tomato blight

Make a pact with your neighbors to remove infected plants asap. Think carefully about using copper sprays, they may not be worth the risks.

Keep an eye on your tomatoes; rip out tainted plants to save the rest.

RODALE NEWS, EMMAUS, PA— Late blight, also known as tomato blight, is the bubonic plague of the tomato world. It spreads rapidly, and once it infects a tomato or potato plant, it causes quick and certain death. Among gardeners it can create the same type of panic that last year's swine flu caused among the general public. And while late blight doesn't hurt humans, it certainly puts a damper on the growing season. But a leading late blight expert may have the answer for stopping its spread: Talk to your neighbors. Tell them how to spot it and how to quickly dispose of infected plants to reduce the spread.

Here's everything you need to know to protect your garden:

What is late blight?

It's a funguslike pathogen. Spores from infected tomato and potato plants are easily swept up in the wind and can even be carried from one state to another. To help you identify it, check these tomato blight pictures.

Where is late blight occurring?

So far this year, late blight has been confirmed in Florida, Pennsylvania, Louisiana, Maryland, Kentucky, Connecticut, New York, and, most recently, Michigan and Ohio. "I can't tell folks enough that this is a community disease that we need to manage together,” says blight expert Meg McGrath, PhD, a plant pathologist at Cornell University. "People need to regularly inspect their plants, manage the problem, and report occurrence, especially early in the season when most plantings are healthy. This way, healthy plants can be saved, which minimizes unnecessary fungicide use."

How can it be prevented organically?

Chemical farmers and gardeners apply toxic fungicides before the disease strikes as a preventive measure, but organic planters have the option of using copper sprays. The sprays approved for organic agriculture carry the Organic Materials Review Institute (OMRI) distinction on the product label. (See a list of copper spray products.)