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How to Manage Pests
UC Pest Management Guidelines
Citrus
Citrus Rust Mite (Silver Mite)
Scientific Name: Phyllocoptruta oleivora
(Reviewed 7/03,
updated 7/03)
In this Guideline:
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DESCRIPTION OF THE PEST
This pest is known as the rust mite
on oranges and the silver mite on lemons. It is an infrequent pest in most
areas. Citrus rust mite is about the
same size as a bud mite and requires a hand lens to view; it is deeper yellow
in color 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
Monitor the citrus 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 populations 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
population increases quickly or if scarring appears, a treatment is generally
required. In some cases, the infestation is localized and a spot treatment
may be sufficient for control.
Common name
(trade name) |
Amount to Use
(type of coverage)** |
Minimum Days
before Harvest+ |
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| A. |
FENBUTATIN OXIDE* |
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(Vendex) 50W |
0.25-0.5 lb/100 gal (TDC) |
7 |
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RANGE OF ACTIVITY:
Narrow (pest mites) |
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PERSISTENCE: Short |
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COMMENTS: For use on all varieties. Do not apply during
bloom. Maximum rate of 4 lb/acre/application. Do not apply more than
2 sprays in any 12-month period or make the applications closer than
60 days apart. |
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| B. |
MICRONIZED SULFUR# |
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(Thiolux 80%) |
20 lb/acre (OC or TDC) |
1 |
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RANGE OF ACTIVITY:
Narrow (mites and citrus thrips) |
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PERSISTENCE: Long |
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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 flareups. |
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| C. |
WETTABLE SULFUR# |
45-60 lb/acre (OC or TDC) |
1 |
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RANGE OF ACTIVITY:
Narrow (mites and citrus thrips) |
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PERSISTENCE: Intermediate |
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COMMENTS: For use on all varieties. Apply from Nov thru
May when monitoring indicates a need. Do not apply more than 6 lb/100
gal water. Do not apply during or preceding high temperatures or within
2 months of a previous oil spray. Do not apply oil 60-90 days after
a sulfur treatment. Not recommended for use in the San Joaquin Valley. |
| ** |
TDC - Thorough distribution coverage
uses 500-3,000 gal/acre, but less than thorough coverage (TC). |
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OC - Outside coverage uses 50-500 gal
water/acre. |
| + |
Minimum days before harvest takes into
account the California restricted entry interval and the federal preharvest
interval and lists the longer interval. (See Table 1 Mandatory
Intervals Between Application, Reentry and Harvest, and Hazards to
Bees.) |
| * |
Permit required from county agricultural
commissioner for purchase or use. |
| # |
Acceptable for use on organically grown
produce. |
UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Kearney Agricultural Center, Parlier
J. G. Morse, Entomology, UC Riverside
N. V. OConnell, UC Cooperative Extension, Tulare Co.
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura Co.
C. E. Kallsen, UC Cooperative Extension, Kern Co.
D. R. Haviland, UC Cooperative Extension, Kern Co.
Acknowledgments for contributions to the insect, mite, and snail section:
J. Barcinas, E. S. I., Corona, CA
R. Dunn, Badger Farming Co., Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
H. Griffiths, E. S. I., Corona, CA
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
T. Roberts, E. S. I., Corona, CA
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA
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