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How to Manage Pests
UC Pest Management Guidelines
Cucurbits
Green Peach Aphid
Scientific Name: Myzus persicae
(Reviewed 12/09,
updated 12/09)
In this Guideline:
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The green peach aphid is rather slender in form, light green or
yellowish in color. Winged
adults of the green peach aphid are pale or bright green and black, with a large dusky
blotch on the dorsum of the abdomen. The immature forms are yellow, pinkish, or
pale green. The mature wingless forms are pale or bright green and have no waxy
covering. The tubercules at the
base of the antennae grow towards each other. Populations tend to start on
lower leaves and move up the plant. The green peach aphid occurs throughout
California and has a wide host range.
In desert areas, watermelon
mosaic virus, zucchini yellow mosaic, and
papaya ringspot virus are transmitted chiefly by the green peach aphid. This
aphid moves into melon fields in large numbers from surrounding vegetation,
carrying viruses as it moves and feeds from one plant to another. In the San
Joaquin Valley, cucumber mosaic, zucchini mosaic, and watermelon mosaic are
often the most important viruses transmitted by this aphid.
Silver reflective mulches have successfully been used to repel
aphids from plants, thus reducing or delaying virus transmission. In some areas
of the state, row covers have also been successfully used. Biological control
can have a significant impact on aphid population so be sure to evaluate
predator and parasite populations when making treatment decisions.
Biological Control
Naturally-occurring populations of the convergent
lady beetle, Hippodamia convergens,
may provide effective control in early spring. Releases of this beetle are not
effective, however, because it generally does not remain in the field following
release. Other general predators, such as lacewing and syrphid larvae, and parasitic wasps, including Aphidius, Diaeretiella,
and Aphelinus
species, also attack aphids. Biological control is not effective in reducing
virus transmission by this aphid.
Cultural Control
To exclude green peach aphid, place row covers over the seed bed
following planting and leave them in place until first bloom. Row covers are
not recommended in the San Joaquin Valley. Silver reflective plastic mulches
applied at planting are effective in repelling aphids from plants, thereby
reducing or delaying virus infection. Mulches help plants get off to a healthy
start, and are effective until expanding foliage covers the reflective surface.
Mulches may need to be removed in the desert areas when summer temperatures are
excessive for optimal growth of plants. However, in the Central Valley and
cooler areas, mulches have not caused plant damage in the summer; in fact, they
improve soil moisture and nutrient retention, which may further aid plant
productivity.
Control weeds along ditch banks, roads, in farmyards, and other
noncultivated areas that contribute directly to the aphid problem. Planting a
habitat for beneficial insects, such as sweet alyssum, around the field may be
helpful. Delay planting until warm temperatures (80° to 85°F) occur and the
spring flight of aphids is over. Do not overfertilize with nitrogen.
Organically Acceptable Methods
Biological and cultural controls and treatments of insecticidal
soaps and certain narrow range oils are acceptable to use in an organically
certified crop.
Monitoring and Treatment Decisions
The decision to treat for aphids is based mainly on visual counts;
measurable thresholds have not been researched. It is important to treat early
to insure that the aphids do not build up to high levels. Early treatment does
not prevent virus introduction; treating, however, may help reduce spread of
the virus if aphid colonies are present. Be aware, however, that parasites and
predators, if present, may prevent an infestation from becoming established
throughout a field, thus eliminating the need to treat.
| Common name |
Amount/Acre |
R.E.I.+ |
P.H.I.+ |
| (trade name) |
|
(hours) |
(days) |
|
| The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, pesticide registrations, information related to natural enemies and honey bees, and environmental impact. Not all
registered pesticides are listed. Always read label of product being used. |
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| A. |
DINOTEFURAN |
| |
(Venom) 70W |
See comments |
12 |
see comments |
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MODE OF ACTION GROUP NUMBER1: 4A |
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COMMENTS: Rates vary depending upon whether a soil or foliar
application. Soil application preferred because it has less impact on
beneficials. Preharvest intervals: foliar application—1 day; soil—21 days. |
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| B. |
IMIDACLOPRID |
| |
(Admire Pro) |
7–10.5 fl oz |
12 |
21 |
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MODE OF ACTION GROUP NUMBER1: 4A |
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COMMENTS: Apply at planting or transplanting and incorporate into root zone. |
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| C. |
THIAMETHOXAM |
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(Platinum) |
5–8 fl oz |
12 |
30 |
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MODE OF ACTION GROUP NUMBER1: 4A |
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COMMENTS: At seeding or transplanting, apply in sufficient
water to ensure uniform application and incorporation into the soil. Provides about 40 days of protection. Use where field has history of these pests. |
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| D. |
PYMETROZINE |
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(Fulfill) |
2.75 oz |
12 |
0 |
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MODE OF ACTION GROUP NUMBER1: 9B |
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| E. |
ROSEMARY OIL# |
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(Hexacide) |
0.75–1.5 qt |
— |
0 |
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MODE OF ACTION: Contact including smothering and barrier effects. |
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COMMENTS: Good coverage is essential for good control. Apply
in a minimum of 25 gal/acre. Less disruptive of beneficials than the other organically acceptable alternatives listed. |
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| F. |
INSECTICIDAL SOAPS# |
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(M-Pede) |
1–2% solution |
12 |
0 |
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MODE OF ACTION: A contact insecticide with smothering and barrier effects. |
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COMMENTS: This material will reduce populations temporarily, but has no residual and requires repeat applications and thorough coverage. |
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| G. |
NARROW RANGE OILS# |
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(Saf-T-Side, Organic JMS Stylet Oil, etc.) |
3–6 qt/100 gal |
4 |
0 |
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MODE OF ACTION: Contact including smothering and barrier effects. |
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COMMENTS: Oil will reduce populations temporarily, but has no
residual and requires repeat applications and thorough coverage. Oils may
cause phytotoxicity problems; exercise care when using these materials. Check with certifier to determine which products are organically acceptable. |
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| H. |
METHOMYL* |
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(Lannate) LV |
1.5–3 pt |
48 |
see comments |
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MODE OF ACTION GROUP NUMBER1: 1A |
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COMMENTS: Labeled for use on melons, cucumbers, and summer
squash only. Apply early and as needed 7 days later. Repeated use of this
material is very disruptive to beneficials. PHI is 1 day if 1.5 pt or less is used/acre; if over 1.5 pt, PHI is 3 days. |
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| I. |
OXYDEMETON METHYL* |
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(MSR Spray Concentrate) |
1.5–2 pt |
14 days |
see label |
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MODE OF ACTION GROUP NUMBER1: 1B |
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COMMENTS: Apply in sufficient water for complete coverage, but
not less than 1 gal/acre. No more than 1 application/season. Repeated use of this material is very disruptive to beneficials. |
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UC IPM Pest Management Guidelines: Cucurbits
UC ANR Publication 3445
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County
J. J. Stapleton, UC IPM Program, Kearney Agricultultural Center, Parlier
C. S. Stoddard, UC Cooperative Extension, Merced & Madera counties
Acknowledgment for contributions to Insects and Mites:
R. L. Coviello, UC Cooperative Extension, Fresno County
L. D. Godfrey, Entomology, UC Davis
C. B. Fouche, UC Cooperative Extension, San Joaquin County
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
J. B. LeBoeuf, AgriData Sensing, Inc., Fresno
M. Murray, UC Cooperative Extension, Colusa/Glenn counties
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