Cheryl Smith '92G is so tuned in to the spots and rots and smuts and wilts of diseased plants that she can't help noticing the telltale signs wherever she sees vegetation. One time when a friend was showing her a snapshot of his wife standing in front of their house, he noticed Smith's expression and said, "OK, what's wrong with the tree?"

Smith, a plant pathologist who also has a degree in entomology, is a professor in the UNH Cooperative Extension program. Informally known as the "Plant Doctor" for the state of New Hampshire, she runs the UNH Plant Diagnostics Lab, where she examines roughly 350 samples of diseased plants a year. Add in phone calls and site visits and it comes to nearly 1,000 contacts a year with landscapers, commercial growers and backyard gardeners.

Like a forensic examiner, Smith deals with "patients" who can't speak for themselves. She does, however, prefer samples that aren't quite dead yet—the best specimens include living as well as dead or dying sections. And the more information the grower can give the better. Was the plant treated with a pesticide? Was it fertilized? (Ironically, the lush growth on well-fertilized lawns is more susceptible to pathogens, she says, and 90 percent of homeowners who fertilize do so without testing the soil to see how much—if any—is needed.)

In her 28 years as a diagnostician, Smith has encountered some unusual cases, like the mold from the top of light fixtures in a clothing store that turned out to be dust. Then there was the man who was convinced that aliens had invaded his backyard garden and had induced his ears of corn to erupt into grotesque gray blobs. (No aliens—just corn smut.)

"Maybe aliens did land in your backyard," Smith assured the man, "but they didn't cause this."

To consult the plant doctor, go to http://extension.unh.edu/agric/AGPDTS/PlantH.htm or call (603) 862-3841.