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Attack Looming on Ohio's Tomatoes

Bob Jones is from The Chefs Kitchen, a 200-acre farm in Huron, Ohio. This year, Jones is keeping an especially watchful eye on his tomato crops.

"It is a very nasty disease. If it gets in it gets established and in some instances there's nothing you can do. It's going to kill the crops," says Jones.

It's called Late Blight disease - a fungal pathogen that attacks primarily tomatoes and potatoes. It's this disease that caused the massive Irish famine and subsequent immigration of the 1840s.

The pathogen is present during many summers. Whether it becomes the plague for crops is a question of weather. Nancy Taylor - director of the plant and pest clinic at Ohio State University - says current weather conditions in Ohio are just what the disease needs to spread.

"The conditions that are highly favorable for this disease are cool nights in the 50s and day temperatures in the 70s or low 80s, which is exactly what we're experiencing. So the conditions are very favorable," says Taylor.

As of today, the only case of Late Blight in Ohio is from a non-commercial grower who purchased the plant from a greenhouse chain.

But just this one case is cause for concern - since Late Blight can spread quickly. Nancy Taylor explains how.

"It is a very significant disease in that when it shows up it moves very quickly. It can travel from 5 to 10 miles in the wind and in the rain," says Taylor.

Late Blight doesn't discriminate when it comes to the types of crops it contaminates - backyard or commercial growers, organic or not. Mike Anderson is with the Ohio Ecological and Farm Association, one of the three organic certifiers in Ohio.

"This disease is going to be an equal opportunity problem here for conventional produce growers or organic growers in the state," says Anderson.

Growers could recognize the onset of Late Blight with black lesions on the plant's leaves. When they dry, the lesions turn into a brownish color with a greenish halo. The lesions on the tomato itself are firm and greasy-looking.

When found infected, the tomato plants should be placed in a plastic bag and thrown in the trash. Taylor stresses the importance of proper disposal.

"Do not compost them, do not leave them lying around in your garden. Get rid of them completely," says Taylor.

Growers can prevent the spread of the disease with fungicides. The Ohio Ecological and Farm Association approves fungicides based on elemental copper.

Bob Jones says it's only a matter of time before he sees the disease make its first contamination attempts in his fields. Despite this, he also says we're far from the conditions that gave rise to the Irish famine of the 1840s - times have changed.

"Because we have ways to prevent it and cure it once it starts if you get in in a timely manner. It may create some shortages. But overall you shouldn't see in the grocery store shelves a huge effect on the availability of these crops," says Jones.