Corporate report

Advisory Committee on Releases to the Environment (ACRE) annual report 2024

Updated 2 May 2025

Foreword by the Chair, Professor Jim Dunwell

This is the 31st annual report of the Advisory Committee on Releases to the Environment (ACRE).

ACRE is an independent advisory non-departmental public body comprising scientific experts and sponsored by the Department for Environment, Food and Rural Affairs (Defra). ACRE’s main function is to provide statutory advice to governments across the UK 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 non-GM species that are not native to Great Britain and proposed for use as biological control agents. 

The report provides an outline of the work of the Committee during the year.

The Precision-Bred Organisms Sub-Group continued to meet throughout the year as necessary. A Precision-Bred Organisms (Animal) Sub-group was set up to assist Defra’s Animal Health and Welfare team to explain the principles and approach to risk assessment as the team develops a regulatory process of assessments under the Genetic Technology (Precision Breeding) Act. The Committee has also provided advice to Welsh Government to support it as it considers its own policy matters. ACRE’s advice is included as Annex A to this report. The full Committee met once in 2024, addressing the full range of ACRE’s statutory duties and responsibilities. All meetings were well attended by members, observers and policy officials. Further ACRE business throughout the year was conducted by correspondence.

Transparency and openness are important for the Committee. I am keen that ACRE continues to uphold these principles by publishing the minutes of its meetings and its advice to government. The February 2024 meeting was open to the public.

I would like to thank the current members of ACRE for their continuing support, and dedication, along with the assessors, and the ACRE Secretariat for their efforts in supporting the work of the Committee.

Main activities

Meetings

ACRE addressed a wide range of business during the year.  This included:

• a research application to undertake a field trial of GM Camelina sativa
• an application to undertake field trials of GM wheat (application ongoing, advice to be published in 2025)
• variations to 2 ongoing GM field trials of wheat
• plans to terminate a GM potato trial
• a clinical trial involving a vaccine (including a variation to it)
• 7 GM food and feed applications
• an application to market a GM veterinary vaccine

The Committee received updates from Defra’s Genetic Improvement Network. It also received regular updates from the Food Standards Agency’s Advisory Committee on Novel Foods and Processes (ACNFP) as they progressed their work on the regulation of precision-bred food and feed products.

The Precision-Bred Organisms Sub-Group met formally and continued some business via correspondence. The group has been advising government as they develop technical guidance to support the regulatory process. The Precision-Bred Organisms (Animals) Sub-Group also met during the year. ACRE’s work with these groups remained within its boundaries of human health and the environment.

ACRE conducted other specific areas of business via correspondence. In line with ACRE’s commitment to openness and transparency, all minutes of meetings and the advice that the Committee provided to government are published on GOV.UK.   

Casework

Applications for GM releases for research purposes

ACRE has advised on several GM research trials during the year. These include:

• GM potato trial 172901 – read ACRE’s advice on application 172901
• GM wheat trial 225501 – read ACRE’s advice on application 225501
• GM camelina sativa trial 230801 – read ACRE’s advice on application 230801
• GM vaccine trial 245601 – read ACRE’s advice on application 245601
• GM wheat trial 245701

Qualifying GM higher plants for research purposes

Defra received 7 notifications of qualifying GM higher plants to be used for research purposes.

Applications for GM releases for marketing purposes

The Committee assessed one veterinary marketing application and is assessing an application to market a GM medical vaccine.

ACRE assessed the environmental risk assessments for 7 applications to market food or feed products for consumption, importation or processing that are made from or contain GMOs. The Committee has generic advice to encompass its GM food and feed related advice in England:

• 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

Proposed biological control agent

ACRE was asked to advise on an application and risk assessment to release predatory thrips into glasshouses in England. ACRE’s advice is included in Annex B to this report.

Governance and transparency

ACRE is a statutory advisory committee appointed under the Environmental Protection Act 1990, Part VI, section 124.  ACRE works within the legislative framework set out in the Genetically Modified Organisms (Deliberate Release) Regulations 2002, which together implement Directive 2001/18/EC (retained EU law) and advise on the regulatory status of qualifying higher plants under the Genetically Modified Organisms (Deliberate Release) (Amendment) (England) Regulations 2022.

Read about the work and membership of ACRE:

• governance agreement
• terms of reference
• biographies and register of interests of ACRE members

Annex A: Welsh Government request for ACRE advice on gene editing

Issue

Welsh Government asked ACRE for scientific advice on precision breeding in light of the UK’s Genetic Technology (Precision Breeding) Act 2023 (The UK Precision Breeding Act). This advice will aid policy formulation in Wales.

Background and Welsh Government position

In the UK, responsibility for regulating genetically modified (GM) plants and animals is devolved. Welsh ministers must approve any use of GMOs in food and feed, and releases of GMOs into the environment. Decisions on the regulation of GMOs follow the precautionary principle. The precautionary principle says policy makers should act with caution where there is a potential risk to the environment or a lack of scientific certainty around the level of risk.

Although precision-bred organisms (PBOs) will be subject to less regulation in England, in Wales they will continue to be regulated as GMOs. The Genetically Modified Organisms (Deliberate Release) (Wales) Regulations 2002 (as amended) and the Retained EU GM Food and Feed Regulations (1829/2003/EC) will continue to apply to PBOs in Wales.

However, by virtue of the UK Internal Market Act (UKIMA), precision-bred products will be legally marketable into Wales. The interaction of UKIMA with the UK Precision Breeding Act is complex. But if precision-bred products undergo a significant regulated production step in Wales, the resultant product will legally be classed as GM. For example, Welsh farmers could buy precision-bred seed, but cultivating it would need regulating under GM regulations. Likewise any food produced or processed from the crop would need to be regulated as a GM food or feed. It will also not be lawful for developers to develop any PBOs in Wales unless they are regulated as GMOs.

Aims

Given this, Welsh Government is considering its position on precision breeding, in line with the precautionary principle. It asked for scientific advice on:

• the risks the technology poses
• the level of scientific certainty around those risks
• how those risks might be mitigated

This advice will be used to help Welsh ministers better understand any risks this technology poses and what mitigation should be put in place. It will also feed into general policy development in this area.

Questions

Welsh Government wanted to understand the risks associated with this technology, particularly on safety and to the environment.

It asked ACRE to provide an assessment of the main safety risks associated with gene editing technology, to explain whether these risks are greater or smaller than safety concerns with traditional breeding methods, and how this assessment has been made.

It requested that ACRE cover several topics, outlined as follows. However, it also invited ACRE to provide any other information or advice it thought would be useful to Welsh ministers as they consider policy in this area. 

Off-target edits

Through the gene editing process, edits may occur in unintended parts of the genome. These off-target edits can be ‘harmless’ or could cause unexpected negative effects. Welsh Government wanted to understand how common such off-target edits are during the gene editing process and how likely they are to cause an unintended or negative effect to the organism. Further, are these off-target edits more or less likely to occur through this technique than other breeding processes, and are they more or less likely to have a negative effect? 

Unintended off-target edits sometimes occur during gene editing. While sometimes raised as a potential safety issue, these occurrences are not necessarily harmful and can usually be removed by segregation in subsequent breeding steps. A useful review of the regulatory approaches to this issue has been published (Lema and others, 2021).

Of the main editing methods developed to date, CRISPR-Cas9 offers the highest level of target specificity by typically using a 20-nucleotide guide RNA that is complementary to desired target sites. Although facilitating a very high level of specificity, the DNA sequences being targeted may not be unique in the genome of interest and the potential to introduce off-target effects has been highlighted as a potential concern in some studies on plants and animals, even when using CRISPR-Cas9 (Graham and others, 2020).

Some sequences will be highly repeated within genomes, and as a result selecting appropriate targets as well as an appropriate editing technology will both play important roles in ensuring high specificity (Burkhard and others, 2019). Many recent genome editing studies on animals have reported no incidences of off-target insertions when using CRISPR-Cas9 (Henning and others, 2020; Zhou and others, 2019). Where off-target insertions have been identified the number of incidences has tended to be low and they have occurred at sites that could be predicted using available software (Dong and others, 2019). This could be monitored using targeted screening if required (McFarlane and others, 2019; Wessels and others, 2024). This may be particularly relevant during the deployment of novel technologies such those using relaxed PAM sites (Ren and others, 2021).

It is also important to note that research is on-going into new methods and approaches that could further reduce the risk of off-target insertions and unintended insertions. Approaches that have already shown promise include:

• modifying the delivery system (Graham and others, 2020)
• use of single stranded DNA repair template (Ren and others, 2021)
• prime editing approaches (Anzalone and others, 2019)

In conclusion, ACRE’s view is that there is no scientific reason to suppose that off-target sequence alterations in gene-edited organisms will result in greater safety concerns than those which result from other forms of mutagenesis. Indeed off-target effects introduced by gene editing methods are significantly rarer than those produced during the course of conventional methods of plant breeding (Graham and others, 2020). Similarly, there is good evidence to suggest that gene editing-induced mutagenesis in animals is no greater than the background rate of mutation (Ayabe and others, 2019).

ACRE was also asked to provide its view on what validation steps, or other checks and balances, should be put in place to minimise the risk of off-target edits. For example, should whole genome-sequencing data be required in any application to authorise a PBO, to ensure no off-target edits are present in the final genome?

From a regulatory perspective, most countries who have reviewed their assessment procedures for GMOs have acknowledged the importance of providing a degree of assurance either that:

• no exogenous DNA has been inserted
• no unacceptable risks are presented by the new trait

As stated previously, off-target edits are not necessarily harmful. If they occur it would be challenging if not impossible to attribute them to the use of gene editing using current molecular techniques. Therefore, ACRE does not consider that whole genome sequencing data will necessarily be helpful for the assessment and confirmation of PBO status. As referred to previously, software programmes may be used by developers to assist monitoring for off-target edits using targeted screening if required.

Introduction of DNA from other species

In some mammalian cell culture systems, during the gene editing process it is possible that, while the cell repairs its DNA, it inadvertently uses DNA from the surrounding medium. ACRE was asked to:

• consider what risk is associated if this happens and the potential consequences
• provide advice on how this risk can be mitigated

While the Welsh Government understands it is common practice to screen for off-target edits, is it equally common to screen for other types of unintended DNA introduction? 

Where functional DNA is unintentionally introduced from a non-sexually compatible species this would mean that the resulting organism would not be a PBO. This is significant because the unintended introduction of (usually non-functional DNA) from other species has been observed during the production of some gene edited animals. This may occur after DNA strands are cut by the gene editing ‘machinery’ at a predetermined site and the repair is driven by the cell’s own mechanisms. If left to chance, the repair process is random, with nucleotides from within the cell or the surrounding media occasionally being incorporated in the repair. Since bovine or caprine serum is frequently used in culture media for mammalian embryos, this has led to reports of bovine or caprine sequences being incorporated into target sites (Ono and others, 2019).

This effect can be mitigated to some extent by using a repair template, but some unintended insertions although uncommon have been reported in the past. This may suggest that some level of genome screening at target sites prior to establishing pregnancies may be useful if a high level of insertion accuracy is required. Avoiding the need to use bovine and caprine serum in culture media would also be expected to reduce the level of risk for target site ‘contamination’. Research is on-going in that area.

In 2020, a paper reported that the genomes of two polled (hornless) Holstein bulls produced in 2015 were found to include unintended DNA (Carlson and others, 2016). While one allele in the genome of the bulls included the target insertion as expected (leading to the hornless characteristic being present), the second allele was found to also include a fragment of DNA from the carrier plasmid (Norris and others, 2020). As part of the original genome editing project, the bulls’ genome had been screened only for off-target insertions of the introduced ‘polled’ allele, and none had been found. However, the authors had not screened for DNA from the carrier plasmid. If it had been included in the initial screening it would likely have allowed its detection and appropriate action to be taken.

Although retained inadvertently, it is important to note that the presence of the plasmid DNA had no observable effects on the bulls’ natural development (or expression of the polled characteristic). There were also no observable effects on the progeny of one of the bulls, which were produced and screened in a later study (Young and others, 2019). Further, it is important to note that the use of a carrier plasmid was a requirement for the specific editing technology used in the study. A carrier plasmid would not be required when using CRISPR-Cas9, which is the technology now most commonly used.

Linked genes

Genes next to each other in the genome are very difficult to separate through traditional breeding. Gene editing makes this separation much easier (Lyzenga, Pozniak and Kagale, 2021). Welsh Government wanted to understand whether there are any inherent risks with this, and whether any so called natural genetic safety features risk being overridden by doing this. If there is a risk, what assurance process should lawmakers put in place to mitigate it?

Linkage drag is a common phenomenon faced by breeders when attempting to introgress desirable traits into elite cultivars. This is caused when meiotic recombination frequencies are too low to physically separate loci containing desired alleles from undesirable ones with ease. Gene editing technology offers a potential solution to this issue (where the relevant sequence information is available). ACRE does not consider that such an approach would be inherently more risky than traditional breeding methods that may be employed to achieve the same outcome (for example, mutagenesis).

Gene drives

The gene drives that have been developed appear to use transgenes and any organism with such a drive would therefore not be classed as a PBO. However, Welsh Government wanted ACRE’s view on whether it is possible an organism with a gene drive could be classed as a PBO in the future, as the science develops? Risks associated with synthetic gene drives exist, such as the drive spilling over into unintended populations and species, and concerns surrounding risk assessments for the removal of entire species being insufficiently robust.  ACRE was asked to provide its view on the risks associated with gene drives, both in terms of safety and risks to the wider environment. Welsh Government understands gene drive development is at a relatively early-stage and it is proving difficult to ensure desired traits are maintained in populations outside of highly controlled laboratory settings.

Engineered gene drive organisms rely on the introduction of transgenic DNA to drive alleles through a population. Under the current regulatory system for PBOs, it is not foreseen that such an organism could be classed as a PBO.

ACRE has previously commented on some key issues associated with the use of gene drives. For example, the robustness and stability of gene drives over time and the potential for gene drive elements and associated traits to spread beyond the target population. These issues are considered in GMO risk assessment more generally (there is a requirement to consider genotypic and phenotypic stability and to characterise vertical and horizontal gene flow). 

The principal challenge is to establish how to address questions about the risk of harm and to establish what is acceptable and not acceptable. Data produced to address risk-based questions will need to be generated throughout the process of development. GMO regulations in the UK foresee a step-by-step approach whereby environmental exposure is increased if uncertainties about risk of harm are satisfactorily addressed.  

A key message from ACRE’s 2013 report is the importance of establishing what constitutes unacceptable harm from the outset. This can be informed by scientific evidence and knowledge, but it also has a social dimension (for example, the acceptability of introducing genetic systems that are designed to persist in populations). There is a tendency for some assessors and regulators to attempt to address this lack of consensus on what constitutes harm by collecting more data or focusing on hazards, which is potentially an open-ended exercise. The World Health Organization (WHO) guidelines emphasise the need for such endpoints (that is, agreed parameters of acceptable and unacceptable harm) at every stage in the development of a GM mosquito. Establishing regulatory endpoints for each case will be important for the regulatory system to work effectively for the deployment of GMOs.

While the communication of new technologies and their risks to a wider audience is important, an article in Nature Biotechnology highlights how a lack of context may misrepresent the actual risks posed by the technology.

Does gene editing technology pose risks to the environment?

Welsh Government acknowledged that many risks associated with the technology relate more to its use rather than the technology itself. However, it was keen to understand whether the technology poses any risks to the environment at the scientific level, or which could be mitigated at that level.

For example, the technology could produce a plant with different nutritional properties, but this could affect any animals (particularly wild animals) that rely on this plant as a food source. Or plants could be developed that out-compete other varieties, negatively impacting the survival of a native species or biodiversity in general.

Further, any natural breeding between the gene-edited plant and a non-edited ‘wild’ plant could negatively affect the status of wild plant. Welsh Government was interested in ACRE’s views on these types of environmental risks and what checks and balances could be put in place to mitigate them.

There is a concern that the technology could produce a plant with different nutritional properties, which might affect wild animals that rely on this plant as a food source. There is no scientific basis for an increased likelihood of adverse effects on wild herbivore populations that might result from feeding on such a crop with altered nutritional properties that are introduced by precision breeding, as compared to the same alteration generated using traditional breeding methods.

There is also a concern that plants could be developed that out-compete other varieties, negatively impacting the survival of a native species or biodiversity in general. Humans have tended to select against the ability to persist in the environment so that farmed crops are now generally unable to do so. Furthermore, gene editing relies on the creation of the same types of genetic variation that are selected for in traditional breeding.

ACRE’s view therefore is that there is no scientific reason that the application of gene-editing technology for crop improvement would lead to a greater likelihood of persistence of these organisms in the wider environment. This characteristic is rarely observed for traditionally bred organisms.

For some aquaculture species ACRE noted that the difference between wild and farmed species is less. This is because their domestication is a more recent event compared to other livestock species. However, the development of genetic sterility through genome editing is showing promise and could provide an added safeguard against accidental crossing (Güralp and others, 2020). Also some aquaculture (such as salmon) uses triploid types, which are intrinsically sterile (or almost so).

EU proposal on new genomic techniques

Welsh Government noted the draft EU regulation on new genomic techniques is different to the approach taken in the UK Precision Breeding Act. The main difference is the decision by the EU not to reduce regulation of precision-bred animals. However, the EU has also taken a slightly different approach to the UK Government in defining new genomic technique plants. For example, Annex I of the proposal sets out category 1 new genomic technique plants must include no more than 20 genetic modifications. The annex then defines the ‘genetic modifications’ criteria. ACRE is asked to opine on whether the environmental risks associated with a category 1 new genomic technique are broadly equivalent to those associated with PBOs in England and to set out any notable differences.

Both category 1 new genomic techniques and PBOs are intended to contain only those changes to their genetic material that could also occur through traditional breeding methods. As such, ACRE considers that the environmental risks associated with both category 1 new genomic techniques and PBOs are the same as each other and also the same as those associated with traditionally bred crops. ACRE considers that it is the trait resulting from a breeding methodology (either traditional or modern biotechnology) that determines environmental risk rather than the method used.

References

Anzalone and others. Nature (2019) volume 576, pp 149–157.

Ayabe and others. Journal of Reproduction and Development (2019) 65 (1): pp 1–5.

Burkard and others. PLOS Pathogens (2019) 23 (DOI:10.1371/journal.ppat.1006206).

Carlson and others. Nature Biotechnology (2016) 34, pp 479–481.

Graham and others. ‘Plant Genome Editing and the Relevance of Off-Target Changes’. Plant Physiol (2020) 183:1453-1471.

Güralp and others. Scientific Reports (2020) 10:18042.

Henning and others. Scientific Reports (2020) 10:22309.

Lema and others. ‘Regulatory Assessment of Off-Target Changes and Spurious DNA Insertions in Gene-Edited Organisms for Agri-Food Use’. Journal of Regulatory Science 9 (2021) pp 1–15.

Lyzenga WJ, Pozniak JC and Kagale S. ‘Advanced domestication: harnessing the precision of gene editing in crop breeding’. Plant Biotechnology Journal (2021), 19, pp 660–670.

McFarlane and others. Frontiers in sustainable food systems (2019) volume 3, article 106.

Norris and others. Nature Biotechnology (2020) volume 38, pp 163–164.

Ono and others. Communications Biology (2019) volume 2, article 57.

Ren Q and others. ‘PAM-less plant genome editing using a CRISPR–SpRY toolbox’. Nature Plants (2021) volume 7, pp 25–33.

Wessels HH and others. ‘Prediction of on-target and off-target activity of CRISPR–Cas13d guide RNAs using deep learning’. Nature Biotechnology (2024) volume 42, pp 628–637.

Young and others. Nature Biotechnology (2019) 38, pp 225–232.

Zhou and others. Frontiers in Genetics (2019) volume 10, article 215.

Annex B: advice of ACRE on an application to release the non-native predatory thrips, Franklinothrips vespiformis, into glasshouses in England for the control of thrips

9 May 2024

Summary

Biobest have applied for a licence to release a non-native invertebrate biological control agent (IBCA), the predatory thrips, Franklinothrips vespiformis, into glasshouses in England. The intention is to control thrip pests, including:

• Chaetanophothrips orchidii
• Echinothrips americanus
• Frankliniella occidentalis
• Heliothrips haemorrhoidalis
• Thrips parvispinus
• T. setosus
• T. tabaci

ACRE was asked to consider the risks of releasing F. vespiformis, and to balance these against any potential benefits of controlling thrip pests. Based on these questions, the following paper sets out the main points considered by ACRE in arriving at a recommendation on whether a licence to release F. vespiformis into glasshouses in England should be given.

ACRE’s considered opinion was that there were 2 main areas of concern with respect to the application.

1. Firstly that the increased winter temperatures seen in parts of the UK required greater clarity with respect to the threat of establishment by F. vespiformis.
2. Secondly that these predators are generalists, being able to feed on other small predators and the application had not considered this in its risk assessment.

Introduction

There are currently 10 non-native augmentative biological control agents that are licensed for release in England. By comparison to classical biological control agents, which are expected to establish in the environment to control a pest in the long term, augmentative biological control agents are not expected to establish in the environment and must be periodically introduced into the crop to control pests.

Biobest has completed an application and risk assessment for the predatory thrips, F. vespiformis, with the intention of obtaining a licence for its release into glasshouses in England for the control of thrips, including:

• Chaetanophothrips orchidii
• Echinothrips americanus
• Frankliniella occidentalis
• Heliothrips haemorrhoidalis
• Thrips parvispinus
• T. setosus
• T. tabaci

A significant part of the risk assessment, particularly in relation to its potential for establishment, relies on conclusions from previous assessments for the use of F. vespiformis in other European countries. The application also draws heavily on a single published review into this predatory thrips to populate both the initiation and biology sections.

Risk assessment

The applicant risk assessed F. vespiformis under the areas of efficacy and benefits, establishment, and host specificity, along with a consideration of any other potential impacts of this release.

Efficacy and benefits

ACRE noted that F. vespiformis has the potential to provide benefits (principally the biological control of thrips), as shown by various studies and trials (Pizzol and others, 2010).

There is also potential for the thrips to reduce pesticide use and its associated negative impacts. Although it was noted by ACRE that, despite the use of this species as an IBCA for many years, there is relatively little positive evidence in commercial crops. This was noted by Hussain and others (2022).

Establishment

A central argument of the applicant’s risk assessment, as stated on page 22 of the application, is that “low temperatures of UK winters would limit survival and reproduction of F. vespiformis larvae and adults, prohibiting successful overwintering outdoors and subsequent establishment of this exotic species.”

ACRE commented that this did not take into account the effect of increased winter temperatures, as seen in recent years, and therefore this part of the risk assessment at least required greater clarity. Although Biobest noted there was a history of safe use, this was predominantly in countries where winters are harsher than significant parts of the UK, such as Sweden, Belgium and the Netherlands.

Furthermore, although being a tropical insect adapted to warmer temperatures, some life stages die quite slowly at temperatures as low as 5°C, while 12°C appears an ideal temperature for cold storage of eggs, enabling them to survive for up to 5 weeks (Larentzaki, Powell and Copland, 2007). ACRE noted that in the Southwest of England for example, there are only 3 to 4 days of frost per annum and long periods of temperatures below 5°C are actually quite rare, with the average minimum for the period covering January to February being approximately 4°C. Read Met Office data for 1991 to 2020 on UK climate averages.

Therefore, it was of concern to ACRE that the applicants had not completed the trophic effects section within the application and had failed to consider that not all areas of the UK might have winters that are harsh enough to prevent survival of F. vespiformis. The collection of data on survivability of newly hatched larvae under mild late winter temperatures, similar to southern UK climatic conditions, would significantly inform the risk assessment.

However, ACRE also noted that these predators do not persist well even in greenhouse environments. The factors behind this lack of persistence in horticulture appear to be unknown, although it is probable that ecological factors other than temperature are involved here.

Furthermore, the product technical sheet points to the product (Vespiformis-System) as being most effective against thrips during spring and summer, but counterintuitively also mentions that it will remain active throughout the year with no real winter rest period (albeit under a temperature range of 18°C to 30°C).

Host specificity

The second problematic area highlighted by ACRE was the recognition that the predatory thrips, F. vespiformis is a generalist and therefore capable of feeding on other small predators (termed intra-guild predation- IGP). This is of concern in a biological control agent (Loomans and Vierbergen, 1999; Loomans and Heijboer, 1999; Araraki and Okajima, 1998).

ACRE advised that this was of greater concern than the lack of overwintering modelling under milder seasonal temperatures, and that it should be noted that this species is much more mobile and generalist than other species that already have a licence for release.

Consequently, ACRE concluded that this thrip was a slightly higher risk IBCA and therefore that its use should be restricted for glasshouse structures and not open polytunnels, which would mirror its current use in Europe (Cox and others, 2006).

Other potential impacts

The section on direct and indirect impacts was left blank by Biobest. However, in other sections of the application they provided information on plant feeding and whether F. vespiformis had caused any adverse impacts to vertebrate animals and humans.

Plant feeding

F. vespiformis feeds on plant exudates and honeydew and is a facultative pollen feeder (Hoddle, 2003). Larvae, for example, can complete their development on a diet of (pine) pollen alone, when supplied on a leaf disk on agar.

Biobest has observed that F. vespiformis can feed on plant parts, but it has not seen plant damage in their trials (field and greenhouse, semi-field and greenhouse, laboratory). ACRE also noted that the thrips have been used for a number of years in several countries as biological control and plant damage has never been reported.

Vertebrate animal and human health effects

Following a comprehensive literature search, using various search terms and multiple data sources, Biobest found no evidence of adverse effects on vertebrate animals and humans by F. vespiformis.

Conclusion

ACRE were asked to consider the risk of releasing F. vespiformis and to balance these against any potential benefits on reducing the impact of thrips on cultivated plants in glasshouses. ACRE’s considered opinion centred around that of raising 2 principal concerns.

ACRE were concerned with the application in the areas of overwintering potential and the generalist nature of this predatory thrips. These 2 areas mean that ACRE advises that a licence for restricted use would be most appropriate, and that this is kept under review, as climatic change may alter the risk of F. vespiformis becoming established.

References

Araraki  N and  Okajima  S. ‘Notes  on  the  biology  and  morphology  of  a  predatory  thrips, Franklinothrips  vespiformis (Crawford) (Thysanoptera: Aeolothripidae): first  record  from Japan’. Entomological Science 1998: volume 1, pages 359-363.

Cox P and others. ‘Potential for the use of biological agents for the control of Thrips palmi (Thysanoptera: Thripidae) outbreaks’. Biocontrol Science and Technology 2006: volume 16, pages 871-891.

Hoddle MS. ‘Predation behaviors of Franklinothrips orizabensis (Thysanoptera: Aeolothripidae) towards Scirtothrips perseae and Heliothrips haemorrhoidalis (Thysanoptera: Thripidae)’. Biolcontrol Control 2003: volume 27, 323-328.

Hussain M and others. (2022) ‘A Review of Franklinothrips vespiformis (Thysanoptera: Aeolothripidae): Life History, Distribution, and Prospects as a Biological Control Agent. Insects’: volume 13, page 108.

Larentzaki E, Powell G and Copland MJW. ‘Effect of temperature on development, overwintering and establishment potential of Franklinothrips vespiformis in the UK’. Entomologia Experimentalis et Applicata 2007a: volume 124, pages 143-151.

Larentzaki E, Powell G and Copland MJW. ‘Effect of cold storage on survival, reproduction and development of adults and eggs of Franklinothrips vespiformis (Crawford)’. Biological Control 2007b: volume 43, pages 265-270.

Loomans AJM and Vierbergen G. ‘Franklinothrips: perspectives for greenhouse pest control’. Bulletin IOBC/WPRS 1999: volume 22(1), pages 157-160.

Loomans AJM and Heijboer A. ‘Franklinothrips vespiformis (Crawford): a polyphagous predator preying on thrips eggs’. Proceedings of the section Experimental and Applied Entomology of the Netherlands Entomological Society (N.E.V.) 1999: volume 10, pages 143-150.

Pizzol J and others. ‘Population dynamics of thrips and development of an integrated pest management program using the predator Franklinothrips vespiformis’, Proceedings of the XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010), Lisbon, Portugal, 22 to 27 August 2010, pages 219-226.

Pizzol J and others. ‘Efficiency of Neoseiulus cucumeris and Franklinothrips vespiformis for controlling thrips in rose greenhouses’, Proceedings of the International Symposium on High Technology for Greenhouse System Management, Greensys 2007, Naples, Italy, 4 to 6 October 2007: volume 801, pages 1493-1498.