Fomozės sukėlėjų Leptosphaeria maculans ir L. biglobosa paplitimas ant bastutinių šeimos augalų ir grybų izoliatų augimo dirbtinėje terpėje dinamika

Abstract

The study was aimed to identify the occurrence and distribution of Leptosphaeria maculans and Leptosphaeria biglobosa species on the plants of various Brassica species (Brassica napus var. biennis, Brassica napus var. annua, Brassica oleracea var. capitata, Brassica oleracea var. italica) and determine growth specificity of fungi, collected from different plant species, in in vitro conditions. Samples of leaves with lesions of phoma leaf spot were collected in the farms of Kėdainiai and Kaunas regions. Isolates of the phoma stem canker causal agent Leptosphaeria spp. fungus were grown in the laboratory. Having done comparative tests on isolates morphology, they were attributed to L. maculans or L. biglobosa species. It was found that the oilseed rape and broccoli phoma stem canker was more often caused by L. maculans than L. biglobosa fungi, and phoma of cabbage was caused just by L. biglobosa fungi. The present study revealed that isolates of different fungi species differed in colony growth dynamics and pigment formation on agar media. The fungi of L. maculans species on artificial nutrient medium grew more slowly than those of L. biglobosa. Isolates of the same species of fungus, isolated from the plants of different Brassica species were characterized by a similar growth rate of fungal colonies. L. biglobosa fungus grown on ¼ PDA medium dyes it brownish-yellow, and L. maculans media do not change colour; this feature can be used to identify fungus