How to Manage Pests

UC Pest Management Guidelines

Citrus

Citrus Rust Mite (Silver Mite)

Scientific Name: Phyllocoptruta oleivora

(Reviewed 2/17, updated 1/19)

In this Guideline:


Description of the Pest

This pest is known as the rust mite on oranges and the silver mite on lemons. It is an occasional pest in coastal areas of Southern California and is a problem in some years in inland Southern California growing areas. Citrus rust mite is about the same size as a bud mite and requires a hand lens to view; it is deeper yellow than the bud mite and wedge shaped. A generation may be completed in 1 to 2 weeks in summer, but development slows or stops in winter, depending on temperature.

Damage

The rust mite feeds on the outside exposed surface of fruit that is 0.5 inch (1.3 cm) or larger. Feeding destroys rind cells and the surface becomes silvery on lemons, rust brown on mature oranges, or black on green oranges. Rust mite damage is similar to broad mite damage, except that somewhat larger fruit are affected. Most rust mite damage occurs from late spring to late summer.

Management

Citrus rust mite tends to occur together with BROAD MITE but usually in greater numbers. Both species thrive in warm, humid conditions. Monitor rust mite from early spring through summer. On orange trees, look for rust mites on young foliage in early spring; by late spring, most of the population will be on fruit. On lemon, rust mites are mostly on fruit throughout the season. To identify previous infestations, check outside fruit for scarred rind tissue. To assess current season levels, examine small green fruit on the inside of the canopy. A 10X to 15X hand lens is necessary to identify these minute mites. They usually feed in protected places, such as the stylar end of the fruit. When mite numbers are high, the mites move over the entire fruit. No effective natural enemies are known, but general mite predators feed on rust mites at times.

Once you find one or more infested fruit and if rust mites were a problem the previous year, watch the orchard closely. Threshold levels depend on last year's rust mite problems and current market conditions. If the mite numbers increase quickly or if scarring appears, a pesticide application is generally required. In some cases, the infestation is localized and a spot treatment may be sufficient for control.

Common name Amount to use REI‡ PHI‡
(Example trade name) (type of coverage)** (hours) (days)
Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.
 
A. SPIRODICLOFEN
  (Envidor 2SC) 12–20 fl oz/acre (OC or IC) 12 7
  RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE-OF-ACTION GROUP NUMBER1: 23
  COMMENTS: Works by contact with the mite so thorough coverage is important. Only one application per season allowed. With ground application,Envidor appears to be more effective without added oil.
 
B. DIFLUBENZURON
  (Micromite 80WGS) 6.25 oz/acre (OC or IC) 12 7
  RANGE OF ACTIVITY: Pests: intermediate (katydids, peelminer, leafminer, grasshoppers); Natural enemies: predatory beetles
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE-OF-ACTION GROUP NUMBER1: 15
  . . . PLUS . . .
  NARROW RANGE OIL
  (415) 0.25–1% See label See label
  RANGE OF ACTIVITY: Pests: broad (unprotected stages of insects and mites); Natural enemies: most
  PERSISTENCE: Pests: short; Natural enemies: short
  MODE OF ACTION: Contact including smothering and barrier effects; also improves insecticide spread and persistence.
 
C. ABAMECTIN
  (Agri-Mek SC) 1–4.25 fl oz/acre (OC or IC) 12 7
  RANGE OF ACTIVITY: Pests: intermediate (citrus thrips, mites, leafminers); Natural enemies: predatory mites and thrips
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE-OF-ACTION GROUP NUMBER1: 6
  . . . PLUS . . .
  NARROW RANGE OIL
  (415) 0.25–1% See label When dry
  MODE OF ACTION: Improves translaminar movement and persistence of insecticide.
  RANGE OF ACTIVITY: Pests: broad (unprotected stages of insects and mites); Natural enemies: most
  PERSISTENCE: Pests: short; Natural enemies: short
  COMMENTS: For use on all varieties. Apply in 50 to 200 gal water/acre. To avoid potential phytotoxicity of oil to the fruit, do not apply 30 days before or after a sulfur application and do not apply to small fruit (less than 1 inch in diameter) on a day when the ambient temperature has or is expected to exceed 95°F or when the relative humidity has or is expected to drop below 20%. Certain formulations emit high amounts of volatile organic compounds (VOCs); use low-VOC formulations. Regulations affect use for the San Joaquin Valley from May 1 to October 31, 2018 and 2019. Review the Department of Pesticide Regulation's updated fact sheet.
 
D. CYANTRANILIPROLE/ABAMECTIN
  (Minecto Pro) 8–12 fl oz/acre 12 7
  RANGE OF ACTIVITY: Pests: broad (many insects mites); Natural enemies: predatory mites
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE-OF-ACTION GROUP NUMBER1: 28/6
  ...PLUS...
  415 NARROW RANGE OIL
  (various products) 0.25–1% See label See label
  RANGE OF ACTIVITY: Pests: broad (unprotected stages of insects and mites); Natural enemies: most
  PERSISTENCE: Pests: short; Natural enemies: short
  MODE OF ACTION: Contact including smothering and barrier effects; also improves translaminar movement and insecticide persistence.
  COMMENTS: Do not exceed a total of 24 fl oz of Minecto Pro or 0.40 lbs a.i. of cyantraniliprole-containing products or 0.047 lbs a.i. of abamectin-containing products/acre per calendar year. Do not apply to nurseries. Aerial application is allowed only for citrus leafminer or Asian citrus psyllid.
 
E. SPIROTETRAMAT
  (Movento) 8–10 fl oz 24 1
  RANGE OF ACTIVITY: Pests: broad (mites, thrips, leafminers, aphids, armored scales); Natural enemies: predatory mites
  PERSISTENCE: Pests: long; Natural enemies: short
  MODE-OF-ACTION GROUP NUMBER1: 23
  COMMENTS: Allow 1 to 2 weeks for systemic movement through the plant. Must be applied with an adjuvant to improve penetration. Do not apply before bloom, during bloom, or 10 days after petal fall.
  . . . PLUS . . .
  NARROW RANGE OIL
  (415) 0.5–1% See label See label
  RANGE OF ACTIVITY: Pests: broad (unprotected stages of insects and mites); Natural enemies: most
  PERSISTENCE: Pests: short; Natural enemies: short
  MODE OF ACTION: Contact including smothering; also improves insecticide uptake.
 
F. MICRONIZED SULFUR#
  (various) Label rate (OC or IC) 24 0
  RANGE OF ACTIVITY: Pests: broad (mites, citrus thrips); Natural enemies: most
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE OF ACTION: unknown
  COMMENTS: For use on all varieties. Do not apply during or preceding high temperatures. Do not apply in any spray containing oil or within 21 days of a previous oil spray. May lead to citrus red mite or mealybug flare-ups.
 
G. WETTABLE SULFUR# Label rates (OC or IC) 24 0
  RANGE OF ACTIVITY: Pests: narrow (mites and citrus thrips); Natural enemies: most
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE OF ACTION: unknown
  COMMENTS: For use on all varieties. Apply from Nov. through May when monitoring indicates a need. Do not apply during or preceding high temperatures or within 2 months of a previous oil spray. Do not apply oil 60 to 90 days after a sulfur application. Not recommended for use in the San Joaquin Valley.
 
H. FENPYROXIMATE
  (Fujimite SC) 2–4 pt (OC or IC) 12 3
  RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
  PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
  MODE-OF-ACTION GROUP NUMBER1: 21A
** OC - Outside coverage uses 100 to 250 gal water/acre.
  IC - Intermediate coverage uses 250 to 600 gal/acre.
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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 (un = unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee).

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441

Insects, Mites, and Snails

E. E. Grafton-Cardwell, Lindcove Research and Extension Center, Exeter and Entomology, UC Riverside
J. G. Morse, Entomology, UC Riverside
D. R. Haviland, UC Cooperative Extension, Kern County and UC IPM Program
B. A. Faber, UC Cooperative Extension, Santa Barbara and Ventura counties

Acknowledgments for contributions to Insect, Mite, and Snails:
J. Barcinas, E.S.I., Corona, CA
R. Dunn, Badger Farming Co., Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
C. E. Kallsen, UC Cooperative Extension, Kern County
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
N. V. O'Connell, UC Cooperative Extension, Tulare County
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
T. Roberts, E.S.I., Corona, CA
T. Shea, UC Cooperative Extension, Riverside County
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA

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