The disease may overwinter in plant debris or cull piles (potato or tomato). The fungus grows most actively from 15- 21☌ (59- 70☏). Lesions on fruit appear as firm greyish-green to brown, rough, irregular shaped blotches, which rapidly enlarge.īuckeye rot (Fruit symptoms are unlikely to be confused with other diseases, except buckeye rot however, late blight causes the fruit surface to become rough.) Under favourable conditions, the pathogen can blight the foliage so quickly, that it appears the plants were hit by frost. These stem lesions may quickly girdle the stem and kill it. Brownish cankers may appear on leaf petioles and stems. On the underside of leaves, spots may develop a grey to white moldy growth, especially under conditions of high humidity. A pale yellow or green halo may surround the leaf lesions. Initial leaf symptoms are pale green to brown water-soaked spots, which enlarge rapidly and become brown to purplish-black. This disease is easily spread by wind and can rapidly destroy the crop. However, late blight causes the fruit surface to become rough. Fruit symptoms are unlikely to be confused with other diseases, except buckeye rot. Symptomatic leaves can be sealed in a plastic bag with a damp paper towel overnight, then checked for a gray to white moldy growth on the underside. Key diagnostic features on foliage are lesions that are not stopped at leaf veins. Cool nights and warm days, with moist weather, are ideal for disease development. The late blight fungus prefers temperatures from 15- 21☌ (59- 70☏).
Spore traps are low-technology devices that sit in a field and collect disease spores from the air and water. The traps are placed in Shelburne, Alliston, and Simcoe-Delhi areas.īanks says two late blight spore traps are up and running in the Alliston area, and two traps will be installed in the Shelburne-Melancthon area on June 19. The year 2020 marks the fourth year spore traps will be set up in potato fields across Ontario to help detect spores of late blight. In Ontario, Eugenia Banks lead a two-year Ontario Potato Board project evaluating one type of spore trapping technology in order to help growers improve late blight management with good results. With this project we are helping to bring back the Alberta advantage.” Spore trapping continues in Ontario “A number of years ago, Alberta potatoes had an economic advantage because late blight was rare in the province. “Another important component of this study is to identify hot-spots for infection and then to educate people in these areas on practices that can help eliminate late blight,” she says. The researchers found that once spore levels spiked in the traps, they had about a 10- to 16-day window before late blight appeared in nearby fields.īack in 2014, Terence Hochstein, executive director of the PGA, said the study did exactly what they’d hoped it would: it provided growers with an early warning about the advancing spread of Phytophthora infestans (the pathogen that causes late blight) so they could tighten up their existing spray programs and stay ahead of the pathogen.īut Kalischuk said at the time that the benefit of the study goes beyond immediate payoffs for growers. The traps were set up at the edges of farmers’ fields, or just west of fields, because late blight spores tend to travel east to west. The PGA also supported the study by disseminating spore-trap counts to growers in real-time. Funding for the study was provided by PGA, Alberta Crop Industry Development Fund, Cavendish Farms, Lamb Weston and Crop Production Services. The study was headed up by Melanie Kalischuk and students at Lethbridge College, with assistance from Michael Harding and Ron Howard with Alberta Agriculture and Rural Development at Brooks, and Lawrence Kawchuk at Agriculture and Agri-Food Canada’s Lethbridge Research Centre. In 2014 in response to the discovery, the Potato Growers of Alberta (PGA) supported a spore-trapping project.
Tomato blight ontario free#
Alberta had almost been late blight free until 2010 when late blight was discovered in many Alberta potato fields.
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