Will there be a sequel to last summer's late blight with tomatoes, potatoes?

Many readers are no doubt aware of last summer's late-blight infestation, in which a fungus, Phytophthora infestans, decimated local tomato and potato plantings. The fungus overwinters in southeastern United States but does not generally overwinter in New England due to the cold temperatures. Instead, the fungus typically works its way northward on summer weather fronts, perhaps arriving in New England, if at all, late in the growing season, after the bulk of the harvest is already assured. Hence the common name, "late blight."

Last summer, however, a large nursery in Alabama inadvertently provided blight-infested tomato seedlings to large retailers across the Northeast, which promptly sold them to home gardeners in May and June. By the end of June, the blight, having effectively hitchhiked north three months early, began its devastation.

But that's ancient history, right? Didn't winter reset the clock?

Maybe not. Late blight does not generally overwinter in northern New England, but it can if it finds a place to snuggle underground on some live host tissue. Tomatoes are not a concern because this past winter, though warm, was more than cold enough to freeze and kill every tomato plant in the region (and the blight cannot survive on tomatoes seeds.)