Controlling five invasive woody weed species using the drill and fill stem injection method

Abstract

A series of field trials were conducted on five invasive woody weeds to determine the efficacy of applying small doses of liquid herbicide directly into the sapwood layer of target plant stems using the application method known as ‘drill and fill’. The five target weeds included four trees: leucaena (Leucaena leucocephala (Lam.) de Wit), pond apple (Annona glabra L.), neem (Azadirachta indica A. Jus,), and African tulip (Spathodea campanulata P.Beauv,), and the vine rubber vine (Cryptostegia grandiflora R. Br.). All five weeds can cause detrimental effects in native ecosystems and significant problems for land managers if unmanaged. Drill and fill is a portable, userfriendly application method that can be safely applied anytime of the year on target weeds growing within desirable vegetation and in environmentally sensitive areas. This paper highlights this technique as an effective management option using minimal volumes of herbicides to achieve high mortality rates.