西蒙得木枯萎病的研究——Ⅱ.病原菌生物学特性和病害发生发展规律

STUDIES ON FUSARIUM WILT OF JOJOBA (SIMONDSIA CHINENSIS)-A NEW DISEASE IN CHINA Ⅱ. Biological Characteristics of the Pathogens and Occurrence of the Disease

引起西蒙得木枯萎病的4种镰刀菌在10～35℃温度范围内均能生长和产生分生孢子,菌丝生长以25～30℃最适,产分生孢子以30～35℃最好。分生孢子萌发所需最适温度因茵种不同而异。茵丝生长和分生孢子萌发能适应的 pH 值较广,但以 pH6～8为佳。分生孢子萌发需高湿条件,以水滴中萌发率最高。菌丝生长所需碳源以淀粉最好,纤维素最差,氮源以蛋白质、天门冬酰胺较好,尿素较差。大田环境下,病株地上部分症状以旱季(云南11月至翌年5月)表现较明显,出现病情高峰;进入雨季(6月至10月)症状相对稳定或消退。病害的发生发展与土壤条件、地形地势以及栽培措施有一定的关系,尤与土壤条件关系最为密切。控制该病应采用以栽培管理措施为主,辅以其它防治方法的综合治理。

The pathogens causing a wilt disease of Jojoba(Simmondsia chinensis(Link) Schneider)are Fusarium oxysporum,F.solani,F.equiseti and F.moniliforme. The temperature range for their mycelial growth and sporulation was 10～35℃;with 25～ 30℃ as the best for mycelial growth and 30～35℃ as the best for sporulation.The optimum temperature for conidial germination differed among these Fusarium species.Mycelia could grow and the conidia could germinate between pH4～9,but the optimum pH range was 6～8.High relative humidity was required for conidial germination and the maximum germination was obtained in water drops.Among the 5 carbon and 5 ni- trogen compounds tested,starch served as the best carbon source,and peptone and asparagine as nitrogen sources were favorable for the mycelial growth of all the four Fusarium species while cellulose and urea were found to be poor sources. Field observation showed that symptoms were particularly prominent in the dry sea- son.The occurrence of the wilt disease of Jojoba was closely related to the soil texture and water content.Based on the above results,it was suggested that the efficient way of con- trolling this disease should integrate the cultivated,ecological and phytopathological measures.