Description of the Pest
The forewings of the adult moth are gray with brown and black markings. The wingspan in about 0.75 inch. Young larvae are white with a large, dark brown head. Mature larvae are about 1 inch long, dusky white, pinkish or dull green in color. Reddish orange frass, webbing, and gum pockets indicate their presence. They overwinter as mature larvae in a cocoon within the tree. There are three to four generations each year.
Damage
Larvae bore into the tree, leaving reddish orange frass and gum pockets. The boring is most damaging to the scaffold crotches or graft unions of young trees. Vigorous trees will heal over, but with heavy, prolonged infestations, scaffolds may break with wind or a heavy crop.
Management
Monitor young orchards in spring and summer for frass and gum pockets. If larvae are present, spray trees from 1 foot above the scaffold crotch to 1 foot below, two to three times during the growing season. The first application should be mid- to late April and subsequent applications at 6-week intervals.
| Common name | Amount to use | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (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. | ||||
| A. | DIAZINON* | |||
| (Diazinon 50W) | 1 lb/100 gal water | 96 (4 days) | 21 | |
| MODE-OF-ACTION GROUP NUMBER1: 1B | ||||
| COMMENTS: Do not exceed 4 lb diazinon 50W/acre per application. Avoid drift and tailwater runoff into surface waters. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| B. | CARBARYL* | |||
| (Sevin 4F) | 2–3 qt/acre | 12 | 1 | |
| MODE-OF-ACTION GROUP NUMBER1: 1A | ||||
| COMMENTS: Do not exceed 14 qt/acre per crop. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| ‡ | 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). |