Callery pear (Pyrus calleryana) can be found across most of the eastern U.S. and in a few western states as well. The nonnative tree was brought to the U.S. in 1917 by a USDA employee searching for a blight-resistant species that could be bred with European pear to increase fruit production.
The most common Callery pear cultivar is the Bradford pear. In the last two decades, this near-ubiquitous landscaping tree has been identified as a serious invasive pest. A new publication examines herbicide treatments to control the spread of Callery pear. Lead author J.T. Vogt is a research scientist with the USDA Forest Service.
When the invasive tree borders roads and fields, its dense growth and sharp thorns threaten equipment and livestock. Callery pear can also grow in the understory of pine plantations, where it can impede some forest management practices.
Vogt and colleagues compared the efficacy of different herbicide treatments at two sites in Georgia and South Carolina. The researchers tested four common formulations: glyphosate, hexazinone, imazapyr, and triclopyr. Using handheld sprayers, the team applied the four herbicides, along with one combination of two, on the basal bark and leaves of Callery pear trees and to the soil around the base of the trees.
The researchers compared the trees treated at each site and included a control group that was not treated. The study showed that the foliar and basal bark treatments were both effective at controlling Callery pear. Additional study is needed to evaluate soil applications, because rainfall at the sites may not have been sufficient.
This research adds to land management control options and supports further development of integrated pest management practices for this invasive species.