How to Manage Pests

UC Pest Management Guidelines

Orange tortrix larvae feed inside nests spun around plant parts. The larvae pupate in dense cocoons inside the nests and adult moths emerge in 8 days to 3 weeks, depending on temperature. Females moths lay 50 to 150 eggs on smooth surfaces such as stems, fruit, and the upper surface of leaves. In coastal areas, orange tortrix may have more than three generations a year, whereas in intermediate districts it has two or three. It is not a problem in the Central Valley.

DAMAGE
Orange tortrix is primarily a pest on Valencias and navel oranges in southern California. First generation orange tortrix larvae feed on leaves. Second generation larvae appear when the growth is hardening off and move preferentially to young fruit and feed around the button. This feeding causes only superficial scars. Later generations feed among clusters of ripening fruit, eating holes into the rind that allow decay organisms to enter; the fruit usually drops within 1 to 2 weeks.

MANAGEMENT
Orange tortrix is generally managed by monitoring throughout spring and summer and treating when necessary. Use selective (toxic to only a narrow group of insects) insecticides to preserve populations of natural enemies.

Biological Control
Several parasites and predators attack orange tortrix. The most common parasites are two wasps, Apanteles aristolidae and Exochus sp. These wasps lay their eggs in tortrix larvae and the parasites develop within. Apanteles pupates in a white cocoon outside the dead larvae, whereas Exochus pupates inside the larva and emerges through a round exit hole.

Organically Acceptable Methods
Biological control and sprays of Bacillus thuringiensis are acceptable for use in organically managed citrus orchards.

Monitoring and Treatment Decisions
While orange tortrix larvae should be monitored throughout spring and summer, the period from May through July is especially important. At 7- to 10-day intervals, look for orange tortrix and evidence of parasitism mainly on the south and east quadrants of trees. If 15 larvae are found per hour of search on oranges and grapefruit, or 30 larvae per hour of search on lemons, a treatment may be warranted, depending on the level of parasitism.

Common name		Amount to Use	Minimum Days before Harvest+
(trade name)		(type of coverage)**
A.	BACILLUS THURINGIENSIS ssp. KURSTAKI#
	(various)	Label rates	4 hours
	RANGE OF ACTIVITY: Narrow (caterpillars)
	PERSISTENCE: Short
	COMMENTS: Can be used during bloom. Timing is important because of short residual period. Apply only during warm weather to control young, actively feeding worms. Use reduced wind velocity and drive 3 mph.
B.	CRYOLITE
	(Prokil Cryolite) 96	8–20 lb/acre (OC)	15
	(Kryocide) 96 WP	8–20 lb/acre (OC)
	RANGE OF ACTIVITY: Narrow (foliage feeders such as worms, katydids and Fuller rose beetle.
	PERSISTENCE: Long, unless washed off by rain.
	COMMENTS: Check label for variety. Use higher rate for larger trees. Slow-acting stomach poison that may take several days of warm weather to kill worms. Use reduced wind velocity and a speed of 3 mph. Do not exceed 90 lb/acre/season.
C.	CHLORPYRIFOS*
	(Lorsban) 4E	1–2 qt/acre (OC or A)	21
	RANGE OF ACTIVITY: Broad (insects and beneficial mites)
	PERSISTENCE: Intermediate
	COMMENTS: For use on all varieties. Do not apply more than twice/fruit year or make applications less than 30 days apart. During the bloom period, apply from 1 hour after sunset until 2 hours before sunrise.
D.	CARBARYL*
	(Sevin XLR Plus) 4F	2 qt/acre (OC)	5
	RANGE OF ACTIVITY: Broad (insects and beneficial mites)
	PERSISTENCE: Long
	COMMENTS: For use on all varieties. During the bloom period, apply from 1 hour after sunset until 2 hours before sunrise. XLR Plus formulation is less toxic to honey bees than the 80S formulation when direct application to bees is avoided, and the spray residues have dried. Check with your local county agricultural commissioner regarding application restrictions during the bloom period.
E.	NALED
	(Dibrom) 8E	2 pt/acre (OC)	7
	RANGE OF ACTIVITY: Broad (insects and beneficial mites)
	PERSISTENCE: Intermediate
	COMMENTS: For use on grapefruit, lemons, oranges, tangerines. This material is hazardous to bees. Do not apply during bloom.
F.	METHOMYL*
	(Lannate LV) 2.4	1.5–3 pt/acre (OC or A)	3
	RANGE OF ACTIVITY: Broad (insects and beneficial mites)
	PERSISTENCE: Intermediate
	COMMENTS: For use on grapefruit, lemons, oranges, tangerines, and tangelos. Apply as needed, except during daylight hours of the bloom period. This material is hazardous to bees. Do not apply during bloom.
G.	CARBARYL*
	(Sevin) 80S	2.5 lb/acre (OC)	5
	RANGE OF ACTIVITY: Broad (insects and beneficial mites)
	PERSISTENCE: Long
	COMMENTS: For use on all varieties. This material is hazardous to bees. Do not apply during bloom.
**	OC - Outside coverage uses 50–500 gal water/acre.
	A - Aircraft applications 5-20 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

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