The Effects of Climate Change on Pest Problems

Moray Anderson Technical Director, Killgerm Group.

Climate change

Examples to be discussed:

New diseases associating with established insect species West Nile Virus.

New invasive insect species New diseases associated with these.

Re-emergence of “old” pest species Microclimatic changes.

Climate change

What is predicted ?

Universal increase in temperatures

Insect metabolism – temperature dependant Small changes can have significant effects

Lengthening of breeding seasons Changes in insect distribution geographically

Bedbug life cycle.

Cimex lectularius – Eggs 

Temperature (°C)

Egg hatching time (days)

13 49

15 34

18 21

22 12

27 5 - 6

Climate change

New diseases associating with established insect species

West Nile Virus.

Mosquito borne disease

Disease transmission – summary

Disease causing pathogen ingested with blood

Multiplies in insect gut

Develops in insect gut

Migrates into mosquito haemolymph (blood)

Transfers to salivary glands

Injected into new host

1999 West Nile Virus

2000

2001

2002

2003

2004

2005

2006

2006

2007

2008

2009

West Nile virus is a flavivirus

Conditions in US perfect for distribution of virus

a) susceptible birds

b) insect vectors present - biting birds

and other vertebrates

c) susceptible horses/humans

WNV in the UK?DoH – surveillance systems for people …… no evidence of WNV

infectionLocal bird population examined ….… positive for WNV antibodiesMosquito surveillance ………… all negative for WNVOverall risk of WNV transmission in the UK categorized by DoH as

‘LOW’..

Level of risk may increase if…

Increase in numbers & distribution of

human-biting mosquitoes in the UK

Introduction of a more efficient mosquito

vector

Changes in human behaviour, encouraging greater human/vector

contact

Changes in climate to allow survival of

efficient vector

Climate change

New invasive species New diseases associated with these.

Aedes albopictus

Aedes albopictus – in USA

Aedes albopictus

• Spread through import and internal movement of used tyres

•Importation into California on “Lucky Bamboo”

Europe

First appearance in Albania in 1979

Since then been reported in: Belgium, Bosnia & Herzegovina Croatia, France, Germany, Greece Italy, Malta, Monaco, Montenegro Netherlands, San Marino, Slovenia Spain, Switzerland, Vatican City

Imported tyres – into UK

(According to “Used Tyre Working Group”)

1999: 20,254 tonnes (units 3,116,000)

2000: 34,921 tonnes (units 5,372,462)

2001: 37,473 tonnes (units 5,765,077)

Research: Mosquito breeding in tyre disposal sites in the West Midlands

Mosquito breeding potential in disposed tyres in the UK

Findings

Mosquitoes breeding at all sites

Within 1m of vegetation: 60% of tyres sampled housed mosquitoes

Within 10m of vegetation, only 3% of tyres had mosquitoes present

Invasive species - UK

Mosquito Watch was established in 2005

Environmental health practitioners (EHPs) in responding to pest issues receive insects from public

Invasive species

EHPs will likely be one of the first groups to be asked identify new mosquito nuisance-biting species.

Need for reporting system that could be related to invasive species.

Invasive species

During five years of the scheme, there were

116 confirmed mosquito reports

21 reports associated with other insect groups.

The most commonly reported mosquito species were: Culiseta annulata (56 reports) Culex pipiens (42) Ochlerotatus detritus (7) Aedes/Ochlerotatus sp. (7) Coquillettidia richiardii (1) Anopheles maculipennis s.l. (1)

UK

No sign of Aedes albopictus in UK as yet !

Raising awareness - information

sheet

London Boroughs of Hounslow / Richmond on Thames

Thames Water

Climate change

Re-emergence of “old” pest species

Microclimatic changes.

Bedbugs

“Microclimate Change”

Household environment

BedbugsBedbugs

Increase in numbers in recent years

Reasons ?

Poor hygiene in communal living

Increase in overseas travel

Freecycle, e-bay

Laundry

Bedbug life cycle.  

Cimex lectularius – Egg to Adult 

Temperature (°C)

Complete cycle (weeks)

13 Not completed

15 34

18 18

22 8

27 4.5

BedbugsBedbugs

Increase in numbers in recent years

Reasons ?

Laundry

Bedbug control

WET/DRY bedding: It is the time time taken to reach the required core temperature of 400C - 500C which is vital

Wet bedding, it took about 2.5 times longer to reach the required core temperature.

Climate change

Conclusions

New diseases associating with established insect species

New insect species

Re-emergence of “old” pests