Friday, April 24, 2015

Late blight

It's been a soggy spring. Does that mean we're in for another round of late blight ruining our tomato crops? 2009 was ruinous.

Late blight

This is a nice healthy tomato plant, one that Meg McGrath, an associate professor of plant pathology at Cornell, no doubt would wish for all of us. McGrath, an expert on late blight, suggested recently that the soggy spring of 2011 has folks once again wondering about - read fearing - this highly destructive disease that spread throughout the northeastern United States in 2009, destroying whole tomato and potato crops on farms, in addition to plants in many backyard gardens.

Late blight is, for lack of a better word, challenging, she says. For one thing, it cannot be "lived with" or managed. If your plants show signs of having it, they must be destroyed immediately - not composted, but burned or disposed of in the trash. Otherwise, the whole crop/garden goes down.

Symptoms include brown spots or lesions on the stems, with white fungal growth, causing the stems to soften, then collapse.

You'll also see brownish spots about the size of a nickel on the leaves and firm brown spots on the tomatoes.

Blight-causing spores are blown far afield by the wind. Cool, rainy conditions are especially helpful in this regard. So keep an eye out, McGrath says.

Not that we need coaxing in that department. We measure our tomatoes' growth by the centimeter!

Inquirer Staff Writer
About this blog
Ginny Smith, a Philadelphia native, joined the Inquirer at 1985. After stints as both reporter and editor in the city and suburbs, she’s been happily writing – and learning - about gardening full time since 2006. She’s won two silver medals of achievement from the national Garden Writers Association and in 2011, Bartram’s Garden honored her with its Green Exemplar award for her stories about “the region’s deeply rooted horticultural history, cultural attractions and bountiful gardens.” She plays in her own – mostly - bountiful garden in East Falls. Reach Virginia A. at .

Virginia A. Smith Inquirer Staff Writer
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