Fungi colonizing various organs of thyme Thymus vulgaris L. cultivated in the region of Lublin
In 1998-2001, the healthiness of thyme cultivated in the region of Lublin was examined. Surveys were made on the one-year-old plantations of thyme at a stage of 6-week-old seedlings and just before the first harvest of the crop, as well as on the two-year-old plantations in spring and before the last harvest. The percentage of the plants showing fungal disease symptoms and the index of infection with fungi were determined. The fungi were isolated from superficially disinfected plant fragments namely from roots, bases of stem and leaves, separately, using mineral culture medium. PDA and SNA media were used to culture <i>Fusarium</i> spp., malt-agar and Czapek-Dox ones to culture <i>Penicillium</i> spp. and malt-agar, oat-agar and cherry-agar ones to culture <i>Phoma</i> spp. The percentage of plant infected with the fungi ranged within 12.18 and 23.05, in case of the one-year-old plantations, and within 29.91 and 43.65 in the two-year-old ones, whereas values of the index of infection ranged within 11.56 and 24.69 and within 20.75 and 43,28, respectively. Necroses were observed on roots and base of stems on one-year-old and two-year-old plantations, but in the last period of vegetation of thyme close to harvest. very often stems and leaves showed symptoms of a complete necrosis. It was found that base of stems and roots of thyme in the first and the second year of cultivation were colonized by a complex of pathogenic fungi:<i>Fusarium spp., Rhizoctonia solani, Thielaviopsis basicola</i> were obtained from the major part of diseased plants. Among the <i>Fusarium</i> species colonizing bases of stems <i>F.culmorum, F.avenaceum, F.equiseti</i> and <i>F.oxysporum</i> dominated, but from roots of thyme most often <i>F.oxysporum, F.equiseti and F.culmorum</i> were isolated. From stems, and particularly from leaves of thyme showing dark spots, commonly <i>Alternaria alternata</i> was obtained. On the other hand, shoots and leaves, but rarely roots of thyme, were colonized by various species of <i>Phoma</i>, particularly by <i>Phoma exigua</i> var. <i>exigua. Colletotrichum gleosporioides</i> occurred rarely on thyme in the area surveyed.