimulants
Summary
Carrot (Daucus carota L.) belongs to the family Apiaceae. It is one of the most popular vegetables, and has great economic importance worldwide. Carrot roots are rich in beta-carotene (vitamin A precursor), and contain vitamin K, vitamin E (alpha-tocopherol), vitamin C, calcium, magnesium, potassium, phosphorus, other vitamins and minerals, phenolic compounds, flavonoids and dietary fiber [3,4,5] This vegetable has many healthy properties: it exerts antioxidation and anticancer effects, strengthens the immune system, lowers cholesterol blood levels, prevents premature ageing and has a positive influence on eyesight, skin, nails and hair [3,6]. In carrot cultivation, healthy, high-quality seeds and roots should be obtained, without any residues of pesticides, heavy metals or mycotoxins harmful to human and animal health Such effects are provided by ecological cultivations based on biological protection [1,7,8,9,10,11,12,13,14]. They reduce the number of chemical protection agents, while limiting plant infection by phytopathogens, including toxigenic fungi (Alternaria sp., Fusarium sp. and Penicillium sp.) [9,15,16,17,18,19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
