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How to Manage Pests

UC Pest Management Guidelines

Plum rust mites.


Eriophyid Mites

Scientific Names:
Plum rust mite: Aculus fockeui
Big beaked plum mite: Diptacus gigantorhynchus
and others in the genus Eriophyes

(Reviewed 6/06, updated 4/09)

In this Guideline:


Eriophyid mites are tiny, microscopic mites that have two pairs of legs near the anterior end of the body. They are yellow to pinkish white to purplish in color, and wedge-shaped with the widest part of the body being just behind the head.


All species feed on leaves. Heavily infested leaves take on a silvery or bronze appearance, depending on the species. Severe infestations can interfere with photosynthesis, but research indicates that yield is not impacted during the year of infestation from populations as high as 120 eriophyid mites per leaf.


Eriophyid mites are more likely to reach high densities in sprayed orchards where predaceous mites are destroyed. If natural enemies are preserved, predaceous mites will suppress light to moderate populations of these pest mites. Treatments are only recommended in orchards with chronic infestations or when there is a danger of defoliation.

Common name Amount to Use** R.E.I.+ P.H.I.+
(trade name) (conc.) (dilute) (hours) (days)

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
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. Not all registered pesticides are listed. Always read label of product being used.
A. WETTABLE SULFUR# Label rates 0 24 0
  MODE OF ACTION: Unknown. An inorganic miticide.
  COMMENTS: Do not apply within 2 weeks of oil spray.
  (Vendex) 50WP 1–2 lb 0.5 lb 48 14
  COMMENTS: Do not apply more than twice a season.
** 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.
+ 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.
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/.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Prune
UC ANR Publication 3464
Insects and Mites
C. Pickel, UC IPM Program, Sutter/Yuba counties
F. J. A. Niederholzer, UC Cooperative Extension, Sutter/Yuba counties
W. H. Olson, UC Cooperative Extension, Butte County
F. G. Zalom, Entomology, UC Davis
R. P. Buchner, UC Cooperative Extension, Tehama County
W. H. Krueger, UC Cooperative Extension, Glenn County
Acknowledgment for contributions to Insects and Mites:
W. O. Reil, UC Cooperative Extension Solano/Yolo counties

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