Does that last bit sound familiar? It has been the weather report for the Northeast this summer, especially in June. Where we saw precipitation fit for Noah’s Ark, late blight found something akin to a four-star hotel. Those soggy fields and backyard vegetable plots? Inviting, and all too easy to check into.

But weather alone doesn’t explain the early severity of the disease this year. We’ve had wet, cool summers in the past, but it’s never been this bad. Instead we have to look at two other factors: the origin of the tomato plants many of us cultivate, and the renewed interest in gardening.

According to plant pathologists, this killer round of blight began with a widespread infiltration of the disease in tomato starter plants. Large retailers like Home Depot, Kmart, Lowe’s and Wal-Mart bought starter plants from industrial breeding operations in the South and distributed them throughout the Northeast. (Fungal spores, which can travel up to 40 miles, may also have been dispersed in transit.) Once those infected starter plants arrived at the stores, they were purchased and planted, transferring their pathogens like tiny Trojan horses into backyard and community gardens. Perhaps this is why the Northeast was hit so viciously: instead of being spread through large farms, the blight sneaked through lots of little gardens, enabling it to escape the attention of the people who track plant diseases.

It’s important to note, too, that this year there have been many more hosts than in the past as more and more Americans have taken to gardening. Credit the recession or Michelle Obama or both, but there’s been an increased awareness of the benefits of growing your own food. According to the National Gardening Association, 43 million households planned a backyard garden or put a stake in a share of a community garden in 2009, up from 36 million in 2008. That’s quite a few home gardeners who  given the popularity of the humble tomato  probably planted a starter or two this summer.

Here’s the unhappy twist: the explosion of home gardeners  the very people most conscious of buying local food and opting out of the conventional food chain  has paradoxically set the stage for the worst local tomato harvest in memory.

So what do we do?

For starters, if you’re planning a garden (and not growing from seed  the preferable, if less convenient, choice), then buy starter plants from a local grower or nursery. A tomato plant that travels 2,000 miles is no different from a tomato that has traveled 2,000 miles to your plate. It’s an effective way to help local growers, who rely on sales of these plants before the harvest arrives. It’s also a way to protect agriculture. If late blight occurs in a small nursery it’s relatively easy to recognize, as straightforward as being able to see the plant, recognize its symptoms and isolate it before it has a chance to spread.

This is less of an option on a farm that’s spread out over dozens of acres, nor is it likely once the plant gets to a large retailer. A plant pathologist from Cornell told me she visited one such store and noticed the tomato plants were infected with blight. She immediately reported it to the manager, who said he couldn’t remove the plants without approval from his superiors (which would take time). The pathologist returned a week later to find that the plants were still there.