1. The Effects of Climate Change on Pest Problems
Moray Anderson
Technical Director,
Killgerm Group.
The Effects of Climate Change on Pest Problems

2. 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.

3. 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

4. Cimex lectularius – Eggs
Bedbug life cycle.
Cimex lectularius – Eggs
Temperature (°C)
Egg hatching time (days) 13 49 15 34 18 21 22 12 27
5 - 6

5. Climate change
New diseases associating with established insect species
West Nile Virus.

7. 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 7

9. West Nile Virus

10. 2000

11. 2001

12. 2002

13. 2003

14. 2004

15. 2005

16. 2006

17. 2006

18. 2007

19. 2008

20. 2009

21. Conditions in US perfect for distribution of virus
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 21

22. WNV in the UK? Level of risk may increase if…
Increase in numbers &
distribution of
human-biting mosquitoes
in the UK
Introduction of a more
efficient mosquito
vector
WNV in the UK?
DoH – surveillance systems for people …… no evidence of WNV infection
Local bird population examined ….… positive for WNV antibodies
Mosquito surveillance ………… all negative for WNV
Overall risk of WNV transmission in the UK categorized by DoH as ‘LOW’..
Level of risk may increase if…
Changes in human
behaviour, encouraging
greater human/vector
contact
Changes in climate
to allow survival of
efficient vector

23. Climate change New invasive species
New diseases associated with these.

25. Aedes albopictus

26. Aedes albopictus – in USA

27. Aedes albopictus Importation into California on “Lucky Bamboo”
Spread through import and internal movement of used tyres
Importation into California on “Lucky Bamboo”

28. 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

30. 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)

31. 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

33. Invasive species - UK Mosquito Watch was established in 2005
Environmental health practitioners (EHPs) in responding to pest issues receive insects from public

34. 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.

35. Invasive species During five years of the scheme, there were
116 confirmed mosquito reports
21 reports associated with other insect groups.

36. 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)

37. UK
No sign of Aedes albopictus in UK as yet !

38. Raising awareness - information sheet
London Boroughs of Hounslow / Richmond on Thames
Thames Water

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

40. “Microclimate Change”
Bedbugs
“Microclimate Change”
Household environment

41. Bedbugs Increase in numbers in recent years Reasons ?
Poor hygiene in communal living
Increase in overseas travel
Freecycle, e-bay
Laundry 41

43. Cimex lectularius – Egg to Adult
Bedbug life cycle.
Cimex lectularius – Egg to Adult
Temperature (°C)
Complete cycle (weeks) 13
Not completed 15 34 18 22 8 27
4.5

44. Bedbugs
Increase in numbers in recent years
Reasons ?
Laundry 44

47. 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.

48. Climate change Conclusions
New diseases associating with established insect species
New insect species
Re-emergence of “old” pests