Study On Epidemic Of Tomato Grey Mold In Greenhouse And Decision Support System For Disease Control

Tomato grey mold which is an important plant disease in greenhouse can severely decrease yield of tomato in greenhouse and be mainly controlled by fungicides today. This study focused on investigating temporal dynamic of the disease in growing season in different type of greenhouse through epidemic means. During the test, the temperature and humidity of air in and out of greenhouse were collected, and the condition of weather was recorded day by day, and airborne spores of Botrytis cinerea were trapped hourly. The main aim is to find the key factors which made spore infect severely and the suitable environmental condition. All the data obtained in 2001 and 2002 were input into a microcomputer for analysis and statistics. The results were as follows:1. The main weather factor to effect airborne spore flying is continue cloudy day or rainy day. The relationship between the quantity of airborne spores of Botrytis cinerea and meteorological factors is highly correlated. The quantity of airborne spores of Botrytis cinerea at each hour in a day has a significant negative correlation with relative humidity (R= -0.8091, P<0.01) and positive correlation with relative temperature (R=0.9295, P<0.01) respectively.2. The conidiospore is a precondition caused disease eruption. The day in which conidiospore infected severely is the day in which the quantity of airborne spores is the most, but the day in which the quantity of airborne spores is the most is not properly the day in which conidiospore infected severely because of different circumstance.3. It was beneficial for spores to bourgeon and infect when there were more than two days' rainy or more than two days' cloudy in greenhouse.4. The suitable condition for severe infection of the disease was relative humidityabove 80% for more than 24 hours, at the same time, the temperature ranged from 7 to 13 .5. The air temperature and relatively humidity in different type of greenhouse can be estimated by different equations. The greenhouse has two styles. In the sunlight greenhouse, the air temperature ( ) (Y) in greenhouse in each hour of a day can be estimated by the equation: Y=1.60+1.08X (R=0.9914, P<0.01), where X is temperature( ) out of the greenhouse. The air relatively humidity(%) (Y) in greenhouse in each hour of a day can be estimated by the equation: Y=2.96+1.07X (R=0.9649, P<0.01), where X is air relatively humidity(%).In the second type of greenhouse, the air temperature ( ) (Y) in greenhouse in each hour of a day can be estimated by the equation: Y=1.76+1.13X (R=0.9856, P<0.01), where X is temperature( ) out of the greenhouse. The air relatively humidity (%) (Y) in greenhouse in each hour of a day can be estimated by the equation: Y=22.10+0.86X (R=0.9378, P<0.01), where X is air relatively humidity (%).According to above conclusion, decision support system which could be used to control tomato grey mold in greenhouse was set up in the computer. After inputing the information of weather forecast weather or the data of temperature and relatively humidity collected in the past days, the system can tell the user whether the circumstance has met the most suitable environmental condition in which conidiospore can bourgeon and infect severely and how to deal with the greenhouse. Comparing to normal disease control in a routine way, it could save much chemical use.