Wireworms, Neonicotinoids and the

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Wireworms, Neonicotinoids and the
Lazarus Syndrome
Bob Vernon1, Wim van Herk1 and Jeff Tolman2
1Pacific Agri-Food Research Centre, Agriculture
and Agri-Food Canada, Box 1000, Agassiz,
British Columbia, CANADA, V0M 1A0
2Southern Crop Protection Food Research Centre,
AAFC, 1391 Sandford St., London, Ontario, CANADA,
V0M 1A0
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damage to potatoes
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Leading Candidate Insecticides for Future
Chloronicotinoids imidacloprid
Thianicotinoids clothianidin
thiamethoxam
Phenyl pyrazoles fipronil
Synthetic pyrethroids tefluthrin
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Objectives

• Determine LC50 and LT50 values for candidate
• insecticides against A. obscurus

2. Determine transitional lethal or sub-lethal
symptoms of insecticide poisoning
3. In light of the above, interpret efficacy of
these insecticides against wws in wheat
and potato field trials
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Post application health checks
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Methods post-application

• State of health determined by ability to move
• Alive can move out of 10cm circle in Petri dish
• Writhing full body movement, but uncontrolled
• Leg Mandibles no visible movement except legs
  mandibles
• Mandibles no visible movement except mandibles
• Dead decomposing, moldy
• Some Mandibles wireworms, which appear dead,
  are capable of full recovery, hence what we term
  the Lazarus Syndrome.
• Low mortality in control wireworms (mean 9),
  even though some treatments took 300 days to be
  resolved.

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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

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3
7
14
28
56
112
168
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mandibles
Writhing

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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Dead

Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Dead

Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts


Dead
Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Dead
Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Dead
Writhing
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• Fipronil 0.0001
• Imidacloprid 1.0
• Clothianidin 0.05
• Tefluthrin 0.25
• Chlorpyrifos 0.1

1
3
7
14
28
56
112
168
Alive
Leg Mouthparts
Dead
Writhing
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OF UNTREATED
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a
a
a
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Conclusions

• Wireworms exposed to neonicotinoids rapidly
• become intoxicated, often appearing dead.
• At below the LC50 levels, intoxicated wws
• recovered fully after several weeks in the lab.

2. In the field, it appears that reductions of
ww damage to wheat and potatoes is likely
due to most wws being intoxicated by
neonicotinoids for prolonged periods, since
their populations had recovered the
following spring.
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Conclusions, cont.

• Fipronil appears to be highly toxic at low
• doses to Agriotes obscurus wireworms.

4. Efficacy trials that are evaluated on the
basis of wireworm damage to crops alone,
may not reflect what is happening to the
actual wireworm population, i.e. low damage
might not mean high ww mortality.
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LC50 Studies in 2006
Five Species Tested
Agriotes obsurus (BC) Agriotes sputator (Nova
Scotia) Limonius canus (BC) Ctenicera destructor
(Alberta) Ctenicera pruinina (Oregon)
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LC50 Studies in 2006
Two Insecticides Tested
Clothianidin - thianicotinoid Chlorpyrifos -
organophosphate
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LC50 Studies in 2006
Results to Date
-Stages of morbidity common among species as
per 2004 study
-Definite differences in LC50 values between
species
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LC50 Studies in 2006
Additional Cool Observation
All 5 species exposed to clothianidin in various
states of morbidity moved from being buried 2cm
in soil to soil surface. Have noticed this a bit
with Cruiser-treated wheat in the field.
This did not occur with chlorpyrifos.
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Thanks to -AAFC IFSP grant -Syngenta -Bayer
CropScience -Hugo Ortiz Saavedra