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Textile consumer trends towards improved product safety and high environmental standards have significantly influenced regulators in key consumer markets. The apparel wool industry sector has responded to regulators, and for three decades the Australia and New Zealand wool industries have managed advancements in ectoparasiticides and improved sheep treatments targeting high environmental, animal health and welfare standards leading to safe wool products. Australian and New Zealand chemical residue data from greasy wool have been consolidated and analysed for organophosphate, synthetic pyrethroid, insect growth regulator, neonicotinoid, macrocyclic lactone and spinosad active. Trend analysis has been applied to time domain data to evaluate advancements in ectoparasiticide technology after revising environmental, animal health and welfare standards. Analysis shows impacts from technology improvement, regulatory change and compliance by sheep farmers meeting or exceeding published European Union residue limits for regulated ectoparasiticides namely organochlorine, organophosphate, synthetic pyrethroid and insect growth regulators. Implications from advancements in ectoparasiticide technology, industry management and regulatory measures, include healthy sheep growing in clean pastoral environments with evidence of reduced wool residue levels which complement high and rising proportions of Australian and New Zealand wool fibre meeting European Union Ecolabel criteria.

The majority of herbivorous insects are specialized feeders restricted to a plant family, genus, or species. The evolution of specialized insect–plant interactions is generally considered to be a result of trade-offs in fitness between possible hosts. Through the course of natural selection, host plants that maximize insect fitness should result in optimal, specialized, insect–plant associations. However, the extent to which insects are tracking plant phylogeny or key plant traits that act as herbivore resistance or acceptance characters is uncertain. Thus, with regard to the evolution of host plant specialization, we tested if insect performance is explained by phylogenetic relatedness of potential host plants, or key plant traits that are not phylogenetically related. We tested the survival (naive first instar to adult) of the oligophagous leaf-feeding beetle, Cassida rubiginosa, on 16 selected representatives of the Cardueae tribe (thistles and knapweeds), including some of the worst weeds in temperate grasslands of the world in terms of the economic impacts caused by lost productivity. Leaf traits (specific leaf area, leaf pubescence, flavonoid concentration, carbon and nitrogen content) were measured as explanatory variables and tested in relation to survival of the beetle, and the phylogenetic signal of the traits were examined. The survival of C. rubiginosa decreased with increasing phylogenetic distance from the known primary host plant, C. arvense, suggesting that specialization is a conserved character, and that insect host range, to a large degree is constrained by evolutionary history. The only trait measured that clearly offered some explanatory value for the survival of C. rubiginosa was specific leaf area. This trait was not phylogenetically dependant, and when combined with phylogenetic distance from C. arvense gave the best model explaining C. rubiginosa survival. We conclude that the specialization of the beetle is explained by a combination of adaptation to an optimal host plant over evolutionary time, and key plant traits such as specific leaf area that can restrict or broaden host utilization within the Cardueae lineage. The phylogenetic pattern of C. rubiginosa fitness will aid in predicting the ability of this biocontrol agent to control multiple Cardueae weeds.

New Zealand pastures largely comprising Lolium ryegrass species (Poales: Poaceae) are worth $19.6B and are subject to major pest impacts. A very severe pest is the Argentine stem weevil Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae). This has been previously suppressed by the importation biological control agent, Microctonus hyperodae Loan (Hymenoptera: Braconidae). However, this suppression has recently declined and is subject to investigation. It has been hypothesised that grass type influences the parasitism avoidance behaviour by the weevil and thus parasitism rates. This study explored the hypothesis using three common pasture grasses: a diploid Lolium perenne x Lolium multiflorum hybrid ryegrass (cv. Manawa), a tetraploid Italian ryegrass L. multiflorum Lam. (cv. Tama), and a diploid perennial ryegrass L. perenne L. (cv. Samson). The described laboratory-based microcosm methodology determined the extent of weevil avoidance behaviour on each of these three grasses when subjected to the parasitoid. Such reaction was gauged by the extent of reduced weevil on-plant presence and feeding compared to the control populations. In the absence of the parasitoid, the hybrid cv. Manawa ryegrass is as highly favoured by the weevil as the tetraploid cv. Tama. On diploid cv. Samson, feeding is considerably less. In the presence of the parasitoid, weevils on the tetraploid cv. Tama plants showed little avoidance activity in response to the parasitoid and it can be argued that the benefits of staying on this plant outweighed the possibility of parasitism. Conversely and surprisingly, in the parasitoid’s presence, weevils on diploid cv. Manawa showed very strong avoidance behaviour leading to levels of exposure similar to those found on the less-preferred diploid cv. Samson. These findings reflect how weevil parasitism rates have declined in most Lolium grasses, particularly diploids, since the 1990s, but not in the tetraploid L. multiflorum . This contribution supports the hypothesis that the decline in weevil parasitism rates has been the result of rapid evolution arising from parasitoid-induced selection pressure and the countervailing effect of the nutritional quality of the host plants.

The folivorous beetle, Cassida rubiginosa Müller (Coleoptera: Chrysomelidae), was released in New Zealand in 2007 as a biocontrol agent against the pasture weed, Cirsium arvense (L.) Scop. The impact of the beetle on shoot population density and spread was assessed over two years on isolated experimental plots within an established population of the weed. Four folivory treatments were imposed by applying 0, 5, 10 or 20 larvae per shoot. Folivory in the 10 and 20 larvae per shoot treatments caused C. arvense population declines of 29% and 75%, respectively, although this effect was not consistent between the two years. Shoot spread was reduced in both years where 10 or 20 larvae per shoot were applied. This study represents the first post-release assessment of this biocontrol agent in New Zealand, and indicates that average densities of ≥ ten larvae per shoot can reduce population density and spread of C. arvense .

The brown marmorated stink bug, Halyomorpha halys , is an agricultural and urban pest that has become widely established as an invasive species of major concern in the USA and throughout Europe. The insect forms large aggregations before entering diapause, and it is often these aggregations that are found by biosecurity officials conducting inspections of internationally shipped freight. Here, we aimed to gain insights into the potential volatile emissions, mobility, and mortality rates of the insects after undergoing a ship voyage across the equator (i.e. from northern hemisphere winter to southern hemisphere summer). Experiments were performed to simulate the effects on aggregations of diapausing H. halys of two variables associated with trans-Pacific voyages, i.e. ship and container movement and temperature changes within containers. Thus, H. halys aggregations were exposed to simulated shipping movement, using a 6-axis VS-6577G-B Denso robot arm, and emission of defence volatiles was measured repeatedly during the “voyage.” We also simulated temperature changes as they occur during a 26-day voyage from Baltimore, northeast USA, to Auckland, New Zealand, and assessed the effects on the mortality and mobility of the bugs. Aggregations that experienced movement were not found to be any more likely to release volatiles than stationary aggregations and neither did the movement affect bug mobility. Temperature changes had a significant effect on mobility. However, towards the end of the temperature simulation, most H. halys had died, probably from a lack of food and moisture. These findings are highly relevant for border biosecurity risk assessment and pathway risk management.

Soil associated with sea freight (shipping containers, flat racks and used machinery) arriving at New Zealand seaports was sampled for bacteria, fungi, nematodes, macro-invertebrates and plant seeds. Pseudomonads were selectively isolated, as several significant plant pathogens fall within this bacterial group. The mean and median sample weight collected from sea freight was found to be 417.3 and 152.7 g, respectively, with most recovered soil (73%) collected from the underside of shipping containers and flat rack containers. Likewise, for used machinery, most recovered soil (75%) was found under the machinery. Flat rack containers had significantly higher soil contamination compared to shipping containers and used machinery, but generally the counts and incidence of taxa were significantly lower compared to these other freight types. Viable bacteria, fungi, nematodes, seeds and arthropods were associated with the soil, with both counts g -1 and prevalence in samples varying with taxa, freight type, and location on the freight. Various regulated biosecurity organisms were recovered from the samples, including Aphelenchoides besseyi (rice white tip nematode), and seeds from genera such as Brachiaria , Cortaderia , Digitaria , Eragrostis and Sonchus . There were also live arthropod taxa that were not recorded as being present in New Zealand. No known plant pathogenic pseudomonads were identified through sequencing of the 16S ribosomal RNA gene. Shipping containers were found to be an important introduction pathway for exotic species, and therefore require careful monitoring and management. Comparisons of the incidence and mean number of organisms associated with soil on sea freight compared to a previous study with soil on footwear, generally showed that incidence and counts of many taxa were lower on sea freight, indicating that biosecurity risk can vary with pathway. However, prioritising one soil pathway over another according to the risks they present, and differentially allocating resources is problematic because the relative risk is dynamic, dictated by factors such as new pests or diseases entering the respective pathways.

To determine if host plant abundance determined the size of clover root weevil (CRW) larval populations, a study was conducted over 4 years in plots sown in ryegrass ( ) (cv. Nui) sown at either 6 or 30 kg/ha and white clover ( ) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012-2015 were 310, 38, 59, and 31 larvae m , respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted, but the numbers came closer to predicted for the 2013 and 2014 populations. These differences are attributed to a CRW population decline that was not accounted by % white clover changes, the CRW decline most likely due to biological control by the Braconid endoparasitoid , which showed incremental increases in parasitism between 2012 and 2015, which in 2015 averaged 93%.

African black beetle, Heteronychus arator (Scarabaeidae), is an exotic pest of pastures in northern New Zealand. Both adults and larvae feed on pasture grasses. Adults disperse by walking (short range) or flying (long range). Dispersal flights are triggered by warm night temperatures in spring and autumn. Short range adult dispersal in search of mates, food or oviposition sites is poorly understood. This study investigated walking activity of H. arator adults over three seasons in New Zealand pastures. Adult walking activity was monitored using pitfall traps along fence lines and in pasture plots on a dairy farm in Waikato, New Zealand, in spring 2013, spring 2014, and autumn 2015. Beetle populations were reduced by application of a biopesticide bait to compare walking activity between treated and control plots for up to 26 days post-treatment. Marked beetles were released into the pasture plots to measure the distance traveled by recaptured individuals. Trap catches along the fence lines were correlated with air temperatures in 2013. Trap catches were male biased in spring 2014 compared with autumn 2015. Trap numbers in the control plots were nearly double that of treated plots in both seasons. More beetles were caught in the pitfall traps at the edges of the treated plots than in the center. Trap catches were consistent throughout the control plot in spring 2014, but in autumn 2015 more beetles were caught in the center of the control plot than at the edges. Few marked beetles were recaptured with dispersal rates estimated as <0.5 m per day. Warmer temperatures encouraged short range dispersal in H. arator. Males were more active than females during the spring mating season. Edge effects were strong and should be considered in the design of field experiments.

The gall fly, Urophora stylata F. (Diptera: Tephritidae), was released in New Zealand in 1998 as a biocontrol agent against the thistle weed, Cirsium vulgare (Savi) Tenore. A survey of 20 randomly selected pasture populations of C. vulgare was conducted to assess the impact of the gall fly on seed production. Attack by the biocontrol agent reduced the number of seeds per seedhead by 47%, individual seed weight by 21%, and seed germination rate by 30%. Where the biocontrol agent was present, population seed reduction ranged from 11 to 61%. The impact of the gall fly significantly increased from southern to more northern latitudes of C. vulgare populations in New Zealand. This study represents the first post-release assessment of this biocontrol agent and indicates that U. stylata can have a significant impact on the seed production of C. vulgare , especially in northern New Zealand where seedhead attack is greatest.

The rationale for this study came from observing grazing dairy cattle dropping freshly harvested plant material onto the soil surface, hereafter called litter‐fall. The Intergovernmental Panel on Climate Change (IPCC) guidelines include N2O emissions during pasture renewal but do not consider N2O emissions that may result from litter‐fall. The objectives of this study were to determine litter‐fall rates and to assess indicative N2O emission factors (EFs) for the dominant pasture species (perennial ryegrass [Lolium perenne L.] and white clover [Trifolium repens L.]). Herbage was vacuumed from intensively managed dairy pastures before and after 30 different grazing events when cows (84 cows ha−1) grazed for 24 h according to a rotational system; the interval between grazing events ranged from 21 to 30 d. A laboratory incubation study was performed to assess potential EF values for the pasture species at two soil moisture contents. Finely ground pasture material was incubated under controlled laboratory conditions with soil, and the N2O emissions were measured until rates returned to control levels. On average, pre‐ and postgrazing dry matter yields per grazing event were 2516 ± 636 and 1167 ± 265 kg DM ha−1 (±SD), respectively. Pregrazing litter was absent, whereas postgrazing fresh and senesced litter‐fall rates were 53 ± 24 and 19 ± 18 kg DM ha−1, respectively. Annually, the rotational grazing system resulted in 12 grazing events where fresh litter‐fall equaed to 16 kg N ha−1 yr−1 to the soil. Emission factors in the laboratory experiment indicated that the EF for perennial ryegrass and white clover ranged from 0.7 to 3.1%. If such EF values should also occur under field conditions, then we estimate that litter‐fall induces an N2O emission rate of 0.3 kg N2O ha−1 yr−1. Litter‐fall as a source of N2O in grazed pastures requires further assessment.