UC IPM: UC Management Guidelines for European Red Mite on Apple

UC Pest Management Guidelines

Apple

European Red Mite

Scientific name: Panonychus ulmi

(Reviewed 8/06, updated 3/09)

In this Guideline:

Description of the pest
Damage
Management

European red mites overwinter as eggs; eggs hatch in spring when trees bloom. With the use of a hand lens, look for overwintering eggs in roughened bark at bases of buds and spurs on smaller branches and twigs, or in wounds. They are globular and red with a slender stalk (stipe) rising from the top center and many grooves extending from top to bottom. During the growing season, eggs are laid on leaves. There are three instars before the adult stage. Immature mites are bright red, except just after molting when they appear bright green. The green color turns to red after the mites resume feeding. Adults are dark red and have six to eight white spots at the base of hairs on the back.

Severe mite infestations can cause bronzing of leaves. Damage is relatively less severe on wide leaf varieties such as Yellow Newton and more severe on narrow leaf varieties such as Red Delicious.

MANAGEMENT
European red mite only occasionally becomes troublesome in apple orchards. Monitor in winter to determine the need for treatment. Dormant oil is the preferred treatment.

Biological Control
If European red mite populations are managed at low levels by treating with a dormant oil, predators including western predatory mite, sixspotted thrips and spider mite destroyer can effectively help to maintain low levels throughout the season. Minimize the use or dosages of materials disruptive to mite predators. Avoid spraying with materials such as lime sulfur which kill the apple rust mite. When apple rust mites are allowed to survive, the predaceous mites feed on them and can build up large enough populations to control European red mites in some areas of California.

Cultural Control
Minimize the potential for mite problems by reducing dusty conditions within the orchard and keeping the trees well irrigated.

Organically Acceptable Methods
Biological and cultural controls and sprays of approved narrow range oils are organically acceptable.

Monitoring and Treatment Decisions
Anytime during winter collect 25 to 100 fruit spurs from trees throughout the block. If less than 10% of the spurs are infested, European red mite probably will not become a problem that season. If more than 10% of the spurs are infested, an oil spray should be applied before bloom. Control improves the closer eggs are to hatching. If summer control becomes necessary, the thresholds range from 10 to 30 mites per leaf depending on the age, variety, and condition of the tree, and the abundance of the mite predators.

Common name

Amount to use**

R.E.I.+

P.H.I.+

(trade name)

(conc.)

(dilute)

(hours)

(days)

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

DELAYED DORMANT (Preferred timing)

NARROW RANGE OIL#

6 gal

1.5 gal

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: Check with certifier to determine which products are organically acceptable.

FOLIAGE SPRAY

ABAMECTIN*

(Agri-Mek) 0.15EC

10–20 oz

2.5–5 oz

MODE OF ACTION GROUP NUMBER¹: 6

COMMENTS: Narrow-spectrum preventive material that can be applied early in the season (from petal fall to 6 weeks later) when mite outbreaks are anticipated. Use with a horticultural spray oil.

CLOFENTEZINE

(Apollo) 50SC

4–8 oz

1–2 oz

MODE OF ACTION GROUP NUMBER¹: 10A

COMMENTS: For early and mid-season mite control; easy on natural enemies. Kills eggs. Need to apply early, before monitoring indicates a need; use in orchards where European red mite is a chronic pest. Good coverage is a must; use a minimum of 50 gal water/acre for concentrate sprays and a maximum of 400 gal water/acre for dilute. To delay development of resistance, use only once per season.

FENBUTATIN-OXIDE*

(Vendex) 50WP

1–2 lb

4–8 oz

MODE OF ACTION GROUP NUMBER¹: 12B

COMMENTS: The liquid formulation gives better control in cooler climates. Do not apply more than 2 times/season. Do not apply more than 4 lb/acre/year.

PYRIDABEN

(Nexter)

5.2 oz

1.3 oz

MODE OF ACTION GROUP NUMBER¹: 21

COMMENTS: Can be used later in the season than preceding materials and is easier on beneficials than dicofol, but more disruptive than fenbutatin-oxide (Vendex). Do not use less than 100 gal water/acre spray volume. Most effective with use of a silicone spreader.

HEXYTHIAZOX

(Savey) 50 WP

Low to mid-label rate

MODE OF ACTION GROUP NUMBER¹: 10B

COMMENTS: Kills eggs. Need to apply early, before monitoring indicates a need; use in orchards where European red mite is a chronic pest. Apply only once per growing season.

FENPYROXIMATE

(FujiMite) 5EC

1–2 pt

—

MODE OF ACTION GROUP NUMBER¹: 21

COMMENTS: New material and there is little experience in California regarding efficacy and effect on beneficials. Most effective with use of a silicone spreader.

ETOXAZOLE

(Zeal)

2–3 oz

0.5–0.75 oz

MODE OF ACTION GROUP NUMBER¹: 10B

COMMENTS: Preliminary research indicates etoxazole has an effect on the reproductive capacity of predatory mites. Most effective with use of a silicone spreader.

BIFENAZATE

(Acramite) 50WS

0.75–1 lb

0.25 lb

MODE OF ACTION GROUP NUMBER¹: 25

COMMENTS: Only one application/crop/year. Most effective with use of a silicone spreader.

DICOFOL

(Kelthane)

Label rates

MODE OF ACTION: UNC

COMMENTS: For use on late-season mite outbreaks. This material is harsh on beneficials so its use is best late in the season when necessary.

For dilute application, rate is per 100 gal water to be applied in 300-500 gal water/acre, according to label; for concentrate applications, use 80-100 gal water/acre or lower if the label allows.

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.

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 the 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: Apple
UC ANR Publication 3432
Insects and Mites
J. L. Caprile, UC Cooperative Extension, Contra Costa County
L. R. Wunderlich, UC Cooperative Extension, El Dorado County
P. M. Vossen, UC Cooperative Extension, Sonoma and Marin counties
W. W. Coates, UC Cooperative Extension, San Benito County
H. L. Andris, UC Cooperative Extension, Fresno County
L. G. Varela, UC IPM Program, Sonoma County
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
C. Pickel, UC IPM Program, Sutter and Yuba counties

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How to Manage Pests

UC Pest Management Guidelines

Apple

European Red Mite

Scientific name: Panonychus ulmi

DESCRIPTION OF THE PEST

DAMAGE

PUBLICATION