Encapsulated Herbicides for Utility Rights-Of-Way and Forest Tree Injection
John J. Bollig and Shepard M. Zedaker
Abstract: Although the risk of exposure during various methods of herbicide application is generally quite low, eliminating the potential of worker exposure by encapsulating herbicides may be desirable. Therefore, three methods of injecting encapsulated herbicides - the FIC™, the Wee-Do™, and the Gelcap™ - were compared to a standard hack-andsquirt technique on two common weedy hardwood species using picloram and triclopyr. Both chemicals showed similar trends over the four injection methods, however, picloram was the more efficacious across all treatments. Mortality rates were highest for the hack-and-squirt technique, with 100% mortality using picloram and 89% mortality using triclopyr. Picloram mortality rates were 81 and 67% for the Wee-Do and FIC methods, respectively, and below 50% when formulated with triclopyr. The Gelcap never exceeded 10% mortality for either chemical. Current relative costs for materials and labor are 1:23:9:27forthe hack-and-squirt, FIC, Wee-Do and Gelcap methods, respectively. The Gelcap proved to be the easiest and most efficient alternative method of injection, however, it unfortunately had the lowest mortality rates. The FIC proved to be the most cumbersome and unreliable injection technique due to both equipment failures and engineering problems. Although the Wee-Do had some minor equipment failures, we found this tool to be the most effective alternative injection technique when considering ease of use, cost and efficacy.