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How to Manage Pests
UC Pest Management Guidelines
Artichoke
Artichoke Aphid
Scientific name: Capitophorous elaeagni
(Reviewed 1/07,
updated 6/09)
In this Guideline:
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Artichoke aphids are
pale greenish white to yellowish green, almost translucent aphids with pale
appendages. The tips of the very long cornicles (siphunculi) are distinctly
dusky in color. The tubercles (located at the base of the antennae) are diverging in contrast to
those in the green peach aphid, which are converging. Wingless adults
have a long capitate hair on the third and the posterior abdominal segments;
winged adults have an almost rectangular solid black spot on their abdomen.
This aphid overwinters on its primary hosts, Elaeagnus species
(Russian olive, silverberry, and others), migrating in summer to thistles (Circium,
Carduus) and to artichokes where it can cause economic
damage.
Large numbers of these
aphids cause artichoke leaves to curl and turn yellow and the plants to show
retarded growth, resulting in the formation of undersize or deformed artichoke
buds. In addition, bud stalks weaken and can no longer support the weight of
developing buds, causing them to droop. Also, buds that are close to harvest
get contaminated with aphid bodies. Besides this direct-feeding damage,
artichoke aphid characteristically secretes copious amount of honeydew, which
is deposited onto leaves and developing artichoke buds in the lower canopy,
giving them a wet and shiny appearance. Honeydew deposits on the foliage result
in the growth of sooty mold, which covers the
leaf surface and interferes with photosynthesis. It is estimated that 10-15% of
the crop harvested during August-September is lost because of poor quality that
is a result of aphid damage. Also, aphid injury may delay the fall harvest by
several weeks because of retarded plant growth.
Artichoke aphid is a
serious problem on perennial artichokes during summer when the average humidity
and air temperature are in the high range; it is not a problem in southern
California annual artichoke fields. When choosing insecticide treatments to
control other pests, consider the impact of the materials on natural enemies of
this aphid. When conditions are ideal for development of populations, monitor
the crop weekly to determine the need to treat.
Biological Control
Several parasitic wasps attack aphids in artichoke, most notably
species in the genera Diaeretiella and Lysiphlebus.
General predators including lady beetles, syrphid fly, and lacewings also consume aphids. In addition, a portion of the
population may be killed by a fungal disease caused by Entomophthora
aphidis. However, naturally occurring predators, parasites,
and pathogenic fungi rarely provide timely control because of considerable time
lag between the buildup of the parasite/predator populations and the aphid
populations. Preserve populations of beneficial insects by avoiding unnecessary
insecticide applications and by providing acceptable habitat for these
predators and parasites.
Cultural Control
Destroy crop residue immediately after harvest.
Organically
Acceptable Methods
Biological controls, cultural controls, and neem oil are acceptable for
use on organically certified crops.
Monitoring
and Management Decisions
An outbreak of artichoke aphids is most likely to occur during periods of high
average daily temperatures coupled with high relative humidity (98–100%).
These conditions generally prevail from June to September. Intensify field
monitoring during this period by making weekly observations.This aphid
remains on the underside of the older leaves when population levels are low; at
higher population levels, aphids spread rapidly throughout the plant. A
population density of an average of 3 aphids per leaflet is considered a
treatment threshold. At this population level, isolated plants will start to
show the sooty mold on the foliage. Within a few days, the infestation becomes
more conspicuous as large contiguous areas start turning black from the growth
of sooty mold.
| Common name |
Amount/Acre |
R.E.I.+ |
P.H.I.+ |
| (trade name) |
|
(hours) |
(days) |
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| When choosing a
pesticide, consider information relating to impact
on natural enemies and honey bees and to the environment. Not all registered pesticides are listed. Always read label of product being used. |
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| A. |
IMIDACLOPRID |
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(Provado) 1.6F |
4–10 oz |
12 |
7 |
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MODE OF ACTION GROUP
NUMBER1: 4A |
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COMMENTS: Do not
apply more than 40 oz/acre/crop season. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area. |
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| B. |
BIFENTHRIN* |
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(Brigade) WSB |
16 oz |
12 |
5 |
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(Brigade) 2 EC |
6.4 fl oz |
12 |
5 |
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MODE OF ACTION GROUP
NUMBER1: 3 |
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COMMENTS: Do not
exceed 16 oz/acre between bud formation and harvest. Do not exceed 80
oz/acre/season. Mixing bifenthrin and permethrin at their half rate gives
acceptable control at less cost; however, be sure to observe all restrictions and precautions on the labels of both products. |
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| C. |
PYRETHRIN/ROTENONE |
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(Pyrellin EC) |
Label rates |
12 |
0.5 |
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MODE OF ACTION GROUP
NUMBER1: 3/21 |
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| D. |
NEEM OIL# |
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(Trilogy) |
1% solution |
4 |
0 |
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MODE OF ACTION: Unknown. A botanical insecticide. |
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COMMENTS: Thorough coverage is important; apply in a minimum of 75 gal water/acre. |
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UC IPM Pest Management Guidelines: Artichoke
UC ANR Publication 3434
Arthropods
M. A. Bari, Artichoke Research Foundation, Salinas
E. T. Natwick, UC Cooperative Extension, Imperial County
Acknowledgment for contributions to Arthropods:
W. E. Chaney, UC Cooperative Extension, Monterey County
W. L. Schrader, UC Cooperative Extension, San Diego County
L. Handel and T. K. Shannon, Kleen Globe, Inc., Castroville, CA
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