Efficacy of herbicides and application methods for management of midstory Callery pear (Pyrus calleryana)

Abstract

Callery pear (Pyrus calleyana Decne.) is a problematic woody invasive plant in eastern North America that invades old fields, forests, and disturbed sites. While management guidance typically suggests foliar, basal bark, cut stump, and hack-and-squirt applications of herbicides for P. calleryana, there is a dearth of studies focusing on the efficacy of specific treatments. We evaluated seven herbicide treatments for control of midstory P. calleryana. Cut stump and hack and squirt applications of glyphosate, imazapyr, and triclopyr and a soil application of hexazinone were repeated at six sites within Georgia, Kansas, and South Carolina, and all study trees were monitored for approximately one year after herbicide application. Cut stump applications of glyphosate, imazapyr, and triclopyr provided the most consistent control with no resprouting and 100% mortality. Hack-and-squirt applications of glyphosate and triclopyr resulted in approximately 80% probability of mortality one year after treatment, while hack-and-squirt application of imazapyr and soil application of hexazinone averaged only 20 and 25% probability of mortality, respectively. Our results demonstrate the efficacy of seven treatment options for P. calleryana control in three geographic locations with varied habitat types, and our data suggest that cut stump applications of glyphosate, imazapyr, or triclopyr or hack-and-squirt application of glyphosate or triclopyr may be useful for reducing populations of P. calleryana. that have grown past the sapling stage.