Among the most troublesome pests for peach growers are peachtree borers. These larvae of clearwing moths attack the roots of the trees or, in the case of the lesser peachtree borer, the aboveground portions, weakening and even killing trees. Researchers at the USDA Agricultural Research Service's Southeastern Fruit and Tree Nut Research Laboratory investigating biological controls of the borers have discovered a species of nematode that attacks these pests. Nematodes are microscopic, soil dwelling worms. While some species are pests themselves on crops we value, other species help us out by preying on pests.
This is the case with Steinernema carpocapsae, the nematode that attacks both kinds of peachtree borers. While the scientists showed that the nematodes were efficient at controlling the borer that feeds underground on the tree roots, the tiny worms lost their effectiveness in controlling the above-ground feeding lesser peachtree borer when exposure to heat and sunlight dried them out and killed them.
So the scientists tried a novel approach to protect the miniscule nematodes. Firefighters use what is called "fire gel" to help prevent the spread of fires between structures by creating a blanket of moisture. To see if the gel could also keep the nematodes from drying out, they sprayed peach trees with a non-toxic, environmentally friendly formulation along with an application of the beneficial nematodes. The first year of the trial only 30 percent of the borers survived on treated trees; by the second year, none survived.
The scientists are getting ready to test the nematode-gel combination in commercial orchards to come up with an efficient, economical, and environmentally safe way for growers to keep borers at bay. They also plan to investigate the potential for this technique to be used to protect other beneficial species of nematodes that are potential controls for a wide range of pests in trees and other crops.
For read more about this research, go to: ARS.
Article published on April 4, 2011.