Biological and epidemiological characteristics of the pathogen of hypertrophy sorosis scleroteniosis, Ciboria shiraiana

Abstract:

[Objective] We studied the biological and the epidemiological characteristics of the pathogen of hypertrophy sorosis scleroteniosis, which is a devastating fungal disease of mulberry. [Methods] We studied the asexual and sexual reproductive phase stages of C. shiraiana, including the infection ability of hyphal, dormancy of sclerotia, the structures, release, number and germination of ascospores from apothecia, as well as the phenology of sclerotial germination. [Results] In C. shiraiana, hyphae had no infection ability toward the female flowers of mulberry. Sclerotia of C. shiraiana must undergo cold treatment above 6 weeks, then the dormancy-breaking sclerotia could germinate to apothecia. One to fifteen apothecia were germinated from one sclerotium, and the number of ascospores in a 1.5 cm diameter apothecia could contain up to (5.6-6.3)×10⁷. Ascospore C. shiraiana had significantly higher germination rates in acid than in neutral and alkaline environments. From late January to middle April, sclerotia germinated to apothecia, and got the highest value in the middle of March. [Conclusion] C. shiraiana is a formidable pathogen to cause epidemic disease and damage in mulberry.