Acyrthosiphon
lactucae
Foxglove Aphid in Desert Lettuce
•
Native to Europe, has been recorded on crops in
Western US since 1940’s, including CA.
•
Has a wide host ranges, but primarily a pest of
potatoes and ornamentals in greenhouse production.
•
•
•
Jul 1998
- Found infesting head lettuce in Salinas.
Jan 1999
- Lettuce aphid found on lettuce in desert.
•
Feb 2002 – Identified Foxglove in Yuma on untreated
lettuce plots at YAC.
Mar 2001 – Found an unidentifid aphid in untreated
lettuce plots at YAC.
Mean Winged Aphid / trap / day
Sticky Trap Monitoring for Aphids 2002-2003
40
35
30
25
No Foxglove
Aphid
20
15
10
5
0
Aug
30
Mean Winged Aphid / trap / day
Gila Valley
Ave 5E and Co. 81/2 St.
Laguna Dam Rd and Gila River
Ave 8E and Co. 71/2 St.
Ave 10 E and Co 8th St
Ave 111/2 E and Co. 5th St.
Sep
23
Oct
11
Nov
2
40
35
30
25
20
Ave 181/2 E and Co. 51/2 St.
Ave 201/2 E and Co. 71/2 St.
Ave 25E and Co. 11th st
Ave 321/2 E and Co. 9th St
Ave 39 E and Co. 61/2 St
Dec
4
Jan
7
Feb
12
Mar
20
Dome Valley / Wellton
No Foxglove
Aphid
15
10
5
0
Aug
30
Sep
23
Oct
11
Nov
2
Dec
4
Jan
7
Feb
12
Mar
20
Mean Winged Aphid / trap / day
Sticky Trap Monitoring for Aphids 2002-2003
Yuma Valley - Colorado River
40
35
30
River and Co. 18th St.
River and Co. 14 1/2 St.
River and Co. 9 1/2 St.
25
20
15
10
5
0
Mean Winged Aphid / trap / day
Aug
30
Sep
23
Oct
11
Nov
2
40
35
30
25
Ave I and Co. 21th St.
Ave G and Co. 20 th St,
Ave F and Co. 14 th St.
Somerton Ave and 8 th St
Dec
4
Jan
7
Feb
12
Mar
20
Yuma Valley - Field
20
15
10
5
0
Aug
30
Sep
23
Oct
11
Nov
2
Dec
4
Jan
7
Feb
12
Mar
20
Foxglove Aphid in Desert Lettuce
•
Nov 2002: First Foxglove aphids found colonizing
untreated head lettuce in Yuma Valley .
•
Jan 2003: Light infestations on numerous untreated
fields in Yuma Valley.
•
Feb 2003: Found on organic lettuce in Bard, CA
and Algodones, Mexico .
•
Feb 2003: Found colonizing mature head lettuce
and Romaine treated with Admire in Yuma Valley.
•
Winter 2004:
?
Will Foxglove Aphid Continue to be a Desert Pest?
Celery
Beans
Brassicas
Peas
Citrus
Potato
Melons
Pecans
Ragweed
Purslane
Pigweed
Ground cherry
Shepards purse
Silverleaf nightshade
Lambsquarter
Dandelion
Avg. Aphids / Plants
Avg. Aphids / Plants
Avg. Aphids / Plants
o
Temperature ( F)
Foxglove Aphid in Head Lettuce
75
70
65
60
55
50
75
70
65
60
55
50
Average Daily Temperature
20
16
2000-2001
2001-2002
2002-2003
20
2000-2001
16
12
12
8
8
4
4
0
0
20
Wet date
Oct 11
Nov 1
Nov 15
Dec 1
Dec 15
20
2001-2002
16
16
12
12
8
8
4
4
0
0
2002-2003
300
300
250
250
200
200
150
150
100
100
50
50
0
0
20
Nov
3
Dec
17
Dec
Oct 10
Oct 28
Nov 15
Dec 3
Dec 13
1
Jan
14
Jan
28
Jan
11
Feb
25
Feb
11
Mar
25
Mar
Oct 10
Oct 29
Nov 14
Dec 3
Dec 12
Green Aphid Complex
o
Temperature ( F)
(Green Peach / Potato / A. lactucae)
75
60
Avg. Aphids / Plant
Acyrthosiphon lactucae
Average Daily Temperature
75
70
65
60
55
50
75
70
65
60
55
50
75
1999-2000
60
45
45
30
30
15
15
0
75
0
75
60
2000-2001
2000-2001
60
45
45
30
30
15
15
0
0
75
60
60
45
30
30
15
15
0
0
400
400
300
300
200
200
100
100
0
0
3
Dec
Oct 11
Nov 1
Nov 15
Dec 1
Dec 15
Oct 11
Nov 1
Nov 15
Dec 1
Dec 15
Oct 10
Oct 28
Nov 15
Dec 3
Dec 13
500
2001-2002
2002-2003
2002-2003
20
Nov
Wet dates
75
2001-2002
45
500
1999-2000
2000-2001
2001-2002
2002-2003
17
Dec
1
Jan
14
Jan
28
Jan
11
Feb
25
Feb
11
Mar
25
Mar
Oct 10
WetOct
date
29
Nov 14
Dec 3
Dec 12
Comparison of Soil-applied Insecticides
For Aphid Control in Head Lettuce
Foxglove Control in Head Lettuce
With Nicotinoids
Mean Aphids / Head
90
106 DAP;
66 DAT SD;
14 DAT #3
Nov 14 wet date
80
80
Foxglove aphid
A. lactucae / Potato aphid
70
90
70
60
60
50
50
40
40
30
73%
20
10
30
80%
82%
20
90%
10
0
0
Admire
16 oz
Platinum
8 oz
Platinum
side-dress
8 oz
Assail
1.7 oz
Untreated
Interactions between Aphid and Thrips
Control in Head Lettuce
Interactions between Aphid and Thrips
Control in Head Lettuce
Mean aphids / plant
25
20
88 DAP;
11 DAT # 2
Dec 1 wet date
Foxglove aphid
Green aphid complex
25
20
15
15
10
10
5
5
91 %
0
Admire
16 oz
Admire 16 oz
Lannate
Mustang
0
Admire 16 oz
Success 6 oz
Untreated
Interactions between Aphid and Thrips
Control in Head Lettuce
Mean aphids / head
90
80
70
109 DAP;
20 DAT # 3
Dec 1 wet date
90
80
Foxglove aphid
Green aphid complex
70
60
60
50
50
40
40
30
30
20
10
20
85%
85%
10
95%
0
Admire
16 oz
Admire 16 oz
Lannate 0.7 lb
Mustang 4 oz
Admire 16 oz
Success 6 oz
0
Untreated
Interactions between Aphid and Thrips
Control in Head Lettuce
Mean aphids / head
50
40
98 DAP;
10 DAT # 3
Dec 12 wet date
Foxglove aphid
Green aphid complex
40
30
20
50
30
40%
10
20
82%
10
80%
0
0
Admire
16 oz
Admire 16 oz
Lannate 0.7 lb
Mustang 4 oz
Admire 16 oz
Success 6 oz
Mustang 4 oz
Untreated
Considerations for Foxglove Control
in Desert Lettuce
• Begin scouting for aphids in October; be
aware of fields adjacent to citrus / houses.
• Consider closing the Admire-free window
earlier :
late October in Yuma Valley.
• Apply a minimum of 16 oz of Admire in
October / early November plantings.
• Increase rates of Admire to 20 oz or >
in mid November – December plantings
Foxglove Aphid Seasonal Contamination
in Head Lettuce
160
Mean Aphids / Head
140
Infested Heads at Harvest in untreated lettuce
160
2001/2002
2002/2003
140
120
120
100
100
80
80
60
60
40
40
20
20
0
0
Oct
10
Nov
2
Nov
14
Wet Date
Dec
3
Dec
12
•
Considerations for Foxglove Control
in Desert Lettuce
Begin scouting for aphids in November; be
aware of fields adjacent to citrus / houses.
• Consider closing the Admire-free window
earlier :
late October in Yuma Valley.
• Apply a minimum of 16 oz of Admire in
October / early November plantings.
• Increase rates of Admire to 20 oz or > in late
plantings:
mid November – December.
• Incorporate foliar aphicides into your thrips
program – Orthene, dimethoate, endosulfan
Foliar Efficacy Against Foxglove Aphid
in Desert Lettuce
YAC, Spring 2003
10- DAT #2
Mean aphids / plant
21
21
18
18
15
15
12
12
9
9
6
6
3
0
3
95%
Provado
Endosulfan
Orthene
1 lb
Dimethoate
12 oz
Endosulfan
30 oz
Untreated
0
Thrips Control in Head Lettuce
100
7 - 10 DAT
% Control (Range)
Larvae
80
60
40
20
0
Adults
80
60
40
20
0
Lannate
0.7 lb
+
Mustang
4 oz
Orthene
1 lb
+
Mustang
4 oz
Dimethoate
12 oz
Dimethoate
12 oz
+
Mustang
4 oz
Endosulfan
32 oz
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