UC IPM: UC Management Guidelines for Brown Mite on Nectarine

UC Pest Management Guidelines

Nectarine

Brown Mite

Scientific Name: Bryobia rubrioculus

(Reviewed 6/06, updated 6/06)

In this Guideline:

Description of the pest
Damage
Management

DESCRIPTION OF THE PEST
Brown mites can be recognized by their flattened bodies and long front legs. Adults are brownish green; nymphs are red at first. Brown mites overwinter as eggs on spurs and branches. Eggs are red and similar in appearance to European red mite eggs but lack a stipe. Eggs hatch in spring and the young move out to leaves where they feed but do not produce webbing. Brown mites feed only during the cool parts of the day and migrate off the leaves during midday.

DAMAGE

Brown mites feed by sucking the contents out of leaf cells. Such leaf damage reduces tree vitality and can adversely affect fruit size. Leaf injury caused by brown mites begins as a mottling and browning of leaves. Trees can tolerate low to moderate populations of brown mite, but heavy populations can remove almost all the chlorophyll from leaves and entire trees will take on a pale yellow appearance.

Maintain mite predators in order to keep brown mite populations at low levels.

Organically Acceptable Methods
Oil sprays and naturally occurring predators serve as organically acceptable management tools.

Monitoring and Treatment Decisions
Monitor for brown mite eggs along with other pests when taking the DORMANT SHOOT SAMPLE. Use dormant sprays with oils at the high rate to help control the overwintering eggs if 20% or more of the shoots have eggs. An insecticide can be added to control other pests. Miticides may be necessary in some orchards in spring or summer but only when mite populations begin damaging foliage. During the hot part of the day, brown mites will not be found on leaves, but they can be monitored using beating trays. 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.

Common name

Amount to Use**

P.H.I.+

(trade name)

(conc.)

(dilute)

(days)

The following materials are listed in order of usefulness in an IPM program, taking into account efficacy, impact on natural enemies and honey bees, and impact of the timing on beneficials. When choosing a pesticide, also consider information relating to environmental impact.

DORMANT OR DELAYED DORMANT (Preferred timing)

DORMANT OIL such as:

DORMANT FLOWABLE EMULSION

6–8 gal

1.5–2 gal

NARROW RANGE OIL#

6 gal

1.5 gal

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: With good coverage, oil will control European red mite and brown mite eggs and low infestations of San Jose scale. Use in conjunction with a bloom time spray of Bt to control peach twig borer.

SPRING AND SUMMER

FENBUTATIN OXIDE*

(Vendex) 50WP

2 lb

0.5 lb

MODE OF ACTION: Unknown. An organotin miticide.

COMMENTS: This material appears to be most effective when applied earlier in the season rather than later. Can be combined with oil. Do not apply more than twice a season in not more than 400 gal water/acre.

NARROW RANGE OIL#

MODE OF ACTION: Contact including smothering and barrier effects.

COMMENTS: Oil used alone will only provide partial control. Always apply oils to well-watered trees and never when trees are stressed by hot (above 90°F), windy, dry (relative humidity lower than 20%) conditions or when such conditions are likely to occur within a few days after application. Additional applications may be needed at 2-week intervals, which may increase the potential for phytotoxicity. Do not apply oil within 2 weeks of captan or sulfur.

**	For dilute applications, 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.
*	Permit required from county agricultural commissioner for purchase or use.
+	Preharvest interval. Do not apply within this many days of harvest.
#	Acceptable for use on organically grown produce.
¹	Modes of action are important in preventing the development of resistance to pesticides. 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. 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 is 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: Nectarine
UC ANR Publication 3451
Insects and Mites
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to the insects and mites section:
R. E. Rice, Kearney Agricultural Center, Parlier

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How to Manage Pests

UC Pest Management Guidelines

Nectarine

Brown Mite

Scientific Name: Bryobia rubrioculus

DAMAGE

MANAGEMENT

PUBLICATION