日光温室黄瓜霜霉病初侵染监测预警方法研究

The primary infection phase is essential for control the cucumber downy mildew in greenhouse, and early warning model for the phase is helpful for improving the control effects and reducing the pesticide usage. The key factors for early warning of primary infection are leaf wetness duraion (LWD) and temperature, and LWD is difficult to monitor and model. The study will be carried in artificial climate chamber with differrent treatment of leaf wetness duration, to investigate the effects of different cucumber cultivars, leaf wetness fraction and duration on pathogen infection of Pseudoperonospora cubensis. The machine vision, digital infrared thermograhy and fluorescence imaging are measured in the process of LWD to develop an early detection method before the symptom appearance of primary infection. The goal is to determine the effective LWD to the primary infection of Pseudoperonospora cubensis, and establish the reference for LWD monitoring in the solar greenhouses. The solar greenhouse experiment will be conducted under the pot-cultivation, plastic membrane mulching and drip irrigation in solar greenhouses, to study the key factors of cucumber leaf wetness duration (LWD) with different varieties, and irrigation amount. Then the estimation model of LWD will be established based on intelligent fuzzy system. Combined with the values from LWD estimation model and temperature, the early warning model of primary infection for cucumber downy mildw will be investigated and the disease occurrance probability model will be established by Bayes method. The early warning system will also be developed. The above study will realize the automatic early warning model and system for primary infection of cucumber downy mildew, and improve the prognosis level of disease management.

日光温室黄瓜霜霉病的防治关键时期是初侵染阶段，研究监测预警方法有助于提高防治效果和减少农药使用，而其中关键指标为叶片湿润时间和温度,其中叶片湿润时间监测模拟为难点。本研究拟在人工气候室接种和不同保湿时间下，研究不同黄瓜品种、叶片湿润面积、湿润持续时间对霜霉病菌侵染的影响。采集黄瓜叶片湿润过程的连续监测可见光、热红外和荧光图像，建立病害显症前的检测方法，结合病原侵染显微镜观察，明晰对霜霉病菌侵染有效的叶片湿润时间，为日光温室监测叶片湿润时间提供依据。在日光温室覆膜盆栽滴灌条件下，研究不同品种和灌水量处理下，黄瓜叶片湿润时间的关键影响因素，研究基于模糊逻辑的日光温室黄瓜叶片湿润时间估计模型。应用叶片湿润时间估计值和温度等数据建立日光温室黄瓜霜霉病初侵染预警模型，采用贝叶斯决策等方法建立发病概率预警模式，并实现预警信息系统，达到对日光温室黄瓜霜霉病初侵染自动监测预警、提高病害防治预见性的目标。

日光温室黄瓜霜霉病的防治关键时期是初侵染阶段，研究监测预警方法有助于提高防治效果和减少农药使用，而其中关键指标为叶片湿润时间和温度,其中叶片湿润时间监测模拟为难点。本研究主要开展了日光温室黄瓜霜霉病侵染与叶片湿润时间的定量关系、日光温室黄瓜叶片湿润时间估计模型和日光温室黄瓜霜霉病初侵染预警模型研究，取得重要结果如下：（1）综合机器视觉、热红外成像和荧光成像技术，研究了黄瓜叶片湿润时间、温度等与日光温室黄瓜霜霉病菌初侵染的定量关系，界定了对黄瓜霜霉病菌侵染有效的叶片湿润时间。结果发现黄瓜霜霉病初显症随着叶片湿润时间的延长而缩短，4小时是保证发病的最低叶片湿润时间；不同湿润时间的叶片，黄瓜霜霉病逐日显症率随显症时间呈先升高后降低的趋势，其中显症后第3或4天是病斑出现的高峰期；叶片湿润时间越长，显症叶片最大温差越低，黄瓜霜霉病初显症日越早。（2）深入分析了日光温室外环境-温室结构-温室内小气候-黄瓜-霜霉病-栽培管理技术的耦合关系，筛选了叶片湿润时间和温度的关键影响因素，耦合机理模型和经验模型，基于热红外和荧光成像等技术，建立了1个新的日光温室黄瓜叶片湿润时间和温度估计模型，估计误差分别在1h和0.1℃以内。（3）结合灾变链式理论和植物病害流行学，重点对灾害天气诱导的日光温室黄瓜病害灾害链进行了系统分析，利用荟萃分析方法构建了日光温室黄瓜霜霉病初侵染预警模型1个，利用田间调查数据进行验证，采用贝叶斯决策方法预测病害发生的概率为97%。基于以上研究基础，利用Visual Studio 2010和SQL Server 2008开发了日光温室黄瓜灾害预警系统1套。综上所述，本研究在黄瓜叶片湿润时间、温度等与日光温室黄瓜霜霉病菌初侵染的定量关系研究基础上，首次提出了基于热红外和荧光成像的日光温室黄瓜叶片湿润时间估计模型，并采用荟萃分析方法构建了日光温室黄瓜霜霉病初侵染预警模型，为提高温室蔬菜相关病害防治预见性提供了理论依据和实用方法。