Managing Potato Blight with Smart Strategies
Early and late blight are two major diseases that worry potato farmers due to their fast spread and potential for heavy crop losses. These blights can affect the crop in the field and during storage if infected tubers are harvested and kept.
According to crop expert Holly Derksen, from UPL, regular scouting and weather monitoring are critical for blight management. Early blight often appears in warm, humid weather, while late blight thrives in cooler nights and moderate days. Both diseases can appear anytime during the growing season, not just early or late as their names suggest.
Each blight has specific symptoms. Early blight causes small dark spots with yellow halos on leaves. Late blight leads to dark, water-soaked lesions and can survive on infected tubers, seed, or plant waste. These infected tubers, when stored, can result in major post-harvest losses.
“Monitoring weather conditions is an important and proactive step growers should take throughout the season to monitor for these destructive diseases,” said Derksen. “Both diseases thrive when conditions are humid, with early blight often emerging in warm temperatures and late blight showing up when the daytime temperatures are moderate, and the nights are cooler.”
To fight these blights, a proactive plan is needed. This includes timely fungicide use, especially before disease symptoms show. One recommended option is MANZATE® MAX, now registered for potatoes in Canada. It contains mancozeb, a multi-site fungicide with low resistance risk. Its liquid form makes it easier and safer to use repeatedly.
Farmers should also keep operations clean. Discarded tubers and compost piles should be far from crops, and clothing used for scouting should be cleaned and disinfected. Rubberized gear is best for this.
By using these practices—scouting, weather checks, fungicide sprays, and hygiene—farmers can reduce the risk of blight and protect their potato yield. For more help, contact a local UPL representative or visit uplcorp.com/ca.
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