Evaluation of herbicides for stem injection of woody weeds in young radiata pine plantations

Abstract

Summary Five herbicides (25% a.i. hexazinone as Velpar L, 20% a.e. dicamba as Banvel 200, 36% a.e. triclopyr amine as Garlon M/3724, 48% a.e. triclopyr ester as Garlon 480 Herbicide and 50% a.e. MCPA amine as Thistle Killem) were evaluated for control of silver wattle (Acacia dealbata) and several eucalypt (Eucalyptias) species in young plantations of radiata pine (Pinus radiata) using a stem injection technique. Each herbicide was injected in either spring or winter at three concentrations; these being undiluted product (100%), 1 part product to 1 part water (50%) and 1 part product to 3 parts water (25%). Injection in spring of all undiluted herbicides caused high mortality of the target species, although eucalypts appeared more susceptible than silver wattle. Velpar L, Garlon M/3724 and Garlon 480 Herbicide were also effective in a diluted form when injected in spring. These three herbicides, depending on the concentration used, were the only treatments which resulted in high mortality of the target sp...