Progress in Management of Avocado Lace Bug
Eduardo Humeres, Mark S. Hoddle, Richard Stouthamer and Joseph G. Morse
Department of Entomology, University of California, Riverside, CA
Medium Nymphs
Adult
90
Corrected Mortality (%)
80
70
60
50
40
30
20
10
0
Small Nymphs
8.00
6.00
4.00
6-Oct-06
8-Sep-06
20-Oct-06
22-Sep-06
28-Jul-06
14-Jul-06
25-Aug-06
11-Aug-06
2-Jun-06
30-Jun-06
16-Jun-06
7-Apr-06
5-May-06
21-Apr-06
19-May-06
24-Mar-06
27-Jan-06
10-Mar-06
13-Jan-06
24-Feb-06
10-Feb-06
30-Dec-05
4-Nov-05
2-Dec-05
18-Nov-05
7-Oct-05
21-Oct-05
9-Sep-05
16-Dec-05
2.00
23-Sep-05
Adults
100
Corrected Mortality (%)
10.00
26-Aug-05
Number of ALB adult / leaf
12.00
0.00
Medium Nymphs
Mortality of ALB Nymphs by Neoseiulus californicus
3.3. Adult female
Neoseiulus californicus
(predaceous mite)
Adult
60
40
20
1st Stage Nymphs
Among the 14 ALB populations studied, there are three different
genotypes detected for the CO1 genetic marker. Except for the population
from Veracruz (Mexico), all other populations are monotypic at the
mitochondrial region, suggesting that the populations that have settled in
the U. S. have different origins (i.e. FL vs. TX and CA). Five out of 24
microsatellite markers showed variation between CA, Weslaco, and
Veracruz populations. There was population variation within the CA
individuals. On the other hand, there was no variation detected within
Weslaco and Veracruz populations. Therefore the CA population may have
originated from an area we have not yet sampled.
20
oil
T7
T6
-p
et
ro
le
+
um
- fe
np
ro
pa
th
ri n
oil
oi
l
m
ec
ti n
-a
ba
T5
-s
p in
os
ad
T4
id
ac
lo
- im
+
pr
id
l
0
Contact Impact of Insecticides on ALB Nymphs
Results: Contact insecticides
100
were evaluated 72 h post72h
90
80
treatment. Pyrethrin was the
70
60
best contact treatment of
50
40
those evaluated to control
30
20
ALB. The two other pyrethrin
10
0
treatments (i.e. pyrethrins
T7
T6
T5
T3
T8
T4
-p
-n
-p
-p
-p
-p
mixed with potash soap or
et
ee
yr
ot
yr
yr
ro
et
as
et
et
m
hr
hr
le
hr
h
o
u
in
in
in
so
il
m
s
s
s
rotenone) were not as
ap
+
oi
+
l
ro
po
te
ta
no
sh
effective as using pyrethrin
ne
so
ap
alone. Petroleum oil and
potash soap tied as the
second most effective treatments. Petroleum oil had no residual impact, but
was effective as a contact insecticide. Neem oil had little impact on ALB
nymphs.
4.3. Susceptibility of Chrysoperla rufilabris to imidacloprid:
80
0
2. Genotyping ALB:
30
20
Average Number of ALB Adults / Leaf from 6 Sites in San Diego Co. 2005-06
(field samples)
14.00
40
4.2. Contact impact of insecticides on ALB:
30
Mortality of ALB by Lacewing
16.00
50
T3
40
100
Results:
After a year of ALB
sampling, the highest
densities of adult ALB
in San Diego Co. were
reached between the
months of August –
December with the
peak occurring in October.
60
50
Small Nymphs
ALB sampling sites were selected based upon high levels of ALB, avocado
tree size, and to achieve a diversity in sample locations. Infested ALB sites
were not found further inland, therefore the six sample sites are located
along the coastal region of San Diego Co.
77 days
112 days
60
0
1. ALB Population Monitoring:
28 days
49 days
70
10
3.2. Second instar larva
of Chrysoperla rufilabris
(green lacewing)
7 days
14 days
70
Corrected Mortality (%)
ALB 2004-05 Survey
3 days
80
10
Small Nymphs
Results:
Adult female Franklinothrips orizabensis preyed mostly on small
nymphs (60% mortality) compared with only 6% and 0%
mortality on medium-sized nymphs and adult ALB, respectively.
These results are not promising. Similar negative results were
obtained with adult female Neoseiulus californicus -- they did not
effectively feed on small ALB stages. On the other hand, studies
with second instar larvae of Chrysoperla rufilabris showed they
efficiently preyed on all ALB stages tested. The highest mortality
was on the ALB medium size nymphs (96%) followed by adults
(71%), and small size nymphs (60%).
Results: Data indicate
that avocado trees treated
with imidacloprid
(Admire Pro®) can cause
lacewing mortality due to
food chain impacts (i.e.
by lacewing larvae being
exposed to imidacloprid
via feeding on poisoned
ALB).
Susceptibility of Lacewing to Admire Pro®
100
90
Corrected Mortality (%)
ALB Fall 2006
Survey
2 New Sites
80
90
80
70
60
50
40
30
20
10
0
-L
w2
-L 4h- A
w4 dm
-L 8h- ire
w- Ad
72 m
h- ire
Ad
T3 m ir
-L e
w
T3 - 2 4
-L h
wT2
-A T3 4 8h
-L
L
T2 B- P w72
-A
r
L e-A h
T2 B- 2 dm
-A 4h
ir
-A e
L
T2 B- 4 dm
-A 8h
ir
LB -A e
T2 - 72 dmi
-L h-A re
w
d
T2 - 24 mir
-L hAd e
w
T2 - 48 m ir
-L h- A e
w72 dm
h- ire
A
T 4 dm
-A ire
L
T4 B- P
r
-A
L e
T4 B- 2
-A 4h
L
T4 B- 4
-A 8h
LB
T4 - 72
-L h
w
T4 - 2 4
-L h
w
T4 - 4 8
-L h
w72
h
Fig. 2
90
Residual Impact of Insecticides on ALB
100
T1
3.1. Adult female
Franklinothrips orizabensis
(predatory thrips)
Fig. 1
Corrected Mortality (%)
100
Results: The insecticides
carbaryl, imidacloprid, and
fenpropathrin were the best
insecticides of those evaluated
to control ALB nymphs at 112
days post-treatment. Spinosad
and abamectin plus oil were
not effective against ALB,
despite past recommendations
for their use against ALB.
-c
ar
ba
ry
Mortality of ALB by Franklinothrips
4.1. Residual impact of insecticides on ALB:
Corrected Mortality (%)
General Protocol:
Predators were starved 24h prior to the bioassay. Predation on
different ALB stages, i.e. nymphs (small, medium and large size)
and adults was evaluated using Munger cells to confine the bugs
in the presence of the predator. The prey/pest ratio used in each
cell was one predator per 5-15 ALB stages per cell. ALB mortality
was assessed 24 hours after the prey were exposed to the
predator.
4. Pesticide Trial:
T2
3.Natural Enemy Studies: Testing natural enemies as
potential augmentative control agents for ALB
T1
(Heidemann), was discovered in September 2004 feeding on backyard
avocado trees in San Diego County. Several ALB surveys were conducted
by the County of San Diego Department of Agriculture, Weights &
Measures (AWM) and the California Department of Food and Agriculture
(CDFA) during 2004-05 (Fig. 1) and 2006 (spring and fall). So far, it
hasn’t been found in commercial avocado groves in San Diego County and
prior to 2006, it was not found north of the Interstate 8 freeway. During
the ALB fall 2006 survey, two new sites were detected near La Jolla
(coastal region) and they are approximately 10 miles above the
northernmost previous ALB site (Fig. 2).
T1
INTRODUCTION: The avocado lace bug (ALB), Pseudacysta perseae
Treatment