Late Blight

Remember how back in May we gave you all those great tips on planting and transplanting your tomatoes? Well forget all that. We’re not going to have any–or many–tomatoes this year. No tomatoes at the market, no tomato tasteoffs, and damn few tomatoes for anybody else either. The problem is called late blight, and it’s a killer. But first a bit of history.

Back in the late summer of 1845, Ireland’s potato farmers began noticing something was amiss. Their potato plants were turning black and dying. Potatoes were a critical component of the rural Irish diet and smaller outbreaks had wiped out crops and left famine in their wake before. But this time the disease–a fungus called Phytophthora infestans–killed half the island’s  potato crop. Perhaps a million people died of starvation–some 12% of the population. Those who survived, ran for their lives, including many who emigrated to the U.S., laying down a new cultural strata here.

So what’s that got to do with our dead tomatoes? The same fungus that wiped out Ireland’s potatoes is killing our plants.

All this month, we have watched with dismay as the leaves of our tomato plants have blackened and died, along with their fruit.

 Yes, we know we just wrote about herbicidal damage from Clopyralid and Aminopyralid–and we’ve had state inspectors in to try to nail down their presence in our compost. (More about that when the results come back in six weeks or so.)

But meanwhile, late blight has been the knockout blow for our reeling tomatoes. And maybe our potatoes as well. You can’t say we didn’t see it coming–the same fungus all but wiped out tomato and potato harvests on the east coast last year and with our freaky coastal NW weather tomatoes are always a crapshoot. We usually try to protect our plants by spraying them with compost tea, an organic brew that contains so many good bacteria that they crowd the bad guys off the leaves.

But compost tea wasn’t going to do the job in the face of this summer’s endless parade of cool, damp mornings–perfect incubation weather for Phytophthora infestans. The late blight moved in with amazing speed. You can’t rip out the plants fast enough to get ahead of it once the spores are in the air. It happens so fast you can’t even save the fruit. You just watch your beautiful tomatoes turn a sickly brown and die.

Of course, we’re not the starving Irish of the 1840s, and we’re not planning to leave our blackened stalks and hit the road in search of some blight-free nirvana. Our farm is churning out vegetables these days and our CSA subscribers and market customers are getting plenty of produce–the cucumbers, for instance, are going nuts this year. But year-in and year-out our customer surveys tell us that what our buyers wait for at this point in the season are those wonderful homegrown tomatoes.

Sorry. Not this year.

If you too have seen evidence of late blight here are a couple of must-do responses:

–Monitor your plants closely. That means checking daily, or even several times a day. Look for brown spots on the plant stems and a white fungal growth spreading down the stalk. Also, look for nickle-size brown patches on the leaves and white fungal growth underneath, especially in the early morning or after a rainstorm.

–Rip those dying plants out of your garden pronto–not just the infected ones but the healthy looking ones next to them. Don’t try to save them. They’re toast. And worse, they’re giving off spores that can travel long distances so you are probably contributing to the next guy’s blight while you dither.

–Don’t burn those plants. That will just send some spores into the air. Double-bag them and get them to a landfill.

–And finally, check later to make sure you have not gained some volunteer plants springing up from seeds that dropped from this year’s infected crop. Be ruthless and kill them since they likely are haboring this very contagious disease.

Next post, we’ll try to have better news.