How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

Texas citrus mite is a sporadic pest of citrus in the inland valleys of California. Adult mites are tan-to-brownish green with dark green to black spots on the upper side of the body. Males are more slender than females and have much longer legs. Females have a more round-to-oval shape and are somewhat flatter than citrus red or Yuma spider mite. All stages of mites, including eggs, tend to be located along the midrib and lateral veins. Eggs are somewhat flat and disklike, are not a uniform color, and range from yellow when laid to a reddish brown before hatching.

In the San Joaquin Valley, Texas citrus mite can sometimes be found in low populations in spring, especially following insecticides such as formetanate hydrochloride (Carzol) or methidathion (Supracide) that disrupt biological control. Populations of this mite decrease in summer but increase from September through December. When weather becomes cold and wet, which usually equates to the first overnight period of dense Valley fog, populations decrease again.

DAMAGE

Texas citrus mite feeds primarily on leaves and can cause significant stippling and leaf drop; significant leaf drop can lead to fruit drop. In the San Joaquin Valley damage is usually limited to early harvested navels where a combination of warm temperatures in fall and deficit irrigation (used to induce increases in sugar levels) allow mites to thrive. Damage often begins in the tops of trees and progresses downward as harvest approaches. Leaf drop from Texas citrus mite is unique because the leaf blade falls to the ground while the petiole remains in the tree. Leaf drop can result in sunburning of fruit, dropped fruit, and reduced photosynthesis.

MANAGEMENT

In the San Joaquin Valley watch for Texas citrus mite in fall on early harvested navels or in spring following treatments of broad-spectrum insecticides. Treat if small amounts of defoliation begin to occur in the outer canopy at the top of trees and cold, wet weather is not anticipated for a period of weeks. Miticides are very effective against Texas citrus mite.

Biological Control
Texas citrus mite is naturally controlled by predators of other mites such as the sixspotted thrips (Scolothrips sexmaculatus), the spider mite destroyer (Stethorus picipes), minute pirate bugs (Orius spp.) and a predatory mite, (Euseius tularensis).

Cultural Control
Adequate irrigation and dust control will reduce the impact of Texas citrus mite.

Organically Acceptable Methods
Cultural and biological controls and certain petroleum oil sprays are organically acceptable methods.

Monitoring and Treatment Decisions
In the San Joaquin Valley, check for Texas citrus mite during spring if broad-spectrum insecticides such as formetanate hydrochloride (Carzol) or methidathion (Supracide) have been used. Treat if significant amounts of leaf drop occur.

In fall look for Texas citrus mite from September through December on trees that bear early harvested fruit, especially navels. Treat if leaves in the outer canopy at the tops of trees begin to defoliate, and cold weather is not anticipated for a period of several weeks. Treatments are not needed if defoliation is limited to the leaves on the extremities of the fall flush that will naturally freeze or be pruned off during winter.

No official treatment thresholds exist. Texas citrus mite is highly susceptible to all miticides labeled for control of citrus red mite and can be controlled with relatively low volumes of water because of to its tendency to be located on newer leaves in the outer tree canopy.

Common name		Amount to Use	R.E.I.+	P.H.I.+
(trade name)		(type of coverage)**	(hours)	(days)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies and honey bees. 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.	NARROW RANGE OIL (92%UR)
	(415, 440)	1.2–1.4% (OC)	4	when dry
	. . . or . . .
	NARROW RANGE OIL (99% UR)
	(415, 435, 440, 455)	1.2–1.4% (OC)	4	when dry
	RANGE OF ACTIVITY: Pests: broad (unprotected stages of insects/mites); Natural enemies: most
	PERSISTENCE: Pests: short; Natural enemies: short
	MODE OF ACTION: Contact including smothering and barrier effects.
	COMMENTS: Use highest rate for July or August applications. Narrow range 440 (or higher) spray oil is preferable in the Central Valley during warmer months because of greater persistence, but risk of phytotoxicity increases unless using products with 99% unsulfonated residues (UR). Low-volume may be preferable. Caution: Serious hazards are associated with oil treatments to green lemons because of phytotoxicity after sweating; check label for preharvest interval.
	. . . or . . .
	NARROW RANGE OIL (92 or 99% UR)
	(415)	6–20 gal/acre (LV)	4	when dry
	RANGE OF ACTIVITY: Pests: narrow (citrus red mite) Natural enemies: predatory mites
	PERSISTENCE: Pests: short; Natural enemies: short
	MODE OF ACTION: Contact including smothering and barrier effects.
	COMMENTS: Use highest rate for July or August applications. Low-volume may be preferable. Caution: Serious hazards are associated with oil treatments to green lemons because of phytotoxicity after sweating; check label for preharvest interval.
B.	ACEQUINOCYL
	(Kanemite) 15SC	21–31 oz/acre (OC)	12	7
	RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
	PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
	MODE OF ACTION GROUP NUMBER1: 20B
	COMMENTS: For use on oranges, grapefruit, and lemons only. Apply by ground using 100-250 gal water/acre. Do not use less than 100 gal water/acre. Do not apply more than 62 oz/acre/season. Allow a minimum of 21 days between applications.
C.	PYRIDABEN
	(Nexter) WSB	Label rate (OC)	12	7
	RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
	PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
	MODE OF ACTION GROUP NUMBER1: 21
	COMMENTS: When this material was used during April and May in the San Joaquin Valley and thrips were abundant, there was an increase in scarring damage caused by thrips. Do not apply more than twice/year.
D.	FENPROXIMATE
	(Fujimite) 5EC	1–4 pt (OC or IC)	12	14
	RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
	PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
	MODE OF ACTION GROUP NUMBER1: 21
	COMMENTS: Do not make more than 2 applications/season and allow 14 days between applications. Use allowed under a Supplemental Label.
E.	WETTABLE SULFUR#	45–60 lb/acre (OC)	24	0
	RANGE OF ACTIVITY: Pests: narrow (mites and citrus thrips); Natural enemies: most
	PERSISTENCE: Pests: intermediate; Natural enemies: intermediate
	MODE OF ACTION: Not available
	COMMENTS: For use on all varieties. Apply from Oct. 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. Do not apply sulfur within 2 months of a previous oil spray, and do not apply oil 60–90 days after a sulfur treatment. Not recommended for use in the San Joaquin Valley.
F.	FENBUTATIN OXIDE*
	(Vendex) 50WP	0.24–0.5 lb/100 gal (OC)	48	7
		...or...
		3 lb/acre (LV)
	RANGE OF ACTIVITY: Pests: narrow (mites); Natural enemies: predatory mites
	PERSISTENCE: Pests: short; Natural enemies: short
	MODE OF ACTION GROUP NUMBER1: 12B
	COMMENTS: For use on all varieties. This material does not work well in cool weather and requires higher rates during these periods. Do not apply more than 1,600 gal dilute spray/acre or use more than 4 lb/acre/season.
**	LV - Low-volume uses 20–100 gal water/acre.
	OC - Outside coverage uses 100–250 gal water/acre.
+	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.
#	Acceptable for use on organically grown produce.
*	Permit required from county agricultural commissioner for purchase or use.
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/.

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 County
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
C. E. Kallsen, UC Cooperative Extension, Kern County
D. R. Haviland, UC Cooperative Extension, Kern County
Acknowledgments for contributions to Insect, Mites, and Snails:
J. Barcinas, E. S. I., Corona, CA
R. Dunn, Badger Farming County, 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
K. Godfrey, USDA Biological Control, Sacramento
D. Headrick, California Polytechnic State University, San Luis Obispo
B. Faber, UC Cooperative Extension, Ventura County
J. Kabashima, UC Cooperative Extension, South Coast Research and Extension Center

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