Description of the Pest
The peach twig borer is widely distributed throughout California and is found on several hosts, but is rarely a problem in mature cherry orchards. The adult moth is about 0.3 to 0.5 inch long, with steel-gray mottled forewings. Small larvae are almost white with black heads. Mature larvae are about 0.5 inch long and have black heads and brownish bodies with white portions between each body segment, giving the appearance of stripes. Peach twig borer overwinters as larvae in tiny cells, called hibernaculum, that are located in the crotches of 1- to 3-year-old wood and at pruning wounds. There may be three to four generations each year, but later generations occur after cherry harvest.
Damage
The peach twig borer in general is a minor pest of cherry. Larvae may burrow in tender shoots and kill the tips. This can cause problems in training young trees if population levels are high but is rarely an issue on mature trees. They also may feed on fruit on mature trees, primarily at the stem end. Either feeding damage or the presence of larvae will cause a fruit to be offgrade.
Management
Dormant or delayed-dormant insecticide sprays will reduce populations of overwintering larvae. When control has not been achieved by delayed-dormant treatment, an insecticide may be applied during the bloom to petal fall period or shortly thereafter, depending on the insecticide. For summer sprays (May-July) on young trees, monitor for flagging or shoot strikes. If you see an unacceptable level of flagging, check with a UCCE farm advisor or PCA for areawide treatment timing or apply a dormant or bloom treatment the following season.
Organically Acceptable Methods
The use of Bacillus thuringiensis or the Entrust formulation of spinosad at bloom is acceptable for use on an organically certified crop.
| 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. | |||||
| BLOOM | |||||
| A. | METHOXYFENOZIDE | ||||
| (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 per 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: Make 2 applications during bloom: the first at early bloom and the second 7–10 days later, but no later than petal fall. Compatible with fungicide sprays. Good coverage is essential. | |||||
| C. | SPINOSAD | ||||
| (Entrust)# | 1.25–2.5 oz | 0.42–0.83 oz | 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. | |||||
| D. | SPINETORAM | ||||
| (Delegate WG) | 3–7 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. | |||||
| SPRING and SUMMER | |||||
| A. | ESFENVALERATE* | ||||
| (Asana XL) | 4.8–14.5 fl oz | 2–5.8 fl oz | 12 | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | |||||
| COMMENTS: Provides long-term control. May cause serious outbreaks of spider mites. Do not exceed 0.375 lb a.i./acre per season. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| B. | METHOXYFENOZIDE | ||||
| (Intrepid 2F) | 8–16 fl oz/acre | 4 | 7 | ||
| MODE-OF-ACTION GROUP NUMBER1: 18 | |||||
| COMMENTS: Do not apply more than 16 fl oz/acre per application or 64 fl oz/acre per season. Coverage is extremely important; sprayer speed should not exceed 2 mph. | |||||
| C. | BACILLUS THURINGIENSIS ssp. KURSTAKI# | ||||
| (various products) | Label rates | 4 | 0 | ||
| MODE-OF-ACTION GROUP NUMBER1: 11A | |||||
| COMMENTS: Most effective on small caterpillars. Does not destroy natural enemies. Make 2 applications during bloom: the first at early bloom and the second 7–10 days later, but no later than petal fall. Compatible with fungicide sprays. Good coverage is essential. | |||||
| D. | SPINOSAD | ||||
| (Entrust)# | 1.25–2.5 oz | 0.42–0.83 oz | 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. | |||||
| E. | SPINETORAM | ||||
| (Delegate WG) | 3–7 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. | |||||
| F. | DIAZINON* | ||||
| (Diazinon 50W) | 1 lb/100 gal water | 96 (4 days) | 21 | ||
| MODE-OF-ACTION GROUP NUMBER1: 1B | |||||
| COMMENTS: Avoid drift and tailwater runoff into surface waters. Where cherries are grown adjacent to waterways, do not use this material. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| G. | CARBARYL* | ||||
| (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 Sevin XLR PLUS/acre per season. The XLR PLUS formulation is less hazardous to honey bees than other formulations 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. |