Vitamins help trees fight pests
Deane Anderson
Vitamins are not only good for people, they also may keep plants healthier. Trees given the vitamins C or E can resist insect and disease attacks better.
The vitamins stimulate trees to increase their natural defenses against such harmful insects as gypsy moths and bark bettles, says Dale Norris, a College of Agricultural and Life Sciences entomologist. In field and laboratory work, Norris and researchers Fanindra Neupane and John Haanstad found that the vitamins reduce leaf loss caused by insect feeding.
Urban foresters and homeowners could use the vitamin treatment as a preventive measure to induce healthy trees to become even more resistant prior to attacks, says Norris.
Norris also has successfully tested vitamin treatments on soybeans, snap beans, sweet corn and other vegetable crops. Because they are not pesticides, vitamins don’t harm the environment of require governmental regulation.
“Here we have compounds that give plants definite defensive protection and we can use them immediately,” Norris says.
Norris cautions, however, that not all trees respond equally to the treatment. “The results we are finding depend upon species, variety, or individual trees,” he says. “In the future, we can work with breeders and nurserymen to breed and select plants for genetic lines we know will respond to the vitamins.”
Insects and the disease-causing microbes they carry often combine to injure or kill trees. For example, certain bark beetles transmit Dutch elm disease. Other bark bettle species and their associated microbes are responsible for causing several other tree diseases.
Trees respond to invading insects and microbes by altering their natural defenses. In some cases, trees are weakened by attacks. In other cases, the defenses are powerful enough to overcome insects and disease.
Norris and graduate student Shao-Hua Liu have found that plant cells contain proteins in their membranes that monitor outside stress such as pest attacks and drought. When a tree is stressed, the proteins tell the cells to respond to environmental changes by altering their defenses.
“Living cells interact with the environment,” Norris notes. “Whether it’s from a soybean plant or an ash tree, all plants have cell membranes that shield them from the environment.”
Certain natural compounds such as vitamins C and E can “trick” the cells into reacting as if the tree is under more stress than it really is, Norris says. The researchers apply the vitamins by misting the leaves with a vitamin solution or wrapping a band containing the vitamins around the base of the tree. The vitamins then elicit a systemic reaction throughout the tree, stimulating cells to produce more natural defenses.
“The vitamins provoke defensive responses by trees in much the same way trees respond to insect attacks,” Norris says.
During the next growing season, Norris will study the proper dosages of vitamins to give to large trees. In the future, he says, it may be possible to sell a vitamin treatment along with a particular tree variety. Costs for using a vitamin treatment would be very competititve with pesticides, Norris says.
COPYRIGHT 1991 Vegetus Publications
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