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In February 2015 an established population of the Queensland fruit fly (Qfly Bactrocera tryoni) was detected in Grey Lynn Auckland It was questionable whether Qfly might successfully overwinter in Auckland and how trap efficacy and mating behaviour would be affected by winter conditions During the official biosecurity response to eradicate Qfly these questions were addressed using published Qfly models that had been developed and parameterised from biological data from its native range A model for cold acclimatisation suggested that Auckland winters would not be sufficiently cold to cause significant mortality of adult Qfly but substantial cold mortality might occur in more southern locations The temperature requirement for mating suggested mating would be relatively rare from June to October and two models for relative trap efficacy suggested that traps would be relatively ineffective until late spring (OctoberNovember) The Ministry for Primary Industrys biosecurity response was successful with no detection of Qfly after March 2015 and eradication formally declared in December 2015

Sitona obsoletus is a serious pasture pest in New Zealand where its root-feeding larvae reduce white clover cover and nitrogen fixation. To maintain production, farmers may compensate by increasing inputs. The parasitic wasp Microctonus aethiopoides Loan was introduced for biological control of S. obsoletus and achieved parasitism rates exceeding 70%. In Southland, where S. obsoletus was first detected in 2010, unusually severe and prolonged infestations during 2013 and 2014 prompted intensive biological control releases in 2014 and 2015. This study evaluated if they were cost effective in 2015. On dairy farms biological control returned $14.78/ha/year or $2.3 million over the 158,017 ha. On sheep and beef farms, the estimated return was $6.86/ha/year or $4.7 million over 719,854 ha. Monte Carlo simulations were used to estimate returns ($/ha/year) using plausible ranges of model parameter values, and returns were positive in at least 97.5% of simulations. Biological control of S. obsoletus has returned a net benefit in Southland.

Tephritid fruit flies have been comparatively well studied because of the damage they cause to horticultural crops in affected countries New Zealand benefits from this knowledge as it continues to exclude economically damaging fruit fly species For example fruit fly development models are used for biosecurity risk analysis and decision making during incursion responses Here the literature was searched for development times for three species of particular concern to New Zealand the Mediterranean fruit fly the Queensland fruit fly and the oriental fruit fly The published data were reanalysed to fit development models to the different life stages and the generation time The new models were then compared with previously published models for these species The generation time models were found to give reasonably accurate predictions when validated against published estimates of field voltinism overseas This paper presents the most comprehensive analysis to date of fruit fly development times and degree day models

Fruit flies (Family Tephritidae), in particular the Queensland fruit fly (Bactrocera tryoni; QFF), areone of the biggest biosecurity risks for New Zealand horticulture. New Zealand has one of the bestscience-based biosecurity systems in the world, based on years of experience and sound research. Theintroduction of fruit flies to New Zealand is now well managed in commercial fruit imports, but the riskis rising from growing trade and travel and, in the case of QFF, climatic adaptation and spread to moresouthern localities. Smarter solutions are continually needed to manage this increasing risk, and to dealwith such pests when they arrive. We present a brief summary of current and anticipated research aimedat reducing the likelihood of entry into New Zealand and/or minimising the impact for the fruit flyspecies of greatest threat to New Zealand. Research spans risk assessment, pathway risk management,diagnostics, surveillance and eradication.

Thermal accumulation ('degree day') methods are routinely used to predict plant and insect phenology. Depending on the data available, prediction may involve three separate steps with associated errors: estimating daily heat units from maximum and minimum temperatures; interpolating daily maxima and minima from monthly averages; and predicting future monthly averages from past climate, potentially including climate change. This research investigated the potential error in thermal accumulation totals arising from each of these factors at nine New Zealand sites. Ten simple heat unit calculations were tested, including two little-known and three new methods. Those utilising the true daily mean temperature performed best, followed by 4-step, triangle and sine approximations. Interpolating between monthly mean temperature extremes introduced much error into daily estimates, and the use of predicted, rather than observed, monthly normals further increased error. Speciic recommendations are made for thermal accumulation methods depending on what temperature data are available.

Hawthorn (Crataegus monogyna), a bird-dispersed, introduced shrub, is becoming increasingly weedy in parts of New Zealand, North America, Australia and elsewhere. In order to identify areas threatened by this species, an eco-climatic model for its potential global distribution was constructed using CLIMEX software. The model was based on the native range of hawthorn in Europe and validated against the invaded range elsewhere in the world. It suggests that hawthorn could potentially invade most lowland and montane areas of New Zealand. In lowland areas, invasion is likely to be limited by grazing pressure, but changes in the management of South Island montane grasslands as a result of the current tenure review process may favour hawthorn invasion in some areas. Pre-emptive action to identify and remove infestations from montane grasslands is recommended.

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A cohort-based model for the seasonal phenology of the black-headed strain of the fall webworm, Hyphantria cunea (Lepidoptera: Arctiidae), was constructed from published development rates for each life stage. Model predictions were successfully verified against field observations from Japan, China, Italy, Serbia and the USA. The model was then used to predict phenology in New Zealand, and the potential for establishment near major ports. Populations are predicted to be bivoltine in the north and univoltine in central areas, but are unlikely to form self-sustaining populations south of Timaru. Fall webworm demonstrated the ability to adapt to specific local conditions after its invasion of Japan, so the risk may be greater than these results suggest. Successful validation of the model means that it could be used to inform surveillance and control operations targeting fall webworm outbreaks overseas and potential invasions into new ranges such as New Zealand.

Sitona lepidus had spread throughout the North Island of New Zealand by 2005 and was first detected in the South Island in January 2006 when one individual was found at Harewood Christchurch Intensive sampling during February 2006 recovered only two additional specimens Several specimens were recovered from a separate Christchurch location in August 2006 Localised S lepidus populations were discovered near Richmond Nelson in April 2006 and in Rai Valley in May 2006 A website established in May 2006 to provide information about S lepidus was visited a mean of 135 times per month but it was never used to report possible new South Island infestations A biological control agent Microctonus aethiopoides was released at Richmond and Rai Valley between August 2006 and March 2007 By May 2007 it was parasitising from 4 to 14 of S lepidus adults which indicates it is likely to become permanently established

Although the painted apple moth (PAM) eradication programme in West Auckland appears to have been successful the large volume of trade from Australia PAMs native range makes reinvasion likely Recent work has focused on modelling the spatial and temporal effects of optimal release strategies in the sterile insect technique (SIT) programme to enable assessment of the time required and likelihood of eradication success However the costeffectiveness of each strategy is not known Based on the rearing and operational costs from the past PAM SIT release programme the unit cost of a single irradiated male moth for a release programme has been quantified A simple economic model for cost analyses and comparison of a few selected SIT release strategies at ge;95 confidence level of eradication success is presented This model could be used to select an appropriate costeffective strategy thus aiding in prompt decisionmaking of PAM reincursion responses

A set of assumptions can be used to estimate the confidence that a continuing lack of detection reflects successful eradication of a pest population This approach is applied to the painted apple moth (Teia anartoides) in Auckland New Zealand based on its known population biology and sterile insect recapture results The analysis suggests that it is extremely unlikely that any wild population might have survived near the core trapping areas beyond mid January 2004 but that there was a significant chance that a small wild population could have remained undetected until then in less intensively trapped areas The moth trapped in Mt Eden in January 2004 plausibly indicates an undetected population there but a continued lack of trap catches over the subsequent year suggests that it is very unlikely that any wild populations now remain undetected within the trapping grid This analysis could be easily adapted for other species targeted for eradication

The parasitoids Microctonus aethiopoides and M. hyperodae have been introduced as biological control agents against Sitona discoideus and Argentine stem weevil Listronotus bonariensis respectively. Collections from ryegrass/white clover pastures in mid-Canterbury found that M. aethiopoides was widespread in L. bonariensis, despite the weevil being a novel host. Microctonus aethiopoides was recovered from 83% of the 65 sites sampled in Canterbury, with parasitism rates of 0.4-19%. Studies in lucerne crops showed that M. aethiopoides preferentially parasitised its natural host S. discoideus, although in some cases up to 10% of L. bonariensis found in the lucerne were parasitised. A possible reason for the prevalence of M. aethiopoides in Canterbury pasture was that the widely-dispersive flights of S. discoideus from aestivation sites provided a source for re-infection of the parasitoid into ryegrass pasture. Analysis of field parasitism suggested that parasitism of L. bonariensis by M. aethiopoides was negatively correlated with parasitism by M. hyperodae.