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How to Manage Pests
UC Pest Management Guidelines
Citrus
Orange Tortrix
Scientific Name: Argyrotaenia (=citrana) franciscana
(Reviewed 7/03,
updated 7/05)
In this Guideline:
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DESCRIPTION OF THE PEST
The larva of the orange
tortrix is a greenish to straw-colored caterpillar with a straw-colored head
and prothoracic shield. The major distinguishing characteristic between orange
tortrix and omnivorous leafroller caterpillars is that the small mounds at the base of the
bristles on the side and back of the omnivorous leafroller are white, whereas
on the orange tortrix they are not.
Orange tortrix larvae feed inside
nests spun around plant parts. The larvae pupate in dense cocoons inside the
nests and adult moths emerge in 8
days to 3 weeks, depending on temperature. Females moths lay 50 to 150 eggs on
smooth surfaces such as stems, fruit, and the upper surface of leaves. In
coastal areas, orange tortrix may have more than three generations a year,
whereas in intermediate districts it has two or three. It is not a problem in
the Central Valley.
DAMAGE
Orange tortrix is primarily a pest on Valencias and navel oranges in
southern California. First generation orange tortrix larvae feed on leaves.
Second generation larvae appear when the growth is hardening off and move
preferentially to young fruit and feed around the
button. This feeding causes only superficial scars. Later generations feed
among clusters of ripening fruit, eating holes into the rind that allow decay
organisms to enter; the fruit usually drops within 1 to 2 weeks.
MANAGEMENT
Orange tortrix is generally managed by monitoring throughout spring
and summer and treating when necessary. Use selective (toxic to only a narrow
group of insects) insecticides to preserve populations of natural enemies.
Biological Control
Several parasites and predators attack orange tortrix. The most common
parasites are two wasps, Apanteles aristolidae and Exochus sp. These wasps lay their eggs in tortrix larvae and the parasites develop
within. Apanteles pupates in a white cocoon outside the dead
larvae, whereas Exochus pupates inside
the larva and emerges through a round exit hole.
Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis are acceptable for use in organically managed citrus
orchards.
Monitoring and Treatment Decisions
While orange tortrix larvae should be monitored throughout spring and
summer, the period from May through July is especially important. At 7- to
10-day intervals, look for orange tortrix and evidence of parasitism mainly on
the south and east quadrants of trees. If 15 larvae are found per hour of
search on oranges and grapefruit, or 30 larvae per hour of search on lemons, a
treatment may be warranted, depending on the level of parasitism.
| Common name |
Amount to Use |
Minimum Days before Harvest+ |
| (trade name) |
(type of coverage)** |
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| A. |
BACILLUS THURINGIENSIS ssp. KURSTAKI# |
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(various) |
Label rates |
4 hours |
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RANGE OF ACTIVITY:
Narrow (caterpillars)
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PERSISTENCE:
Short
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COMMENTS: Can be used during bloom. Timing is important
because of short residual period. Apply only during warm weather to control
young, actively feeding worms. Use reduced wind velocity and drive 3 mph.
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| B. |
CRYOLITE |
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(Prokil Cryolite) 96 |
8–20 lb/acre (OC) |
15 |
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(Kryocide) 96 WP |
8–20 lb/acre (OC) |
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RANGE OF ACTIVITY:
Narrow (foliage feeders such as worms, katydids and Fuller rose beetle.
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PERSISTENCE:
Long, unless washed off by rain.
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COMMENTS: Check label for variety. Use higher rate for larger
trees. Slow-acting stomach poison that may take several days of warm weather
to kill worms. Use reduced wind velocity and a speed of 3 mph. Do not exceed
90 lb/acre/season.
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| C. |
CHLORPYRIFOS* |
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(Lorsban) 4E |
1–2 qt/acre (OC or A) |
21 |
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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 more than
twice/fruit year or make applications less than 30 days apart. During the
bloom period, apply from 1 hour after sunset until 2 hours before sunrise.
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| D. |
CARBARYL* |
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(Sevin XLR Plus) 4F |
2 qt/acre (OC) |
5 |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Long
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COMMENTS: For use on all varieties. During the bloom period,
apply from 1 hour after sunset until 2 hours before sunrise. XLR Plus
formulation is less toxic to honey bees than the 80S formulation when direct application
to bees is avoided, and the spray residues have dried. Check with your local
county agricultural commissioner regarding application restrictions during
the bloom period.
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| E. |
NALED |
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(Dibrom) 8E |
2 pt/acre (OC) |
7 |
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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 grapefruit, lemons, oranges, tangerines.
This material is hazardous to bees. Do not apply during bloom.
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| F. |
METHOMYL* |
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(Lannate LV) 2.4 |
1.5–3 pt/acre (OC or A) |
3 |
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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 grapefruit, lemons, oranges, tangerines,
and tangelos. Apply as needed, except during daylight hours of the bloom
period. This material is hazardous to bees. Do not apply during bloom.
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| G. |
CARBARYL* |
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(Sevin) 80S |
2.5 lb/acre (OC) |
5 |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Long
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COMMENTS: For use on all varieties. This material is hazardous
to bees. Do not apply during bloom.
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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. OConnell, 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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