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How to Manage Pests
UC Pest Management Guidelines
Citrus
Mealybugs
Scientific Names:
Citrus mealybug: Planococcus citri
Citrophilus mealybug: Pseudococcus calceolariae
Longtailed mealybug: Pseudococcus
longispinus
Comstock mealybug: Pseudococcus comstocki
(Reviewed 7/03,
updated 7/03)
In this Guideline:
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DESCRIPTION OF THE PESTS
Mealybugs are soft, oval, flat, distinctly segmented, and covered with a white,
mealy wax that extends into spines (filaments) along the body margin and the
posterior end. The species differ mainly in the thickness and length of the
waxy filaments. Citrus mealybug, the
most common species, has a pinkish body that is visible through the powdery
wax. The filaments around its margins are not appreciably longer at the
posterior end. The Comstock mealybug
primarily occurs on lemons in the San Joaquin Valley and has a thicker wax
cover than the citrus mealybug. In addition, it has two spines at the posterior
end, about one-quarter the length of the body. The other two mealybug species
are usually not a problem in citrus because they are kept at low population
levels by parasites.
Female mealybugs lay several hundred
eggs on the leaves, fruit, or twigs;
eggs for some of the species are laid in cottony egg sacs. Newly hatched nymphs
are light yellow and free of wax, but soon start to excrete a waxy cover. There
are two to three overlapping generation a year.
DAMAGE
Mealybugs extract plant sap, reducing tree vigor, and excrete honeydew. If a
cluster of mealybugs feeds along a
fruit stem, fruit drop can occur.
Damage is most severe in spring and fall.
MANAGEMENT
Mealybugs are primarily managed by conserving their natural enemies and
reducing ant populations. Treatment is rarely required.
Biological Control
Parasites provide good control of
the
citrophilus, longtailed, and Comstock
mealybugs if they are not destroyed by treatments for other pests. Native
predators include lady beetles,
lacewings, and
syrphid flies. An introduced predator of
the citrus mealybug, the mealybug destroyer, Cryptolaemus montrouzieri, is a voracious feeder of the
pest in both the larval and adults stages. Its larvae resemble a mealybug but
are about twice as large as the adult citrus mealybug females. The adult is a
small beetle with dark brown wing covers and a light brown head and prothoraic
shield. Because Cryptolaemus does not survive the winter well, it can be
purchased from commercial insectaries in early spring and released in orchards
where citrus mealybugs were a problem the previous year. Release about 500
Cryptolaemus per acre.
Organically Acceptable Methods
Biological control, including the release of Cryptolaemus montrouzieri,
is acceptable in organically managed citrus groves.
Monitoring and Treatment Decisions
If a heavy population of mealybugs must be reduced quickly, a treatment can be
applied, but release Cryptolaemus after about 2 weeks to reestablish
biological control.
Common name
(trade name) |
Amount to Use
(type of coverage)** |
Minimum Days
before Harvest+ |
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| A. |
CRYPTOLAEMUS MONTROUZIERI# |
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(Mealybug destroyer) |
500/acre |
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RANGE OF ACTIVITY:
Narrow (mealybugs) |
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PERSISTENCE: Intermediate
(does not survive winters well) |
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COMMENTS: Release in early spring in orchards where citrus
mealybugs were a problem the previous year. |
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| B. |
CHLORPYRIFOS* |
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(Lorsban) 4E |
0.75 pt/100 gal (TDC) |
See comments below |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites) |
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PERSISTENCE: Intermediate |
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COMMENTS: For use on all varieties. Do not apply during
bloom or make second application within 30 days; do not exceed 2 applications
or 12 pt/acre/year. Minimum period before harvest is 21 days up to
7 pt/acre and 35 days above 7 pt/acre. |
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...PLUS...(optional) |
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NARROW RANGE OIL |
1.2-1.4 gal/100 gal |
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(415, 440) |
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RANGE OF ACTIVITY:
Broad (unprotected stages of insects and mites) |
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PERSISTENCE: Short |
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COMMENTS: Use highest dosage of oil for July or Aug applications.
Caution: Serious hazards
are associated with oil treatments to green lemons because of phytotoxicity
after sweating; check label for preharvest interval. |
![[Precautions]](/IMAGES/btn-precautions_bul.gif)
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UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Kearney Agricultural Center, Parlier
J. G. Morse, Entomology, UC Riverside
N. V. O'Connell, UC Cooperative Extension, Tulare Co.
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura Co.
C. E. Kallsen, UC Cooperative Extension, Kern Co.
D. R. Haviland, UC Cooperative Extension, Kern Co.
Acknowledgments for contributions to the insect, mite, and snail section:
J. Barcinas, E. S. I., Corona, CA
R. Dunn, Badger Farming Co., Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
H. Griffiths, E. S. I., Corona, CA
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
T. Roberts, E. S. I., Corona, CA
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA
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