The physiological properties of fungus Monilinia laxa f. sp. mali (Wormald et Harrison)

Abstract

In laboratory experiments we have analysed the physiological properties of fungus Monilinia laxa f. sp. mali (Wormald et Harrison). Potato-dextrose, malt and Czapeck-Dox agars proved to have different effect on fungus growth. The potato-dextrose agar proved to be the most adequate for the cultivation of fungus. The most adequate temperature for its growth was 25 ⁰C, and 93% relative air humidity. The minimum temperature for successful growth was 5 ⁰C and maximum at 25 ⁰C. The light slowed down the growth of fungus and did not induce sporulation. The fungus exploited some sources of both, carbon and nitrogen, although organic sources of nitrogen gave better results. In laboratory conditions sporulation was hindered. Acetone did not induce sporulation, it reduced growth to a great extent. Also the more acidified agar did not enable sporulation. The production of spores (conidia) appeared only on apple fruits which we inoculated with discs of mycelium. The conidia reached 15.4 m m in length and 10.6 m m in width. The average length of microconidia was 2.7 m m. In our experiment spores and mycelium caused infection of blossoms. The characteristic symptoms of the infection were the decay of blossoms, one year shoots and apple fruits, and cancer formations in wood.