Corporate report

ACRE annual report 2020

Published 2 March 2021

Foreword by the Chair, Professor Jim Dunwell

This is the twenty-seventh annual report of the Advisory Committee on Releases to the Environment (ACRE). The report highlights the work of the Committee during the year.

Find out more information about ACRE's work on GOV.UK.

ACRE is sponsored by the Department for Environment, Food & Rural Affairs (Defra) and is an advisory non-departmental public body.

ACRE provides statutory advice to the UK Government and the devolved administrations of Scotland, Wales and Northern Ireland. On the potential risks to human health and the environment from the release and marketing of genetically modified organisms (GMOs).

ACRE also advises on the release of certain species that have not been genetically modified (GM) that are proposed for use as biological control agents and are not native to Great Britain.

During 2020 ACRE issued advice on five GM products for commercial import and/or processing:

• assessed one application for a GM trial for research purposes
• advised on three application to release non-native species as a bio-control agent
• considered two EU applications for marketing GM medicinal products (three human medicines and two veterinary medicines)

Beth Purse decided to step down as a member of ACRE. Her expertise, particularly with respect to non-native bio-control agents was gratefully appreciated.

Ian Crute, CBE has retired from the Committee. He has 40 years of expertise in plant pathology and genetics (with a particular interest in the sustainability of agricultural systems).

It was my pleasure to welcome Andy Peters and Alan Raybould to the Committee. I hope that they find their time serving on the Committee rewarding.

I would like to express my thanks to current members of ACRE for their continuing support and dedication.

I would also like to thank the assessors, and the ACRE secretariat for supporting the work of the Committee.

Openness and transparency are important principles of the Committee and ACRE continues to do this by publishing its advice and its meetings are open to the public.

Main activities

Meetings

ACRE met virtually in May and its sub-groups met to discuss specific areas of business.

You can find the minutes of the committee's meetings and advice they provided published on ACRE's pages of GOV.UK .

Casework

Applications for GM releases for research purposes

ACRE has assessed one application for research purposes under Directive 2001/18 and the Genetically Modified Organisms (Deliberate Release) Regulations 2002.

Find out more about the application, ACRE's advice, and the outcome of the application on GOV.UK

Food and feed marketing applications

ACRE considered five opinions issued by the European Food Safety Authority (EFSA) on notifications for placing GM maize, soybean and oil seed rape on the market.

The applications were for import or processing and not cultivation. In each of the cases considered, ACRE was satisfied that the genetically modified products posed no greater risk to human health or the environment than their conventional counterparts.

Nearly all the marketing applications that ACRE assessed were processed through Regulation (EC) No. 1829/2003.

Click on the links below to access the details of the products:

• ACRE advice: applications to market GM soybeans and maize
• ACRE advice: applications to market GM cotton and rice
• ACRE advice: applications to market GM oilseed rape

Medicinal marketing applications

ACRE was asked to advise the government on the environmental risk assessment aspects of marketing applications for two medicinal products containing or consisting of a GMO.

These applications were submitted to the European Medicines Agency under Regulation (EC) No. 726/2004.

Under this Regulation information on the assessment of the application is only made available as part of The European Public Assessment Report following the European Commission's decision at the end of the assessment process.

Other advisory duties

The Animal and Plant Health Agency (APHA) an agency of Defra received 3 applications to release non-native species within Great Britain as bio-control agents.

As the species are not native to Great Britain a license as a non-native biological control agent under the Wildlife and Countryside Act 1981 is required to be able to release them into the environment. APHA sought ACRE's advice on these applications to release the:

• parasitoid wasp Torymus sinensis into England as an agent to control the chestnut gall wasp Dryocosmus kuriphilus
• invertebrate weevil, Listronotus elongatus in England for the control of the aquatic weed Hydrocotyle ranunculoides
• nematode Phasmarditiis californica (Rhabditida: Rhabdioidea) in England for the control of slugs.

ACRE’s advice on applications is included in the annexes of this report.

Governance and transparency

ACRE is a statutory advisory committee appointed under section 124 of the Environmental Protection Act 1990. The Committee provides advice to government regarding the release and marketing of GMO’s.

ACRE works within the legislative framework set out in Part 6 of the Environmental Protection Act and the GMO Deliberate Release Regulations 2002 which together implemented the EC Directive 2001/18/EC.

The work and membership of ACRE

• framework agreement
• terms of reference
• members' biographies and register of their interests

Annex A: ACRE advice on an application to release the non-native parasitoid wasp Torymus sinensis into England

Introduction

Alien, or non-native species are recognised as the largest threat to biological diversity after that of habitat destruction. The oriental chestnut gall wasp D. kuriphilus is the most damaging insect pest of chestnut species (Castanea spp.) worldwide.

This invasive alien species is currently established in Southern England and it is a significant pest of sweet chestnut where it forms galls. The sweet chestnut tree itself is an introduced species in the UK with significant amenity value.

In forming galls the wasp D. kuriphilus can cause significant reduction in both this, and in its value for sale.

In studies in 2019 the gall wasp was shown to significantly impact the growth of coppiced sweet chestnut trees by reducing the area of their foliage resulting in them having smaller and fewer leaves.

Although D. kuriphilus was an accidental introduction to the UK as recently as 2014 as it spreads across South-East England the economic impact due to this is likely to become of greater in the future.

The only effective management of this pest is by way of a classical biological control agent (BCA), Torymus sinensis (a parasitoid wasp) which is not native to Great Britain.

Under the Wildlife and Countryside Act 1981, it is an offence to release an animal into the wild which is not ordinarily resident in and is not a regular visitor to Great Britain.

However, these animals can be released into the wild if they have a non-native biological control licence, which has been approved by Defra.

There are currently three classical non-native biological control agents that have been approved for release into the UK:

• Rhizophagus grandis (a beetle used to control the bark beetle)
• Dendroctonus micans, the psyllid
• Aphalara itadori (used to control the invasive Japanese knotweed)
• Fallopia japonica
• Aculus crassulae (a mite used to control Australian swamp stonecrop)

Crassula helmsii. T. sinensis would represent the fourth classical biological control agent release into England if it is approved.

In Fera Science Ltd application they had completed a risk assessment for T. sinensis, identifying and addressing the risks associated with the intentional release of the wasp into England.

ACRE considered this application from the point of view of three principal areas:

Efficacy and benefits

The release of T. sinensis has occurred in Croatia, France, Hungary, Japan, Portugal, Slovenia, Spain, Turkey and the USA, without ill-effects.

It is an extremely successful biocontrol agent for its target (the cynipid D. kuriphilus). The wasp has proven highly successful in Northern Italy, where D. kuriphilus infestation rates have been reduced to almost zero, nine years after release.

Equally in Southern Italy the BCA affected a drastic reduction in D. kuriphilus numbers within only five years.

The principal benefits gained from the suppression of D. kuriphilus populations are twofold. Firstly, by lowering the risk of galls reducing foliage area and affecting branch architecture, which is detrimental to the quality of coppice grown for fencing.

Secondly, a reduction in the numbers of galls, thereby improving the appearance of sweet chestnut trees; the latter being introduced to the UK due to it having significant amenity value.

ACRE considered that this application therefore highlights one problem for which there appears to be a cost effective solution.

That is when placing the chestnut gall former D. kuriphilus in the context of a number of expanding threats to UK broad leaved trees, which include ash dieback, chronic oak dieback, horse chestnut leaf miner, Dutch elm disease among others.

ACRE also noted there is in this case an additional protection against spread of the regulated disease sweet chestnut blight and its causal agent the plant pathogen (Cryphonectria parasitica).

This is because the aim of the biocontrol agent is to reduce the incidence of galls and the subsequent holes left by emerging adult D. kuriphilus, and it is these holes that can act as entry points for C. parasitica.

The application included a Cost Benefit analysis indicating that the release programme provides value for money as the benefits of a recovery in the yield and non-market benefits of sweet chestnut trees outweighs the programme's outlays by a ratio of 0.59.

Uncertainties

Host specificity

ACRE noted that, contrary to initial reports, T. sinensis is not completely specialised on its target host.

Host range studies were not fully completed prior to release in Italy because the target pest was so damaging to the timber industry.

Post release studies in that country showed it parasitising other gall forming wasps on oak, but the incidence of this was found to be very low (only 0.01% of adults reared from 14,512 non-target galls).

Subsequent to the release in Italy, more complete host range studies were conducted and FERA's risk assessment takes these into account.

There is only one threatened gall forming wasp in the UK and it is not thought that it would be in any danger from release of T. sinensis.

ACRE further noted that said attack rates on non-targets were very low (\<1% parasitism)in the context of less than 50% parasitoid attack of these gall formers in natural communities. The latter levels of host parasitism have been recorded in more than one European study.

ACRE further considered that this rate of non-host parasitism may be a high estimate as the data collection took place when the target host population was crashing and there may have been an excess of parasitoids to targets.

The application reports that host range appears to be expanding; that the reasons for this expansion are not fully understood, and that potentially this impact could be exacerbated in the UK as D. kuriphilus are less abundant when compared to Italy.

To act as a counter to this, the application makes reference to studies, including one in France, wherein T. sinensis underwent an extended diapause (a form of embryonic dormancy) covering two years rather than merely overwintering in response to the drastic reduction in D. kuriphilus numbers.

ACRE noted that FERA considered this an adaptive mechanism in their risk assessment, where they described it as a 'bet-hedging' strategy.

Suggesting the expansion of host range to make up for a collapse in the D. kuriphilus population is not so important as that of waiting for its main host's numbers to recover.

This appears to lead to cyclic waves in the respective population of pest and parasite. The latter following the former and so controlling it.

Hybridisation

ACRE noted that T. sinensis has been observed mating with T. beneficus (a native parasitoid) post release in Japan, and this mating has resulted in the displacement of the late spring strain of T. beneficus.

The early spring strain of T. beneficus has also been displaced, but this was likely due to competition from T. sinensis rather than hybridisation.

Displacement of native species in the UK is unlikely to happen because there are no native species that rely on D. kuriphilus as their main host.

Experiments in Italy have confirmed elevated levels of mating specificity and no evidence for potential hybridisation with parasitoid wasps of native European origin; therefore, interbreeding with native Torymus species is unlikely.

There have been no other records of hybridisation by T. sinensis in Europe, and no evidence that it will do so in the UK, despite experimental attempts at such crosses being made.

ACRE also considered what the ill effects of any such hybridisation might be and was satisfied that these were unlikely to be severe.

Other considerations

ACRE agreed with the FERA risk assessment in that it could see no other identifiable threats to the UK environment from the release of this species, and that no negative environmental impacts have been noted in prior releases.

Effect of UK climatic conditions on the establishment potential of T. sinensis

ACRE noted that the risk assessment used Climatic modelling to indicate that the wasp should be able to establish in South-East England where D. kuriphilus occurs.

Factors that may interfere with establishment include:

• the relatively low density of sweet chestnut trees
• a low density of D. kuriphilus galls
• the mortality of T. sinensis in galls overwintering on the ground
• the effect of climate on synchronisation between the gall formation
• T. sinensis adult emergence, and effects of hyper-parasitism

ACRE agreed with the application that any expansion of host range by T. sinensis is likely to be negatively affected by the different climatic conditions. This is reinforced by studies conducted in France.

However, FERA have set out in their application plans for extensive post-release monitoring in order to assess both this and the other areas of uncertainty above, so as to better inform subsequent biocontrol agent releases.

Conclusion and recommendation

ACRE, in reviewing this application, highlighted the uncertainty as to how widely T. sinensis could spread in the UK. Potential alternative native species targets, and the effect of climate differences with respect to Italy where these aspects have been well-studied.

However, ACRE noted that FERA's risk assessment had addressed these points and taken them into account in its proposed post-release monitoring to inform more fully subsequent biological control agent releases.

ACRE was content with the information presented in the risk assessment and its advice was to recommend that a licence to release should be granted.

Annex B: ACRE advice on an application to release the non-native invertebrate weevil Listronotus elongatus into England

Summary

ACRE was asked to consider the risk of releasing the non-native invertebrate weevil Listronotus elongatus into England, and to balance this against any potential benefits of controlling the invasive aquatic weed floating pennywort, Hydrocotyle ranunculoides.

Based on this assessment, the following paper sets out the main points considered by ACRE in arriving at a recommendation on whether a licence to release L. elongatus should be given.

ACRE found the application comprehensive and that the risk assessment aspect was a particularly impressive body of work.

This included both the host testing of non-target plant species based on taxonomic relatedness and importance – mainly economic, and extensive climate modelling to predict likely areas of colonisation and persistence by L. elongatus.

ACRE was happy with the evidence presented in this risk assessment and, the knowledge of how successfully L. elongatus is able to control H. ranunculoides in the Americas.

To recommend that a license for the release of L. elongatus should be given.

Introduction

The invasive aquatic weed Hydrocotyle ranunculoides (floating pennywort) was first recorded as naturalised in Essex in 1990.

Having been introduced from the Americas as an ornamental through the aquatic trade. It is likely that it escaped or deliberately discarded into the wild from garden ponds.

Floating pennywort occurs in shallow pools, drawdown zones of lakes and in shaded, seasonally inundated wetlands.

In England it has been recorded from still or slow flowing freshwater in lakes, ponds, streams, ditches, and canals and favours these slower moving watercourses with slack edges and backwaters.

Because of its preference for these ecological locations H. ranunculoides is responsible for a range of economic, environmental and social problems in England.

The weed clogs up slow-moving water bodies hampering access for recreational activities which would have a knock on effect on tourism.

It also negatively impacts on water flow, sedimentation, and light and oxygen levels and endangers communities of native macrophyte species and the fauna that rely upon them.

Flooding is a further issue that is exacerbated by the weed.

The management of H. ranunculoides is currently labour intensive, expensive and generally ineffective. Fast growth and vegetative reproduction allow for rapid recolonization after attempts at mechanical control and because of this, floating pennywort has gone on to spread widely to colonise thousands of waterbodies.

The classical biological control agent, the South American weevil Listronotus elongatus, is potentially a very potent weapon in the fight against floating pennywort as has been seen in Argentina and Paraguay.

Releasing this species in England may help to reduce the spread of the weed and could be integrated with other management options to prevent the re-incursion of the weed back into previously treated areas.

CABI have completed a risk assessment for L. elongatus, with the intention of releasing the weevil in England to control H. ranunculoides.

This would be the fourth classical invertebrate non-native biological control agent (IBCA) approved for release in England. The risk assessment includes consideration of the economic cost of this invasive weed.

ACRE reviewed this risk assessment and made comments in the following three principal areas A to C

Efficacy and Benefits

ACRE considered that significant biocontrol benefits arising from the effects of L. elongatus on H. ranunculoides were presented in the application.

The mode of attack by adults of the weevil was well-described: they fed on the surface of the leaves and at 20°C were shown in laboratory studies to consume around 20% of the leaf's surface over 5 days.

Larvae also damage the plant, by mining through the petiole and stolon as well as tunnelling by as much as 10 to 15 cm over their lifespan.

Heavy infestations of the weevil can kill the leaves and cause the petioles and stolon's to wilt and rot.

In Argentina, the weevil is considered responsible for the periodic collapse of wetland patches of H. ranunculoide's.

The scope of the application was also highlighted by ACRE in that section 3 on risk assessment included some studies and their interpretation that were more concerned with the likely efficacy of the IBCA (that is the opportunities and economic benefits its release would create) rather than whether it would pose any ecological risks.

It should be noted this assessment was made by the Centre for Agriculture and Bioscience International (CABI) in the light of the serious economic impacts that floating pennywort has had, and continues to have on recreational use of inland waterways across England.

ACRE did not criticise this approach but merely asked whether section 3, and the application in general, was designed to assess only risk or was it a risk and opportunity assessment?

ACRE considered that some clarification of this may help future applicants avoid potentially unnecessary work – or at least unnecessary reporting of potential efficacy in a risk assessment.

Host specificity and off-target effects

The application concentrated on host range testing including both no-choice as well as assessing damage to rare UK plants.

ACRE commented on how thorough this assessment was in that it included a consideration of the potential for full life cycling of the insect on this and other potential host plants.

The application also involved extensive host range testing of close relative, confamilial species and more distantly related plants.

ACRE also noted that the involvement of botanists on the steering committee to help draw up a target list for a taxonomically complex plant group was a particularly thorough approach.

The no-choice host range testing identified two plant species on which it is possible for this species to complete development from egg to adult.

Such feeding produced sickly adults with low survival rates that died before being able to mate, a finding that suggested they are not likely to constitute host plants for this biocontrol agent.

ACRE acknowledged that, although laboratory host ranges occasionally lack optimal replication, these tests confirmed the Argentinian field studies, which indicated that this beetle is highly specialised on its target host.

Furthermore, since larvae feed and pupae develop inside petioles, the argument that survival would be further compromised in field conditions was a reasoned one in ACRE's view.

ACRE also observed that one of the few potential alternative hosts, Hydrocotyle vulgaris, was itself under threat from the target weed H. ranunculoide's.

A potential negative impact that the risk assessment looked at was possible damage to Apium repens, a rare aquatic plant that appears to be restricted to a single site in Oxfordshire.

However, L. elongatus cannot complete its full life cycle on this species and so damage would primarily occur from insects moving off their specialised host.

ACRE noted that on balance the probability of significant damage to this species was low, as the weevil exhibited very low preference for this species even in laboratory conditions.

In choice tests A. repens suffered 0.13% leaf damage compared to 25% in the control, suggesting that only very stressed or very hungry insects will oviposit on this plant in the field.

ACRE also commented that A. repens is extremely rare and under threat of extinction from factors unrelated to herbivory.

In general, ACRE commented that the applicant had drawn on expert advice in testing for non-target effects of biological control, and consequently the testing strategy, execution of the tests and interpretation of the results seemed entirely suitable.

ACRE therefore agreed with the applicant's conclusions that any adverse effects of herbivory of non-target effects were likely to be localised and vastly outweighed by the ecological benefits if the IBCA were to work as intended.

Environmental impact and climate modelling to gauge persistence

The thorough approach adopted by CABI to host range and efficacy assessments were similarly mirrored in the detailed climate modelling presented in the application.

ACRE found this to be an extremely thorough assessment and noted this use of climate modelling to further gauge probability of current establishment gave further valuable data to inform the risk assessment.

The climate modelling suggested L. elongatus may have 1 to 2 generations a year in the south of England but brought into question how effective any release will be in the North of England.

ACRE did not consider that this was a reason to advise against release. In particular, given that even if some areas are unsuitable for establishment of L. elongatus, the weevil may still have some control in "sink" populations due to spill-over immigration from more fecund areas.

ACRE observed that the extensive climate modelling was carried out to fully model both the risks to and opportunities for establishment of the ICBA in order to gauge the outer limits of geographical persistence likely within England.

However, ACRE felt it might be pertinent to ask whether some of the distribution modelling under various climate scenarios was perhaps too detailed if CABI's purpose were solely for risk assessment.

Conclusion and recommendation

ACRE commented that the risk assessment was an impressive body of work. Problem formulation concentrated on producing a list of priority non-target plant species for testing based on taxonomic relatedness and importance – mainly economic.

This strategy seemed sensible given the number of species in the same family as the target weed that could be exposed to releases of the IBCA.

However, this host range assessment was also balanced by extensive climate modelling to predict likely areas of colonisation and persistence by L. elongatus and therefore how this could overlay the geographical extent of H. ranunculoide's within England.

ACRE noted that Invasive Aquatic weeds such as H. ranunculoides can cause impacts that are environmentally damaging in a range of ways and are particularly difficult to control.

Other weevil species have been very successful as introduced biological control agents across the globe and considering the ability to control H. ranunculoides shown by L. elongatus in parts of South America (where they have naturally co-exist) there is a high likelihood that L. elongatus will provide effective control across a large part of England.

Therefore, ACRE recommends that DEFRA grant a license for the release of L. elongatus.

Annex C: ACRE advice on an application to release the non-native nematode Phasmarhabditis californica (Rhabditida: Rhabdioidea) into England

Summary

ACRE was asked to consider the risk of releasing P. californica into England, and to balance this against any potential benefits of reducing common land slugs. Based on this, the following paper sets out the main points considered by ACRE in arriving at a recommendation on whether a licence to release P. californica should be given.

On balance, ACRE was content, and generally supported the consensus view from the other organisations consulted on the proposed release.

The view was taken that no specific reason can be given to refuse the application, but ACRE expressed some doubts and suggested if it were possible to plan a phased release. So that some further data could be obtained on persistence and host range.

Even though there were some concerns about the written and evidential quality of the application ACRE's advice was to recommend that a licence to release should be granted.

Introduction

Slugs are among the most important pests of agriculture and horticulture, including high value crops as well as fruits, vegetables and ornamentals in both, professional and domestic markets.

Besides others, Deroceras reticulatum, Arion vulgaris, Arion distinctus and Lehmannia valentiana represent slugs accounting for direct losses in crop or plant yield and quality (fecal and mucus contaminations). In addition, slugs represent potential vectors of plant and mammalian pathogens.

BASF Ltd have submitted a licence application for the commercial use of the entomopathogenic nematode Phasmarhabditis californica (Rhabditida: Rhabdioidea) for the control of slugs. This species was described from specimens isolated from invasive slugs in California in 2016.

Under the Wildlife and Countryside Act 1981 it is an offence to release an animal into the wild which is not ordinarily resident in, and is not a regular visitor to Great Britain.

However, these animals can be released into the wild if they have a non-native biological control licence, which is approved by Defra.

Until recently there were three non-native nematodes licensed as biological control agents in the UK – Heterorhabditis bacteriophora, Heterorhabditis downsei and Steinernema carpocapsae.

These three species are pathogens of arthropods rather than molluscs.

The requirement for a licence to release S. carpocapsae was removed in 2018 following the publication of new evidence to show that it is a native or naturalised species.

Nematode non-native biological control agents have been licensed in England as augmentative biological control agents rather than classical biological control agents because they are not thought to persist in the environment after release and have a low capacity for spread.

In compiling this application, BASF Ltd have completed a risk assessment for P. californica, identifying and addressing the risks associated with the intentional release of the nematode into England.

ACRE considered this application from the point of view of the following 6 main areas:

Non-native status of P. californica

The critical question for ACRE was whether P.californicais native to England and the UK. The isolate for release originated from Wales and there are also reports of this species in Ireland.

The risk assessment also referenced molecular evidence indicating that this nematode is in England (albeit giving the reference incorrectly it was in Rae, 2017 Sci Rep not Rae, 2019 as quoted in the application).

The issue of whether this nematode is 'native' in terms of there being evidence of it being present for many generations was raised by the Welsh authorities.

ACRE acknowledged that this historical evidence was lacking. However, ACRE felt that this must be put in perspective of the historic under-sampling of this group (nematodes in general, but also nematodes that are pathogenic to molluscs).

This was primarily because the study of nematodes involved the use of very labour-intensive methods and hence few research groups targeted them. The advent of less intensive methods first published in 2016 almost immediately enabled scientists to re-examine and expand the geographical range of P. hermaphrodita.

On balance, ACRE expressed agreement with expert nematological opinion backed up by accumulating recent reports, that these Phasmarhabitisswere global cosmopolitan species and that historical under-sampling of this group skewed earlier data on distribution.

Principle benefits of P. california introduction

The target species that BASF quote (Arion distinctus, Arion hortensis, Deroceras invadens, Deroceras reticulatum, Arion lusitanicus, Arion rufus, Arion vulgaris, Deroceras laeve, Lehmannia valentiana and Milax gagates).

ACRE recognised were universally considered to be pest species and disliked by farmers, fresh produce producers and private gardeners.

The other principal benefit gained from this biocontrol of slugs was that the biocontrol agent-based product, being much less hazardous than metaldehyde (currently approved for this purpose) to birds and mammals, so there were likely to be strong benefits from its introduction.

ACRE were also aware that other existing chemical control measures such as slug pellets also had significant negative environmental impacts and any alternative means of control was to be actively encouraged.

ACRE noted that the application included reference to an analysis, made in-light of the upcoming ban on metaldehyde, indicating that a lack of slug control products could cost UK crop production £100 million a year.

This reinforces the significant benefit that this biocontrol agent could bring to both growers and the cost of UK food production.

Host specificity of P.californica

ACRE were concerned that section 3.7.2 on conclusions to be drawn on host range of the biocontrol agent had not been completed. Furthermore, the risk assessment presented very limited data on host range, and that while relatives of this species (P. hermaphrodita) are not efficient at infecting snails there are little data on P. californica.

ACRE members were aware of a recent paper Tandingan De Ley, 2020, Mortality of the invasive white garden snail Theba pisana exposed to three US isolates of Phasmarhabditis spp (P. hermaphrodita, P. californica, and P. papillosa) which was not in the reference list.

This study revealed that P. californica can infect and kill an invasive snail in the US and in particular that P. californica was isolated from a Glass snail.

ACRE were also keen to explore if studies of the host range of P. californica were conducted under conditions that would lead to death or sublethal adverse effects of the intended target.

That is, as bacteria and nematodes are required for efficacy (section 2.4.3), the necessary bacteria were present in the non-target studies.

Ideally, one might have a concurrent bioassay with a target species to confirm that the nematode treatment used in the non-target testing was bioactive.

The necessary data may be present in the studies report but were not in the application.

ACRE thought that BASF would be keen to have more data on host range in snails both from a perspective of pest management as well as from predicting impacts on non-targets and in light of comments from other reviewers of the application were minded to ask for more data on at least some of the common native UK snails.

Monitoring early use of the product would be an option if significant uncertainty about the host range remains after section 3.7.2 is completed.

ACRE appreciated that any concerns about host range needed to be viewed in the light of the previous comments that this nematode is most likely native or already established in the UK.

Bacterial associations with P. californica and possible human health concerns

Members of ACRE were minded to consider the bacteria associated with the nematode and had some reservations about the detail within the application.

The referenced material within the application pointed to the likelihood of a standard set of bacteria being associated with the nematode in commercial production.

ACRE were concerned with any differences in the bacteria associated with P. hermaphrodita and P. californica, and whether they could pose different threats to human or animal health if for example they were inhaled or inoculated.

On this basis, ACRE had reservations as to whether the applicant could justify the statement that it was reasonable to extrapolate pathogenicity to mammals on the basis of P. hermaphrodita studies.

ACRE were aware of published papers revealing that P. hermaphrodita could associate with a range of different bacteria and this did not affect its virulence on slugs.

However, when used commercially, P. hermaphrodita are raised on a pure culture of a particular bacterium and it is this species that predominates in the commercial preparation.

The applicant refers to the same co-formulants being used in the preparation for P. californica and therefore presumably the same bacterial species (Moraxella osloensis) would be used to cultivate P. californica.

ACRE felt that if this understanding was correct, then it would be reasonable to assume there would not be any additional health effects due to the bacterium alone in this case and concluded that more information to clarify this would be useful.

Other environmental considerations

ACRE agreed with the risk assessment in that it could see no other identifiable threats to the UK environment from the release of this species, and that negative environmental impacts from releases of augmented biocontrol agents were very unlikely.

This is because augmentation is based on the fact that artificial application of the nematode requires an immediate food source and ideal environmental conditions to sustain populations before populations rapidly decline.

Effect of UK climatic conditions on the establishment potential of P. californica

ACRE noted that as mentioned in the risk assessment, the nematode in this application was isolated from Wales and has also been found in England and Ireland.

Therefore, it is likely that the nematode is already native and widespread to the UK. This led to ACRE concluding that it was difficult to argue that the species would not establish as it was likely suited to the UK climate and environmental conditions.

Conclusions and recommendation

ACRE, in reviewing this application, highlighted the uncertainty as to the non-native status of P. californica in the UK, and the lack of detailed host range studies on UK native species.

The benefits of its introduction as an environmentally beneficial slug control product were self-apparent and ACRE could see no reason to refuse this application for a licence to release to be granted.

ACRE found the application to be poorly written and in at least two areas there was insufficient information provided for the conclusions drawn therein.

This included impacts on human health and host range and specificity. ACRE recommended that the applicant review these sections, along with considering further studies on possible unintended targets.

An approach supported by comments from the consultation group.