Wireworm Management in Horticultural Crops

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

Contact information

[email protected] - Phone 902-370-1374