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Item Ecosystem services provided by North Island brown kiwi (Apteryx Mantelli) in two horticulture settings : vineyards and kiwifruit orchards : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Palmerston North, New Zealand(Massey University, 2025) Gong, WeiEcosystem services provide essential benefits to humans from natural ecosystems. Recognising and valuing these services is crucial. By implementing sustainable management practices that balance human needs with biodiversity preservation, we can ensure the long-term health of both ecosystems and people. North Island brown kiwi (Apteryx mantelli), an endemic New Zealand bird are nocturnal ground insectivores whose numbers are increasing following conservation management practices. They are now being reported more frequently from human-modified landscapes. This study explores the possible role of the brown kiwi as pest controllers in vineyards and kiwifruit orchards, focusing on its foraging behaviour and habitat use. I collected data using acoustic recorders only in one study site, and camera traps, pitfall traps, and kiwi faeces analysis across four study sites. These methods aimed to investigate their activity pattern, habitat use, diet composition, and the invertebrates’ composition in this specific area. Acoustic recorders provide kiwi vocal behaviour, estimate population density, and at the same time, camera traps monitor their movement and habitat preference between orchard and bush areas. Pitfall traps and faecal analysis help to identify available and consumed invertebrate prey for them. I used capture rate calculations, Non-Metric Multidimensional Scaling (NMDS), and Spatial Capture-Recapture (SCR) modelling for statistical analyses. That is to assess kiwi activity, diet overlap between seasons and study sites and estimate population density. I found that they were more active in bush areas, but also used orchards, especially those with dense canopy cover, like Puriri Park. Seasonal changes affected invertebrate availability and their behaviour. Kiwi were most active in summer and less active in winter. Kiwi faeces contained potential orchard pest species, suggesting they may be a potential pest controller. Using predator heat maps made with camera trap data, I found different levels of threat at different locations, with higher numbers of predators closer to the bush area. The spatial capture-recapture model estimated a low kiwi density, which may be due to detection limitations and small sample sizes. It may be necessary to increase the sample size in future studies to reflect the most realistic results. Overall, the findings suggest that habitat characteristics such as canopy cover, soil conditions and surrounding vegetation influence their behaviour and that horticultural landscapes can support kiwi if managed properly. Additionally, my findings show that kiwi use modified landscapes and can inform orchardists on how to make horticultural settings more kiwi-friendly through improved habitat and pest management. Future research should increase the number of orchards used and include more diverse horticultural settings to test the replicability of these findings and their extent. Research could also assess the effectiveness of different orchard management practices on their behaviour. These efforts will support better conservation strategies and promote eco-friendly orchard management in New Zealand.Item Effectiveness and energy efficiency of pulsed electric microshocks for killing young weeds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Manawatū, New Zealand(Massey University, 2024-08-30) Bloomer, Daniel JamesAlternatives to herbicides are needed due to increased occurrence of herbicide resistance, regulatory restrictions, and consumer preferences. This thesis presents results of research into ultra-low energy weeding systems using very short pulses of very high voltage direct current electricity. Proof-of-concept trials found that small Capsella bursa-pastoris weeds in a fallowed vegetable bed were killed by single 10 kV pulses of about 5 J. Grasses were harder to kill. In replicated greenhouse trials, small Chenopodium album plants collapsed, and three quarters were dead 4 weeks later. Shocks instantly impacted small Lolium multiflorum plants, but death rates were very low. Applying multiple-pulse treatments using a probe electrode precisely placed against the stems of bagged plants showed Amaranthus powellii could be well controlled, but Solanum nigrum could generate adventitious roots and recover. While L. multiflorum treated with probe-electrodes again had a high survival rate, biomass reduced with increasing energy doses. Seeking a more practical application method, I showed that a flat plate electrode applying multiple pulses to the plants’ leaves or to the plant pressed against the soil was effective, with Polygonum aviculare, A. powellii, Amaranthus deflexus and Solanum nitidibaccatum weeds successfully controlled. While only half of L. multiflorum plants were killed, data indicated a 90% death rate would be achieved at 200 J plant⁻¹. Moving outdoors, I treated small plants in the ground using flat plate electrodes and achieved excellent control of Lepidium didymum, A. powellii and L. multiflorum. Flat-plate electric weeding using pulsed microshocks is a novel development that gives effective control of individual or small clumps of weeds in the field. Observations of plant responses during almost 30 trials suggest the mode of action is not cell rupturing from resistive heating as usually claimed for electric weeding, but an increase in membrane permeability. My trials showed that small broadleaf weeds and grasses can be controlled at a density of 5 plants m⁻² using less than 1 MJ ha⁻¹, a fraction of the energy required by any other weeding system. Combined with automation technologies and artificial intelligence, it offers an autonomous, low-energy, non-chemical, selective weeding system for integrated management of weeds.Item Biological control ecology of Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) on Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science (Entomology) at Massey University, Manawatū, New Zealand(Massey University, 2023) Chen, ChenTamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important primary parasitoid of tomato-potato psyllid Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), a serious invasive pest of solanaceous crops. It kills its hosts by both feeding and parasitisation. However, its biological control ecology is still not well known, making it difficult to develop an effective biological control programme using this parasitoid. In this thesis, I investigated adult circadian rhythms, diets, life history strategies, and host selection behaviour in T. triozae. My results show that most emergence occurred in the morning and most mating took place early the next morning. Oviposition only occurred during the daytime, peaking between mid-morning and mid-afternoon while host feeding had three peaks in the early morning, late afternoon, and dawn. Adults fed with honey for four days with no access to hosts or with water or yeast for one day followed by host feeding for three days had similar longevity and lifetime pest killing ability. Adults fed with only water for one day immediately before release had significantly greater intrinsic rate of increase, shorter doubling time, and higher daily fecundity peak. Adults fed with honey or yeast for one day followed by host feeding for three days significantly flattened their daily oviposition curves. T. triozae females could feed on nymphs of all instars but preferred mid-aged ones for feeding. Most parasitisation occurred on older nymphs. Host feeding and parasitism peaked during the first week of female life and declined markedly after two weeks. Parasitoids allocated more fertilised eggs to older and larger nymphs. The oviposition of fertilised eggs peaked when females were four to five days old, with > 90 % of daughters produced during the first half of their life. There was a positive relationship between the host size at parasitisation and parasitoid offspring fitness. The parasitoid behaviours consisted of encounter, evaluation, piercing for feeding, feeding, oviposition probing, and oviposition, and host defence behaviours included body swaying and escaping. Female wasps were more likely to encounter and evaluate older and larger hosts. However, encounter and evaluation did not necessarily translate into feeding and oviposition success. Older nymphs had more resources, thicker integument and stronger defence ability and the opposite was the case for younger ones. The present study provides novel knowledge for development of effective T. triozae mass rearing, shipment, and release programmes for the control of B. cockerelli.Item Unravelling the molecular basis of subcuticular host-colonization by the apple scab fungus, Venturia inaequalis : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy (PhD) in Plant Science, School of Agriculture and Environment, Massey University(Massey University, 2023) Rocafort Ferrer, MercedesScab, caused by the fungal pathogen V. inaequalis (Vi), is the most economically important apple disease. During infection, Vi occupies the subcuticular environment, where it develops specialized infection structures, called stromata and runner hyphae. These structures are thought to be important for fungal nutrition and the delivery of proteins, with many of these anticipated to function as virulence factors (effectors) in promoting host infection or avirulence factors (Avr effectors) in triggering host resistance. To date, nothing is known about how these structures are differentiated and protected from recognition by the host immune system. Likewise, little is known about the identity and function of Vi effector proteins. To better control scab, a greater understanding of the molecular mechanisms underpinning infection structure differentiation and protection, as well as Vi virulence and avirulence, is first needed. In Chapter 2, a comprehensive review of apoplastic effector proteins from plant-associated fungi (and oomycetes) was provided. Given that Vi is an extracellular pathogen, this review provided insights into the potential types of effector proteins secreted by Vi into the subcuticular environment. Then, in Chapter 3, a multidisciplinary approach based on bioinformatics, transcriptomics, and structural biology was used to identify and characterize Vi effector candidates (ECs). This revealed that ECs were predominantly expressed in two temporal waves, and that many belonged to expanded protein families with predicted structural similarity to virulence and avirulence effectors from other plant-pathogenic fungi. This analysis helped to generate a list of ECs for further study and contributed to a better understanding of effector biology and evolution. Next, in Chapter 4, a multidisciplinary approach based on transcriptomics, proteomics, glycomics, and confocal microscopy was used to study Vi cell wall carbohydrate composition during the differentiation of infection structures. This iii revealed that Vi down-regulates genes putatively associated with the biosynthesis of immunogenic carbohydrates, and deacetylates surface-exposed chitin to the less immunogenic carbohydrate, chitosan. Finally, in Chapter 5, CRISPR-Cas9 technology was applied to Vi for the first time, which will enable genes identified in this study to be functionally characterized. Altogether, this thesis has furthered our understanding of the Vi –apple pathosystem and has provided novel data that can be used to inform the development of new scab control strategies against Vi.Item Life history strategies of the spider mite, Tetranychus ludeni Zacher, in response to environmental conditions : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Entomology at Massey University, Manawatu, New Zealand(Massey University, 2022) Ristyadi, DwiTetranychus ludeni Zacher (Acari: Tetranychidae) is an invasive pest of many horticultural crops and now occurs in all continents except Antarctic. Its invasive nature and pest status have stimulated the need for understanding the plasticity of its life history strategies under different environmental conditions. So far, little is known about effects of environmental factors on the life history traits in T. ludeni. In this thesis, I investigated its life history strategies in response to temperature, food deprivation, and predator threat. I show that life history traits of T. ludeni were highly flexible and adaptive to dynamic thermal environment. Higher temperature accelerated development but reduced adult body size and longevity. Increasing temperature elevated the intrinsic rate of increase (rm) but shortened generation time (T) and the time to double the population size (Dt). The net population growth rate (R0) was higher at 20 and 25ºC compared to lower and higher temperatures. Thermotolerance in T. ludeni was stage-dependent with eggs being the most vulnerable and adults the most tolerant. No eggs hatched after exposed to 45°C for ≥ 15 hours, 48°C for ≥ 12 hours, or 51°C for three hours; no adults survived 51°C or 54°C for ≥12 hours or 57°C for ≥ six hours, and heat tolerance of other life stages fell in between. Intermittent fasting (IF) had sex-specific and mating status-specific effects on the lifespan of T. ludeni. It extended the lifespan of females regardless of mating status but shortened that of mated males and had no effect on virgin males. IF reduced fecundity and egg size and extended offspring developmental time. My study indicates that predator-induced fears significantly lowered the fitness of T. ludeni. Cues from predators and injured prey shortened the longevity by 23–25% and oviposition period by 35–40% and reduced the fecundity by 31–37% in T. ludeni females. These cues significantly reduced intrinsic rate of increase (rm) and net population growth rate (R0), and extended time to double the population size (Dt). Findings from this study contribute to our understanding of the effects of environmental stressors on life history traits in T. ludeni, providing knowledge for pest risk analysis and development of pest management programs.Item Investigating organic control methods for bronze beetle (Eucolaspis sp.) in New Zealand organic apple production : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, Palmerston North, New Zealand(Massey University, 2022) Wyatt, Sarah MargaretBronze beetle (Eucolaspis sp.), an insect native to New Zealand (NZ), is one of the most prevalent threats to the NZ organic apple industry. In organic orchards, bronze beetle can potentially damage or destroy 40-50% of the crop. At Bostock New Zealand, a large organic company that produces approximately 90% of NZ’s organic apples, the beetle causes losses of approximately ‡6 million per year. The lack of effective control methods available for use in organic production systems exacerbates the population numbers and severity of this pest. Two separate experiments were carried out to help alleviate this problematic pest. The first was a laboratory bioassay trial comparing the efficacy of three conventional insecticides with three organic insecticides containing the active ingredients spinosad (Entrust™ SC Naturalyte™ 240), pyrethrin (PYNZ28 EC), and azadirachtin (NeemAzal-T/S™ 40 EC). The objective of this experiment was to determine if any of the organic insecticides had the potential to provide an acceptable level of control in controlled conditions. If so, they should be investigated commercially. The organic insecticide Entrust SC Naturalyte (commonly called Entrust) provided over 90% control five days after application to leaves, a level of control similar to all three conventional insecticides trialled (Vayego® 200 SC, Calypso® 480 SC, and Avaunt® 300 WDG). NeemAzal-T/S, the organic insecticide containing azadirachtin, also showed some potential but at a lower level compared to Entrust, as the control achieved was over 80% seven days after direct application to leaves. The second experiment investigated the host plant attraction of bronze beetle, as it is known that they use plant volatiles to locate host plants. Based on this, apple, plum, and blackberry leaves were compared (with a clean air control) to identify which of these crops was the most attractive to bronze beetle. The purpose of this was to investigate the possibility of using these crops as attractants in a potential organic control programme. However, there were few responses to treatments, and all four treatment options appeared equally attractive to bronze beetle during this experiment, with any differences attributed to random variability.Item Growth, yield and quality response of beetroot to organic mulches in tropical conditions : submitted in partial fulfilment of the requirement for the degree of Master of Science (Horticultural Science) at Massey University, Manawatu, New Zealand(Massey University, 2021) Addo, ElizabethA field experiment was conducted in Malawi (Bvumbwe, Thyolo) between June and September 2020 to evaluate the impact of locally found organic mulches, viz maize straw (SM) and compost mulches (CM), with an un-mulched control, on the growth, yield and quality of three beetroot varieties, viz Detroit dark red (DDR), Crimson globe (CG) and Globe dark red (GDR). The experiment was set up under a split-plot design, randomized, and replicated three times. During the experiment, observations on plant height, number of leaves, leaf length and width, marketable and non-marketable yield, root diameter, shoot and root dry weights and dry matter content were recorded. The profitability of the two mulch treatments was assessed by working out the net profit for each treatment per hectare. The results showed that mulching improved all growth parameters and yield in beets. Additionally, net return was maximized by mulching. Compost mulch produced superior results with the highest plant height (20.6cm) and marketable yield (2423g) while the control had the least plant height (12.7cm) and marketable yield (443g) which subsequently reduced the overall net profit. However, mulching did not affect dry matter percentage as there were no significant differences observed between the control and straw mulch. However, the lowest dry matter content was found in beets planted under compost mulch. The total net return was higher in all mulched plots with compost mulch giving the maximum net return. There were no significant differences observed between the effects of mulches on the three beetroot varieties. However, Detroit dark red and Globe dark red produced the maximum plant height and yield respectively. Based on the results of this study, it can be concluded that mulching was the most effective treatment compared to non-mulched treatment. Therefore, it is recommended for commercial beetroot cultivation in farmers’ fields.Item Development and validation of a robust and rapid isothermal loop-mediated amplification (LAMP) assay for the detection of Black Sigatoka Disease (Pseudocercospora fijiensis) in bananas : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science (Agricultural Science) at Massey University, Manawatū, New Zealand(Massey University, 2020) Bob, Luania KoiBlack Sigatoka disease is a serious threat to banana and plantain production. However, the causal agent of the disease, Pseudocercospora fijiensis, is difficult to distinguish from related species associated with yellow Sigatoka disease (P. musicola) and eumusae leaf spot disease (P. eumusae) on the basis of symptomology or morphology. These similarities complicate pathogen identification. Molecular methods such as conventional PCR have been used in diagnosing this disease, but the time and cost of testing as well as the requirement for specialised equipment and infrastructure have limited its usefulness. New molecular approaches are reducing the barriers to molecular testing by allowing testing to be conducted in non-laboratory settings. Given the serious threat of black Sigatoka disease, a simple and rapid isothermal loop-mediated amplification (LAMP) assay has been developed to improve pathogen detection. A potential target region within the mitochondrial small ribosomal subunit (ssRNA) gene was identified and a set of four LAMP primers were developed. Initial trials established optimal reaction conditions for the P. fijiensis LAMP assay. These were a 1:8 primer ratio with an amplification temperature of 60˚C and an amplification time of 60 minutes. Laboratory validation of the assay suggests specific amplification in the presence of the target organism with no cross-reaction with several related species and other fungal pathogens of bananas and it detects anything above 9.1 × 10⁶ copies of the target. The LAMP assay was used against foliar and mycelial samples from Papua New Guinea and foliar samples from Fiji. Testing of foliar samples identified P. fijiensis in >90 % of the samples. These results were confirmed using PCR and sequencing. Nuclear ribosomal ITS sequencing suggested that non-target pathogens dominated the mycelium samples. However, LAMP testing indicated P. fijiensis was present in 50% of these samples. These results were confirmed using a PCR marker specific to P. fijiensis. In combination it suggests P. fijiensis was present on culture plates but competing species grew more rapidly. The testing performed suggests the LAMP assay provides a specific test for P. fijiensis that is sensitive enough to identify this pathogen from symptomatic tissue. Further work is needed to develop protocols for field testing and to examine the potential for testing non-symptomatic material.