Oak Processionary Moth Operational Report 2018

Introduction

Oak Processionary Moth (OPM) operational activity was conducted in line with the

2018 operational and communications plan that was agreed with the OPM Project

Board in early 2018.

With the aim to:

To limit the rate of spread and reduce the impact of OPM on tree health and human/animal health;

To robustly deal with new findings that threaten the development of a new outbreak centre;

To maintain the range of control activities (survey, control comms etc.);

To provide an operational ‘test and development’ function to build knowledge

and evidence;

To continue building a partnership approach to OPM management, and land

owner/manager expertise in managing OPM.

Defra funded operational outputs

Statutory Plant Health Notices (SPHNs):

745 Statutory Plant Health Notices issued between February and August 2018, to all known infested areas outside the ‘core’ area-where control and

surveillance work is undertaken by landowners / managers (Figure 1);

Approx. 40 of the 745 SPHNs, the landowner funded the spraying activity

themselves

Control work:

495 sites were sprayed, (26,201 trees sprayed in most places twice) in the control zone with Bacillus thuringiensis;

Nest removal was not under the Defra funded programme this year but we

issued 129 SPHNs for nest removal to be done at the landowner’s expense;

Surveillance:

302 pheromone traps were deployed in London and SE England, these were along 16 transects with 18 traps in each transect approximately 1km apart;

7559 trees found with nests (this will be an underestimate and includes sites in the core);

67,665 trees visually surveyed during 2018;

Over 50 surveyors submitted records using the OPM reporting app;

268 tree alerts from the Tree Health Diagnostic and Advisory Service at Forest Research reporting OPM.

Operational results

Notable observations on OPM distribution & density from 2018:

1. M4 Junctions 9/10 – This finding was discovered by a contractor working on the

Smart Motorway Upgrade. This highlights how important stakeholder reports are to the OPM programme;

2. Transect findings (*) East Hertfordshire, Mole Valley, Dartford, Reigate and Banstead and Chalfont St. Peter- All of the OPM discoveries were a part of the

wider evidence gathering work for male captures in pheromone traps;

3. Woking- this was a public sighting, further investigatory work found additional

nests in the area;

4. Belhus Chase (Thurrock) – following on from the finding in 2017 OPM has

become more established in this area;

5. Tandridge- This individual nest was discovered by a contractor undertaking tree

safety inspections within a school. A further survey of the area found no further OPM nests.

6. Royal Wootton Bassett On 24th May 2018 the Forestry Commission (FC) received a report from a planting contractor of caterpillars in a newly planted

oak tree in Royal Wootton Bassett (Figure 5). OPM was confirmed and the site

was informed that all the newly planted Oak trees would need to be destroyed. The site was fully surveyed prior to the destruction and no further OPM was

found. Subsequent survey both visually and using pheromone traps through the summer revealed no OPM, pheromone traps were put up – no OPM moths

were detected.

Figure 2 – Map showing results of the visual survey where no infestation of OPM was found in 2018

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Figure 3 – showing OPM outer extent since 2006 in the London / SE England area

Figure 4– Map showing outer known extent of OPM since 2006, in a UK context

Note: the dots indicating interceptions in Leeds, Sheffield, Pangbourne & Royal Wootton Bassett where OPM populations did not establish.

Figure 5 – showing OPM interception at Royal Wootton Bassett (orange dot)

Efficacy of the spraying programme in 2018

58% of sites that had been sprayed spring 2018 were subsequently found to be

infested in summer 2018. This compared with 32% in 2017. 2018 was a particularly challenging year for OPM control spraying with the caterpillar emerging the latest we

observed and then pupating three weeks earlier than was expected. This meant that some of the spraying was not carried out at the preferred target

Tree and human/animal health impacts identified during 2018

Tree Health Impacts - working with Defra we have begun the first of a five year study

looking at the effects of OPM defoliation on oak trees, this will help us to narrow the

knowledge gap and provide evidence for how OPM may affect the health of our oaks. There are still no reports of OPM being the primary cause of oak tree death.

Human health impacts –There were a mixture of public and occupational based reports, nearly all associated with direct or close contact with OPM infestation. In all

cases the FC sent advisory information on OPM to people affected by OPM.

Animal health Impacts –There were a small number of reported cases of animals

being affected by OPM.

Biological & climatic observations in 2018

OPM egg plaques were monitored by the Royal Parks for emergence of the

caterpillars. Emergence was first observed on 16th April this year; emergence was noted on the 9th-10th April in the Netherlands in 2018;

The warm, dry weather during May and June was conducive for rapid caterpillar

development and moths were observed in pheromone traps from the 19th July. This meant that the control spraying programme had to be completed very

quickly as there was very little time to do control before the adults began to disperse. Note that this is about 3 weeks earlier than normal.

Pheromone trapping results

Summary of pheromone trap in numbers:

437 (302 Defra funded) traps deployed, with most being visited on 4 occasions

with the lure changed twice;

384 traps with at least one moth;

The highest number in a trap was 309 (the highest number in 2015 was 65, in 2016 it was 184 and in 2017 it was 386);

6981 moths caught in total.

Figure 6 – Map showing distribution of traps and no. of OPM male moths captured in each trap.

Note: the dotted line indicates the outer extent of visually observed infestation in 2017.

In 2017 the pheromone programme involved the use of 528 traps (including 92

erected by partner organisations). The 2018 pheromone trapping programme

consisted of 437 traps (135 by third party stakeholders).

The main objectives of the 2018 trapping programme are as follows:

i) To understand the relationship between the numbers of male moths caught in a

trap and the likelihood of an OPM breeding population.

ii) To try to determine the outer extent of OPM breeding populations. As Figure 6

indicates, male moths continue to be found over a wide area, significantly further than where nests have been found by the visual surveys.

There appear to be higher populations of OPM towards the centre of London with a general decrease in male OPM captures as you move out of London.

Operational Budget Spend FY 2018-19The overall spending on OPM was similar to previous

years - £1.247m. The majority of expenditure was surveying for OPM, both visually and with

pheromone traps. Another major operation was spraying to control OPM. There was also work

of evidence gathering such as the effects OPM has on defoliating trees.

OPM communications

3 press releases connected with key points in the OPM season (emergence, nest

formation);

Twitter messages at key points during the OPM season (in line with press releases);

OPM website kept updated and progress is ongoing developing resources for new OPM material to be hosted on Forest Research website for 2019;

7 OPM newsletters issued; Over 10,000 leaflets distributed;

OPM banners reused by e.g. Local Authorities; 30 events/talks helping to raise OPM awareness.

Research

The OPM research programme in 2018 focused on 4 key areas: Surveillance – Defra / FC continue to work very closely with Cambridge University to

design our approach to OPM surveillance

OPM Control – includes work to analyse the type and rate of parasitism and

predation of OPM in order to understand the potential scale of biological control of

OPM.

Impacts – including a review of literature addressing the biodiversity impacts of the

three most commonly used chemical control agents, work to produce a Lepidoptera

‘risk map’ for south east England, and work to understand host tree defoliation by

OPM in order to understand the impact of the pest on oak tree health.

Building partnerships – Defra / FC have been working closely with a team of social

scientists at Forest Research to improve our understanding of stakeholders and their

attitudes to OPM.

Stakeholder liaison

Training and awareness events from April to December 30 events were run to a wide range of audiences;

OPM Advisory Group – the former group was dissolved and terms of reference for a new Strategic Advisory Group have been developed with members. The

first meeting was be held in Dec 2017 and the next in Jan 2019;

October stakeholder workshop – summary of results, research findings and latest thinking on future policy presented. Significant amount of intelligence

collected on the work and findings of stakeholders, including core zone activity and human/occupational health reports;

Partnership working – there has been good collaboration with a range of major

landowners and Local Authorities for example Bexley, West Sussex County Council, LTOA, TfL, Network Rail, Crown Estates, Hertfordshire, Surrey Heath,

National Trust, Woodland Trust, Environment Agency, City of London (Epping Forest) Guildford and Waverley Borough Councils - enhanced pheromone

trapping programme and contributed to data collection.

Andrew Hoppit, OPM Manager January 2019