How to Manage Pests

UC Pest Management Guidelines

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+
A.	FENBUTATIN OXIDE*
	(Vendex) 50W	0.25-0.5 lb/100 gal (TDC)	7
	RANGE OF ACTIVITY: Narrow (pest mites)
	PERSISTENCE: Short
	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.
B.	MICRONIZED SULFUR#
	(Thiolux 80%)	20 lb/acre (OC or TDC)	1
	RANGE OF ACTIVITY: Narrow (mites and citrus thrips)
	PERSISTENCE: Long
	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.
C.	WETTABLE SULFUR#	45-60 lb/acre (OC or TDC)	1
	RANGE OF ACTIVITY: Narrow (mites and citrus thrips)
	PERSISTENCE: Intermediate
	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).
	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.

PUBLICATION

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. O’Connell, 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

Top of page