UC IPM: UC Management Guidelines for Redhumped Caterpillar on Cherry

UC Pest Management Guidelines

Cherry

Redhumped Caterpillar

Scientific Name: Schizura concinna

(Reviewed 4/06, updated 4/06)

In this Guideline:

Description of the pest
Damage
Management

The redhumped caterpillar is easily recognized because of its striking appearance: the main body color is yellow and is marked by longitudinal reddish and white stripes; the head is bright red, and the fourth abdominal segment is red and enlarged. Redhumped caterpillars pass the winter as full grown larvae in cocoons on the ground. In early summer, moths lay egg masses on the undersides of leaves. Eggs hatch into larvae that begin feeding on leaves. There are at least three generations each year in northern California.

Redhumped caterpillars are mainly a problem on young trees where they skeletonize leaves, leaving behind only leaf veins. They do not web leaves.

Redhumped caterpillar can be a pest of cherry orchards in the Central Valley but is rarely found in the Central Coast. Biological control and pruning are often sufficient to manage the pest; use the monitoring guidelines below to determine need for treatment.

Biological Control
The most common parasite species are Hyposoter fugitivus, which forms a single pupal case that is white with a black band around the middle, and Apanteles sp., which forms a fluffy white mass of pupal cases.

Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis and the Entrust formulation of spinosad are acceptable for use on an organically certified crop.

Monitoring and Treatment Decisions
On small trees, cut out and destroy infested twigs. Insecticide sprays applied for other pests often keep these leaf-eating caterpillars in check. When monitoring, look for the presence of parasites. If 80% or more of the larval population is parasitized, no treatment is needed. If insecticide treatments are required, localized treatments on individual trees applied when evidence of caterpillars is first observed are generally all that is necessary. Mature trees usually don't require controls.

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 and impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact.

SPINOSAD

(Entrust)#

1.25–2.5 oz

0.3–0.6 oz

(Success)

4–8 oz

1–2 oz

MODE OF ACTION: A microbial (Group 5)¹ insecticide.

COMMENTS: Do not apply more than 29 oz/acre/year of Success or 9 oz/acre/year of Entrust.

BACILLUS THURINGIENSIS ssp. KURSTAKI#

(various products)

Label rates

MODE OF ACTION: A microbial (Group 11.B2)¹ insecticide.

COMMENTS: Most effective on small caterpillars. Does not destroy natural enemies. 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.

DIAZINON* 50WP

3 lb

1 lb

4EC

2–4 pt

1 pt

MODE OF ACTION: A microbial (Group 11.B2)¹ insecticide.

COMMENTS: Avoid drift and tailwater runoff into surface waters.

CARBARYL*

(Sevin) 80S

4–5 lb

1–1.25 lb

MODE OF ACTION: A carbamate (Group 1A)¹ insecticide.

COMMENTS: May cause increased spider mite problems or leaf yellowing under some conditions.

AZINPHOSMETHYL*

(Guthion Solupak) 50WP

1.5 lb

0.5 lb

MODE OF ACTION: An organophosphate (Group 1B)¹ insecticide.

COMMENTS: May cause increased spider mite problems. Postharvest use only. Allow at least 14 days between applications. Do not exceed 6 lb/acre/season. Apply dilute in 300 gal water. Check label for restricted entry intervals, which vary according to activity.

**	For concentrate applications, use the amount given in 80–100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300–400 gal water/acre, according to label.
+	Preharvest interval. Do not apply within this many days of harvest.
*	Permit required from county agricultural commissioner for purchase or use.
#	Acceptable for use on organically grown produce.
¹	Modes of action are important in preventing the development of resistance to pesticides. Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode of action is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

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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How to Manage Pests

UC Pest Management Guidelines

Cherry

Redhumped Caterpillar

Scientific Name: Schizura concinna

DESCRIPTION OF THE PEST

DAMAGE

MANAGEMENT

PUBLICATION