If you’re interested in canning tomatoes en mass to use throughout the winter, you’ll want to start looking for tomato suppliers immediately. Good organic canning tomatoes will cost $2-4 per pound (depending on supply). Conventional tomatoes should run $1-2 per pound (if you buy in bulk).

Your local food co-op is a good place to start. You can usually place bulk orders there and get a case or two of tomatoes as farms drop them off. Alternatively, you could ask farmers directly at the next farmer’s market near you.

We canned some tomatoes in my home last season as part of a test run. Late blight choked the supply and drove prices up, so we didn’t process as many as we had hoped for. Those that did make it, though, tasted amazing in December and January.

So far in 2010, late blight hasn’t impacted Michigan tomato crops (though it has been spotted in New York and Wisconsin). That’s good news for the mitten state; and as long as temperatures stay warm, the threat of late blight will be reduced.

Late blight is a fungal disease that attacks the leaves and fruits of potatoes, but can also spread to tomatoes. Depending on weather conditions, the highly infectious blight can destroy entire crops within days if it goes unchecked. Fungicides exist to combat late blight, but at best they only slow down its spread.

What does this mean for locavores? The annual tomato harvest of mid-to-late August has been severely stunted. Residents of Northeast and mid-Atlantic states have seen much higher prices than usual on tomatoes and potatoes, in some cases 2-3 times as much. It’s also much harder to find tomatoes in bulk, say if you want to go canning.

While late blight is not uncommon in late August, the scale and scope of this year’s epidemic has reached historical size. Accounts from farmers impacted by the fungus are downright frightening.

The first signs of the fungus are gray leaves. A couple of days later, the plants are dead. “It’s nasty,” Mr. King said. “You go out to look at your tomato plants and two days later your plant’s dead … black crisp dead.”

“We have it. It’s horrible,” said Kira Kinney, of Evolutionary Organics in New Paltz. “We’ve lost most of the potatoes and one entire field of tomatoes and now it’s starting in the other tomatoes. … You are supposed to maybe hold it at bay but once it’s started it’s in there.”

Still, the spread of late blight is unlikely to affect large tomato processors who typically import their red fruit from places like California.

This outbreak is more likely to impact people who cultivate  vegetables in home gardens and the farmers who grow their crops for local eaters to buy at market. It’s a sad story, and hopefully one that won’t repeat itself in 2010.

As late blight progresses (or diminishes) through the rest of the harvest season, we will try to post updates.