How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

Brown mite eggs hatch in early spring. The newly hatched mites are red with six legs and after the first molt are brown with eight legs, resembling the adult. Adults are flattened with long front legs and are the largest in size of all cherry pest mites. Brown mites feed only during the cool parts of the day and night, and migrate off the leaves during midday. They are not active during hotter periods of the summer. There are two to three generations per year between February and June.

DAMAGE

The brown mite can be an economic pest of cherries. Mite feeding causes chlorosis, but leaves rarely drop. Infestations are generally confined to a few trees or localized and tend to be more common in cherry trees located near almond orchards.

MANAGEMENT

Predators will generally keep brown mite populations below damaging levels. Allowing low populations of brown mites in the orchard during spring enables mite predators to increase their population to levels that are more effective in controlling webspinning mites. Generally, hot weather and predators cause brown mite populations to decline in summer.

Biological Control
The western predatory mite and brown lacewing are both effective predators. It is important to avoid insecticides that kill these natural enemies.

Organically Acceptable Methods
Biological control and oil sprays are acceptable for use on an organically certified crop.

Treatment Decisions
When necessary, control these mites with a dormant spray. Occasionally there is an infestation during a cool spring when dormant treatments were inadequate.

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 impact on natural enemies and honey bees and environmental impact. Not all registered pesticides are listed. Always read label of product being used.
DORMANT
A.	NARROW RANGE OIL#	4–8 gal	1.5–2 gal	see label	0
	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 apply oils to water-stressed trees. Not all oils are organically acceptable; be sure to check individual products.
**	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.
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 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/.

IMPORTANT LINKS

• Photos of natural enemies of mites

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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