Description of the Pest
The orange tortrix is found mainly in coastal areas. It overwinters as larvae inside fruit mummies or on alternative hosts and has two to four generations each year. Mustard family weeds are a favored host. Larvae are straw-colored to light green caterpillars with brown heads. When disturbed, they wiggle backward and drop to the ground on a silken thread. Adults are light orange or tan moths with darker mottling on the forewings. Eggs are laid on leaves in overlapping rows that resemble fish scales.
Larvae feed on leaves and buds. They also feed on fruit during late spring, resulting in shallow feeding damage. Leaves webbed together to form protective cases often indicate the presence of orange tortrix.
Orange tortrix is a cyclical pest and a minor problem in cherries. In coastal orchards, natural enemies and treatments for other pests usually keep this pest controlled. In other areas treatment is not needed.
Several parasites and predators attack orange tortrix. The parasitic wasps Apanteles aristoteliae, Exochus, and Hormius basalis, the tachinid fly (Nemorilla pyste), spiders, and brown lacewings are the most important. These natural enemies usually keep orange tortrix populations under control.
Organically Acceptable Methods
Biological control and sprays of the Entrust formulation of spinosad are acceptable for use on an organically certified crop.
Monitoring and Treatment Decisions
Check the orchard at bloom for presence of larvae and feeding damage. (For more information, see MONITORING PESTS AT BLOOM.) Dormant spray programs for scales and aphids generally help reduce populations. When necessary, apply an insecticide at petal fall or shortly thereafter.
|Common name||Amount to use**||REI‡||PHI‡|
|(Example trade name)||(conc.)||(dilute)||(hours)||(days)|
|Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.|
|(Intrepid 2F)||8–16 fl oz/acre||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 18|
|COMMENTS: Most effective when applied at petal fall. Do not apply more than 16 fl oz/acre per application or 64 fl oz/acre/season. Coverage is extremely important; sprayer speed should not exceed 2 mph.|
|B.||BACILLUS THURINGIENSIS ssp. KURSTAKI#|
|(various products)||Label rates||4||0|
|MODE-OF-ACTION GROUP NUMBER1: 11A|
|COMMENTS: Least harmful to beneficials. Bacillus thuringiensis is a stomach poison and must be consumed by the leafroller; therefore it is most effective when applied during warm, dry weather when larvae are actively feeding. Most effective against young larvae. Requires more than 1 treatment; apply second application 7–10 days after first.|
|(Entrust)#||1.25–2.5 oz||0.42–0.83 oz||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 5|
|COMMENTS: Most effective when applied at petal fall. This product is toxic to bees for 3 hours following treatment; apply in late evening after bees have stopped foraging. Do not apply more than 9 oz/acre per year.|
|(Delegate WG)||4.5–7 oz/acre||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 5|
|COMMENTS: Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.|
|MODE-OF-ACTION GROUP NUMBER1: 28|
|COMMENTS: Do not use with an adjuvant. A newer material; impact on beneficials not yet determined. May cause mite flare ups.|
|(Sevin XLR PLUS)||3–4 qt/acre||12||1|
|MODE-OF-ACTION GROUP NUMBER1: 1A|
|COMMENTS: May cause increased spider mite problems. Do not apply more than 14 qt XLR PLUS/acre per season. The XLR PLUS formulation is less hazardous to honey bees than other formulations of Sevin if applied from late evening to early morning when bees are not foraging.|
|**||For concentrate applications, use the amount given in 80–100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300–400 gal water/acre, according to label.|
|‡||Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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.|
|*||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).|
|#||Acceptable for organically grown produce.|