Microbial control of soil-borne pathogens in Hungary1

Biological control of soil-borne pathogens has been the aim of the Biological Control Laboratory in Hódmezövásárhely since 1982. In Hungarian glasshouses (this means areas both under glass and plastic foil cover), the growing medium is still the natural soil or mixtures based on soil. This is the reason why soil-borne pathogens, such as species of Fusarium, Sclerotinia, Pythium, Botrytis, Rhizoctonia and Alternaria, cause increasing problems, especially at sites where there has been intensive continuous cropping for many years. Soil steaming is very expensive, while methyl bromide and other soil disinfectants are harmful for the environment and especially for the soil microflora. All this favours the introduction of biological control against soil-borne plant diseases. After laboratory tests, experiments have been carried out over a 9-year period, with good results, on several Trichoderma species and strains in relation to practically all glasshouse crops (capsicum, lettuce, tomato, ornamentals, etc.) and in some field crops also. Since 1986, experiments have been done with Finnish-originated strains of Streptomyces griseoviridis, then with the preparation Mycostop which was developed from this actinomycete. These were carried out on ornamentals, on vegetables and on some cereals. The preparation was especially effective against Fusarium spp. but also against other pathogens.