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

UC Pest Management Guidelines

Apricot

European Red Mite

Scientific name: Panonychus ulmi

(Reviewed 11/07, updated 11/07)

In this Guideline:

Description of the pest
Damage
Management

European red mites overwinter as eggs located at the base of buds and spurs on smaller branches or in wounds. Eggs are red with a slender stipe arising from the center. Newly hatched mites are green, but with feeding turn red with a white spot at the base of each hair. These mites have 5 to 10 generations per year.

European red mites cause leaf stippling. Prolonged feeding causes leaves to pale and appear bronzed and burned at the tips and margins. Leaf drop can occur at high infestation levels (in excess of 100 mites per leaf for extended periods). At low levels, this mite can be beneficial; it serves as an alternative food for predators.

Predators will generally keep European red mite populations at low levels. Allowing low populations in the orchard during spring enables predators populations to increase to levels that are more effective in controlling webspinning mites. Hot weather and predators cause European red mite populations to decline in summer.

Biological Control
Several predaceous species feed on European red mite, including lacewings (Chrysoperla spp., Chrysopa spp., and Hemerobius sp.), damsel bugs (Nabis sp.), lady beetlesStethorus picipes), and minute pirate bug (Orius tristicolor). Western predatory mites, Galendromus (= Metaseiulus) occidentalis, also feed on European red mite but are not as effective predators as they are on webspinning mites because of their inability to break through the egg shell of the European red mite.

Organically Acceptable Methods
Certain oil sprays are acceptable for use on organically grown apricots.

Monitoring and Treatment Decisions
Monitor orchards once a week during the growing season when monitoring for other pests. No treatment thresholds have been established, but trees are able to tolerate greater numbers of European red mites than webspinning mites per leaf. A dormant oil spray is the preferred treatment and is intended to control European red mite eggs.

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.

DORMANT

NARROW RANGE OIL#

4–8 gal

1.5–2 gal

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: Cover all parts of the tree. Oil alone will control low to moderate infestations. Do not use oil sprays on water-stressed trees. Some of the new lower-chilling varieties, especially Poppycot, can be highly susceptible to oil damage. Use extreme care when applying oil to these varieties. Check with certifier to determine which products are organically acceptable.

SPRING

CLOFENTEZINE

(Apollo SC)

2–4 oz

0.5–1 oz

MODE OF ACTION GROUP NUMBER¹: 10A

COMMENTS: This material is more effective in the early part of the year; apply after sampling indicates pest mites are increasing but before significant damage or webbing is present. Kills eggs and young larval stages. Good coverage is a must; use a minimum of 50 gal water/acre for concentrate and a maximum of 400 gal water/acre for dilute. To delay development of resistance, use only once/season.

NARROW RANGE OIL#

4–8 gal

1.5–2 gal

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: Be sure that trees are well watered before treating. Check with certifier to determine which products are organically acceptable.

**	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.
#	Acceptable for use on organically grown produce.
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

European Red Mite

Scientific name: Panonychus ulmi

DESCRIPTION OF THE PEST

DAMAGE

MANAGEMENT

PUBLICATION