Peach gummosis disease caused by Botryosphaeria dothidea in Taiwan

Botryosphaeria dothidea引起之桃流膠病

柯勇(Yeong Ko) ； 孫守恭(Shou-Kung Sun)

《植物病理學會刊》 1卷2期 (1992/06) Pp. 70-78

https://doi.org/10.6649/PPB.199206_1(2).0004

摘要

近年來本省中部地區栽培之熱帶種桃樹，發生嚴重的流膠病，從罹病桃樹之主幹、主枝和側枝進行徒手切片鏡檢和病原菌之分離、培養,常發現到Botryosphaeria dothidea (Moug. ex Fr.) Ces. et de Not.之存在。以當年生之幼嫩枝條進行接種試驗，無論以B. dothidea的培養菌絲塊或以胞子懸浮液行傷口接種，都可形成典型之流膠病病徵，證實B. dothidea爲引起桃流膠病之病原菌。病害初期，罹病枝幹樹皮表面上之皮目周圍呈褐色凹陷，繼之出現疣狀凸起，每一小疣下之皮層組織呈褐色壞疽；病害中後期，疣狀凸起出現裂紋，並有膠狀液體從罹病之皮目內溢出，雨後流膠更多常垂落於地上。在田間B. dothidea之無性世代爲Fusicoecurn sp.、柄子殼扁球形，黑色或暗褐色，大小爲143-207 prn (直徑)。分生胞子無色，單胞的紡綞形，其大小爲12.5-17.8 × 3.8-5.0 μm。子囊殼燒媺狀，大小爲173-248 μm (直徑)，內含雙膜(bitunicate)棍棒狀子囊，其大小爲95.0-123.5 × 12.7-18.5 μm。每個子囊內含有8個無色，單胞的紡綞形子胞子，其大小爲22.5-30.0× 9.3-12.5 μm。B. dothidea菌絲生長在馬鈴薯培養基和燕麥培養基上最爲良好，最適溫度在24-32 C。分生胞子發芽之最適溫度則在24-36 C範圍內，而發芽管生長適溫爲28 C，4小時後其長度平均爲134 μm。在24 C溫度下，於2%水瓊脂培養基上培養4小時，分生胞子之發芽率可達96%，而水分潛勢從-1 bar到-45 bars範圍內，分生胞子的發芽率隨水分潛勢之降低而減少；而於-55 bars時分生胞子即不發芽。光照可促進分生胞子之產生於128 ± 25 μE．m^(-2)．s^(-1)連續光照下培養7-9天，產量約爲2.1-3.6 x 10^5個分生胞子/cm^2。查閱文獻資料顯示桃流膠病爲本省之新病害。

關鍵字

桃流膠病

並列摘要

A gummosis disease on low-land peach trees has been found occurring severely in recent years in Taiwan. The disease has seriously affected many thousands of trees in central part of Taiwan where peach was grown economically. Botryosphaeria dothidea (Moug. ex Fr.) Ces. et de Not. was always found from free hand sections and cultures made from diseased twigs, limbs and trunks of the peach trees. Inoculation of current-season shoots with the fungus isolated from diseased tree showed typical symptoms which indicated that B. dothidea was the causal agent. Principal symptoms including sunken necrotic lesions in bark around lenticels. from which gum exudated, brown necrotic areas in bark beneath infected lenticels, and convex warts on surfaces of infected twigs and shoots are characteristic Anamorph stage of B. dothidea, Fusicoccum sp., is common in nature. Pycnidia are black or dark brown. I43-207 μm in diameter, with hyaline and non-septate conidia, 12.5-I 7.8× 3.8-5.0 μm Ascostrona are black, 173- 248 μm in diameter, usually produced in dead wood. Asci are cylindrical eight-spored, btunicate, 95.0-123.5× 12.7-18.5 μm. Ascospores are hyaline, one-celled and ovoid 22.5-30.0 × 93-1 2. 5 μm. Growth rate was greatest on potato-dextrose agar (PDA) and oatmeal agar after 72 hr, and least on V-8 juice agar and peach-shoot decoction agar. The optimum temperature for mycelial growth were 24-32 C and for conidial germination was 20- 36 C. For elongations of germ tube 8 C was the optimum (134 μm after 4 hr incubation). Conidial germination in 2% water agar reached 96% in 4 hr at 24 C and declined as water potential reduced from -1 bar to-45 bars, no germination was observed at-55 bars. Continuous light is essential for the promotion of conidial formation Under 128 ± 25 μE．m^(-2)．s^(-1) condition, approximately 2.1-3.6× 10^5 conidia/cm^2 could be harvested from 7-day to 9-day-old PDA culture. Literatures revealed that the peach gummass disease is a new record Taiwan.

並列關鍵字

peach gunimosis ； Botryosphaeria dothidea