Biological invasions can cause major ecological and economic impacts. During the early stages of invasions, eradication is desirable but tactics are lacking that are both effective and have minimal non-target effects. Mating disruption, which may meet these criteria, was initially chosen to respond to the incursion of light brown apple moth, Epiphyas postvittana (LBAM; Lepidoptera: Tortricidae), in California. The large size and limited accessibility of the infested area favored aerial application. Moth sex pheromone formulations for potential use in California or elsewhere were tested in a pine forest in New Zealand where LBAM is abundant. Formulations were applied by helicopter at a target rate of 40 g pheromone per ha. Trap catch before and after application was used to assess the efficacy and longevity of formulations, in comparison with plots treated with ground-applied pheromone dispensers and untreated control plots. Traps placed at different heights showed LBAM was abundant in the upper canopy of tall trees, which complicates control attempts. A wax formulation and polyethylene dispensers were most effective and provided trap shut-down near ground level for 10 weeks. Only the wax formulation was effective in the upper canopy. As the pheromone blend contained a behavioral antagonist for LBAM, ‘false trail following’ could be ruled out as a mechanism explaining trap shutdown. Therefore, ‘sensory impairment’ and ‘masking of females’ are the main modes of operation. Mating disruption enhances Allee effects which contribute to negative growth of small populations and, therefore, it is highly suitable for area-wide control and eradication of biological invaders.

Herbicides are used to control competing vegetation during tree establishment, and are often critical to the productivity and economic viability of a planted forest crop. Despite increasing public concern over herbicide use in planted forests and potential impact on the environment, there is limited information on the aquatic fate of many of these herbicides when applied in forests according to standard operational procedures. Two herbicides commonly used in New Zealand’s planted forests, terbuthylazine and hexazinone, were aerially applied during two consecutive years at 7.4 kg and 1.1 kg ha-1 respectively, to a 12.5 ha catchment of newly planted Pinus radiata (Radiata pine) in the Bay of Plenty region of New Zealand. One hundred percent of the area was sprayed during Year 1 while 85% of the area was sprayed during Year 2. The highest concentrations of both herbicides were measured in stream water, sediment and algal samples on the day of herbicide application during Year 1 (September 2012 to June 2013), mainly as a result of spray drift, and in stream water during Year 2 (September 2013 to April 2014) at the time of a rainfall event seven days after herbicide application. Terbuthylazine concentrations exceeded New Zealand and World Health Organisation drinking water standards for <24 hours on both occasions. For the remainder of the trial period, concentrations of both herbicides were below safe drinking water standards. Herbicide concentrations in stream flow declined immediately below the trial site and were close to or below detection limits at the bottom of the catchment. The concentrations of terbuthylazine and hexazinone in stream flow during this trial, posed a short-term and low risk to algae. Peak concentrations of both herbicides were several orders of magnitude lower than Lethal Concentration (LC)50 concentrations for Daphnia and rainbow trout (Oncorhynchus mykiss). These results highlight the need to include data from both field and laboratory based trials when assessing the aquatic risk of these two herbicides when applied under operational conditions in planted forests.

No abstract

No abstract

Background: Wilding conifers are a major threat to biological conservation within New Zealand and currently cover at least 500,000 ha throughout the South Island. A range of herbicide treatments was applied to field trials established within wilding Pinus contorta (height range 1 -15 m) and P. mugo (height range 0.5 -5 m) infestations. Measurements of mortality taken two years post herbicide application were used to determine the efficacy of (i) the traditionally used contact herbicide diquat, applied in an application volume of 300 L ha -1 , and (ii) a range of systemic herbicides applied in an application volume of 150 L ha -1 .