Mope for Elms

"My boyhood home had tremendous elms," recalls John Hansel, 45, a New Jersey manufacturer of watercoolers. "Those trees were my symbols of the past." In fact, Hansel bought his present house in Riverside, Conn., mainly because four venerable elms shaded the front yard. Unfortunately, two of the trees soon died, victims of the Dutch elm disease that now kills about 1,000,000 trees a year in the U.S. Distraught, Hansel launched a personal crusade to save the threatened species. In 1965, unimpressed by the botanists who believed that the American elm was doomed, Hansel set up Elms Unlimited, which has since promoted the planting of 20,000 elm seedlings. In 1967 he changed the 500-member organization's name to Elm Research Institute and aimed it at the root of the problem. Said he: "The fight against Dutch elm disease will be won in the laboratory."

Hansel was not the first to mount a scientific assault on elm disease. Experts have long known that it is caused by a fungus, carried by the elm-bark beetle, that clogs the tree's circulatory system. But ever since the disease hit the U.S. in the early 1930s, every cure has failed. DDT may kill birds as well as the beetles; another pesticide named Bidrin sometimes destroys the trees. Frantic elm owners have resorted to such quack remedies as turpentine injections or driving galvanized nails into the trunks (in hopes that the zinc oxide will deter the fungus). So far, the only solution has been to chop down and haul away infected trees, a process that prevents the disease from spreading to healthy elms.

Hardy Siberians. Now there is new hope for elm lovers. Funded with a $30,000 grant from Hansel's institute, Entomologist Dale Norris of the University of Wisconsin recently discovered a subtle chemical reaction that occurs when beetles attack elms. It is the quinol compounds in elm bark, he found, that make the tree delectable to beetles. Paradoxically, when the insects begin to munch, oxidation changes the tasty quinols into quinones that repel the beetles. By this time, unfortunately, the beetles have already infected the tree with deadly fungus. To ward off the beetles, Norris is now working to synthesize a quinone-like, nontoxic repellent that can be injected into the tree or sprayed on the bark.

In a parallel attack on elm disease, the U.S. Department of Agriculture intends to cross the disease-prone American elm with the hardy Siberian variety. Even if the hybrid is a success, elm lovers are not likely to be pleased. The new tree clearly lacks the grace of its American parent. "It has a single, central trunk rather than our beautiful vaselike division," says Hansel. "Who will want a tree that looks more like a maple than an elm?"

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