wireworm management in horticultural crops
TRANSCRIPT
Wireworm management in
horticultural crops Dr. Christine Noronha
Agriculture and Agri-Food Canada Charlottetown
Research and Development Centre
Presentation to ACORN November 25, 2015 - PEI
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.
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
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 eggs Five years later
Ten years later
Population increase
• 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
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
Wireworm have an aggregated distribution in the field
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.
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.
15%
5%
10%
Incidence of wireworm reports across Canada
1%
5% 10% 10%
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.
• 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.
Wireworm damage to various crops
Cabbage Corn Crambe
Wireworm damage in root crops
Wireworms attack germinating seeds in
the spring
co2 co2 co2 co2
Plow-down of green material can
result in increased damage
Plow-down of green material
can result in increased damage
18
Fig 1. Damage to tubers caused by wireworm feeding following
a spring or fall plow-down of green sod
CROP ROTATION STRATEGY
TO REDUCE WIREWORM
DAMAGE
Wireworm research at AAFC Charlottetown: Crop
Rotation Study To Reduce Wireworm Damage (funded by
Pest Management Centre, 2007-2010)
Brown Mustard, Buckwheat, Barley /Clover
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.
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
Why does Brown Mustard work?
• The plant tissue has
Allyl-glucosinolate (GTC)
• 2-phenylethyl in its roots
which is toxic to insects
• Brown Mustard (Brassicae juncea var. Centennial)
10lb/ac or 11.2kg/ha
• Buckwheat (var Mancan) 40lb.ac or 44.8kg/ha
• 2 crops /year for 2 years
• Fertilizer 300lb/ac or 335kg/ha 17:17:17 banded at
planting in the spring
• Plant early June
Crop Rotation
• 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
DISK THE CROP IN LATE JULY BEFORE
SEEDS MATURE
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
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
Buckwheat as ground cover in the fall (PEI)
Brown Mustard as ground cover in the fall (PEI)
Buckwheat as ground cover in the fall (PEI)
Brown Mustard as ground cover in the fall (PEI)
Dr. Christin Noronha
Buckwheat as ground cover in the fall (PEI)
Brown Mustard as ground cover in the fall (PEI)
Treat the brown mustard and
buckwheat like a crop
Using brown mustard as a nurse crop
Brown Mustard was planted in the
potato rows at 5 different seeding
dates throughout over the
Summer.
Seeding date July 14 Seeding date July 30 Seeding date Aug 13
Seeding date Aug 20 Seeding date Aug 28
Growth of Brown mustard planted in the potato row on
September 16
Figure 1. Number of blemishes caused by wireworm feeding in plots
planted with brown mustard as a nurse crop on 5 different dates
during the growing season 2015
a
ab
ab ab
ab
b
41
POTATO VARIETRY TRIAL
42
Twenty varieties and six replicates per variety
43
Figure 2. Mean number of blemishes (holes+scars) in different potato
varieties grown without an insecticide application to protect against
wireworm damage
BIOLOGICAL CONTROL
RESEARCH
Todd Kabaluk
AAFC- Agassiz, BC
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
Metarhizium spore dust
Metarhizium spore spray
What about
in the field?
Metarhizium spore granules
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
The Concept – Attracting Beetles to Bands of Biocontrols using Pheromone Granules
Click beetles recaptured 16 days post-treatment
Pheromone granules synergize the efficacy of Metarhizium when targeting A. obscurus click beetles using a banded application
Mean number + s.e. of beetles per passive pitfall trap (mean of 8 traps in each of 5 replications =40 traps/data point)
Un
trea
ted
Dea
d
Met
arh
iziu
m
Almost all beetles killed
STRATEGIES TO REDUCE DAMAGE
1. Find out if you have wireworms in your field.
2. If you work up a long term sod field do not plant a
valuable crop the first year.
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.
ACKNOWLEDGEMENTS
• Agriculture and Agri-Food Canada
• PEI Department of Agriculture
• PEI Potato Board
• PEI Horticulture Association
