Quentin Paynter

• Doctor of Philosophy
• Senior Researcher at Manaaki Whenua - Landcare Research

Improving success rates of classical weed biocontrol programs is an ongoing effort that requires a variety of different approaches. Previous assessments indicated biocontrol agent taxonomy and feeding characteristics and weed life history traits are associated with better control outcomes. We examined weed biocontrol releases for correlations betwe...

A cost benefit analysis of all weed biocontrol in New Zealand (NZ) was undertaken, using available data, to support future funding decisions by stakeholders. The analysis showed that 2022 investment in weed biocontrol in the productive sector was NZ$0.69 million, yielding an annual benefit of NZ$85 million (potentially reducing to NZ$57 million to...

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sp...

Microbes can be an important source of phenotypic plasticity in insects. Insect physiology, behaviour, and ecology are influenced by individual variation in the microbial communities held within the insect gut, reproductive organs, bacteriome, and other tissues. It is becoming increasingly clear how important the insect microbiome is for insect fit...

Invasive alien species are among the most important threats to biodiversity, with invasive plants ranking among the highest. Classical weed biological control—or biocontrol—reunites exotic plants with hostspecific natural enemies from their native range with the aim of controlling the invasive plant.We reviewed the attention classical weed biocontr...

Mass-production of arthropods for biological weed control can increase the rate of field establishment of agents for biological control of damaging nonnative, invasive weeds of aquatic, riparian, rangeland and forest environments, with possible application to crop weeds. Mass-rearing of biological control agents (BCAs) of weeds is almost always per...

A ‘relative risk score’ approach to help determine the potential impact of biological control agents on non-target species, previously proposed for weed biocontrol agents and aphid parasitoids, was examined in a retrospective study for Microctonus spp. parasitoids introduced to control pest weevils in New Zealand. ‘Relative risk scores’ (% parasiti...

The bacterium, Candidatus Liberibacter europaeus (Leu) was reported in New Zealand (NZ) in 2011 in Scotch broom, Cytisus scoparius Link, and its biocontrol agent, Arytainilla spartiophila Förster (Hemiptera: Psyllidae). The aim of the study was to investigate the pathway by which Leu arrived in NZ using a retrospective risk assessment of Leu being...

Sericothrips staphylinus was introduced to New Zealand as a biological control agent for gorse, Ulex europaeus (Fabales: Fabaceae), an invasive weed of European origin, but has proven to be an ineffective agent. We investigated and compared the functional responses of a predatory mite found on gorse in New Zealand, Amblyseius herbicolus, with two w...

A ‘relative risk score’ approach to help determine the potential impact of biological control agents on non-target species, previously proposed for weed biocontrol agents and aphid parasitoids, was examined in a retrospective study for Microctonus spp. parasitoids introduced to control pest weevils in New Zealand. ‘Relative risk scores’ (% parasiti...

Globally, invasive non‐native plants are an increasing threat to indigenous biodiversity and ecosystems, but management can be compromised by poor efficacy of control methods, harmful non‐target effects or secondary invasions by other non‐native plant species. A 5‐year field trial compared two stakeholder‐selected control methods for heather, a Eur...

Larvae of Heliconius erato cyrbia, a biocontrol agent for invasive Passiflora rubra in the Cook Islands, were discovered feeding on Passiflora edulis seedlings in Rarotonga in April 2018. This represents only the fifth known example worldwide where non-target attack has occurred on a plant species that had been included in host-range tests and deem...

Biocontrol of invasive alien weeds has produced great benefits, but concerns over undesirable impacts on non-target plants and/or indirect interactions between biocontrol agents and other biota impede the implementation of biocontrol in some countries. Although great strides have been made, continuing uncertainties predicting the realized host rang...

The sap-sucking lace bug Gargaphia decoris Drake (Hemiptera: Tingidae) is a biological control agent released in New Zealand to control the invasive small tree or shrub Solanum mauritianum Scopoli (Solanaceae). The aim of this study was to investigate the effect of temperature, photoperiod and humidity on selected G. decoris life history traits. Th...

The broom leaf beetle (Gonioctena olivacea) and the Honshu white admiral butterfly (Limenitis glorifica) have been introduced into New Zealand as biocontrol agents of the weeds Scotch broom (Cytisus scoparius) and Japanese honeysuckle (Lonicera japonica) respectively. However, neither agent has been successful yet. Larval predation of these species...

A ‘risk score’ approach to help determine the potential impact of biological control agents on non-target species, previously proposed for weed biocontrol agents, was examined in an ex post study for insect biocontrol agents. ‘Risk scores’ (% parasitism for non-target aphid species/% parasitism for target aphid species) were calculated for 19 aphid...

Gorse, Ulex europaeus, is an invasive weed that has serious agricultural, economic and ecological impacts. Although various biological control agents have been released in New Zealand, these have showed no noticeable impact on gorse populations. One such agent, Sericothrips staphylinus, was introduced to New Zealand in 1990 and although laboratory...

1. Whether the release of non‐native insect species benefits or harms ecosystem services has been the subject of debate. In New Zealand, the release of new non‐native dung beetle species was intended to enhance ecosystem services but concerns were raised over possible negative effects. 2. Field cage trials used three newly released dung beetle spec...

A persistent problem in weed biocontrol is how to reliably predict whether a plant that supports development in laboratory host-specificity testing will be utilized in field conditions, and this is undoubtedly preventing releases of safe and effective agents. Moreover, the potential for unanticipated undesirable indirect effects of weed biocontrol...

Spathodea campanulata Beauv (Bignoniaceae) has become a highly damaging environmental and agricultural weed in the Pacific Islands. It has been targeted for biological control due to the costly and inefficient nature of physical and chemical control methods. Determining the origin of weed populations has been increasingly recognised as an important...

Showcasing innovative experimental techniques using biocontrol beetles and translocating missing keystone species for restoring biodiversity in threatened ecosystems.

We investigated host-plant utilisation by the candidate biocontrol agent Paradibolia coerulea (Coleoptera: Chrysomelidae) on the target plant Spathodea campanulata Beauv. (Bignoniaceae) and a closely related non-target plant, Kigelia africana (Lam.) Benth. (Bignoniaceae). Paired-choice and sequential no-choice experiments were performed and coupled...

We investigated the influence of biological control agent rearing success on weed biocontrol programs in New Zealand. Difficulties have been experienced in rearing approximately one third of all arthropod species imported into New Zealand containment as candidate weed biocontrol agents, and 16% of species could not be reared at all. Rearing success...

Introduced plants may initially experience enemy release, but some of those interactions may be reinstated through biological control. These cases provide opportunities to explore the dynamics of broken and remade consumer–resource interactions. The European shrub broom ( Cytisus scoparius ) was introduced to New Zealand without a specialist seed p...

Biosecurity organisations need to assess the risk to their country's indigenous flora from invertebrate herbivores that may invade and establish. Some of the more than 600 known adventive herbivores in New Zealand attack indigenous plants. From an extensive review of the literature the numbers and proportion of each major taxonomic group of adventi...

biocontrol agents. Their larvae cause potentially complementary damage to leaves, shoot-tips and mature stems, respectively. Several pathogens, including a rust, were rejected before we selected the Kordyana species. Host range testing of all four agents showed sufficient host-specificity for consideration for release in NZ. Neolema ogloblini and L...

ABSTRACT: New Zealand has a serious problem with unwanted exotic weeds. Invasive plants threaten all ecosystems and have undesirable impacts on primary production and biodiversity values, costing the country billions of dollars each year. Biocontrol is a key tool for reducing the impacts of serious, widespread exotic weeds. We review the nearly 90-...

The boneseed leafroller moth Tortrix s.l. sp. ‘chyrsanthemoides’ (BSLR), originating from Western Cape Province, South African was introduced into New Zealand for the biological control (biocontrol) of a South African shrub boneseed Chrysanthemoides monilifera ssp. monilifera but has established only patchily. We investigated factors hypothesized t...

Biological control (biocontrol) can provide permanent cost‐effective control of plant pests, but has variable success. The ability to predict the success of weed biocontrol should improve target prioritisation and the cost‐benefit ratio of weed biocontrol. We compiled a data base of the quantitative impacts of weed biocontrol programmes against 80...

Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator...

The gorse pod moth Cydia succedana was released in New Zealand as a biological control agent against gorse Ulex europaeus L. in 1992 and is now widely established. Post-release evaluations of the host range of C. succedana were undertaken using both laboratory assays and field collections on native and exotic plants related to gorse. Field surveys...

The gall mite Aceria genistae, a biological control agent of Scotch broom Cytisus scoparius, was first released in New Zealand in 2007. The dispersal ability of A. genistae was investigated to determine whether slow dispersal might limit its ability to control Scotch broom in forestry plantations, where a rapid impact of biocontrol is required. Tra...

Exotic plant invasions are a key threat to New Zealand biodiversity. Alligator weed (Alternanthera philoxeroides; Amaranthaceae) is an invasive, herbaceous weed native to South America. Little is known about its dynamics in natural ecosystems in its introduced range, despite known agricultural impacts. We quantified alligator weed infestation at La...

Terrestrial Alternanthera philoxeroides is difficult to control with current tools. Shading as a control tool depends on the relative shade tolerances of the target weed and co-occurring species. This study examined A. philoxeroides’ shade tolerance with inter-specific competition from pasture species. In glasshouse conditions, shade and competitio...

• The risk posed to New Zealand native flora by the recently-established pest of Australian origin Uraba lugens Walker (Lepidoptera: Nolidae) (gum leaf skeletonizer) was assessed. Weed biological control host range testing methods were applied to identify those New Zealand plant species potentially at risk. Native plants tested were primarily in th...

1. Classical weed biological control programmes aim to rapidly establish biocontrol agent populations throughout the range of a weed. Release strategies, however, may often be suboptimal because the natural dispersal ability of a new agent is rarely known, potentially resulting in unnecessarily intensive release programmes for fast-dispersing agent...

Some potentially invasive herbivores/pathogens in their home range may attack plants originating from another geographic area. Methods are required to assess the risk these herbivores/pathogens pose to these plants in their indigenous ecosystems. The processes and criteria used by weed biological control researchers to assess the impact of potentia...

Invasive Alternanthera philoxeroides (alligator weed), when controlled by biocontrol agent Agasicles hygrophila, is known to differ from native vegetation in its decomposition dynamics. This study investigated whether this difference would have indirect effects for fungal-feeding Coleoptera. The study tested the hypothesis that fungivores would be...

1. Natural enemies may reduce the effectiveness of weed biocontrol agents and can also cause environmental damage, for example to a shared native insect host through apparent competition. Indeed, successful biocontrol may rely on enemy-free space and avoidance of apparent competition in the area where the biocontrol agent is introduced. 2. We surve...

1. A seed-feeding biocontrol agent Bruchidius villosus was released in New Zealand (NZ) to control the invasive European shrub, broom Cytisus scoparius, in 1988 but it was subsequently considered unable to destroy sufficient seed to suppress broom populations. We hypothesized that an invasive mite Varroa destructor, which has caused honeybee declin...

Invasive weeds have been shown to alter ecosystem processes such as decomposition and nutrient cycling. However, little is known about the effects of introduced biocontrol agents on these processes. This study examined the effects of alligator weed (Alternanthera philoxeroides) and its biocontrol agent, the alligator weed flea beetle (Agasicles hyg...

Lantana camara is an environmental weed in the northern North Island of New Zealand. It is an increasingly observed problem in forest margins, coastal scrublands, dunes, plantations and island habitats, and its rapid, uncontrolled growth can create dense impenetrable thickets, suppressing vegetation and bush regeneration. Biological control options...

Introduction: Mimosa pigra L., a prickly, perennial, woody shrub native to tropical America from Mexico to Argentina, is listed in the Global Invasive Species Database as one of the One Hundred of the World's Worst Invasive Alien Species. We refer to M. pigra in the strict sense, which excludes M. asperata, a close relative which some authors have...

Female Glossina morsitans morsitans Westwood were video-recorded in a wind-tunnel as they entered, in cross-wind flight, a broad plume of CO2 (a component of host odour). At a wind speed that corresponds with peak catches in the field (c. 0.6 ms-1) odour produced both significant upwind turning responses (in-flight anemotaxis) and kinetic responses...

Tsetse flies (mainly Glossina pallidipes Aust.) were captured by various means at sources of artificial host odour in Zimbabwe and Kenya. Their rates of arrival and flight directions were compared with simultaneous data on the wind's speed and direction, on time-scales ranging from 1 s to 30 min. It was predicted that because increasing wind speed...

The arrival of individually marked Glossina pallidipes Austen at a host odour source after their video-timed release from 30–75 m downwind was measured in the field in Zimbabwe. In the absence of odour, the proportion recaptured was <2% (= - random expectation); when synthetic ox odour was released, the probability of recapture at the source increa...

a b s t r a c t Contrary to predictions based on host-range testing, the gorse pod moth (GPM) infests pods of several exotic Genisteae and Loteae species, as well as the target weed gorse Ulex europaeus, throughout New Zealand. The original host-range tests were conducted on moths collected in southern England; however, the offspring of Portuguese...

Female Glossina morsitans morsitans Westwood were video-recorded in a wind-tunnel as they entered, in crosswind flight, a broad plume of either octenol or acetone (two components of ox odour). Both odours produced upwind turning responses (in-flight anemotaxis) to a range of concentrations, with thresholds at around 10-8mg1-l for octenol and 10-6mg...

The agromyzid leaf-mining fly Phytomyza vitalbae, which was introduced into New Zealand as a biological control agent of the invasive deciduous European vine Clematis vitalba L. (old man’s beard; Ranunculaceae) in 1996, was recorded attacking native non-target Clematis forsteri and Clematis foetida in New Zealand, with C. foetida being most commonl...

Some weed biological control agents are released despite predictions that they might damage nontarget host plants in the field. Based on prerelease laboratory tests it was predicted that Neurostrota gunniella, an agent released in Australia against Mimosa pigra, may occasionally use Neptunia spp. as hosts. However, due to high larval mortality on t...

Biological control of weeds has a history spanning over a century; projects began on lantana in Hawaii (1902), and on cactus in Australia (1912). Many projects have been initiated in Australia and New Zealand, while the Pacific Islands have depended on the transfer of agents from elsewhere. There are 26, 12, and four weeds currently biological cont...

Ninety isolates of root nodule bacteria from an invasive Mimosa pigra population in Australia were characterized by PCR assays and by sequencing of ribosomal genes. All isolates belonged to the same bacterial genus (Burkholderia) that predominates on M. pigra in its native geographic range in tropical America. However, the Australian Burkholderia s...

We estimated the potential benefits and costs of introducing three candidate biological control agents against the invasive weed Scotch broom Cytisus scoparius into New Zealand. Farming, forestry, the Department of Conservation, district and regional councils should benefit from a successful biological control programme against broom. However, cost...

The impact of biological control on the woody weed, Mimosa pigra was investigated by comparing litterfall in 2001–2003 with a previous study performed at the same site, in 1984–1986, before biological control agents were released, and correlating litterfall to individual agent damage. Total litterfall was similar in both studies. However, leaf litt...

Insecticide and fungicide exclusion experiments were performed to determine the impact of two biological control agents, an agromyzid leaf-mining fly Phytomyza vitalbae Kaltenbach and a coelomycete fungal pathogen Phoma clematidina (Thüm.) Boerema, on the growth and percentage cover of Clematis vitalba L. (Ranunculaceae) plants. Both insecticide an...

Evaluation of the success of biological control agents is essential to improve the efficiency and safety of future programmes. This study assessed the impact of Carmenta mimosa , a stem‐mining moth, introduced into northern Australia as a biological control agent of mimosa Mimosa pigra . Litter fall, seed banks, vegetation cover, density and age st...

Malacorhinus irregularis Jacoby (Coleoptera: Chrysomelidae: Galerucinae: Galerucini), from Mexico is identified as a potential biological control agent for Mimosa pigra L. (Mimosaceae), a serious weed of northern Australia and Asia. The adults feed on leaves of the host, and the larvae develop on seedlings, roots, and perhaps other plant parts. The...

Summary Methods for floodplain revegetation using native species were investigated, following clearance of the invasive shrub Mimosa pigra L. (Mimosaceae) in the Northern Territory of Australia. Prolific revegetation occurred naturally and several species were identified that have potential for revegetation at sites where natural regeneration is po...

The safety record of weed biocontrol was questioned recently when examples of damage to nontarget plants were reported overseas Until now systematic investigations of nontarget feeding have not been performed in New Zealand Results of surveys looking for evidence of nontarget damage caused by 20 biological control agents released against weeds in N...

In Australia, biological control is a promising long‐term management strategy for the woody weed mimosa Mimosa pigra but does not yet provide adequate control. Other management techniques, including herbicides and fire, can be ineffective and their impact on biological control agents is unknown. We investigated the potential of integrating control...

Where biocontrol programmes for invasive plants are in place, only one‐third are fully successful. Integrated weed management (IWM) emphasizes the use of several complementary control measures. We used models of increasing complexity to determine which parameters affect site occupancy of an invasive shrub, Mimosa pigra , in tropical Australia. Two...

To be successful, integrated weed management (IWM) requires sufficient knowledge of the ecology of the weed and the invaded system to allow prediction of the outcome of control efforts. We studied the age and size structure of both native and exotic populations of Scotch broom Cytisus scoparius to test predictions regarding why it is invasive in ex...

Weeds are serious threats to Australia's primary production and biodiversity conservation. For example, a recent Australia Bureau of Statistics survey found that 47% of farmers across Australia have a significant weed problem. A literature review revealed that legumes represent a significant proportion of the national weed problem and most serious...

The ecology of the woody shrub Cytisus scoparius was studied for 4 years in its native range in southern France to investigate how it can become an invasive weed. The proportion of the seed bank that germinated each year was highest in disturbed plots and was correlated with the March rainfall. The seed bank declined at a rate of c. 50% per year wh...

Herbivory by Neurostrota gunniella stunts mimosa (Mimosa pigra) plants, which should diminish seedling survival during wet-season floods, reduce competition with regenerating grasses and, therefore, reduce the need for repeated herbicide applications to control mimosa regenerating from the seed bank following clearance of dense stands. Few or no mi...

Summary • The effective management of invasive plants requires an understanding of their invasiveness in contrasting environments. The effects of disturbance on recruitment of broom Cytisus scoparius, a European shrub invading parts of Australasia, was assessed in a 7-year experiment carried out in two countries, respectively, in its native and exo...

Mimosa, Mimosa pigra L., is renowned for producing an abundance of seeds, many of which remain in the population as a persistent seed bank. Integrated control programs have been effective in reducing the above-ground cover of mimosa but little is known about its effect on the soil seed-bank. The viability of mimosa soil seed banks following integra...

Biological control is seen as the most promising long-term control technique for mimosa. However, other control techniques are currently required. 2. Fire and a range of chemical and mechanical control techniques have been used against mimosa, but are rarely effective when used in isolation. We therefore investigated the impact of combinations of t...

The impact of a stem-boring moth Neurostrota gunniella and a fungal plant pathogen Phloeospora mimosae-pigrae on Mimosa pigra seedlings was investigated in a shade house. N. gunniella and P. mimosae-pigrae , either alone or in combination, reduced seedling growth by approximately 29-38% which, in field conditions, should be associated with reduced...

This book contains 11 chapters by 35 contributors, which are noticed elsewhere. The papers were presented at an international symposium held in Montpellier, France, on 17-20 October 1999.

This study quantifies the invertebrate fauna found on broom, Cytisus scoparius, L. (Link), in two countries where it grows as a native plant (France and England) and two countries where it grows as an alien plant (New Zealand and Australia). The data are used to test three hypotheses concerning the predicted differences in invertebrate community st...

The European woody leguminous shrub Scotch broom (Cytisus scoparius (L.) Link; Genisteae, Fabaceae) is a serious weed in several countries including Australia, New Zealand, Canada and the USA. A rust fungus was found on Scotch broom in France in 1995, where it was infecting stems and leaves, causing severe dieback of branches. Depending on the taxo...

The tropical American shrub, Mimosa pigra L. (Mimosaceae) is now widespread throughout the world's tropical wetlands. In Australia, it forms impenetrable thickets over more than 800 km2 of the Northern Territory (NT), greatly reducing biodiversity. It competes with pastures, hinders mustering and access to water. Biological control is a promising c...

Cytisus scoparius (Scotch broom) is an aggressive invader of agricultural, forestry, and conservation lands in many parts of its exotic range. Biological control programmes for Scotch broom with insects began in the USA in the 1950s, in New Zealand in 1981, and in Australia in 1990. Two insect species (Exapion fuscirostre and Leucoptera spartifolie...