Integrated pest management
of cabbage stem flea beetle
Steve Ellis, ADAS High Mowthorpe
www.adas.uk
Sept
Adults move to new crop,
mate and feed on leaves
causing ‘shot holing’
Sept-Oct
Eggs laid at base of
plants if mild
June-July
Adults emerge and
feed on foliage
Life cycle
Oct-Feb
Eggs hatch when mild
and larvae feed in leaf
petioles
May
Larvae pupate in soil
March-April
Larvae feed on main stem behind growing
point
Courtesy of Caroline Nicholls, HGCA
Autumn assessment
(Source Fera Crop Monitor)
CSFB numbers by county 2015/16
(Source Fera Crop Monitor)
Spring 2016
Proportion of crops affected by csfb
autumn 2015 (23 agronomists, 42 counties, 62,000ha)
CSFB larval survey (Feb/March 2016)
‘High’ risk sites
Mean total larvae per plant
40
30
20
10
0
Stem
Petiole
Autumn
threshold
Yield impacts (2015 yield minus the five year
average yield, 22% variance accounted for)
Integrated pest management of cabbage
stem flea beetle in oilseed rape
• New 3+ year AHDB funded project
• Started: September 2016
• Aim: Develop an IPM strategy for CSFB
control.
Partners: Fera Science Ltd, Bayer
CropScience Ltd, Syngenta UK Ltd and
Cotton Farm Consultancy Ltd
Project objectives
• Objective 1: Review how agronomic factors
affect CSFB.
• Objective 2: Determine the effect of agronomic
factors on CSFB.
• Objective 3: Understand crop tolerance to
CSFB
• Objective 4: Assess alternative control options
• Objective 5: Create an IPM strategy for CSFB
• Objective 6: Knowledge transfer
Objective 1: Review how agronomic
factors affect CSFB
• Drilling date – Early drilling = ↓ damage
• Soil type – Heavy cloddy soil = ↑ damage
• Weather – Warm & dry = ↑ damage
• Seedbed quality – rolling & good consolidation
= ↓ damage
• Proximity to last rape – closer = ↑ damage
Objective 1: Review how agronomic factors
affect CSFB
Meta-analysis to determine factors that affect CSFB
adult feeding and larval infestation
Dataset
Number of sites
2015 Bayer & Syngenta derogation monitoring
48
2015 AHDB funded larval survey
15
2016 AHDB funded larval survey
24
Fera survey (2003 – present)
>1000
Factors studied: drilling date, establishment method, soil type,
previous cropping, location of previous OSR, straw incorporation,
seed rate & variety (e.g. hybrid vs conventional).
Objective 2: Determine the effect of
agronomic factors on CSFB.
• CSFB damage survey
• 75 sites/year, 2 years, assess damage at cotyledon2-3 leaf stage
• Assessment of varietal tolerance/resistance
• Assess 3 AHDB RL trials, measure adult damage &
larval infestation
• Additional variety x seed rate studies
• Two experiments, 10 varieties, one sown at five
seed rates (e.g. 10, 20, 40, 80, 160 seeds/m2).
Varietal differences
Obj. 2 Are there differences in varietal
tolerance to CSFB?
Years 1 & 2
• Monitor 3 RL trials
• Sites with moderate CSFB pressure
• CSFB adult & larval damage and
yield
• Varietal characteristics (e.g. spring
vigour, glucosinolate content)
Years 2 & 3
• 2 variety/seed rate trials
• Interaction of varietal tolerance and
seed rate
• Adult damage, larval populations &
yield
Objective 3: Understand crop tolerance
to CSFB
• Current autumn treatment threshold for larvae = >5
larvae/plant
• Based on Purvis (1986). Field studies showed a
yield response of 0.34 t/ha at 5 or more larvae per
plant.
• Does this threshold hold for modern varieties and
agronomic practices?
Objective 3: Understand crop tolerance
to CSFB
• Experimentally manipulate
larval populations by
fleecing plots for different
durations.
• Assess impact on yield at
harvest.
• 2 x standalone trials in Years
1 & 2.
• 1 x variety/seed rate trial in
Years 2 & 3.
Artificial cabbage stem flea
beetle
• Does what it’s asked
• Can be relied upon to
cause consistent leaf
damage
Tolerance of OSR to loss of leaf area
Creating cabbage stem flea beetle
adult damage
Treatment
Both cotyledons
Leaf 1
Leaf 2
1
None
N/A
N/A
2
Slight
N/A
N/A
3
Moderate
N/A
N/A
4
Severe
N/A
N/A
5
Moderate
Slight
N/A
6
Moderate
Moderate
N/A
7
Moderate
Severe
N/A
8
Moderate
Slight
Slight
9
Moderate
Slight
Moderate
10
Moderate
Slight
Severe
11
Moderate
Moderate
Slight
12
Moderate
Moderate
Moderate
13
Moderate
Moderate
Severe
14
Moderate
Severe
Slight
15
Moderate
Severe
Moderate
16
Moderate
Severe
Severe
Tolerance of OSR to loss of leaf area
– Green leaf area (Bars = LSD P<0.05)
Green leaf area cm2
600
500
400
300
200
100
0
% cotyledon, leaf 1 & leaf 2 removed
Tolerance of OSR to loss of leaf area
– Dry matter (Bars = LSD P<0.05)
5
Dry matter (g)
4
3
2
1
0
% cotyledon, leaf 1 & leaf 2 removed
Objective 4: Assess alternative
control options
• Trap crops
• Defoliation
Obj. 4 Novel non-chemical control
methods – Trap crops
• Sowing trap crop for CSFB is
expensive.
• Consider leaving volunteer
OSR until CSFB migration
complete.
• Exploits biological quirk of
CSFB.
• Wing muscles degenerate
following arrival on a host.
• Limit subsequent ability to
move to newly emerged OSR.
• 2 fields coming out of
OSR adjacent to fields
going into OSR.
• Volunteers controlled in
one field and left in
other.
• Destroyed after new
OSR crop has
emerged.
• Monitor adults, crop
stand and feeding
damage.
Defoliation treatments
Impact of Defoliation December, 2014
Impact of defoliation on yield
7
Yield (t/ha)
6
5
4
*
*
HM14
RM14
3
2
1
0
Defoliated
RM15
Non Defoliation
HM15
Kirkegaard et al, 2008 Australian
Journal of Agricultural Research
Variety
Yield t/ha
Oil %
Ungrazed
Grazed
Ungrazed
Grazed
Hyola 60
4.8
4.6
50.5
50.5
Moxol
4.1
4.3
47.9
46.1
Capitol
4.1
4.0
48.4
47.6
No significant effect of grazing on yield or oil
Obj. 4 Novel non-chemical control
methods – Defoliating (mowing)
• 1 x trial in Years 1 & 2
• 3 mowing treatments
•
Pre stem extension 1
•
Pre stem extension 2
•
Post stem extension
• Assess larval numbers before
and after mowing.
• Yield at harvest.
Thank you