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Social wasps are amongst the most loathed exotic predators in New Zealand, with widespread adverse impacts on native ecosystems and fauna. Sustainable alternatives to pesticides are sorely needed i...

Epiphyas postvittana is a major horticultural pest in many countries, including New Zealand. Recently, two minor components (E)-11-tetradecen-1-ol and (E)-11-hexadecenyl acetate were found to increase the attraction of a previously identified two-component sex pheromone (95:5 blend of (E)-11-tetradecenyl acetate [E11-14:Ac] and (E,E)-9,11-tetradecadienyl acetate [E9,E11-14:Ac]) of Epiphyas postvittana. We hypothesised that the interaction between these minor components and the behavioural antagonist (Z)-11-tetradecenyl acetate (Z11-14:Ac) would modulate its antagonistic effect. The effect of increasing the ratio (0.5—10%) of Z11-14:Ac was tested in traps baited with E11-14:Ac and E9,E11-14:Ac (95:5), with or without the addition of the two minor compounds. Catch decreased as the percentage of Z11-14:Ac increased (χ2=108.74; d.f.=9; P

The sterile insect technique (SIT) potentially provides a socially acceptable approach for insect eradication of new pest incursions. The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), was discovered in Berkeley (CA, USA) in 2006, leading to an incursion response that included this technology. In this study, we assessed factors affecting mating success from a bisex release of irradiated moths: effects of radiation dose on male multiple mating, male flight competition, female sex pheromone titre and attractiveness of irradiated females to males, and identification of successful mating in vineyards of either irradiated or wild males (identified by isotope analysis of spermatophores from sentinel females). There was a significant negative relationship between male radiation dose and mating frequency. In head-to-head flights of irradiated males against non-irradiated males to a pheromone lure in a wind tunnel, irradiated males reached the lure first only 31% of the time. With increasing radiation dose, the production of the major sex pheromone component in females, (E)-11-tetradecenyl acetate, dropped, from 0.7 ± 0.1 ng per female in non-irradiated females to 0.2 ± 0.07 ng per female when irradiated at 300 Gy. Male catch was reduced to 11% of control females in traps containing females irradiated at 300 Gy. Isotope analysis of spermatophores found in the bursa copulatrix of females indicated that mating success of irradiated males inside the live (entry-only) traps containing virgin females was lower (13.1 ± 3.3%) than suggested by male catch (21.2 ± 3.8%) in pheromone traps, the current standard for assessing field competitiveness. Impacts of irradiation on male and female moth fitness should be taken into account to improve estimates of irradiated to wild male E. postvittana overflooding ratios needed for population suppression.

A new four-component sex pheromone blend for light brown apple moth (Epiphyas postvittana) was examined for efficacy of communication disruption in laboratory and field trials. Vineyard trials using SPLAT LBAM™ examined disruption of traps in the presence of: a) the current two-component ((E)-11-tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate, 95:5), b) a new four-component blend ((E)-11-tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate plus (E)-11-tetradecen-1-ol and (E)-11-hexadecenyl acetate (10:0.5:0.1:0.05)), c) higher ratio of the two new compounds (10:0.5:10:10), d) four compounds with an antagonist ((Z)-11-tetradecenyl acetate) added, e) three compounds with antagonist minus the most expensive component ((E,E)-9,11-tetradecadienyl acetate), compared to f) untreated controls. In the laboratory, 69.0% of untreated pairs mated, and communication was suppressed by both attractive blends (41.1% communication (P = 0.024, two-component blend), and 18.4% communication (P = 0.003, four-component blend)). In vineyards, totals of 24,776 and 41,053 male moths were caught in the two trials, respectively, to delta traps baited with four-component lures and virgin females. Communication disruption was achieved at a higher level with a four-component blend for 13/14 weeks in disruption trial one and for 10/10 weeks in disruption trial two, compared with the two-component blend. Disruption was on average improved by 12% with the four-component blend compared to the two-component blend (P = 0.091). Other blends were less effective at communication disruption. The best formulation released from SPLAT™ was only weakly attractive compared to rubber septa, so false trail following to point sources was unlikely to be as important as other mechanisms.