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How to Manage Pests
UC Pest Management Guidelines
Citrus
Amorbia (Western Avocado Leafroller)
Scientific Name: Amorbia cuneana
(Reviewed 7/03,
updated 7/05)
In this Guideline:
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DESCRIPTION OF THE PEST
Amorbia is primarily a pest
of avocado, but can also occasionally cause damage in citrus groves, primarily
in southern California and the San Joaquin Valley. The larva has two dark
horizontal lines on each side of its head and prothoracic shield that
distinguish it from other caterpillars that occur in citrus. There are two to
three generations a year.
DAMAGE
Amorbia larvae may feed on young fruit at petal fall. They
also feed on new growth flushes, often rolling the leaves or tying leaves to fruit and feeding
on the peel of young or maturing fruit and under the calyx. Damaged fruit often
decays at the feeding site.
Infestations generally occur in groves planted near avocado.
MANAGEMENT
Amorbia is generally managed by monitoring from petal fall through
fall. Use selective (toxic to only a narrow group of insects) insecticides to
preserve populations of natural enemies.
Biological Control
A variety of natural enemies attack egg, larval, and pupal
stages of amorbia. One of the most effective egg parasites is the tiny wasp, Trichogramma
platneri.
Parasitized eggs are black. Mass
releases of T. platneri are used for
control in avocado. A tachinid fly and several
parasitic wasps attack the larvae stages. The tachinid
fly attaches
its eggs near the head of the larva and the emerging maggots bore into the amorbia larva
to develop inside.
Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis are acceptable for use in organically managed citrus
orchards.
Monitoring and Treatment Decisions
When monitoring for citrus thrips at petal fall, especially in groves
near avocados, check under the button on the base of fruit for small amorbia
larvae. Monitor larger larvae later in spring by looking for webbing and leaf rolls
in young foliage and feeding damage on young and mature fruit located on the
outside canopy.
| Common name |
Amount to Use |
Minimum Days before Harvest+ |
| (trade name) |
(type of coverage)** |
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| A. |
BACILLUS THURINGIENSIS ssp. KURSTAKI# |
| |
(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 |
0.5–2 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. 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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