First drone releases of the biological control agent Neomusotima conspurcatalis on Old World climbing fern

Abstract

ABSTRACT Biological control is a sustainable method of weed management because agents can establish persistent and self-dispersing populations on a landscape scale. Strategic releases are often conducted to accelerate the widespread dispersal and establishment of agents. Drones (unmanned aerial systems, UAS) could facilitate these releases, particularly in remote areas that are difficult or dangerous for humans to access. Lygodium microphyllum (Lygodiaceae), Old World climbing fern, is a damaging weed that outcompetes native plants in many habitat types in Florida. This weed often occurs in remote conservation areas accessible only by helicopter, airboat, or swamp buggy. Although the biological control agent Neomusotima conspurcatalis (Lepidoptera: Crambidae) is established and dispersing in Florida, populations are patchy and additional releases are needed, particularly in conservation areas where human access is limited. We conducted the first releases of N. conspurcatalis using a drone to test agent survival and larval transfer to field populations of L. microphyllum. In the survival experiment, 85% of individuals were recovered from the flight, flight with impact, and control treatments with no treatment differences. In the larval transfer experiment, significantly more larvae and pupae were recovered four days post-release from the drone releases than hand releases. Drone releases of N. conspurcatalis could improve the establishment and potential impact of this agent on a landscape scale. In general, drone releases in L. microphyllum and other biological control systems could help to mitigate limits of agent dispersal.