Tomato blight warning
Photo courtesy of AVRDC/The World Vegetable Center
University of Maryland agriculture officials are asking vegetable gardeners in Maryland to be on the lookout for late blight, a serious fungal disease that afflicts tomatoes and potatoes.
The Plant Diagnostics Lab received a suspect sample from a Howard County garden in June and found it to be infected.
Despite the name, late blight can occur anytime plants are actively growing and is especially damaging during cool, wet weather, which we have had plenty of.
It first appears as dark, water-soaked spots on leaves. The leaves quickly shrivel and die. Dark brown spots also appear on plant stems. The disease can be slowed by hot, dry weather.
Infected tomatoes can have shiny, dark or olive-colored lesions that may cover large areas. The infection can produced a foul odor as well
This is the same blight that caused the famous potato famine in Ireland in the 1840s, and can be particularly destructive in home gardens.
It is possible that the blight, appearing this early and with such a potential to spread, might effect the quantity and price of tomatoes this season. Usually, the blight hits plants late, after most of the fruit has been harvested.
Here are a few tips for dealing with the blight, courtesy of the University of Maryland Home and Garden Information Center.
- Keep foliage dry. Avoid overhead watering. Avoid crowing plants.
- Always purchase new need potatoes that are certified "disease-free."
- Do not compost store-bought potatoes and don't store infected tubers.
- Pull out and destroy all infected plants.
- Keep developing tubers covered with soil.
- Place infected plants or fruit in a sealed bag and dispose.
- Protectant fungicides like chlorothalonii and fixed copper can help protect foliage if applied prior to infection.