This document summarizes the costs and benefits analysis of implementing nursery best practices for biosecurity. Based on data collected from 17 nurseries in the UK, the preliminary results suggest that implementing all 12 best practices is unlikely to be cost-effective from the nurseries' perspective, as the costs of setting up and maintaining the practices would be greater than the benefits of reducing risk of a Phytophthora outbreak. Similarly, implementing the 8 practices that are not currently common practice among the nurseries also appears unlikely to be cost-effective. While some nurseries expressed strong concerns about biosecurity risks, the benefits of reduced risk of other pests and diseases needs further consideration to determine if best practices would be cost-effective.

1. Costs & Benefits of nursery best
practices
Gregory Valatin
20th
November 2018

2. 2
LWEC Phyothreats project CBA
3.2.5 nursery best practice cost-benefit analysis:
• Little response initially to questionnaires
• Opportunity to join visits organised by FERA
on biosecurity & costs (Jan 2018)
• Summer Intern / new FR member of staff
helping with data collection

3. Phytothreats: Nursery Best Practices
12 ‘Best practices’ focused on:
•1) water testing for plant pathogens (including Phytophthora).
•2) water treatment facility if using river/spring/pond water or recycling water.
•3) ‘Clean/cleaned’ water storage in fully enclosed tanks.
•4) Facilities for clean/covered storage of unused growing media.
•5) drains or free-draining gravel beds to minimise effects of flooding & avoid
puddle formation.
• 6) raised benches to keep containers off the ground.
• 7) disinfectant station(s) using recommended disinfectant for re-used pots &
tools.
• 8) ‘quarantine’/holding area for imported plants on a well-drained, contained,
possibly concrete bed located away from main stock (with separate drainage system
so that run-off water can be treated).
• 9) appropriately contained composting or incineration facility for disposal of
organic waste/sick plants.
• 10) boot washing station.
• 11) vehicle washing station.
• 12) Buy only from ‘accredited/trusted’ UK suppliers.
12/18/183

4. 4
Nursery perspective: Costs>Benefits?
Preliminary results (17 nurseries) Min Max Mean N No data
1) Water testing Annual cost (£/yr) 250 20000 5213 4 11
2) Water treatment facility set up (£) 2000+ [α] 30000 1200 3 12
Annual maintenance cost (£/yr) 1000 10000[βiii] 4000 3 12
3) Covered water storage set up (£) 1200 60000 21140 5 10
Annual maintenance cost (£/yr) 50 50 50 2 13
4) Covered storage of growing media set up (£) 4000 5000 4500 1 14
5) Drains/free-draining gravel beds set up (£) 11000 250000 68417 [βi] 6 [µ] 8 [µ]
Annual maintenance cost (£/yr) 0 15000 5508 [βii] 6 9
6) Raised benches set up (£) 7000 1600000 410100 4 [δ] 10 [δ]
Annual maintenance cost (£/yr) 0 20000 10000 2 13
7) Disinfection stations set up (£) 10 30000 6260 6 9
Annual maintenance cost (£/yr) 7.5 40000 6821 6 9
8) Quarantine/holding area set up (£) 1200 50000 21300 4 11
Annual maintenance cost (£/yr) 15
9) Contained composting /incineration facility set up (£) 2000 12500 6833 3 12
Annual maintenance cost (£/yr) 15
10) Boot washing station set up (£) 10 1500 379 7 8
Annual maintenance cost (£/yr) 20 1000 368 4 11
11) Vehicle washing station set up (£) 650 30000 9730 5 10
Annual maintenance cost (£/yr) 15
12) Buy only UK supplies Annual cost (£/yr) insignificant infeasible 3500 [ ]ϕ 1 [Ψ] 12 [Ψ]
Total costs (for those costs estimated) set up (£) 25070 2069000 561059
Annual cost (£/yr) 4328 102550 35459
Benefits * Avoided cost of outbreak 0 60000 [Ω] 20200 [Ω] [βiii] 6 9
[α] response coded as £2k for purposes of computing the mean; [β] response coded as midpoint for purposes of computing the mean: i) £12k-£15k coded as £13.75k;
ii) £10k-£15k coded as £12.5k; ii) £7k-£10k coded as £8.5k; iii) £0-£k coded as £2.5k [ ] ‘insignificant’ & ‘infeasible’ responses excluded in computing mean; [µ]ϕ
excludes one partial response (£2k per tunnel); [δ] excludes one partial response (£90 for 2.5m); [Ψ] excludes two partial responses: +35% and +20% to +30%; [Ω]:
excludes one response: ‘anything from zero to complete right off’
*how many outbreaks a year avoided on average (worst case): one?

5. Baseline for nursery practice?
Baseline selection: Which of the ‘Best practices’ are ‘common practice’?
If benchmark a simple majority of the nurseries (more use measure than not): 4
•1) water testing for plant pathogens (including Phytophthora).
•2) water treatment facility if using river/spring/pond water or recycling water.
•3) ‘Clean/cleaned’ water storage in fully enclosed tanks.
•4) Facilities for clean/covered storage of unused growing media.
•5) drains or free-draining gravel beds to minimise effects of flooding & avoid
puddle formation.
• 6) raised benches to keep containers off the ground.
• 7) disinfectant station(s) using recommended disinfectant for re-used pots & tools.
• 8) ‘quarantine’/holding area for imported plants on a well-drained, contained,
possibly concrete bed located away from main stock (with separate drainage system
so that run-off water can be treated).
• 9) appropriately contained composting or incineration facility for disposal of organic
waste/sick plants.
• 10) boot washing station.
• 11) vehicle washing station.
• 12) Buy only from ‘accredited/trusted’ UK suppliers.
12/18/185

6. 6
common practice baseline: Costs>Benefits?
Preliminary results (17 nurseries): Min Max Mean N No data
1) Water testing: (11/13 don’t currently) Annual cost (£/yr) 250 20000 5213 4 11
2) Water treatment facility (10/13 don’t currently) set up (£) 2000+ [α] 30000 1200 3 12
Annual maintenance cost (£/yr) 1000 10000[βiii] 4000 3 12
3) Covered water storage (9/13 do currently) set up (£) 1200 60000 21140 5 10
Annual maintenance cost (£/yr) 50 50 50 2 13
4) Covered storage of growing media (9/10 don’t currently) set up (£) 4000 5000 4500 1 14
5) Drains/free-draining gravel beds (10/11 do currently) set up (£) 11000 250000 68417 [βi] 6 [µ] 8 [µ]
Annual maintenance cost (£/yr) 0 15000 5508 [βii] 6 9
6) Raised benches (7/13 do currently) set up (£) 7000 1600000 410100 4 [δ] 10 [δ]
Annual maintenance cost (£/yr) 0 20000 10000 2 13
7) Disinfection stations (8/13 don’t currently) set up (£) 10 30000 6260 6 9
Annual maintenance cost (£/yr) 7.5 40000 6821 6 9
8) Quarantine/holding area (11/15 don’t currently) set up (£) 1200 50000 21300 4 11
Annual maintenance cost (£/yr) 15
9) Contained composting /incineration facility (12/13 don’t
currently)
set up (£) 2000 12500 6833 3 12
Annual maintenance cost (£/yr) 15
10) Boot washing station (7/13 do currently) set up (£) 10 1500 379 7 8
Annual maintenance cost (£/yr) 20 1000 368 4 11
11) Vehicle washing station (8/13 don’t currently) set up (£) 650 30000 9730 5 10
Annual maintenance cost (£/yr) 15
12) Buy only UK supplies (7/11 don’t currently) Annual cost (£/yr) insignificant infeasible 3500 [ ]ϕ 1 [Ψ] 12 [Ψ]
Total costs (for measures that a majority of the
nurseries do not implement currently)
set up (£) 9860 157500 60623
Annual cost (£/yr) 4258 66500 19534
Benefits* Avoided cost of outbreak 2000 60000 [Ω] 20200 [Ω] [βiii] 4 11
[α] response coded as £2k for purposes of computing the mean; [β] response coded as midpoint for purposes of computing the mean: i) £12k-£15k coded as £13.75k;
ii) £10k-£15k coded as £12.5k; ii) £7k-£10k coded as £8.5k; ii) £0-£k coded as £2.5k; [ ] ‘insignificant’ & ‘infeasible’ responses excluded in computing mean; [µ]ϕ
excludes one partial response (£2k per tunnel); [δ] excludes one partial response (£90 for 2.5m); [Ψ] excludes two partial responses: +35% and +20% to +30%; [Ω]:
excludes one response: ‘anything from zero to complete right off’
*how many outbreaks a year avoided on average (worst case): one?

7. 7
‘Typical’ (1 ha) nursery?: Costs>Benefits?
Expert Judgement based costs: Min Max Mean
1) Water testing: (11/13 don’t currently) Annual cost (£/yr) n.a. n.a. n.a.
2) Water treatment facility (10/13 don’t currently) set up (£) 1500 10000 6500
Annual maintenance cost (£/yr) 750 750 750
3) Covered water storage (9/13 do currently) set up (£) 2500 7000+ 5000 [α]
Annual maintenance cost (£/yr)
4) Covered storage of growing media (9/10 don’t currently) set up (£)
Annual maintenance cost (£/yr)
n.a. n.a. n.a.
5) Drains/free-draining gravel beds (10/11 do currently) set up (£) per ha 100000 100000 100000
Annual maintenance cost (£/yr)
6) Raised benches (7/13 do currently) set up (£) 3000 6000 4500
Annual maintenance cost (£/yr)
7) Disinfection stations (8/13 don’t currently) set up (£) per above ground tank 2000 2000 2000
Annual maintenance cost (£/yr) 500 500 500
8) Quarantine/holding area (11/15 don’t currently) set up (£) for 1 ha nursery 35000 35000 35000
Annual maintenance cost (£/yr)
9) Contained composting /incineration facility (12/13 don’t
currently)
set up (£) 8000 8000 8000
Annual maintenance cost (£/yr)
10) Boot washing station (7/13 do currently) set up (£) 350 650 500
Annual maintenance cost (£/yr) 200 200 200
11) Vehicle washing station (8/13 don’t currently) set up (£): if large enough for a
lorry
5000 5000 5000
Annual cost (£/yr): if 30 lorries/yr 450 450 450
12) Buy only UK supplies (7/11 don’t currently) Additional cost of supplies (%) 9% 13% 11%
Total costs (all measures excluding : 1) water testing,
4) covered storage of growing media , & 12) UK
supplies only)
set up (£) 156600 164900 160750
Annual cost (£/yr) 1900 1900 1900
Total costs (common practice baseline; 5 additional
best practices for which estimates available)
set up (£) 50750 50750 50750
Annual cost (£/yr) 1700 1700 1700
Benefits* Avoided cost of outbreak 2000 60000 [Ω] 20200 [Ω] [βiii]
[α] max coded as £7.5k for purposes of computing the mean; [Ω]: excludes one response: ‘anything from zero to complete right off’
*How many outbreaks a year avoided on average (worst case): one?
How much smaller would expected benefits be for a 1 ha nursery?
Which practices to assume already adopted (e.g. none or majority)?

8. 8
‘typical nursery’: best practice specification?
Expert judgement based costs: Specification?
1) Water testing: (11/13 don’t currently) Annual cost (£/yr)
2) Water treatment facility (10/13 don’t currently) i) Semi-automated facility?
ii) Fully automated facility, chem. treatment (with basis being present)
iii) Fully automated facility, chem. treatment (including building)
3) Covered water storage (9/13 do currently) i) Lid only?
ii) set up from scratch (£): (i) lid+tank+ concrete base+ installation+pump+
piping (how much)?
4) Covered storage of growing media (9/10 don’t
currently)
5) Drains/free-draining gravel beds (10/11 do currently)
6) Raised benches (7/13 do currently) i) in existing glasshouse?
ii) including building a glasshouse?
7) Disinfection stations (8/13 don’t currently)
8) Quarantine/holding area (11/15 don’t currently)
9) Contained composting /incineration facility (12/13
don’t currently)
10) Boot washing station (7/13 do currently) i) foampad + brush + liquid?
ii) stainless steel + handrail?
11) Vehicle washing station (8/13 don’t currently) How many lorries per year (e.g. 30)?
12) Buy only UK supplies (7/11 don’t currently)

9. Phytothreats CBA: preliminary conclusions
I) Costs & benefits of best practices:
difficult for many nurseries to quantify but
results so far suggest that:
a) Baseline 1: Implementing all 12 ‘Best practices’
•not generally cost-effective from a nursery perspective
• Costs greater than benefit of reducing risk of phytophthora outbreak to the nursery itself
b) Baseline 2: Implementing 8 ‘Best practices’ not common practice:
•similarly unlikely in general to be cost-effective from a nursery perspective
• Costs greater than benefit of reducing risk of phytophthora outbreak to the nursery itself
Baseline ‘average’ current nursery practice an intermediate case?
• Nurseries contacted predominently those with relatively good biosecurity?
c) Cost perspective for a ‘typical’ nursery:
•also unlikely to be cost-effective from a nursery perspective
• Set-up costs greater than benefit of reducing risk of phytophthora outbreak to the nursery
•Take-up of voluntary accreditation scheme might be expected to be low?
12/18/189

10. Phytothreats CBA: preliminary conclusions
Some of the qualitative responses support conclusion that implementing the
best practices not generally cost-effective from a nursery perspective:
Q: Were it to be affected by a phyophthora outbreak in future, what cost to your
nursery would you anticipate in terms of (please provide a range or estimate if
providing a single answer is difficult):
• Loss of value of nursery stock (£)
• Other costs (please specify…………………….) (£)
Of the qualitative responses from the 17 nurseries:
• 2 replied ‘small’
• 1 replied ‘anything from zero to a complete write-off’
• 1 replied ‘depends upon the strain of phytophthora’
• 1 replied ‘hypothetical risk: no data’
• 1 replied ‘no idea’
what about benefits of reduced risks of other pests & diseases (e.g. Xylella)?
12/18/1810

11. 11
Biosecurity: some nurseries very concerned
Perspectives expressed included:
•current biosecurity measures far from sufficient to
prevent introduction of new pests and diseases
• Xylella of particular concern due to expected regulatory
measures if found and due to :
• difficulties in spotting symptoms
• lack of awareness of buyers & those travelling abroad
• some traders/retailers willing to take risks
• potential impacts for their business relatively minor
• lack of effective action by government putting UK
nurseries at risk
• especially ‘producers’ growing own plants
• current European Plant Health regime and plant passporting not ‘fit
for purpose’
• E.g. being on a Dutch passport does not
necessary mean grown in the Netherlands