To manage LB well, farmers need basic knowledge and access to technologies such as resistant varieties. Baseline surveys have indicated that resource-poor potato farmers in developing countries have a general idea of how environmental factors affect disease development, but they are unaware that a microbe is involved. They are generally poor at diagnosis and decision-making. To allow farmers to learn about disease and other key aspects of potato pest and crop management, and to get their input into the latest stages of the breeding program, CIP is working with diverse partners to develop farmer field schools for potato producers in areas where LB is a major concern. Late blight is caused by the fungus-like oomycete Phytophthora infestans .
Spores transported in the wind or infected tubers carried to new areas can cause infestation.
Late blight first appears as a few grayish specks on the plant's leaves, and then a cottony film appears. The disease also affects tubers, and can make the crop unfit for storage. The disease can be controlled using resistant varieties, and cultural practices such as fungicides. However, many developing country farmers do not have the sufficient knowledge to manage the disease well. On top of that, the level of resistance in current potato cultivars is only intermediate, and access to resistant varieties by farmers is often limited.