How to Manage Pests
UC Pest Management Guidelines
Cherry
Western Tussock Moth
Scientific Name: Orgyia vetusta
(Reviewed 4/06,
updated 4/06)
In this Guideline:
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The western tussock moth is
an occasional pest in coastal cherry orchards. Tussock moths survive the winter
as fuzzy egg masses that female moths cement to their pupal cases and cover with hairs. Mature larvae are
gray caterpillars with numerous red, blue, and yellow spots and four white
tufts of hair on their backs, two black tufts on their heads, and one on their
tail ends. Larvae emerge in
March and mature in May; when mature they are 0.5 to 1 inch long. Adults are
active from May through July. Males are gray moths; females are grayish white
and lack wings. Only one generation is produced each year.
Larvae are insignificant foliar feeders, but may feed on the surface
of fruit sufficiently in some years to warrant control measures. Feeding
results in shallow, scabby, depressed areas at harvest.
Natural enemies usually keep tussock moth under control.
Biological Control
Natural enemies, including larval
parasites (Hyposoter exiguae, H. fugitivus, Dibrachys sp.) and a predatory beetle (Trogoderma sternale), usually keep tussock moth under control.
Cultural Control
Localized infestations can be pruned out
and destroyed. Population buildups tend to be localized because the females are
flightless.
Organically Acceptable Methods
Biological and cultural controls and
sprays of Bacillus thuringiensis and the Entrust formulation of
spinosad are acceptable for use on an organically certified crop.
Monitoring and Treatment Decisions
Watch for tussock moth egg cases on leaves
and twigs as you monitor orchards in spring before and during bloom. Begin to
look for larvae in March. Infestations can be controlled with Bacillus
thuringiensis while larvae are small. Petal fall sprays to control other worm problems generally control this pest. Later
instars are difficult to control. Localized infestations can be pruned out and
destroyed. This pest is cyclic and often controlled by parasitic wasps.
| Common name |
Amount to Use** |
P.H.I.+ |
| (trade name) |
(conc.) |
(dilute) |
(days) |
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| The following materials are listed in order of usefulness
in an IPM program, taking into account efficacy and impact on natural
enemies and honey bees. When choosing a pesticide,
also consider information relating to environmental impact.
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| A. |
DIAZINON* 50WP |
3 lb |
1 lb |
21 |
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MODE OF ACTION: An organophosphate (Group 1B)1
insecticide.
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COMMENTS: Avoid drift and tailwater runoff into surface waters. Where cherries are grown adjacent to waterways, do not use this material. |
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| B. |
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: Is not harmful to beneficial insects. Apply when
larvae are small. Make 2 applications during bloom: the first at early bloom
and the second 7–10 days later, but no later than petal fall. Compatible with fungicide sprays. Good coverage is essential. |
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| C. |
SPINOSAD |
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(Entrust)# |
1.71–2.5 oz |
0.43–0.6 oz |
7 |
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(Success) |
6–8 oz |
1.5–2 oz |
7 |
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MODE OF ACTION: A microbial (Group 5)1 insecticide. |
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COMMENTS: Most effective when
applied at petal fall. This product is toxic to bees for 3 hours following
treatment; apply in late evening after bees have stopped foraging. Do not apply more than 29 oz/acre/year of Success or 9 oz/acre/year of Entrust. |
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| D. |
CARBARYL* |
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(Sevin) 80S |
4 lb |
1 lb |
1 |
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(Sevin) XLR PLUS |
4 qt |
1 qt |
1 |
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MODE OF ACTION: A carbamate (Group 1A)1
insecticide.
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COMMENTS: May cause increased spider mite problems. Do not
apply more than 17.5 lb Sevin 80S or 14 qt XLR PLUS/acre/season. The XLR PLUS
formulation is less hazardous to honey bees than other formulations if applied from late evening to early morning when bees are not foraging. |
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UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440
Insects and Mites
R. A. Van Steenwyk, Insect Biology, UC Berkeley
K. M. Daane, Kearney Agricultural Center, Parlier
J. A. Grant, UC Cooperative Extension, San Joaquin County
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