Miconia (Miconia calvescens DC.) is a tropical tree species from South and Central America that is a highly invasive colonizer of Hawaii's forested watersheds. Elimination of satellite populations is critical to an effective containment strategy, but extreme topography limits accessibility to remote populations by helicopter operations only. Herbicide Ballistic Technology (HBT) is a novel weed control tool designed to pneumatically deliver encapsulated herbicide projectiles. It is capable of accurately treating miconia satellites within a 30 m range in either horizontal or vertical trajectories. Efficacy was examined for the encapsulated herbicide projectiles, each containing 199.4 mg ae triclopyr, when applied to miconia in 5-unit increments. Experimental calibrations of the HBT platform were recorded on a Hughes 500-D helicopter while conducting surveillance operations from November 2010 through October 2011 on the islands of Maui and Kauai. Search efficiency (min ha−1; n = 13, R2 = 0.933, P< 0.001) and target acquisition rate (plants hr−1, n = 13, R2 = 0.926, P< 0.001) displayed positive linear and logarithmic relationships, respectively, to plant target density. The search efficiency equation estimated target acquisition time at 25.1 sec and a minimum surveillance rate of 67.8 s ha−1 when no targets were detected. The maximum target acquisition rate for the HBT platform was estimated at 143 targets hr−1. An average mortality factor of 0.542 was derived from the product of detection efficacy (0.560) and operational treatment efficacy (0.972) in overlapping buffer areas generated from repeated flight segments (n = 5). This population reduction value was used in simulation models to estimate the expected costs for one- and multi-year satellite population control strategies for qualifying options in cost optimization and risk aversion. This is a first report on the performance of an HBT helicopter platform demonstrating the capability for immediate, rapid-response control of new satellite plant detections, while conducting aerial surveillance of incipient miconia populations.
