Forecasting And Management System Of Cucumber Powdery Mildew And Downy Mildew In Plastic Greenhouse Tunnel

Cucumber powdery mildew and downy mildew are the popular diseases that seriously restrict the yield and quality of cucumber, and the occurrence and epidemic of the two diseases in plastic greenhouse tunnel are little known. Forecasting models and management databases of cucumber downy and powdery mildew in plastic greenhouse tunnel were established based on outdoor investigation and indoor simulation experiments in this thesis.The interaction among pathogen of powdery mildew, cucumber host and environmental conditions in plastic greenhouse tunnel was simulated with manually inoculating pathogen and controlling condition in a got-up climate box. Three forecasting factors for occurrence time and four forecasting factors for disease severity were chosen separately, and the forecasting models for occurrence and severity were developed by mathematic method and SAS software based on data from indoor simulating tests. The root mean square error (RMSE) values of the occurrence models are less than 2, and the occurrence time errors are 0 -2.6 days between model forecasting and box surveying. The RMSE values of severity models are around 5, and the disease index errors are 0.0081-12.9404 between forecasting and surveying. The results demonstrated that these models could be used to simulate and forecast the disease occurrence and development of cucumber powdery mildew in the plastic greenhouse tunnel.The relationship between the prevalence of cucumber downy mildew and microclimate of plastic greenhouse tunnel was investigated. The six forecasting factors were selected, and the models for disease severity forecasting were produced by mathematic method and SAS software based on data from plastic greenhouse tunnel tests in Shanghai. The RMSE values are about 5, and the disease index errors are 0.08-8.33 between model forecasting and field surveying. The results showed that the models could be also used in practical forecasting for disease index of cucumber downy mildew in the plastic greenhouse tunnel.The expert system of cucumber powdery and downy mildew in plastic greenhouse tunnel was developed by the objected-oriented design (OOD) method and Visual Basicprogrammed language based on the artificial intelligence theory. The system includes model modules, diagnose modules, control knowledge modules. The system is an assistant decision-making system that can be used not only to forecast the occurrence and epidemic tendency of the two disease, and instruct the prevention and controlling management against the two diseases, but also to offer symptom recognition, disease diagnose, and optional controlling measures for the two diseases in plastic greenhouse tunnel.