Emerald Ash Borer

1
What is an EABs Favorite Meal and Why is it
Important?
Therese M. Poland Deborah G. McCullough Andrea C.
Anulewicz Deepa S. Pureswaran
2
EAB Host Range
China - Fraxinus spp. Japan Korea Juglans
- Pterocarya- Ulmus North America - ??
3
Why Study Host Range?

• Know what species are at risk
• Understand susceptibility of urban forest trees
• Improve survey and detection
• Enhance management options
• Propogate and enhance resistance

4
Host Range Objectives
Assess EAB feeding preference larval
development (1) Alternate species of concern
(2) Compare North American Species (3) Stressed
vigorous trees (4) North American Asian ash
5
(1) Alternate Species of Concern
No-choice lab bioassay
Caged adult female male with wood section ash
leaf. American elm, black walnut, shagbark
hickory, hackberry privet tested. Reared until
females died. After 4 weeks, eggs counted bark
dissected to assess 1st stage larval galleries.
6
EAB eggs on or just under bark
7
Mean no. eggs per cm2 no-choice test n 5
No. eggs per cm2
8
Evaluated 1st stage larval galleries
9
Density of galleries per 100 cm2 no-choice
test n 5
10
No-choice lab bioassay
Black walnut
Black ash
11
Caged-Stem Bioassay
Screen cages confined 3 pairs of beetles on each
tree Dead beetles replaced June-Sept. Stems
dissected 4 blocks in Nov.6 blocks in
March Repeated in 2004 2005
12
EAB Gallery Density per m2 on Caged Stem Bioassay
13
Host Range Field Tests Ash, Elm, Walnut, Hickory,
Hackberry logs drain pipe set on t-posts at 4
sites. Adult landing rates monitored using
Tanglefoot. Logs dissected.
14
Landing Rates of EAB Adults
Total adults
Elm
Green ash
Hickory
Pipe
White ash
Hackberry
Black walnut
15
Gallery Density in Logs Strapped to T-Posts
16
Host Range Field Tests Green ash, elm walnut
logs suspended in heavily infested ash tree
canopies Will EAB females make a mistake? Logs
dissected.
17
Mean density of EAB galleries per m2 in
Suspended logs
3 logs per tree on 5 trees in 2 sites 30 total
logs
Green ash 195.5 49.5 Elm
0.0 Walnut 0 0
18
Host range field test 1st 2nd stage larvae
inserted into green ash, elm black walnut
19
Larval insertion green ash, elm black walnut
trees logs
20

• Alternate Species Results
• Adults will oviposit on alternate species under
  no-choice conditions.
• Oviposition mistakes occur but rare.
• 1st stage larvae fed readily on ash species a
  few larvae attempted to feed on other species but
  development impaired.

21
(2) Preference Among North American Ash Species
Green vs. White ash trees 4 neighborhoods over 3
years.
2003 canopy dieback was significantly higher in
green ash than white ash 2004 canopy dieback
increased in both species, still higher in green
ash 2005 canopy dieback reached 100 for most
green ash and rose sharply in white ash
Similar pattern for exit holes and woodpecker
attacks.
22
Preference Among North American Ash Species
White vs. Blue ash trees 2 woodlots over 2
years.
2004 exit holes and woodpecker attacks were
significantly higher in white ash than blue
ash 2005 exit holes and woodpecker attacks
increased in white ash but not blue ash and the
difference was more significant.
23
Host selection and feeding preference on ash spp.

• Green F. pennsylvanica
• Black F. nigra
• White F. americana
• Blue F. quadrangulata
• European F. excelsior
• Manchurian F. mandshurica

24
Experimental set up
beetles released
25

• Host selection - landing
• number of beetles on each ash species counted
  every 2h during the day for 48h
• Feeding preference amount consumed
• Leaves were scanned before and after the
  experiment
• Amount fed determined

26
a
2
males
1.8
b
Host selection - landing
1.6
b
1.4
No. of beetles on foliage (mean SE)
1.2
c
1
c
0.8
c
0.6
0.4
0.2
0
a
2.2
females
2
ab
ab
1.8
1.6
1.4
bc
1.2
c
c
1
0.8
0.6
0.4
0.2
0
green
black
white
blue
European
Manchurian
species
27
ab
a
males
12
Feeding preference
10
8
ab
bc
6
4
cd
d
2
0
Amount of foliage consumed ()
14
a
females
a
12
a
a
10
8
b
6
b
4
2
0
green
black
white
blue
European
Manchurian
species
28
(3) Stressed and Vigorous Trees Trap trees with
different stress treatments Girdled, herbicide,
methyl jasmonate, wounded Plantation study
Girdled, fertilized, and control trees of
different ash species
29
(4) Beetle performance on American vs. Asian
Species

• Raised beetles (n40) on green and Manchurian ash
  until they died
• Leaves changed and retrieved each week
• Measured amount consumed, weight gained / lost
  over two weeks and longevity

30
Foliage consumption
16
a
20
a
14
18
16
12
14
10
b
12
total amount consumed (cm)2
proportion consumed ()
8
10
b
8
6
6
4
4
2
2
0
0
green
Manchurian
green
Manchurian
31
Beetle performance
a
a
6
20
a
18
a
5
16
14
4
longevity (days)
12
weight loss at age 2 weeks (mg)
3
10
8
2
6
4
1
2
0
0
green
Manchurian
green
Manchurian
32
Results

• Total amount and proportion of foliage consumed
  was greater in beetles fed on green ash compared
  to Manchurian
• No difference in weight or longevity

33
What may be going on?

• Higher nutritive value of Manchurian ash?
• Presence of anti-feedants in Manchurian ash?
• Higher consumption of green ash by larvae
  mortality of trees in North America?

34
Compounds Identified and Quantified in Different
Ash Species

• hexanol
• E-2-hexenal
• Z-3-hexenol
• E-2-hexenol
• butoxyethanol
• Z-3-hexenyl acetate
• hexyl acetate
• E-ß-ocimene
• nonanal / linalool
• nonatriene
• Z-E-a-farnasene

Green White Black Blue European Manchurian
35
Z-3-Hexenol
36
Z-3-hexenyl-acetate
37
healthy
3
green
2.5
black
white
2
blue
1.5
European
1
Manchurian
0.5
0
-0.5
-1
-1.5
-3
-2
-1
0
1
2
3
4
stressed
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
-3
-3
-2
-1
0
1
2
3
4
38
Hybrid study

• North American ashes are preferred relative to
  Chinese ashes
• What would happen with hybrids?
• Crossed F. americana with F. chinensis to obtain
  two putative hybrids chiam1 and chiam2
• Tested beetle landing and feeding on the four
  genotypes
• Compared volatile profiles by aeration

39
Host selection by landing and feeding preference
F. americana
F. chinensis
Chiam 1
Chiam 2
40
Hybrid study Beetles released in cages
41
Hybrid study landing
Mean number of beetles
Observations over time
42
Hybrid study feeding
a
a
a
a
amount consumed (cm2) (mean SE)
a
a
a
a
proportion consumed () (mean SE)
species
43
Hybrid study Aerations
Super-Q
44
Compounds quantified

• hexanal
• e-2-hexenal
• z-3-hexenol
• e-2-hexenol
• z-3-hexenyl acetate
• hexyl acetate
• e-ß-ocimene
• nonanal / linalool
• farnesene

Gas chromatography
45
Hybrid study Comparison of volatiles
F. americana
40
35
30
25
20
15
10
5
0
F. chinensis
40
35
30
25
20
15
10
5
0
chiam1
Amount (ng / g dry wt)
40
35
30
25
20
15
10
5
0
40
chiam2
35
30
25
20
15
10
5
0
e-ocimene
hexanal
linalool
nonanal
farnesene
z-3-hexenol
e-2-hexenal
e-2-hexenol
hexyl_acetate
z-3-hexenyl_acetate
46
Hybrid study - Results

• Landing and feeding no significant differences
• Hybrids have taken on some characteristics from
  F. americana parent
• Volatile profiles of hybrids different from
  either parent may not be simply inherited

47
Conclusions

• EAB feed and develop in all ash species
• No evidence of larval survival or development on
  any non-ash species
• EAB prefer GreengtBlackgtWhitegtgtBlue ash
• EAB prefer N. American ash to Asian ash
• Hybrids may be intermediate and volatile
  characteristics are not simply inherited
• Surveys should focus on preferred trees (green
  ash)
• More research needed to develop resistance and
  attractive lures