葡萄霜霉病初次侵染来源和初侵染的特点及防治

The First Time Infection Source of Grape Downy Mildew and Its Characteristics and Some Control Approaches

【目的】明确葡萄霜霉病菌初次侵染来源及初侵染的特点,为霜霉病的防治提供理论依据。【方法】观察该病病枝条越冬情况、卵孢子越冬前后形态、病残体作为初侵染源情况,该病初发期发病场所、发病位置、发病处地形和管理情况,调查春季温室大棚内发病情况,明确该病的初次侵染来源。分析初期发病与气候因子关系,明确初侵染发生的特点。【结果】该病在新疆石河子葡萄产区,主要以卵孢子在病残体上越冬,温室大棚中的病苗也可作为初次侵染的来源。采用常规观察的方法卵孢子不易发现,采用病部研磨-过筛-离心-镜检的方法较易发现。该病初侵染发生的早晚主要与5月下旬和6月上旬温湿度和6月上旬降雨量相关。【结论】该病初侵染主要发生在地势低洼、长势茂盛、枝条未修剪、杂草丛生、距地面较近、空气湿度大的环境中。应采取治早、治少、抓好早期防治的措施。

【Objective】The source of primary inoculum and infection characteristics of grape downy mildew were determined to provide theoretical basis for disease control.【Method】The primary source of primary inoculum was determined through the observation of overwintering diseased branches,morphology of oospores（ pre- overwintering oospores and overwintered oospores） and plant residues as the primary infection source,and the investigation of grape downy mildew in greenhouses. At the same time,the primary infection characteristics were identified by surveying administration,primary infection sites,positions and topography,and relation between primary infection and climatic factors was analyzed in order to make prevention and control measures for primary infection.【Result】The fungus as overwinter oospores on plant residues was found in wine- growing region of Shihezi and the diseased seedlings could be the primary source in greenhouses. It was easy to find oospores in the process of grinding – sieving – centrifugating – microscopic examination,but was hard bythe conventional methods. The occurred time of primary infection was mainly related to not only temperature and humidity of the last ten days in May but also temperature,humidity and rainfall of the first ten days in June. The primary infection mainly takes place in the environment with low- lying,luxuriant growth,untrimmed branches,weed infestation,and places near the ground with high air humidity.【Conclusion】According to source of primary inoculum and infection characteristics of the disease,many proposals and measures for the prevention and control were made before it became more serious.