Notes on the Perithecial Stage of Rosellinia Parasitic on Tea Plant

Abstract

The white root rot of tea in Japan has been supposed to be due to Rosellinia necatrix (HART.) BERL., though the reports were rarely based on the actual observations of its perithecial stage. WATANABE (1963) consequently suggested the possibility that there may be another species of Rosellinia attacking tea or other trees in Japan than R. necatrix.
In this study, two specimens of white root rot of tea bearing perithecial stage of Roselli nia were examined for the morphological characters. One was found to be just identical with R. ne-catrix described by the previous investigators, while the other specimen from Kanaya, Shizuoka Pref., was somewhat different from R. necatrix in its size and shape of ascospores (Tablel, Fig. 1, and Fig. 2).' The ascospores of the latter species are longer in size and with more slender and attenuate ends than the former, R. necatrix.
This newly found fungus from Kanaya is similar in its shape of ascospores to R. arcuata PETCH reported to be parasitic on tea in Ceylon by PETCH (1923), though the length of ascospores is not identical. R. arcuata illustrated by BUTLER (1918) rather resembles R. necatrix in its shape of ascospores than the authors' fungus from Kanaya. R. bunodes (B. et BR.) SACC., another species parasitic on tea reported by PETCH (1923), is quite different from the authors' species in its perithecial surface covered with minute warts and also in its longer ascospores with thread-like ends.
The identification of the authors' fungus from Kanaya is not concluded here because of the lack of direct comparison with the specimens of the related species, especially with R. arcuata. The name "white root rot" of tea is proposed to be applicable to both fungi, R. necatrix and the newly found Rosellinia sp., though the latter still remains unidentified.