How to Manage Pests
UC Pest Management Guidelines
Plum
Orange Tortrix
Scientific name: Argyrotaenia citrana
(Reviewed 5/06,
updated 5/06)
In this Guideline:
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DESCRIPTION OF THE PEST
The orange tortrix is only found in coastal areas. Its larvae are
light green caterpillars with brown heads; they resemble obliquebanded
leafroller caterpillars. When disturbed, the larvae wiggle backwards and drop
to the ground on a silken thread. Adults are
fawn or gray-colored moths with a darker mottling on the forewings. The orange
tortrix overwinters as larvae and there are two to four generations each year
in coastal areas.
DAMAGE
Larvae feed on leaves, buds, and the surface of fruit, causing
severe damage as well as contamination with their excrement.
MANAGEMENT
Orange tortrix is a cyclical pest. In coastal orchards, natural
enemies and treatments for other pests usually keep this pest controlled. In
other areas treatment is not needed.
Biological Control
Several parasites and predators attack
orange tortrix. Parasites include the wasps Cotesia
(Apanteles) aristolidae, Exochus sp., and Hormius basalis and a tachinid fly (Nemorilla pyste). Predators include spiders and brown
lacewing larvae (Hemerobius pacificus).
Cultural Control
Remove and dispose of mummy fruit to
reduce overwintering orange tortrix. Also, remove weed hosts such as mustard.
The use of grass cover crops helps reduce overwintering hosts.
Organically Acceptable Methods
Biological and cultural controls and
sprays of Bacillus thuringiensis are organically acceptable
controls.
Monitoring
and Treatment Decisions
If you suspect orange tortrix is a problem
and your orchard is located in coastal areas, sample fruit on a weekly basis
for damage beginning in June to determine spray timing. Sample 20 fruit on 15
trees for a total of 300 fruit. Treat if between 1 and 2% damage occurs on
fresh market fruit (check with cannery fieldman for damage acceptable for
processing fruit).
Take a fruit damage sample at harvest to assess the effectiveness
of the current year's IPM program and to determine the needs of next year's program.
See FRUIT EVALUATION AT HARVEST. Record results
on a monitoring form .
| Common name |
Amount to Use** |
P.H.I.+ |
| (trade name) |
(conc.) |
(dilute) |
(days) |
|
| The following materials are listed in order of usefulness in an IPM program,
taking into account efficacy, impact on natural enemies and honey bees, and
impact of the timing on beneficials. When choosing a pesticide, also consider
information relating to environmental impact. |
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| A. |
BACILLUS THURINGIENSIS# ssp. KURSTAKI |
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(various products) |
Label rates |
— |
0 |
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MODE OF ACTION: A microbial (Group 11.B2)1
insecticide.
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COMMENTS: Timing is important because of short residual
period. Apply only during warm dry weather to control young actively feeding worms; may need to be applied more than once. Good coverage is essential. |
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| B. |
DIAZINON* 50WP |
3 lb |
1 lb |
21 |
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DIAZINON* 4EC |
3 pt |
1 pt |
21 |
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MODE OF ACTION: An organophosphate (Group 1B)1
insecticide.
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COMMENTS: Avoid drift and runoff into surface waters. Where plums are grown near waterways, do not use diazinon. |
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UC IPM Pest Management Guidelines: Plum
UC ANR Publication 3462
Insects and Mites
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to the insects and mites section:
R. E. Rice, Kearney Agricultural Center, Parlier
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