SPORNADO: Disease Alert System
Early Detection, Better Prevention
Phytophthora infestans causes late blight in potatoes and also infects tomato, eggplant, pepper, and other solanaceous plants. The disease is more severe in humid conditions and if left untreated, has the potential to wipe out an entire crop. Blight is believed to be responsible for the famous Irish potato famine in the 19th century.
The disease symptoms include lesions on the stems, leaves, and tubers. The infected tubers are also susceptible to secondary infections from other microbes. Infected leaves develop dark spots that spread and eventually become brittle, and white mildew will grow on the underside of the leaf in high humidity.
There are many subspecies of P. infestans and no potato varieties are resistant to all of them. Removal of infected seed tubers and foliar fungicide are key to controlling this disease. The use of disease free seed tubers is critical to reducing the spread of late blight because P. infestans overwinters as mycelia in infected tubers.
Sclerotinia sclerotiorum causes stem rot in canola. The symptoms of the disease include browning of the petals, whitish-grey lesions on the stems, brittle stems, and discoloration.26,27 Crop losses are highly variable depending on the weather and the timing of infections, and losses can reach as high as 50% per infected plant.
Canola is under threat from S. sclerotiorum when it is in bloom because the flowers are the initial site of infection for the fungus. In two main species of canola, Brassica rapa and B. napas, it takes between 30-50 and 40-60 days, respectively, between seeding and first flower, and the flowering period last for 14 to 21 days in both species. It can take as little as 4 to 8 days to reach full bloom after first flower.