This document summarizes information about wireworm management in grain production. It discusses what wireworms are, their lifecycle, species that cause damage, and monitoring techniques. It notes that wireworm populations can build up over years and infestations are difficult to control. Crop rotation strategies using brown mustard or buckwheat are effective at reducing wireworm damage. Biological control using fungi like Metarhizium that kill the beetle hosts is also being researched. Proper monitoring of fields is important to assess infestation levels.

1. Wireworm management in grain
production
Dr. Christine Noronha
Agriculture and Agri-food Canada, Charlottetown
Research and Development Centre
Presentation to ACORN November 24, 2015 - PEI

2. What are Wireworms
• Larvae of click beetles.
• Several species cause crop damage.
• An emerging pest worldwide.
• Affect a wide variety of crops.
• Can render root crops unmarketable.
• Very limited means of control.

3. Lifecycle of Wireworms
They pupate in the soil and
emerge as adults in the spring.
Lifecycle 5 years
Spring-early summer
Adults lay 100-200
eggs in the soil
Spring – damage seeds
and seedling roots
Later Fall- hibernate in the
soil. Return to the surface in
the spring.
Click
beetles
Larvae
Fall damage root crops

4. May
2010
eggs
May
2011
May
2012
May
2013
May
2014
May
2015
eggs
Yr.1 L
Yr.2 L
Yr.3 L
Yr.4 L
Yr.5 L – pupa -Adults
hibernate
Hibernate
Hibernate
Hibernate
Hibernate
Once a field is infested it will be remain so until wireworms are killed
Larval Duration

5. 1 female lays 100-200 eggs
If only 8 larvae survive to become
adults in year five, with 4 females
and four males each females
produces 100-200 eggsFive years later
Ten years later
Population Increase

6. 2012
2013
2014
2015
2016
2017
15
1000
5
200
2
50
6
500
1000
3000
Yr1 1000
Yr2
Yr3
Yr4
yr5
Yr1 200
Yr2 1000
Yr3
Yr4
Yr5
Yr1 50
Yr2 200
Yr3 1000
Yr4
Yr5
Yr1 0
Yr2 50
Yr3 200
Yr4 1000
Yr5
Yr1 500
Yr2 0
Yr3 50
Yr4 200
Yr5 1000
Yr1 3000
Yr2 500
Yr3 0
Yr4 50
Yr5 200
Damage can be worse in some years and
less is others in newly infested fields?

7. • Agriotes sputator (NS, NB and PEI
• Agriotes obscurus PEI and NS
• Agriotes lineatus PEI and NS
• Hypnoidus abbreviatus
• Ctenicera pulchra
• Dalopius sp
European Species
Other species
48 species of click beetles in PEI, 98 in NB and 101 NS
Click Beetle Species

8. Where do they prefer to lay their eggs
Sod fields
Pasture fields
Under-seeded fields
Undisturbed fields with green plant material are preferred
Adults will also lay eggs in bare soil,
egg survival may be compromised

9. Wireworm have an aggregated distribution in the field

10. Monitoring Click Beetles
• Wireworm populations have
been closely monitored in PEI
using pheromone traps.
• Pheromones are chemical
produced by females to attract
males.
• Pheromone are available for
some of the European species.
• Traps collect only male beetles.

11. Range
of
beetle
numbers
Prince
County
No.
of
Farms
Queen
County
No.
of
Farms
Kings
county
No.
of
Farms
2009
2012
2014
2009
2012
2014
2009
2012
2014
0
4
4
1
0
0
0
2
1
0
1-­‐10
16
25
2
8
6
0
10
12
0
11-­‐50
7
5
7
7
4
3
3
7
2
51-­‐100
0
2
1
1
3
3
0
0
1
101-­‐500
0
2
4
2
5
4
0
0
2
501-­‐1000
0
0
2
0
5
2
0
0
1
>1000
0
1
0
0
3
5
0
0
0
Total
#
of
beetles
214
1969
2812
1308
10,438
14,152
76
197
1298
Total
per
trap
7.9
50
83
72
401.46
416.23
5.4
9.8
108
Table 1. Comparisons of the number of farms with beetles numbers ranging for
0 - >1000 in 2009 and 2012, and 2014 for each county in Prince Edward
Island.
** 500 beetles and over can result in crop failure.
Survey of Click beetles across PEI

12. 15%
5%
10%
Incidence of wireworm reports across Canada
1%
5%
10% 10%

13. Potential to impact agriculture
• Once infected, agricultural land will remain
infected until adequate control measures to
eliminate the larvae are implemented.
• If wireworms are not controlled, the land
may become a important source of adult
beetle that will infest other fields.
• Because of the wide host range, good
agricultural land may become unsuitable for
crop production.

14. • 5 year life cycle.
• Soil dwelling.
• Difficult to monitor because of aggregated field
distribution.
• Several generations in the same field.
• Damage occurs in the spring and fall.
• Feed on a wide variety of crop species – oats, wheat,
barley, clover, corn, carrots, lettuce, onions, peas,
potatoes, parsnips cabbage, beans, rutabagas etc.

15. Wheat field in Alberta, 2012
Courtesy of Dr. Bob Vernon

16. Barley field with wireworm damage

17. Wireworms attack germinating seeds
co2 co2
co2 co2

18. Grain crops
• Grain crops provide a good food source for
wireworms
• Growing grain for several years in a row
can influence the buildup of wireworm
population
• Under-seeding results in abundance of food
which is beneficial to wireworm survival
18

19. CROP ROTATION STRATEGY
TO REDUCE WIREWORM
DAMAGE

20. Wireworm research at AAFC Charlottetown: Crop
Rotation Study To Reduce Wireworm Damage (funded by
Pest Management Centre, 2007-2010)
Brown Mustard, Buckwheat, Barley /Clover

21. Crop Rotation
Crops
Total
Market
yield (t/
ha)
Tubers
with no
Damage
(t/ha)
Average
Number
of Holes
per tuber
Tonnes/ha
lost due to
damage (for
Processing)
(t/ha)
Tonnes/ha
Marketable
(for
Processing)
(t/ha)
Brown
Mustard
45.6 a1 16.2 a 04 a 0.5 a 45.1 a
Buckwheat 45.9 a 12.6 a 06 a 2.6 a 43.3 a
Barley 47.3 a 2.3 b 20 b 16.8 b 30.5 b
Table 1. Total market yield, number of undamaged tubers, holes per tuber, tonnes
per hectare lost due to wireworm damage and marketable yield for the processing
market in a potato crop following a 2 year rotation with brown mustard, buckwheat,
barley/clover or alfalfa at Hazelbrook in Prince Edward Island, Canada.

22. Why does Brown Mustard work?
• Because the plant tissue has
Allyl-glucosinolate (GTC)
• When plant material starts to
breakdown and enzyme
Myronase reacts with the tissue to
produce Isothiocynates (ITC)
Glucosinolate
Enzyme Myronase
+ Isothiosynate
ITC

23. Why does Brown Mustard work?
• The plant tissue has
Allyl-glucosinolate (GTC)
• 2-phenylethyl in its roots
which is toxic to insects

24. • Brown Mustard (Brassicae juncea var. Centennial) 10lb/
ac or 11.2kg/ha
• Buckwheat (var Mancan) 40lb.ac or 44.8kg/ha
• 2 crops /year
• Fertilizer 300lb/ac or 335kg/ha 17:17:17 banded at
planting in the spring
• Plant early June
Crop Rotation

27. • Brown Mustard (var Centennial) 8-10lb/ac or
11.2kg/ha
• Buckwheat (var Mancan) 40lb.ac or 44.8kg/ha
• 2 crops /year
• Fertilizer 300lb/ac or 335kg/ha 17:17:17 banded at
planting in the spring
• Plant early June
• Disk the crop in late July before seeds mature
Crop Rotation

28. DISK THE CROP IN LATE JULY BEFORE
SEEDS MATURE

29. Crop Rotation
• After two-three weeks harrow the field to level it
• Depending on the seeder you may need to roll it
before planting, mainly because you don’t want
the mustard seed planted too deep
• Do not need to add fertilizer for the second
planting

30. Crop Rotation
• The 2nd crop should go in by the mid-late August
• Wireworms come to the surface to feed by mid to
late September
• You want the crop established and producing the
chemicals
• This second crop does not need to be disked as it
will act as ground cover and will not produce
seeds

31. Buckwheat as ground cover in the fall (PEI)

32. Brown Mustard as ground cover in the fall (PEI)

33. Buckwheat as ground cover in the fall (PEI)

34. Brown Mustard as ground cover in the fall (PEI)

35. Buckwheat as ground cover in the fall (PEI)

36. Brown Mustard as ground cover in the fall (PEI)

37. Treat the brown mustard and
buckwheat like a crop

38. BIOLOGICAL CONTROL
RESEARCH
Todd Kabaluk
AAFC, Agassiz, BC

39. X
X
Can Metarhizium control wireworms by controlling click beetles?
(in the years leading up to planting potatoes)
X
First of all, is Metarhizium even pathogenic to the adult beetles?
Tests in the lab say
YES

40. Metarhizium spore dust
Metarhizium spore spray
What about
in the field?
Metarhizium spore granules

41. Conidia spray
Conidia dust
Conidia granules
Number of days after treatment
% beetle
mortality
Matador (λ – cyhalothrin)
-spray positive control
Application of Metarhizium spores
kills click beetles in the field

42. The Concept – Attracting Beetles to Bands of Biocontrols using Pheromone Granules

43. Click
beetles
recaptured
16
days
post-­‐treatment
Pheromone
granules
synergize
the
efficacy
of
Metarhizium
when
targe>ng
A.
obscurus
click
beetles
using
a
banded
applica>on
Mean
number
+
s.e.
of
beetles
per
passive
piMall
trap
(mean
of
8
traps
in
each
of
5
replicaPons
=40
traps/data
point)
Untreated
Dead
Metarhizium
Almost
all
beetles
killed

44. • Use Bait traps
• Could be done in the spring or fall.
• Depending on the size of the field at least 15
bait stations per acre
Assessing wireworm infestation in a field

45. Lightly pack soil back down
(leave for 7 days)
Place soil back in hole
Place approximately ¾ cup
of cut up carrots in the
hole around the flag
Place wire flag in the
center of the hole
Set Bait probe on top of the
ground and step on it creating
a nice circular hole 3 ½ inches
across and 5 ½ inches deep
Placing Bait Traps

46. Place wire flag in the center
of bait probe and push the
probe into the ground
Pull bait probe from the
ground
Place bait probe into a 12lb
bag and remove sample
Check to see if any carrots
remain in the hole and if some
remain collect them as well
Label bag with appropriate tag
and tie and store at 4C until time
to sort for wireworms
Collecting Bait Traps

47. • Count the number of wireworms and
calculate number per bait
• Threshold 1-2 wireworms per bait
• Finding no wireworms does not necessarily
mean that none are present in the field. The
higher the number of bait stations the better
the accuracy
Assessing wireworm infestation in a field

48. Baiting your field
Baits should be placed randomly across the field to compensate for
this aggregated distribution of wireworms

49. 49
Doing On-Farm research

50. 50
60
50
75
100
100
Treatment A
Treatment B
40
80
30
25
35
40
30
20

51. 50
60
50
75
100
100
Treatment A
Treatment B
40
80
30
25
35
40
30
20
6 rows
30 rows

52. Treatment A
Treatment B
Check
12+ rows
12 + rows
12+ rows

54. STRATEGIES TO REDUCE DAMAGE
1. Find out if you have wireworms in your field and
assess populations.
2. If you work up a long term sod field do not plant a
valuable crop.
3. Plant brown mustard (Brassice juncea var centennial)
or buckwheat (var Mancan) as a rotation crop as
shown above.
4. Try not to plant a preferred host such as grain every
year.
5. For root crops harvest early
before wireworms come up to
the surface to feed in the fall.

55. Contact information
Christine.noronha@agr.gc.ca - Phone 902-370-1374