Costs and benefits of forest biosecurity: Established pests. Case study I. – Eucalyptus leaf beetle

Tim Wardlaw*, Nick Cameron, Tyron Venn, Angus Carnegie, Simon Lawson* Forestry Tasmania

Outline of the presentation

• Context within framework of forest biosecurity

• Understanding leaf beetles – informing management

• Operational management of leaf beetles

• Analysis of the costs and benefits developing and using the IPM

• Informing future investments in managing pests and diseases by the plantation forestry sector

Inte

rcep

tion

Initi

al e

stab

lishm

ent

(era

dica

ble)

Esta

blish

ed(o

ngoi

ng m

anag

emen

t)The biosecurity continuum

Offshore origin Australian port

Metropolitan parkCommercial plantation

The biosecurity continuum

Offshore Intercepted Established

Ong

oing

man

agem

ent

Pre-

rele

ase

insp

ectio

ns

High

-risk

site

surv

eilla

nce

Rout

ine

surv

eilla

nce

/ ad

hoc

insp

ectio

ns

Offs

hore

inte

llige

nce

Impo

rt ri

sk a

sses

smen

t(im

port

rest

rictio

ns, p

hyto

-sa

nita

ry tr

eatm

ents

)

Eradication option

$/ha/yr(costs / losses)

Case studies for cost-benefit analysis

Monochaemus alternans(Japanese sawyer beetle)

Paropsisterna bimaculataTasmanian leaf beetle

Sirex noctilioSirex wood wasp

Exotic wood borerNot established

Exotic wood borerEstablished

Native defoliatorEstablished

Tasmanian leaf beetle cost-benefit analysis

Scope• Research - IPM (1974 – 2014)• Research – soft chemicals (1989 – 2012)• Operational management (2003 – 2034)

• Averted losses due to management (2003-2034)

Cost

sBe

nefit

s

Research: leaf beetle Integrated Pest Management

Life history

(Elliott & de Little)

1975-1980

Natural enemies

(Elliott & de Little)

1975-1980

Growth impact

(Elliott, Greener,

Elek, Candy)

1974-1996

Population –

damage relationship

(Candy)

1994-1996

Population sampling

(Candy, Bashford)

1994-1996

Operational spray trials

(Elliott, Bashford, Elek)

1987-1993

Research: softer chemicals

Bacillus thuringiensis var. tenebrionis

1989-1997

Spinosad (Success)

1998-2002

Lethal trap trees(proof-of-concept for “attract and kill”)

2005-2011

Operational leaf beetle IPM

summeremergence

adultseggs

1st instar larvae (L1)

2nd instar larvae

(L2)

3rd instar larvae (L3)

4th instar larvae(L4)

pupae

Responsible for themajority of the

defoliation damage

Majority of predation by

natural enemies

models

Population monitoring

teneral adults

pre-control sample

initial sampleControl decision

spring/summer dispersal of adults over-wintering adults

control

Trial: 1990Operational: 1992Refine 1: 2000Refine 2: 2011

$

Some definitions

Over-threshold: a leaf beetle population that if not managed would cause severe defoliation (>50% current seasons foliage removed)

Leaf beetle risk: Likelihood of plantation experiencing over-threshold populations: three classes (low, medium and high) based on altitude (>550m) and proximity to native grassland

Low risk Plantation below 550m and >10 km from native grassland

Medium risk: Plantation either above 550m or <10km from native grassland

High risk: Plantation above 550m and < 10km from native grassland

The leaf beetle populations

0

10000

20000

30000

40000

50000

60000

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

Tota

l are

a es

tabl

ishe

d (h

a)

Pulpwood Pruned

Measured populations

Simulated populations

2034

Over-threshold populations peak at early age then decline

0

5

10

15

20

25

30

3 5 7 9 11 13

Coup

es w

ith o

ver-

thre

shol

dpo

pula

tions

(% o

f all

coup

es)

Plantation age (years)

Over-threshold

All populations

Medium and high risk plantations experience more over-threshold populations than low risk plantations

0.00.10.20.30.40.50.60.70.80.91.0

0.0 0.2 0.4 0.6 0.8 1.0

Cum

ulat

ive

prop

ortio

n of

co

upes

in ri

sk g

roup

Proportion of years with O/T populations

Low Medium HighLeaf beetle risk group

15%

55%

The scenarios

Low risk plantationsNumber of over-threshold populations

Age 1 2 3 53 x x4 x x x5 x x x6 x7 x8 x9

101112

Medium-high risk plantationsNumber of over-threshold populations

Age 1 2 3 4 5 6 83 x x x x4 x x x5 x x x6 x x x x7 x x x x8 x x9 x x x

10 x x11 x12 x

Calculating losses in wood volumes for scenarios

01020304050607080

0 5 10 15

% o

f no

defo

liatio

n CA

I

Plantation age (years)

Growth reduction from severe (75%) defoliation by over-threshold populations

Yield tablesSite Index (4) x Leaf beetle scenario (11) x Regime (4) = 144 FFT runs

RegimesPulpwood: 15 years, no thin; 4 site index classes (<21, 21-22, 22-25, >25)Pruned: 25 years, thin 12 y.o.; 4 site index classes (<23, 23-26, 26-28, >28)

Volume losses averted by protecting from severe defoliation

020406080

100120140160

2003

2005

2007

2009

2011

2013

2015

2017

2019

2021

2023

2025

2027

2029

2031

2033

Incr

ease

in y

ield

from

IPM

(m3

x 10

00)

Year

PulpwoodUnpruned peelerPruned sawlog

Pruned sawlog($40/m3)

Unpruned peeler($20/m3)

Pulpwood($15/m3)

Total increase from IPM (m3) 86,088 690,211 1,016,188m3/ha 1 8 11% of volume (no leaf beetle) 3.9 6.4 9.9Losses averted (Ha/yr) 81 177 274

Management effort for IPM

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

2003

2005

2007

2009

2011

2013

2015

2017

2019

2021

2023

2025

2027

2029

2031

2033

Area

man

aged

(ha)

Year

MonitoringSpraying

Monitoring cost: $3.80/ha (2015 $)Spraying cost: $56/ha ($2015 $)

Total costs of research and management

$0

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

$400,000

$450,000 IPM Spraying Cost IPM Monitoring CostIPM R&D Cost (soft insecticides) IPM R&D Cost (conventional insecticides)

Cashflow from IPM (2015 $)

-$500,000

$0

$500,000

$1,000,000

$1,500,000

$2,000,000

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

2011

2013

2015

2017

2019

2021

2023

2025

2027

2029

2031

2033

Long time between when research commenced and when positive cashflow

begins

Control provides strong benefit when fully deployed

Fully established plantation estatePeriod of plantation expansion

Key findingsOver the 60-year period (1975-2034) of the “IPM project” research was the major cost (2/3 of cost).

Once operational the IPM provided strong benefit (BCR > 7)

• Staging of research is important – the sooner management arising from research is applied the better

• Centralise research costs AND maximise adoption of the resultant operational management (by as many growers of susceptible plantations as possible)