湿地松色二孢菌和可可球二孢菌根腐病研究

    DIPLOIA AND BOTRYODIPLODIA ROOT ROT OF PINES

    • 摘要: 松树根腐病在我国首次发现于雷州半岛10年生左右的湿地松林分。病原菌被鉴定为松色二孢菌Diplodia pinea,另外还发现可可球二孢菌Botryodiplodia theobromae不侵染马尾松,但对湿地松、火炬松和加勒比松也是一种病原菌。 松色二孢菌在林间土病根内以菌丝体方式可存活150天以上,在室内5~50%含水量自然土中,菌丝体和分生孢子可存活120天以上。 松色二孢菌在含水量为40%的湿地松离体根内扩展较快.在含水量为50~70%的离体根内扩展较慢。不论接种前或接种后调节土壤的含水量,一年生松苗的死亡率在含水量为50%土壤中较低,在含水量为5~25%土壤中较高。苗木要经过约20天的干旱影响后,才显示出较易受病菌的侵染。

       

      Abstract: A root rot disease of pines was found lor the first time in about ten-year-old Pinus ell-iottii stands in the Leizhou Penisula oi Guangcong l rovince of China. Field survey and inoculation tests provided convincing evidence that P p od a n en was the primary pathogen of the disease,and Botryodiplodia theobromae also a pathogen of P. e p P aeda and P.caribaea.Inoculation tests indicated that the pathogencity of D.pirea varted among different s-pecies of pines. Pinus elliottii was more susceptible to attack by D. pirea than P.taeba and P. caribaea, and that P. massoniana was resistant.The mycelia of D.pinea could survive lor more than 150 days in infected roots of P. elliottii under natural conditions, and for 120 days in natural soil of different water contents, when soil moisture was 5%, 15%, 25%, 50%,conidia could also survive for more than 120 days in natural soil. These results indicated that D.pinea was likely a soil-borne fungus.The infection of P.pinea was also related to water content, Low water content was favourable to infection by the fungus. When the water content was below 50%, D. pinea attacked lateral root section easily;wben the water content was above 50%, it was difficult for the fungus to attack. Soil moisture may also influence the occurrence and development of the disease. Lower water content lasting for 20 days could make P.elliottii seedlings more susceptible to the disease.

       

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