Department of Pest Management and Conservation

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https://hdl.handle.net/10182/35

The Department of Pest Management and Conservation carries out research and teaching in the following specialist areas: Animal behavior; Conservation and biodiversity; Ecological restoration; Evolutionary biology; Fire ecology; Molecular ecology; Plant microbiology; Plant pathology; Remediation of degraded and contaminated land; Soil ecology; Sustainable agriculture and ecosystem services; Wildlife and pest management.

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An investigation of systematic camera trap monitoring for kiwi (Apteryx spp.) : A thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2023) Tansell, A Jane S
Introduction: Kiwi (Apteryx spp.) are one of New Zealand’s national taonga/taoka (treasures) that are our responsibility and privilege to protect. To inform protective management, we need to monitor kiwi population responses to management, for which a non-invasive method that can detect all age classes has been lacking. Camera traps are non-invasive monitoring devices, which are increasingly used with recently developed analyses to monitor cryptic terrestrial species around the world. To apply these methods to kiwi, standardized methods need to be developed and benchmarked against existing methods. Aims: The aims of this study were to 1) summarise previous monitoring work on kiwi to develop a draft systematic camera trap monitoring method for kiwi, 2) determine optimal site selection and camera trap set-up, 3) determine optimal survey length and camera trap spacing for use with spatial presence-absence (SPA) analysis and identify whether realistic population estimates are obtained, 4) compare camera traps with a current noninvasive method using acoustic recorders to determine if they give realistic and comparable estimates when used with SPA, 5) compare camera traps with dog survey and an observer listening survey to assess kiwi population health, 6) trial alternative analyses for use with camera traps in high density sites, 7) investigate stereo cameras for their potential to add value to camera trap surveys. Materials and methods: We summarised the current literature on monitoring kiwi and the use of camera trap surveys. We deployed 34 camera traps over six seasons in Orokonui Ecosanctuary. We deployed 29 acoustic recorders and carried out detector dog surveys to compare the number of juveniles detected. We deployed 17 camera traps in Rotokare Scenic Reserve and 18 camera traps in the Cape Sanctuary to examine their effectiveness in high kiwi density areas. We constructed a stereo camera by chaining two off-the-shelf trail cameras together to trigger from one PIR sensor and briefly trialled the stereo camera at Orokonui. Results: Cameras were able to detect kiwi of all age groups and to provide credible population densities and trends. Kiwi detections can be maximised by using a detector dog team to select camera sites and through camera orientation. Comparable population estimates were obtained using spatial presence-absence (SPA) analysis with an optimal survey length of four months, during peak incubation, and optimal camera spacing of 350 m. Cameras and acoustic recorders gave comparable population estimates using SPA. Estimates were realistic based on matrix population model projection. Camera traps and detector dog surveys found a similar number of juvenile kiwi. Estimates obtained using Royle-Nichols analysis likely underestimated population size but correctly indicated population trend direction and magnitude, while the index-manipuation-index method did not give a biologically possible estimate of population density. The stereo camera method using two trail cameras was capable of giving surprisingly accurate bill measurements, but further work in necessary to achieve repeatability. Discussion and conclusions: Systematic camera trapping is capable of monitoring the whole kiwi population, including female and young kiwi that are usually under-recorded by other methods. Systematic camera trapping paired with spatial presence-absence analysis performed well in a low density population. Camera monitoring shows much promise as another useful noninvasive tool in the kiwi monitoring toolbox.
Open Access
AI feedback loops in Aotearoa New Zealand: A Human-centered creative problem-solving approach
(Center for Open Science, 2024-05-10) Agyepong, V; Cattoen, C; Adusei-Fosu, K; Buelow, FA; Wilson, TK; Qasim, M; Grimshaw, GM; Godsoe, W
Artificial Intelligence (AI) can have unintended consequences in systems where they are deployed. Researchers have found that by increasing contextual understanding of AI feedback loops, cause and effect in systems, especially in high-risk applications like health, biosecurity, conservation, justice systems, and transport, AI tools can learn to improve over time and leverage wider neural networks. This paper fills the knowledge gap on how to consider varying competencies of human-AI teams to identify feedback in AI systems leveraging eight disciplines outside commerce and computer science. The study found that academic actors from more than one discipline tend to identify more relevant sources of feedback in AI systems, especially in high-risk applications. The paper recommends the integration of human lived experiences, knowledge generated from partial exposure of academic ideas to non-academic actors, and knowledge of decision making in the natural environment to reduce the incidence of misinformed human decision-making, especially in high-risk applications.
Open Access
Summary for Policymakers of the Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services
(IPBES, 2023-09-04) Roy, HE; Pauchard, A; Stoett, P; Renard Truong, T; Bacher, S; Galil, BS; Hulme, Philip; Ikeda, T; Sankaran, KV; McGeoch, M; Meyerson, LA; Nunez, M; Ordonez, A; Rahlao, SJ; Schwindt, E; Seebens, H; Sheppard, AW; Vandvik, V; Piero, G; Wilson, JR
The thematic Assessment of Invasive Alien Species and their Control, or “Invasive Alien Species Assessment” in short, is part of a series of reports whose production was initiated during the “first work programme of IPBES, 2014 2018” and concluded during the current “IPBES rolling work programme up to 2030”. The Invasive Alien Species Assessment has been carried out by a multidisciplinary team of 86 selected experts from all regions of the world, including early career fellows, assisted by about 200 contributing authors. More than 13,000 scientific publications were analyzed as well as a substantive body of Indigenous and local knowledge. Its chapters were accepted, and its summary for policymakers was approved, by the IPBES Plenary composed of 143 member States at its tenth session held from 28th August to 2nd September 2023 in Bonn, Germany. The Invasive Alien Species Assessment builds on the landmark IPBES Global Assessment Report on Biodiversity and Ecosystem Services launched in 2019. The Global Assessment identified invasive alien species as a one of the five main direct drivers of biodiversity loss, with 1 million species of plants and animals now at risk of extinction. The Invasive Alien Species Assessment explores how invasive alien species affect nature and people globally. It analyzes the status and trends of alien and invasive alien species in all regions of Earth, and identifies major pathways for and drivers of the introduction and spread of such species between and within countries. The Assessment also assesses the effectiveness of management actions across scales and in various contexts. The Invasive Alien Species Assessment finally outlines key responses and policy options for the prevention, early detection, and effective control of invasive alien species and mitigation of their impacts in order to safeguard nature, nature’s contributions to people and good quality of life.
Open Access
Survival of Escherichia coli in edible land snails: Implications for heliciculture and public health
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-03) Tanyitiku, MN; Nicholas, G; Sullivan, Jon; Petcheu, ICN; On, Stephen
Background: Land snails are considered a delicacy in many countries in Europe and sub-Saharan Africa. However, the interaction of microbial pathogens with land snails may present a public health threat when handling and/or consuming snails. This study examines the survival of Escherichia coli in edible land snails in a model system. Methods: Well-studied Shigatoxigenic (STEC) and non-STEC strains were compared. Mature Helix spp. were experimentally fed with E. coli-inoculated oats for 48 h. The snail feces after inoculation were periodically sampled and cultured for a 30-day period and subjected to microbiological analyses. Results: The average rate of decline of the non-STEC strain CSH-62 in the feces of live snails was significantly (p < 0.05) faster than that of STEC ERL 06-2503. In addition, the viable population of E. coli ERL 06-2503 significantly (p < 0.05) persisted for a longer time in the intestine of land snails than E. coli CSH-62. Conclusion: The results showed that the viable population of the E. coli strains examined demonstrated first-order kinetics, and their survival (CFU/mL) appeared significantly (p < 0.05) dependent on the E. coli pathotype. In addition, the continuous enumeration of E. coli in snail faeces indicated that land snails could serve as a mode of transmission of microbial pathogens to susceptible hosts, including humans. Further research is recommended to better quantify the direct and indirect health risks of pathogen transmission by edible snails to humans.
Open Access
Turning up the heat: Climate change consequences for Pinot Noir berry quality
(Winetitles, 2024-04) Moukarzel, Romy; Parker, Amber; Schelezki, Olaf; Gregan, S; Jordan, B
Temperature increase due to climate change affects grapevine productivity and berry quality. Studies have shown that higher temperatures lead to increased sugar concentrations at harvest, or earlier harvests to retain the same sugar targets. Temperature increases may also impact anthocyanins (colour) and amino acids crucial for fermentation. New Zealand researchers out to explore how microclimates influence anthocyanin, phenolic compounds and amino acids in Pinot Noir.
Open Access
Osmotic stress responses, cell wall integrity, and conidiation are regulated by a histidine kinase sensor in Trichoderma atroviride
(MDPI, 2023-09) Calcáneo-Hernández, G; Landeros-Jaime, F; Cervantes-Chávez, JA; Mendoza - Mendoza, Artemio; Esquivel, E
Trichoderma atroviride responds to various environmental stressors through the mitogen-activated protein kinase (MAPK) Tmk3 and MAPK-kinase Pbs2 signaling pathways. In fungi, orthologues to Tmk3 are regulated by a histidine kinase (HK) sensor. However, the role of T. atroviride HKs remains unknown. In this regard, the function of the T. atroviride HK Nik1 was analyzed in response to stressors regulated by Tmk3. The growth of the Δnik1 mutant strains was compromised under hyperosmotic stress; mycelia were less resistant to lysing enzymes than the WT strain, while conidia of Δnik1 were more sensitive to Congo red; however, ∆pbs2 and ∆tmk3 strains showed a more drastic defect in cell wall stability. Light-regulated blu1 and grg2 gene expression was induced upon an osmotic shock through Pbs2-Tmk3 but was independent of Nik1. The encoding chitin synthases chs1 and chs2 genes were downregulated after an osmotic shock in the WT, but chs1 and chs3 expression were enhanced in ∆nik1, ∆pbs2, and ∆tmk3. The vegetative growth and conidiation by light decreased in ∆nik1, although Nik1 was unrequired to activate the light-responsive genes by Tmk3. Altogether, Nik1 regulates responses related to the Pbs2-Tmk3 pathway and suggests the participation of additional HKs to respond to stress.
Open Access
Citizen science is a vital partnership for invasive alien species management and research
(Elsevier on behalf of Cell Press, 2024-01-19) Pocock, MJO; Adriaens, T; Bertolino, S; Eschen, R; Essl, F; Hulme, Philip; Jeschke, JM; Roy, HE; Teixeira, H; de Groot, M
Invasive alien species (IAS) adversely impact biodiversity, ecosystem functions, and socio-economics. Citizen science can be an effective tool for IAS surveillance, management, and research, providing large datasets over wide spatial extents and long time periods, with public participants generating knowledge that supports action. We demonstrate how citizen science has contributed knowledge across the biological invasion process, especially for early detection and distribution mapping. However, we recommend that citizen science could be used more for assessing impacts and evaluating the success of IAS management. Citizen science does have limitations, and we explore solutions to two key challenges: ensuring data accuracy and dealing with uneven spatial coverage of potential recorders (which limits the dataset's “fit for purpose”). Greater co-development of citizen science with public stakeholders will help us better realize its potential across the biological invasion process and across ecosystems globally while meeting the needs of participants, local communities, scientists, and decision-makers.
Open Access
Evaluating the densities and distribution of root-lesion nematodes (Pratylenchus spp.) in wheat grown in Canterbury, New Zealand
(New Zealand Plant Protection Society (Inc.), 2023-05-18) Thiellier, MJ; Kularathna, Manjula
Species of root-lesion nematode (Pratylenchus spp.) are associated with significant reductions in wheat yield in wheat-growing regions around the world. Of these, Pratylenchus thornei and P. neglectus are known to cause the highest damage to the Australasian wheat industry. New Zealand is known to produce high wheat yields on a per-hectare basis yet little research has been conducted to date to determine the effects of Pratylenchus spp. on the production of wheat in New Zealand. Therefore, as the first step towards filling this knowledge gap, the current research focused on conducting surveys to determine the population densities and distribution of Pratylenchus spp. in wheat-growing regions in Canterbury, South Island, New Zealand. Surveys were conducted at ten selected sites that were geographically distinct from each other. At six of the ten sites, lesion nematode populations were reported to be above the recorded Australian threshold of 2000 nematodes per kg of soil. In Australia, it’s been recorded that around 50% yield reductions can occur in intolerant wheat varieties when population densities reaches this number. Differences in population density within each location was also observed indicating the uneven distribution of lesion nematodes within a field. Morphological measurements of the nematodes collected from multiple sites during this study confirmed the presence of P. thornei and P. neglectus in Canterbury wheat-producing areas indicating a potential threat to the New Zealand wheat industry by root-lesion nematodes. Further studies need to be conducted to fully understand the situation and to develop management strategies to mitigate threats from nematodes.
Open Access
Soil carbon, erosion, and the stormflow mobilisation of sediment and nutrients in a high-country landscape : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2023) Provost, Shyam Michael
This study was carried out at Mt. Grand Station, a high-country pastoral farm in the South Island of New Zealand. The landscape (400 - 1300 m altitude) supports a gradient and mosaic of native and endemic woody shrub and tussock grassland vegetation amongst more productive exotic pasture, the latter established through aerial seed top-dressing and fertilisation. In recent years several areas of the farm at higher altitudes have been converted to conservation management following Tenure Review, placing additional pressure on the remaining farmland to maximise productivity, a situation similarly faced by many other high-country farms. However, further intensification of pasture grassland would compromise existing less productive native vegetation. This research project investigated soil conservation and loss, and freshwater quality, aiming to advance existing knowledge relating to environmental sustainability of the high-country. Topsoil carbon stocks were quantified beneath various vegetation communities at different altitudes of the station to gain a better understanding of soil carbon and its dynamics. Two watershed catchments were targeted for high-frequency sampling during rainfall events, to investigate the likely significance of water flow on the mobilisation of sediment and nutrients, and to help improve the accuracy of existing run-off estimates. In addition, soil erosion was estimated from differences in residual soil 137Cs activity, which was generated from historic Pacific nuclear testing, between two of the dominant types of vegetation cover. The results revealed the potential for native vegetation to enhance soil carbon sequestration. At low - middle altitudes (450 - 850 m) of the farm, topsoil beneath a woody shrub (kānuka) vegetation cover had significantly higher carbon concentrations and carbon stocks than areas of adjacent pasture. At higher elevations (>1000 m) topsoil beneath dominant snow tussocks had significantly higher carbon, nitrogen and phosphorus concentrations, with higher carbon stocks than adjacent inter-tussock spaces. The total loads of suspended solids, nitrogen and phosphorus exported to catchment waterways were significantly larger during high-flow events in comparison to baseflow conditions, and large proportions of the high-flow loads were mobilised on the rising hydrograph following high rainfall. These findings draw attention to the significance of taking account of the early stages of rainfall events to improve accuracy when quantifying high-country catchment loads. Data for 137Cs were variable but these provisional results indicate that soil beneath kānuka is likely to have undergone lower rates of erosion over the previous 65 years in comparison to areas of adjacent pasture. The combined findings of the three parts of the experimental work in this study are interpreted as being indicative of the present and future potential for South Island high-country farming environments to make a significant contribution towards climate change mitigation through vegetation management, resultant soil building and prevention of soil erosion. It is argued that closer attention to ecological restoration is likely to have mutual benefits for conservation, the farming system and the environment. Maintenance and better-informed management of the mosaic of native and exotic vegetation can play a more important role in longer-term sustainability of this high-country land management system than is currently appreciated.
Open Access
Copper contamination of fruit orchards soils: Biotic Impacts : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Jeon, Dasom
Extensive use of fungicide copper (Cu) has a more recent history in New Zealand than in many other parts of the world where long-lasting Cu accumulation in soil has become a major environmental issue. However, Cu is extensively applied in New Zealand orchards, including organic orchards, with some awareness that the consequences of its current and future accumulation on soil health are relatively unknown and under-explored. This doctoral study aimed to investigate the impact on soil functional processes and plants of soil copper contamination associated with cherry, apple and kiwifruit orchards, vineyards and hops. The research encompassed experimental work on soil respiration, plant growth, earthworms, soil microbial activity, root growth and plant cell culture through a combination of fieldwork, glasshouse and laboratory studies. The central hypothesis of this study was that accumulation and persistence of Cu in orchard soils are likely to adversely affect critical aspects of soil biology and functionality. Following a detailed survey of accumulation and spatial variability of soil Cu across different fruit orchards up to 73 years old, practical investigations involved soil respirometry, analysis of microbial carbon (C) and nitrogen (N), and rhizobox and pot plant growth assays, as much as possible using in-situ field measurements or soils collected from orchards and transferred to the glasshouse and laboratory. In an earthworm behavioural and Cu-uptake study, a native anecic species was exposed to soils from the same orchard with differing histories of fungicide use. Three hop varieties (Cascade, Nelson Sauvin and Riwaka) were used for plant growth trials on the same soils. Plant stress responses were investigated using callus incubation trials on cell lines isolated from three apple cultivars (Braeburn, Fuji, and Cripps Pink) grown on a Cu-spiked growth medium. All practical work was carried out from 2020 to 2023. The results showed that soil Cu concentrations in orchards frequently and substantially exceeded most published threshold limits. Whilst soil Cu concentrations could largely be explained by modelling the age of the orchards, fruit type and soil organic matter (SOM) also had a large role in Cu retention. When SOM and existing Cu concentrations were amended in four soils from different blocks of the same cherry orchard, the ecotoxicological impact differed, and it was found that SOM could be a more powerful determinant than Cu of the biotic responses. Earthworm survivorship and growth in these soils were significantly determined by both SOM and Cu; earthworms exhibited a preference for soils with concentrations of Cu elevated substantially above background (to 160 mg kg-1), where SOM content was also high. A variable impact of Cu contamination on soil microbial activity was recorded across soils with elevated Cu concentrations (from 195 to 405 mg kg-1). Only a weak correlation was found between soil total Cu concentration and soil respiration when data for all orchards were combined, but the impact of Cu was more evident when each type of fruit orchard was evaluated separately. Microbial biomass carbon (MBC) and nitrogen (MBN) analyses similarly provided only a weak or negligible correlation with soil Cu, but artificially spiked soils provided a more consistent response to elevated Cu. Confounding factors appeared to relate to vegetation cover within and between rows and the amount of cultivation of the soils used to manage weeds (and bronze beetle in apples). The influence of management variables requires a more detailed study. Root growth in hop varieties was negatively affected at Cu concentrations exceeding 263 mg kg-1, whilst best growth was observed at 160 mg kg-1 in conjunction with abundant SOM. In callus culture assays, Cu negatively impacted the growth of Braeburn and Fuji apple varieties at concentrations exceeding 15 mg kg-1, while Cripps Pink had higher Cu tolerance. The value of using biological and ecological indices to assess the impacts of agricultural chemicals and contaminated soils is discussed. The findings have identified detrimental biotic impacts of soil Cu concentrations that already exist in orchards, which are probably reflected in a negative influence on soil health. Transfer rates of Cu to fruits through uptake from soil or from foliar absorption are negligible, but stress responses in plants and soil fauna and impacts on soil biology and ecology have been detected. Currently, the deleterious impact of elevated Cu is largely mitigated by SOM content in combination with the avoidance of low pH in orchard soils. Whilst this implies there is a potential avenue for amelioration of toxicity and maintenance or restoration of soil health, residual fungicide Cu will not significantly dissipate and is likely to continue to accumulate. Sustainable soil health management in New Zealand's orchards is not viable with longer-term continued usage of Cu fungicides.
Embargo
Investigation of the microbiome structure and function in grapevines escaping trunk diseases : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2023) Adejoro, Damola
Grapevine trunk diseases (GTD) represent a substantial challenge to viticulture in New Zealand and other winegrowing regions worldwide. With no approved fungicides for their eradication, alternative methods, such as biological control, are of significant interest. Key international studies have identified plants, called disease escape plants, that remain healthy under a high disease pressure, and this trait has been linked to microbiome function. In some New Zealand vineyards, such disease escape vines have been observed in backgrounds of heavy GTD pressure. This study aimed to investigate a microbiome approach to GTD management by surveying New Zealand vineyards for the occurrence of GTD escape vines and characterising the trunk microbiome of such vines. Based on preliminary assessments of nine vineyards across Hawke's Bay and Canterbury, New Zealand, a detailed visual survey was conducted in four vineyards, two each in Hawke's Bay and Canterbury. Candidate GTD escape vines were identified based on the absence of GTD symptoms, chlorophyll content of leaves, and high GTD pressure in the vineyard block. Woody trunk tissue samples were collected from these vines and the diseased vines nearby. The fungal and bacterial communities in the samples were characterised using a combination of DNA metabarcoding of the ribosomal internal transcribed spacer 1 (ITS1) and 16S ribosomal RNA gene and microbial isolations. The results showed that the status of the vine as either GTD escape or diseased was a strong determinant of the structure of the bacterial and fungal microbiomes of the grapevine trunk. For bacteria, the GTD escape vines consistently harboured Pseudomonas and Hymenobacter in higher relative abundance. Aureobasidium, Seimatosporium, Cladosporium, and Rhodotorula were fungal genera differentially associated with GTD escape vines. On the other hand, the GTD pathogen, Eutypa lata, was differentially associated with diseased vines. Bacterial and fungal isolates matching the key taxa identified by DNA metabarcoding from GTD escape vines were retrieved and tested for inclusion in microbial consortia. Additional selection criteria for inclusion were the microorganism's functional properties, such as not being a known plant pathogen, not causing lesions on grapevine shoots, and exhibiting desirable inhibitory activities against E. lata and Neofusicoccum luteum in dual culture plate assays. Using these criteria, consortium members Aureobasidium pullulans, Seimatosporium vitis, and seven Pseudomonas isolates were selected. Combined and separate fungal and bacterial consortia were tested in plant assays against the GTD pathogens E. lata and N. luteum. Over 3 months, the bacteria successfully established and persisted within the grapevines, significantly altering the grapevines' microbiome structure. Treatment with combined bacterial and fungal consortia resulted in significantly shorter lesions (71% reduction, p = 0.002) than the pathogen controls. The relative abundance of E. lata was reduced by 85% in the presence of the bacteria-only consortium. This research enhanced knowledge of the grapevine trunk microbiome structure within the context of the GTD escape phenotype. In addition, it expanded the understanding of grapevine microbiome manipulation by developing and delivering microbial consortia into grapevines, which resulted in changes in the grapevine microbiome structure. These results highlight the potential of using selected microbial consortia as a promising strategy for controlling GTD pathogens in planta. Given the perennial nature of grapevines and the extended development periods associated with GTD, future research could investigate the potential long-term impact of grapevine microbiome manipulation on the protection of grapevines against GTD pathogens.
Open Access
Adaptation and survival of marine-associated spiders (Araneae)
(Annual Reviews Inc., 2024-01) Leggett, MA; Vink, Cornelis; Nelson, XJ
Aquatic environments are an unusual habitat for most arthropods. Nevertheless, many arthropod species that were once terrestrial dwelling have transitioned back to marine and freshwater environments, either as semi-aquatic or, more rarely, as fully aquatic inhabitants. Transition to water from land is exceptional, and without respiratory modifications to allow for extended submergence and the associated hypoxic conditions, survival is limited. In this article, we review marine-associated species that have made this rare transition in a generally terrestrial group, spiders. We include several freshwater spider species for comparative purposes. Marine-associated spiders comprise less than 0.3% of spider species worldwide but are found in over 14% of all spider families. As we discuss, these spiders live in environments that, with tidal action, hydraulic forces, and saltwater, are more extreme than freshwater habitats, often requiring physiological and behavioral adaptations to survive. Spiders employ many methods to survive inundation from encroaching tides, such as air bubble respiration, airtight nests, hypoxic comas, and fleeing incoming tides. While airway protection is the primary survival strategy, further survival adaptations include saltwater-induced osmotic regulation, dietary composition, predator avoidance, reproduction, locomotory responses, and adaptation to extreme temperatures and hydrostatic pressures that challenge existence in marine environments.
Open Access
Individual and combined effects of predatory bug Engytatus nicotianae and Trichoderma atroviride in suppressing the tomato potato psyllid Bactericera cockerelli in greenhouse grown tomatoes
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-12) Veronesi, ER; Cairns, SM; Alizadeh, Hossein; Hampton, John; Maris, R; Godsoe, William; Goldson, Stephen; McCormick, AC
The tomato potato psyllid (TPP) Bactericera cockerelli is a serious pest of the Solanaceae family. The management of this pest using synthetic pesticides is problematic because of the development of pesticide resistance and environmental concerns including impacts on non-target organisms. The predatory bug Engytatus nicotianae has recently been identified as a useful biocontrol agent for TPP in greenhouses. The soil fungus Trichoderma Pers. is commonly used as a plant growth enhancer and biocontrol agent against phytopathogenic fungi. Therefore, there could be advantages associated with the combined use of these biocontrol agents. Some reports in other systems suggest that Trichoderma inoculation may alter the behaviour of pests and their natural enemies by modifying plant defence metabolites such as volatile organic compounds (VOCs). For this reason, this study aimed to investigate the individual and combined efficacy of these biocontrol agents (i.e., Trichoderma atroviride and E. nicotianae) against TPP in greenhouse grown tomatoes (Solanum lycopersicum cv. Merlice). To this end, we compared the effect of each biocontrol agent and their combination on TPP abundance across different developmental stages (egg, nymphs, adults) and the number of infested leaves. We also investigated plant VOC emissions under the different treatments. Across all measured TPP stages, the treatments tested (E. nicotianae alone, T. atrovirdae alone, and T. atrovirdae + E. nicotianae) significantly reduced mean TPP counts relative to the control, and no significant differences were observed in VOC emissions among treatments. Overall, T. atrovirdae alone was less effective than E. nicotianae alone and its combination with T. atrovirdae in suppressing TPP populations. However, the combined use of Trichoderma + E. nicotianae did not show significant advantages over the use of E. nicotianae alone in controlling TPP. Therefore, their combined use needs to be further assessed in light of other advantages of Trichoderma to the crop (e.g., growth promotion or pathogen defence).
Open Access
Spider and harvestmen biodiversity in New Zealand horticultural ecosystems
(Taylor & Francis Group, 2023-11-29) Sullivan, N; Black, Amanda; Sharp, J; Marsh, A; Butler, R; Vink, Cornelis
Spiders contribute to pest suppression in agroecosystems by direct and non-direct consumption. They provide an ecosystem service which provides economic gains to horticultural growing systems, such as apples, wine grapes, and kiwifruit. Very few studies on spider biodiversity in cropping systems have been completed in New Zealand, and no studies have been published for New Zealand orchard systems. In this study, spiders and harvestmen were sampled from vineyards, apple orchards, and kiwifruit orchards in three New Zealand locations, Waipara, Motueka, and Kerikeri. Spiders were sampled using pitfall traps, sweep netting, active day sampling, and active night sampling. A total of 1359 spiders and 87 Opiliones were caught in this study, from 17 families and 31 species. Sixteen of the 31 (51.6%) species found were introduced, 9 (29%) endemic to New Zealand, two species (6.4%) native to New Zealand, and four (12.9%) unknown. There were five dominant spider families caught (Araneidae, Lycosidae, Theridiidae, Linyphiidae, and Desidae), and of the adults, there were five dominant species: Anoteropsis hilaris, Tenuiphantes tenuis, Cryptachaea veruculata, Cryptachaea blattea, and Steatoda capensis. This study provides the first important step in describing the spider families and species found in three economically important New Zealand horticultural systems.
Open Access
Harnessing microbes for vine growth, nutrient uptake and disease protection: The benefits of arbuscular mycorrhizal fungi
(Winetitles Media, 2022-01) Moukarzel, Romy
Viticulture is a major economic activity in may countries and grapes are one of the most widely grown fruit crops. According to the New Zealand Winegrowers report (2020), there are around 40,000 hectares of grapes in production and more being planted in response to strong demand.
Open Access
Unveiling the hidden economic toll of biological invasions in the European Union
(Springer Nature, 2023) Henry, M; Leung, B; Cuthbert, RN; Bodey, TW; Ahmed, DA; Angulo, E; Balzani, P; Briski, E; Courchamp, F; Hulme, Philip; Kouba, A; Kourantidou, M; Liu, C; Macêdo, RL; Oficialdegui, FJ; Renault, D; Soto, I; Tarkan, AS; Turbelin, AJ; Bradshaw, CJA; Haubrock, PJ
Background: Biological invasions threaten the functioning of ecosystems, biodiversity, and human well-being by degrading ecosystem services and eliciting massive economic costs. The European Union has historically been a hub for cultural development and global trade, and thus, has extensive opportunities for the introduction and spread of alien species. While reported costs of biological invasions to some member states have been recently assessed, ongoing knowledge gaps in taxonomic and spatio-temporal data suggest that these costs were considerably underestimated. Results: We used the latest available cost data in InvaCost (v4.1)—the most comprehensive database on the costs of biological invasions—to assess the magnitude of this underestimation within the European Union via projections of current and future invasion costs. We used macroeconomic scaling and temporal modelling approaches to project available cost information over gaps in taxa, space, and time, thereby producing a more complete estimate for the European Union economy. We identified that only 259 out of 13,331 (~ 1%) known invasive alien species have reported costs in the European Union. Using a conservative subset of highly reliable, observed, country-level cost entries from 49 species (totalling US$4.7 billion; 2017 value), combined with the establishment data of alien species within European Union member states, we projected unreported cost data for all member states. Conclusions: Our corrected estimate of observed costs was potentially 501% higher (US$28.0 billion) than currently recorded. Using future projections of current estimates, we also identified a substantial increase in costs and costly species (US$148.2 billion) by 2040. We urge that cost reporting be improved to clarify the economic impacts of greatest concern, concomitant with coordinated international action to prevent and mitigate the impacts of invasive alien species in the European Union and globally.
Open Access
Measuring the flammability of common agricultural plant species across the year and understanding the perceptions of rural landholders towards fire risk in Canterbury, New Zealand : A dissertation submitted in partial fulfilment of the requirements for the Degree of Agriculture Science (Honours) at Lincoln University
(Lincoln University, 2023) Woods, Georgina
Anthropogenic drivers of climate change are altering the nature of fires globally. Hotter, drier and windier weather conditions are contributing to lengthening of fire seasons and making ignitions easier in many parts of the world, including Canterbury, New Zealand. The looming threat of increasingly destructive wildfire events highlights the need for further research into wildfire management. One tool that has the potential to reduce or stop the spread of wildfire is green firebreaks. To understand which plant species are good candidates for green firebreaks, we empirically test their flammability, i.e. their capacity to ignite and sustain a fire. However, there is generally a lack of information of flammability on plant species found in agricultural landscapes. Additionally, flammability is potentially affected by plant physiology and phenology changes throughout the year, though again research on this is scarce. Filling these research gaps will benefit rural landholders, iwi, governments and ultimately assist with reconfiguring rural landscapes. While it is vital to produce such information it is also important to ensure such information is reaching those who need it. Hence, it is necessary to understand the perceived fire risk of rural landholders in Canterbury. This will help in indicating whether plant flammability research will be taken up and how to create science communication strategies which are effective and efficient. This dissertation intends to address both of these knowledge gaps by testing the shoot flammability of common agricultural pasture, crop and weed species that are found in agricultural landscapes in Canterbury, New Zealand across different times of the year and also investigate the perceptions that Canterbury rural landholders have towards fire risk on their properties. The results showed that lucerne (Medicago sativa) was consistently the least flammable species, whereas wheat (Triticum aestivum) and barley (Hordeum vulgare) were consistently the most flammable species. Half of the species tested did vary in flammability across sampling periods throughout the year, while the other half did not. This suggests that species- specific plant flammability research is critical when assessing the suitability of species for green firebreaks. The species identified as being low in flammability year round were: lucerne (Medicago sativa), white clover (Trifolium repens), cocksfoot (Dactylis glomerata) and yarrow (Achillea millefolium); these would be good candidates for green firebreaks in agricultural landscapes. The survey found that the mean annual fire risk rating of rural landholders did not change across system type (dairy, cropping, or sheep and beef) or land type (flat, rolling-moderate hill country, steep). Furthermore, the mean annual fire rating was similar across all rural landholders, most consistently being scored as moderate risk. Of the sheep and beef farmers, the seasonal annual fire risk rating did not change across land type and showed consistent trends across each season with fire risk perceived to be highest in summer and lowest in winter. This suggests that as fire risk is perceived similarly across system and land type of the surveyed farmers, plant flammability research can be communicated in a streamlined approach to stakeholders, with relevant changes made where necessary (e.g. certain plant species will be grown in some systems more commonly than others). My study has identified species that are good candidates for green firebreaks and that rural landholders are aware of fire risk on their properties, with the seasonal risk rating of sheep and beef farmers coinciding with the fire season in New Zealand. Overall, this will help to redesign agricultural landscapes and take appropriate precaution at times of the year where fire risk is higher than others, depending on the system type.
Open Access
New Zealand Wakatipu white-tailed deer (Odocoileus virginianus): past and future management : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctorate of Philosophy at Lincoln University
(Lincoln University, 2023) Pinney, Kaylyn
I attempt to highlight the large gap in knowledge required to pursue New Zealand’s new approach to deer management. This approach requires identifying a complex array of species and site specific factors that potentially influence population success, impacts, value, and management for one of New Zealand’s smallest deer herds, the Wakatipu white-tailed deer (Odocoileus virginianus). White-tailed deer in North America (and in introduced populations around the world) have been researched extensively, providing an unparalleled base of knowledge to review factors that may affect Wakatipu white-tailed deer population dynamics, including habitat quality, disease, hunter harvest and interspecies competition. An overlapping spatial mosaic of limiting factors that may influence white-tailed deer population success across the Wakatipu range were identified. Further research to determine the impact these factors have on the Wakatipu white-tailed deer population, individually and collectively across the landscape, is requried to support this herd’s management. Understanding how deer populations utilise local habitat is a critical first step in designing deer management plans. I used GPS telemetry technology to identify habitat use of Wakatipu white-tailed deer. Initial disturbance to deer behaviour is commonly observed following capture and handling for collar placement. We compared the behaviour of ten deer; four resident and six translocated into a novel, geographically disjunct area, over 50 days following helicopter capture and GPS collar placement. I identified the point at which behaviour disturbed by the capture deer returned to a stable nature. Habitat use by collared deer was patchy across the landscape and did not vary between resident and translocated groups. These results suggest the probability of habitat use could be mapped to predict the presence/absence of Wakatipu white-tailed deer across the wider landscape, thus informing those areas where management and monitoring of Wakatipu white-tailed deer and their impacts on the environment should be focused. A factor limiting population success unique to New Zealand was identified. Intensive ground-based searches for white-tailed deer carcasses were conducted in the Dart Valley/Routeburn catchments following the aerial application of 1080 (sodium fluoroacetate) containing cereal baits as part of a predator control program. Frequent predator control operations will likely affect the sustainable hunting of Wakatipu white-tailed deer and growth in their population. The efficacy of two deer repellents for repelling captive white-tailed deer from consumption of nontoxic cereal baits was assessed. Both repellents significantly decreased bait consumption and I observed clear displays of aversion to repellent baits by captive deer. Ten GPS collared wild white-tailed deer were then monitored following a predator control operation using one of the deer repellents; EDR. One collared deer was poisoned following the operation confirming that EDR is not 100% effective. To support management for hunting, the most effective available deer repellent should be used in future predator control operations over the Wakatipu white-tailed deer range. Deer management plan development requires an in-depth understanding of governing legislation, population management tools and monitoring techniques. I outlined the status of these pertaining to deer management in New Zealand and identify a range of opportunities and challenges within each for developing a management plan for the Wakatipu white-tailed deer herd. Many of these are related to policy development and strategic planning, funding, and implementation processes. Also, monitoring of the Wakatipu white-tailed deer population and its environment needs to be developed from scratch. Overall, I highlight the significant research required to pursue New Zealand’s new approach to deer management. A question remains, who undertakes this work and who pays for it?
Embargo
Fungal endophytes of grapevine trunks: community structure and implication for grapevine trunk diseases : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2023) Besselma, Noureddine
The grapevine trunk is colonized by a diverse community of fungi, collectively referred to as the endophytic mycota. These communities are shaped by different factors, both biotic and abiotic, including diseases status. Pathogens and beneficial fungi play important roles in grapevines, and these endophytes are considered key players that enhance plant growth, reduce plant disease and can improve the ability to adapt to stress. Some pathogenic fungi are known to be the causal agents of grapevine trunk disease (GTD) and are considered latent pathogens. Studying variation in their disease expression in response to the endomycobiome can guide the identification of disease suppressive microbial antagonists against (or that interact with) GTDs pathogens. Understanding of the processes by which these endophytic fungi initiate, maintain, or modulate trunk diseases is lacking. This thesis focused on characterising the taxonomic diversity and the composition of the trunk endophytic mycota (endomycobiome) colonizing symptomatic and asymptomatic trunk tissues of old and young vines from different management systems, by using both culture- dependent and high-resolution culture-independent approaches. Samples were taken from nine vineyards in the Marlborough region. The samples encompassed 60 mature vines (>10 years old) and 30 young vines (<9 years old), with each age group consisting of equal numbers of apparently healthy and symptomatic vines. A culture collection of 2116 fungal isolates from 90 vines (270 tissue samples) were created. As some endophytic fungi are uncultured, this work was complemented by amplicon sequencing to characterise both the unculturable and culturable endophytes. This approach generated a total of 10 M reads. These were divided into 1892 distinct operational taxonomic units (OTUs). The results from both approaches demonstrated a complex community that was dominated by Ascomycetes species. The community analysis revealed that health, tissue age, and type of management were major drivers of the trunk endophytic community structure. The same fungal genera from culturome were identified as the most abundant using metabarcoding. Consequently, the key indicator fungal isolates recovered from trunk tissues were evaluated for their co-occurrence and interaction with GTD pathogens. Isolates of Botrytis cinerea recovered from symptomatic and asymptomatic woody tissues were pathogenic on grapevine stems. The interaction between Botrytis cinerea and two common botryosphaeriaceous species (N. parvum and D. seriata) on the expression of symptoms in young grapevine plants were explored using detached and attached assays. The co-inoculation on detached material did not show any evidence of synergism. However, co inoculation onto attached shoots on potted plants produced contrasting results. Inhibition of N. parvum lesion development by B. cinerea was observed. Next, in detached and attached grapevine assays the interaction between A. pullulans and the grapevine trunk pathogens and their effect on symptom expression demonstrated that A. pullulans could reduce the disease expression/colonisation by both N. parvum and D. seriata indicating possible antagonistic activity against these pathogens by this fungal species. The interactions between Seimatosporium spp. and the grapevine trunk pathogens N. parvum and D. seriata in detached and attached grapevine shoots showed that Seimatosporium spp. were effective in reducing the colonisation of shoot tissues by D. seriata in detached experiments, but had no significant effect in attached shoot tissues. Additionally, both S. vitis and S. sp. nov were effective in reducing lesion length caused by N. parvum in detached shoots, while S. vitis also showed a reduction in lesion length in attached shoots of potted vines. The overall results of this thesis showed that culturome and NGS metabarcoding complement each other and can be applied to gain knowledge about microbial dynamics inside the grapevine trunk. This is the first study investigating the combined effect of three factors on the endomycobiome. The findings of this study provide valuable insights into the complex interactions between pathogens associated with GTD and other fungal species isolated as endophytes from the same grapevine woody tissues.
Open Access
Grapevines escaping trunk diseases in New Zealand vineyards have a distinct microbiome structure
(Frontiers Media S.A., 2023) Adejoro, Damola; Jones, Elizabeth; Ridgway, HJ; Mundy, DC; Vanga, BR; Bulman, SR
Grapevine trunk diseases (GTDs) are a substantial challenge to viticulture, especially with a lack of available control measures. The lack of approved fungicides necessitates the exploration of alternative controls. One promising approach is the investigation of disease escape plants, which remain healthy under high disease pressure, likely due to their microbiome function. This study explored the microbiome of grapevines with the disease escape phenotype. DNA metabarcoding of the ribosomal internal transcribed spacer 1 (ITS1) and 16S ribosomal RNA gene was applied to trunk tissues of GTD escape and adjacent diseased vines. Our findings showed that the GTD escape vines had a significantly different microbiome compared with diseased vines. The GTD escape vines consistently harbored a higher relative abundance of the bacterial taxa Pseudomonas and Hymenobacter. Among fungi, Aureobasidium and Rhodotorula were differentially associated with GTD escape vines, while the GTD pathogen, Eutypa, was associated with the diseased vines. This is the first report of the link between the GTD escape phenotype and the grapevine microbiome.

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