Optimising aerial herbicide treatment for control of dense conifer infestations: a New Zealand case study

Abstract

Conifers, mainly of the genus Pinus, have invaded natural and productive landscapes worldwide. Controlling dense conifer invasions is challenging and requires both effective initial control methods and long-term site management to prevent re-invasion. Broadcast aerial herbicide application is often the preferred treatment method for dense infestations of pines with high rates of complex herbicide mixtures used. The objective of this study was to: (i) test the efficacy of four simple herbicide mixes (containing two active ingredients and one adjuvant) as compared to an operational standard (four active ingredients and three adjuvants) for control of Pinus contorta invasions in a field trial and (ii) to quantify the effect of treatment mixes on non-target vegetation to determine impacts to plant community composition.