中国胡椒疫霉种及交配型的研究

胡椒Piper nigrum L.是我国重要的热带经济作物，胡椒瘟病是危害其生产的第一大病害。为了明确胡椒主产区海南万宁瘟病病原菌种类，筛选具有防控潜力的杀菌剂，本研究采用形态特征和ITS序列特异性相结合的方法，对采自海南万宁的7株胡椒瘟病样品进行病菌的分离鉴定，并采用生长速率法检测我国当前登记的20种杀卵菌剂对其菌丝生长的室内毒力。结果发现，3株从海南万宁地区分离的胡椒瘟病菌均为辣椒疫霉Phytophthora capsici；20种卵菌杀菌剂中抑制胡椒瘟病菌菌丝生长活性最高的是吡唑醚菌酯、氟啶胺、福美双、烯酰吗啉、氰霜唑、甲霜灵等药剂，EC₅₀ < 1 μg/mL；其次是喹啉铜、百菌清、代森锰锌、代森锌、氢氧化铜等药剂，1 μg/mL < EC₅₀ < 10 μg/mL；然后是氧化亚铜、王铜、嘧菌酯、香芹酚、霜脲氰、小檗碱等药剂，10 μg/mL < EC₅₀ < 50 μg/mL；几丁聚糖和三乙膦酸铝最低，EC₅₀ > 300 μg/mL。该结果可为热带辣椒疫霉机理研究和防控技术开发奠定基础。

Major diseases of black pepper and their management

Black pepper (Piper nigrum L.) is an important tropical cash crop in China and suffers huge economic losses every year due to foot rot disease. In order to clarify the pathogen in black pepper main producing area and screen potential fungicides for disease control. Seven strains were isolated from Wanning City of Hainan Province and identified by morphological characteristics and ITS sequence specificity. The laboratory toxicities of 20 fungicides, registered for the control of oomycete diseases, were determined by the mycelial growth rate method. Results showed that all three strains isolated from black pepper foot rot disease samples, were Phytophthora capsici. Among the 20 tested oomycete fungicides, pyraclostrobin, fluazinam, thiram, dimethomorph, cyazofamid, and metalaxyl showed the highest activity in suppressing the mycelial growth of three P. capsici isolates (EC₅₀ < 1 μg/mL), followed by oxine-copper, chlorothalonil, mancozeb, zineb, copper hydroxide (1 μg/mL < EC₅₀ < 10 μg/mL), and then cuprous oxide, copper oxychloride, azoxystrobin, carvacrol, cymoxanil, berberine (10 μg/mL < EC₅₀ < 50 μg/mL). Chitosan and fosetyl-aluminium exhibited the lowest inhibition activity (EC₅₀ > 300 μg/mL). This study would help further the understanding and management of tropical P. capsici diseases.