A eu-form rust fungus, Zaghouania phillyreae Patouillard (Pucciniaceae) on a variety of sweet olive (Osmanthus aurantiacus (Makino) Nakai var. thunbergii (Makino) Honda) (Oleaceae)
1990
Terashita, T. (Kagoshima Univ. (Japan). Faculty of Agriculture) | Yamauchi, H. | Arimura, S.
This report deals with ecological, morphological, physiological characteristics and control of Zaghouania phillyreae found on Osmanthus aurantiacus var. thunbergii in Kagoshima Prefecture. Main results are as follows: 1) The variety tree was a new host-plant to the fungus. 2) Teliospore and sporidium started their forming from late December to early January. Sporidium caused severe rust-disease, invading new shoot and new leaf during the period between late winter and early spring. 3) Aeciosorus and aeciospore were formed in spring on new shoot and new leaf. 4) Aeciospore invaded fresh leaf, but the pathogenicity of the spore was weak, causing inconspicuous spotty discoloration. However, the discoloration became clearer gradually from early summer to early winter. New teleutosorus, teliospore and sporidium were formed again on the lower surface of the host-leaf. 5) A few uredospores were formed under the state of being mixed with teliospores and sporidia even at the early stage of their appearance. However, the rate of uredospore-number in the sorus increased in correspondence with the decline of teliospore and sporidium. Between late February and early March, the whole sporosorus was occupied by uredospores, exclusively. 6) Uredospore survived until early summer, without showing any pathogenicity. The reason for the existence of the spore on the fungus was not clear. 7) The fungus was distributed at more than 15 locations in 9 towns, ranging from the southern most town of Satsuma Peninsula to a town about 70km north of the former town. Almost all of the fungus were found on the variety tree among a few Osmanthus species. 8) Sporidium germinated comparatively well at low air temperature, showing its optimum germination temperature at about 20 degrees C. However, the spore did not germinate at 35 degrees C
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