UC IPM: UC Management Guidelines for Fruittree Leafroller on Apricot

UC Pest Management Guidelines

Apricot

Fruittree Leafroller

Scientific name: Archips argyrospila

(Reviewed 11/07, updated 11/07)

In this Guideline:

Description of the pest
Damage
Management

Adult fruittree leafroller moths are about 0.5 inch long, with rusty brown wings marked with areas of white and gold. When at rest the adults show the typical bell-shaped pattern common to the family Tortricidae. The eggs are laid in masses on limbs and twigs and are covered with a gray secretion that turns white upon aging. Larvae are green with a black head. The intensity of the green color varies from a light green in young larvae to a darker green as they mature. Fruittree leafroller larvae are difficult to distinguish from the more damaging obliquebanded leafroller larvae.

The fruittree leafroller overwinters in the egg stage. Eggs usually hatch in early spring. Larvae feed within opening buds. As they mature they tie leaves together and feed on leaves, blossoms, and small fruit. Adults emerge in May or June. These adults then lay egg masses that overwinter. There is one generation per year.

Larvae feed on leaves and buds, webbing them together to form a protective case. Fruit damage is usually shallow and superficial and often occurs when leaves and fruit are webbed together.

Delayed dormant treatments and bloom time applications for other pests help keep leafroller populations under control. However, regular monitoring each season is important so that prompt action can be taken if damaging populations develop. Throughout the season, watch for the presence of leafrollers while monitoring for other pests.

Biological Control
A number of parasites, including species of Macrocentrus, Apanteles, and Exochus, attack leafroller larvae. General predators such as lacewings, assassin bugs, and minute pirate bugs may feed on eggs and larvae. Preservation of natural enemy populations is an important part of keeping leafroller numbers low. Use selective materials that are least disruptive of biological control when treating other pests.

Organically Acceptable Methods
Sprays of Bacillus thuringiensis and the Entrust formulation of spinosad are acceptable for use on organically grown apricots.

Monitoring and Treatment Decisions
Examine tree prunings during the dormant season for egg masses. In early spring (March-April), check the orchard for presence of larvae and feeding damage. When necessary, apply an insecticide at petal fall or shortly thereafter.

Common name

Amount to Use**

R.E.I.+

P.H.I.+

(trade name)

(conc.)

(dilute)

(hours)

(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)#

1.71–2.5 oz

0.43–0.6 oz

(Success)

6–8 fl oz

1.5–2 fl oz

MODE OF ACTION GROUP NUMBER¹: 5

COMMENTS: Most effective when applied at petal fall. This product is toxic to bees for 3 hours following treatment; apply in the late evening after bees have stopped foraging. Do not apply more than 29 fl oz/acre/year of Success or 9 oz/acre/year of Entrust.

BACILLUS THURINGIENSIS ssp. KURSTAKI#

(various products)

Label rates

—

MODE OF ACTION GROUP NUMBER¹: 11.B2

COMMENTS: Make two applications during bloom: the first between popcorn and the beginning of bloom and the second 7–10 days later, but no later than petal fall. Good coverage is essential. Ground application using a concentrate rate (80–100 gal water maximum) is preferred. If aerial applications must be made because conditions do not permit ground application, a concentrate rate (5 gal or less) is preferred. Fly material on at a height of about 20 ft over the canopy using appropriate nozzles to allow better deposition on the tree tops. Compatible with fungicide sprays, and can be tank mixed with them. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i.

METHOXYFENOZIDE

(Intrepid) 2F

8–16 fl oz

2–4 fl oz

MODE OF ACTION GROUP NUMBER¹: 18A

COMMENTS: Do not apply more than 16 fl oz/acre/application or more than 64 fl oz/acre/season.

PHOSMET

(Imidan) 70WP

4.25 lb

1 lb

3 days

MODE OF ACTION GROUP NUMBER¹: 1B

DIAZINON* 50WP

3 lb

1 lb

MODE OF ACTION GROUP NUMBER¹: 1B

COMMENTS: Avoid drift and tailwater runoff into surface waters. Where apricots are grown adjacent to waterways, do not use this material.

**	For concentrate applications, use the amount given in 80-100 gal water/acre or lower if the label allows; for dilute application, amount is per 100 gal water to be applied in 300-400 gal water/acre, according to label.
+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
*	Permit required from county agricultural commissioner for purchase or use.
#	Acceptable for use on organically grown produce.
—	Not recommended or not on label.
¹	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 to help prevent development of resistance. 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 Group numbers are 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: Apricot
UC ANR Publication 3433
Insects and Mites
W. W. Coates, UC Cooperative Extension, San Benito Co.
R. A. Van Steenwyk, Insect Biology, UC Berkeley
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare Co.
K. A. Kelley, UC Cooperative Extension, Stanislaus Co.
J. L. Caprile, UC Cooperative Extension, Contra Costa Co.
Acknowledgment for contributions to the insects and mites section:
L. C. Hendricks, UC Cooperative Extension, Merced Co.

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How to Manage Pests

UC Pest Management Guidelines

Apricot

Fruittree Leafroller

Scientific name: Archips argyrospila

DESCRIPTION OF THE PEST

DAMAGE

MANAGEMENT

PUBLICATION