Potato Late Blight: How Growers are Overcoming the Challenge
Potato late blight has been detected in Wisconsin, but don’t think this disease has the upper hand when it comes to your vegetables. Wisconsin’s potato and vegetable growers are staying ahead of the curve to properly manage this fast-moving community disease to ensure a healthy and adequate food supply.
First, a bit of background on late blight. This disease can be a serious problem to everyone growing potatoes, tomatoes, eggplants and similar crops with no distinction between commercial growers, garden centers or home gardeners.
The fungus causing this devastating disease (Phytophthora infestans) is the same organism that caused the Irish potato famine and brought mass starvation to Europe in the late 1800s by destroying the Irish potato crop.
Fortunately, the organism in its current form cannot survive Wisconsin’s winters. The soundest way to control the problem is to inspect seed tubers and host transplants coming into the state, and limiting the protected sites where it might be able to survive by destroying all potato waste from storage.
However, in spite of best efforts to limit the introduction of the disease, when weather conditions are perfect for development, potato late blight can still slip through and quickly become a problem.
Wisconsin’s growers and University of Wisconsin specialists have an extensive monitoring program to determine if the disease is present in the state and due to this diligence, potato late blight was confirmed in Wisconsin this year on June 26th.
Since late blight can cause devastation to the crop throughout the whole region, growers are proactively destroying large portions of fields where late blight was found. This seems drastic, but it is the only effective way to stop the disease from spreading. Growers ultimately lose more if they let it spread to other fields and neighboring locations. Growers routinely clean and sanitize all equipment, even their own boots, before entering fields to avoid spreading the fungal spores of this dangerous disease.
Growers in Wisconsin’s Central Sands region use a sophisticated weather and disease forecasting model (Blightcast), that indicates when they should begin applying crop protectant materials to limit initial infection. The forecasting model calculates disease severity values, which accumulate when conditions are prime for disease development, usually during high temperatures, high humidity and rain. Growers use trained scouts to inspect fields closely to detect infection early before the disease becomes established and can still be treated.
Finally, growers realize that time is of the essence when potato late blight appears and it takes a joint effort by all growers to be watchful and ready to act!
When potato late blight disease is detected in the state, growers actively communicate with each other, their industry, home and market gardeners and UW-Extension specialists to ensure proper management is enacted to limit impact on all growers alike. For updates and information about this serious problem, reference the University of Wisconsin Vegetable Disease Extension site: http://www.plantpath.wisc.edu/wivegdis/index.htm.