Biocontrol microorganisms for soil-borne pathogens of tomato plants
Author: Eligio Malusa, INHORT
Soil-borne pathogens are extremely dangerous for any crop, but are particularly damaging for vegetable crops that are grown in tunnels, where the conditions are inducive for the pathogenic fungi. Therefore, Excalibur has included in its work several trials to test potential or well known microorganisms that can reduce the risk of damages from soil-borne pathogens. Some of the trials are conducted by the Department of Plant Protection at the National Institute of Horticultural Research in Skierniewice, Poland.
The biocontrol ability of strains owned by the Institute (Trichoderma harzianum and Paenibacillus polymyxa) and by other partners (Clonostachys rosea), particularly the Slovenian Institute of Horticulture – KIS was assessed against pathogens such as Phytophthora nicotianae and Fusarium oxysporum. These pathogens are the causal agents of root rot, stem base rot and wilting of tomato, respectively. Formulations of T. harzianum, C. rosae and P. polymyxa were obtained using as substrate rice kernels. This is a technique that allows to produce quickly and reliably products easily applied by the farmers. Tomato seedlings planted into an artificially infested soil, to which the beneficial microorganisms had been previously applied, were evaluated for their growth and the colonization of the plant roots and soil by the biopesticides verified by molecular (DNA) tests. The three strains confirmed the positive effects of the tested microorganisms on the health and growth of tomatoes in comparison to untreated plants grown in the infested substratum. These results will be used to fine tune to application of the different strains, as well as their formulation, in the field trials that are planned to start this spring and continue also next year. Follow us to read about the outcomes of these trials!
Fig. 1: The tomato plants grow more and are healthier when inoculated with beneficial microorganisms (right side).
Fig. 2: The effect of different beneficial microbial strains can be diverse due to their different mechanisms of activity against the pathogens, as in the case of the fungus T. harzianum and the bacterium P. polymyxa.