Description of the Pest
In California, this aphid is prevalent in the San Joaquin Valley. Winged and wingless adults of the black peach aphid are shiny black and about 0.1 inch long. The nymphs are reddish brown. Wingless forms overwinter on the roots of nectarine and other closely related trees. In early spring, some migrate from roots to new growth and start colonies on the young leaves. Several generations of female aphids are produced. In early summer, winged adults are produced and migration to other trees occurs. Aboveground colonies usually disappear by midsummer as wingless forms migrate to the roots to feed and overwinter.
Damage
Injury consists of leaf curling, yellowing, and premature drop; the leaf curling is first evident at shoot terminals. If aphids are abundant, honeydew excretion may cause black sooty mold to appear on leaves and fruit. Ants may also become a problem, because they tend the aphids while they are on the roots.
Management
In spring when growth begins, look for colonies of this aphid when monitoring other pests. The multicolored Asian lady beetle, Harmonia axyridis, is a common predator of these aphids. This aphid is not particularly damaging, and populations may be managed by predators. If this aphid has presented problems in the past, take control measures in spring.
| Common name | Amount per acre** | 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 and 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. | IMIDACLOPRID | |||
| (Admire Pro) | 1.4–2.8 fl oz | 12 | 0 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Apply as foliar spray after pollination is complete and bees are no longer present in the orchard. Thorough, uniform coverage is essential. Review and follow the California neonicotinoid regulations effective January 1, 2024. Permissible application rates of this insecticide may be lower than label rates if applying more than one neonicotinoid active ingredient or using more than one application method in the same season. |
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| B. | ACETAMIPRID | |||
| (Assail 70WP) | 1.1–2.3 oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| ** | For dilute applications, rate is per 100 gal water to be applied in 300-500 gal water/acre, according to label; for concentrate applications, use 80-100 gal water/acre, or lower if the label allows. |
| ‡ | 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. |
| 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). For additional information, see their Web site at http://www.irac-online.org/. |