Late blight evolves. The devastating fungal disease even jumps between crops. Potato growers have to stay on top of the latest methods of control to stay ahead in this high-stakes battle.
There are 24 strains of late blight in North America so far. In fact, a new strain from tomatoes was the main cause of late-blight infection in potatoes in Western Canada in 2010. So, what can you do to keep late blight away?
Infected seed is usually the culprit
Carefully grade-out infected seed, cut and plant as soon as possible. Use a seed treatment that contains mancozeb, and do not over irrigate. Eliminate cull piles immediately.
Use DuPont™ Curzate®
During the growing season, watch for potential hot spots – low-lying areas or spots that receive more irrigation than others.
Dr. Ron Howard, a plant pathology research scientist with Alberta’s department of Agriculture and Rural Development, says that while there are many fungicides on the market for late blight prevention, DuPont™ Curzate® stands apart for late blight control because it has both preventative and post-infection properties.
“Curzate® will kill infections of late blight, provided they are not too advanced,” he notes. “It should be used only once or twice a season to minimize the risk of resistance development in the pathogen.” It is recommended to use Curzate® as a tank-mix with a protective fungicide like Manzate® Pro-Stick™.
Apply Curzate® early
An early application of Curzate® is important. Sequential early Curzate® applications from 90-95% emergence to row closure are critical in preventing blight establishment. The goal is to control “point sources,” or the first cycle of disease, and stop late blight before it becomes established in the field. Early applications target seed-borne sources and the anti-sporulant activity will protect surrounding healthy plants. Starting early with systemic Curzate® makes sense.
Manzate® and Pro-StickTM are registered trademarks or trademarks of UPI used under license.