How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

The female European red mite is about 0.02 inch long and has a brick red, globular body with long curved hairs that arise from white spots or tubercles on the back. Nymphs or unfed females may appear greenish. European red mite eggs are red, slightly flattened, and have a stipe protruding from the top. They overwinter in the egg stage on twigs and spurs. Eggs hatch in early spring just after the trees leaf out, and many generations (8–10) are produced before fall. Ordinarily European red mite populations build up slowly during spring and do not become apparent until large populations are present.

DAMAGE

European red mites remove the contents of the leaf cells as they feed, causing leaves to take on a finely mottled appearance. Rarely do European red mites cause leaf drop in cherry trees.

MANAGEMENT

European red mites provide an early season food source for predatory mites and do little damage unless the orchard is heavily infested. Allowing low populations of European red mites in spring helps build predator mite populations to build, which can later help control the more damaging webspinning mites. Generally treatments for this mite are applied in the dormant/delayed-dormant season.

Biological Control
The same predators that feed on Pacific and twospotted mites will also feed on European red mites. While the western predatory mite can sustain itself on European red mites, it cannot break the shell of European red mite eggs. Thus it takes longer for this predator to bring a population of these mites under control.

Cultural Control
Culturally, little can be done to control European red mites, as it is generally more abundant in well-managed, vigorous orchards.

Organically Acceptable Methods
Biological control and sprays of narrow range oil are organically acceptable management tools.

Monitoring and Treatment Decisions
A dormant oil spray is the preferred treatment and is intended to control European red mite eggs. In orchards with a history of problems with this mite, treat during dormancy to help control the overwintering eggs. Remember that low-to-moderate populations are beneficial because they provide food for predators.

Common name (trade name)			Amount/Acre**		R.E.I.+ (hours)	P.H.I.+ (days)
			(conc.)	(dilute)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, impact on natural enemies and honey bees. When choosing a pesticide, also consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
DORMANT and DELAYED DORMANT
A.		NARROW RANGE OIL#
		(460 or higher)	4–6 gal	1–1.5 gal	4	0
		MODE OF ACTION: Contact including smothering and barrier effects.
		COMMENTS: Choose a narrow range oil with a 50% distillation point of 460 or higher for dormant season use. With good coverage, oil will control European red mite and brown mite eggs and low infestations of San Jose scale.
**		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.
+		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.

PUBLICATION

UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440
Insects and Mites
J. A. Grant, UC Cooperative Extension, San Joaquin County
J. L. Caprile, UC Cooperative Extension, Contra Costa County
W. W. Coates, UC Cooperative Extension, San Benito County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
K. M. Daane, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
J. Colyn, Mid-Valley Ag. Services
M. Devencenzi, Devencenzi Ag. Pest Mgmt. and Research
P. McKenzie, Mid-Valley Ag. Services

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