Prediction of Disease Infection of Welsh Onions by Rust Fungus Based on Temperature and Wetness Duration

The style of agriculture practiced in Japan and other countries in Asia is small scale compared to that in North America. While systematic production and management systems have been maintained in Europe and America, Japanese agricultural style tends to depend on past experiences, and application of agricultural chemicals is guided by the calendar and past experiences. Japan is also advanced in the field of plant disease prediction. This paper focuses on a prediction model of disease infection for a foliar parasite on Welsh onions. Rust fungus disease is the most typical disease on Welsh onions, and the Weibull probability density function is appropriate for approximating the infection rate of the disease. The model utilizes temperature and wetness duration to predict the infection of Welsh onions by rust fungus. Producers, then, can use the model to determine the day on which the infection rate will rapidly increase, then carry out appropriate countermeasures to the disease. The proposed prediction method is applicable to several infections found throughout Asia.