黑老虎枝枯病病原鉴定及其生物学特性

Identification and characterization of causal organism of Kadsura coccinea twig blight

黑老虎[Kadsura coccinea(Lem.)A.C.Smith]又名冷饭团、布福娜,果实含丰富的Vc、Ve及多种微量元素,是山区野果珍品[1]。上世纪末,人们从野外引种试栽,目前在黔东南地区实现了规模化栽培。笔者于2017和2018年调查发现,黑老虎枝枯病在黔东南州各种植基地普遍发生,造成严重损失,但关于黑老虎病害的报道甚少[2,3]。

Kadsura coccinea(Lem.)A.C.Smith has been wildly cultivated in Southeast of Guizhou province,bearing fruit as an excellent nutrition source being rich in vitamin C,vitamin E,and a variety of trace elements.In 2017-2018,we found twig blight on Kadsura coccinea with small black dot-like structure in the late stage on lesion,a very common disease causing significant economic losses.The fungal isolates were recovered from the symptomatic stem tissues and small black dot(pycnidium)which contained transparent,unicellular and spindle-shaped conidia of(17.4±1.2)μm×(6.5±0.7)μm.The purified culture with the grayish white to dark grayish-green as well as partial straight hyphae on PDA plate was consistent with Neofusicoccum parvum,supported by the aliment and phylogenetic analyses of ITS,Ef1αand Tub2 gene sequences(GenBank no:MK563984、MK563986 and MK563987).The pathogenicity test on leaves and stems with needle-punching method matched the symptoms described above and re-isolated the fungus confirming the Koch’s postulate.The lethal temperature for mycelial growth was 54℃for 10 min;The strain could grow normally in most carbon and nitrogen sources except ammonium carbonate.This is the first report of Neofusicoccum parvum causing twig blight on Kadsura coccinea in China.