The Effects of Climate Change on Pest Problems
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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
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