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UC Pest Management Guidelines

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Citrus

Omnivorous Leafroller

Scientific Name: Platynota stultana

(Reviewed 7/03, updated 7/05)

In this Guideline:

Description of the pest
Damage
Management

DESCRIPTION OF THE PEST
The larva of the omnivorous leafroller resembles other tortricid caterpillars, especially the orange tortrix, but it has white tubercles at the base of the bristles on its sides and back. Early instars have a black head and prothoracic shield; later instars have a light brown head and prothoracic shield. The larvae roll and tie leaves together or to fruit with silken threads. When mature they pupate inside the rolled leaves within a cocoon. Adult female moths lay overlapping eggs in clusters that resemble fish scales on the upper surface of leaves and on fruit. There are five to six generations a year, depending on temperatures.

DAMAGE
Omnivorous leafroller is only rarely a pest of citrus in the San Joaquin Valley and in interior and intermediate districts of southern California. In spring, small larvae spin webs and feed on new foliage. Later in the season they tie leaves to fruit and feed under the buttons, leaving ring scarring similar to that of citrus thrips. In summer and fall, they tie leaves to ripening fruit and feed on the rind.

MANAGEMENT
Omnivorous leafroller is generally managed by monitoring from spring though fall 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 attack the larva of the omnivorous leafroller. The most common are a tachinid fly, Erynnia tortricis, and an eulophid wasp, Elachertus proteoteratis. Trichogramma spp. attack the eggs.

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

Monitoring and Treatment Decisions
Monitor omnivorous leafroller weekly from spring through fall in south and east quadrants of trees. In spring, look for small larvae under sepals when you monitor for citrus thrips. During summer, less frequent monitoring may be sufficient but check to see if parasites are effective. A higher number of larvae can be tolerated in spring, when they feed on young leaves, than in fall, when they are more likely to damage ripening fruit. Keeping this qualification in mind, a control action threshold of about 30 larvae per hour of search can be used.

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 grapefruit, oranges. 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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