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How to Manage Pests
UC Pest Management Guidelines
Carrot
Green Peach Aphid
Scientific Name: Myzus persicae
(Reviewed 10/05,
updated 10/05)
In this Guideline:
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Green peach aphid is most common in spring and fall
but may be found at any time throughout the year. It is a medium-sized aphid
and the wingless forms are uniformly pale green in color. At times, a pinkish
form may be present. During cool weather, individuals of both color forms may
be slightly darker than those found during hotter times of the year. Both
winged and wingless forms have prominent cornicles that are slightly swollen
and clublike in appearance. The frontal tubercles at the base of the antennae
are very prominent and are convergent. The winged forms have a distinct dark patch on the top of
the abdomen; wingless forms lack this dark patch.
The green peach aphid vectors more plant viruses than any other
aphid, transmitting over 100 different virus diseases. It does not, however,
vector carrot motley dwarf or carrot red leaf virus. Virus-infested leaves are
distorted and curled. If populations are high enough, stunting may occur.
Infestations on young plants are more serious than those on older plants.
Biological Control
Green peach aphid is attacked by a number of common predators and parasites and is susceptible to the fungus disease that commonly attacks aphids.
Common predators include green lacewing, lady
beetles, and syrphid fly larvae.
Cultural Control
Field sanitation is important in reducing the number of aphids in and
around carrots.
Organically Acceptable Methods
Biological and cultural controls are acceptable for use on organically
grown produce.
Monitoring and Treatment Decisions
Monitor fields for aphids weekly during spring and summer by examining
the upper and lower surfaces of leaves. Also, look for evidence of predators
and parasites and their impact on aphid populations. Small colonies
occasionally develop on carrot leaves and may reach treatable levels, but no
treatment thresholds for green peach aphid on carrots have been established.
Green peach aphid has developed a high level of resistance to many chemicals
and may be hard to control.
| Common name |
Amount/Acre**
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P.H.I.+ |
| (trade name) |
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(days) |
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| When choosing a pesticide, consider information relating
to water quality and impact on natural enemies and bees.
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| A. |
IMIDACLOPRID |
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(Provado) 1.6F |
3.5 fl oz |
7 |
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MODE OF ACTION: A neonicotinoid (Group
4A)1 insecticide.
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COMMENTS: Thorough, uniform coverage is
important for good control. Use allowed under a supplemental label.
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| B. |
ENDOSULFAN* |
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(Thionex) 3EC |
1.33 qt |
7 |
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MODE OF ACTION: An organochlorine (Group 2A)1 insecticide. |
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COMMENTS: Do not use treated tops for food. See label for
application limits. |
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| ** |
See label for dilution rates. |
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| + |
Preharvest interval. Do not apply within this many days of harvest. |
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| 1 |
Modes of action are important in preventing the development
of resistance to pesticides. Rotate chemicals with a different mode-of-action
group number, and do not use products with the same mode-of-action group
number more than twice per season. For example, the organophosphates
have a group number of 1B; chemicals with a 1B group number should be
alternated with chemicals that have a group number other than 1B. Mode
of action is assigned by IRAC (Insecticide Resistance Action Committee).
For additional information, see their Web site at http://www.irac-online.org/. |
| * |
Permit required from county agricultural commissioner for purchase
or use. |
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UC IPM Pest Management Guidelines: Carrot
UC ANR Publication 3438
Insects
C. G. Summers, Entomology, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey Co.
E. T. Natwick, UC Cooperative Extension, Imperial Co.
D. R. Haviland, UC IPM Program, Kern Co.
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