Description of the Pest
Foxglove aphid has several color forms, ranging from green to orange to pink. Most wingless aphids have dark green areas at the base of the cornicles (projections from the rear of the abdomen). Some of the wingless aphids have many black markings on the top of the abdomen as well. The winged adults are browner in color than the wingless forms, but also have various black markings.
Foxglove aphid is a pest of lettuce in California's Central Coast, although it may also occur on other crops. Foxglove aphid is nearly indistinguishable in the field from another pest of lettuce, the lettuce aphid (Nasonovia ribis-nigri), and in fact in many parts of the world the two commonly infest the same fields. These two aphids, however, can be distinguished from green peach aphid by the lack of prominent, converging antennal tubercles.
Foxglove aphid has a very short life cycle and populations can build rapidly. It has a wide host range.
Damage
Foxglove aphids feed deep inside the plant on younger leaves. It is known to vector several viral diseases.
Management
Monitoring and Treatment Decisions
Monitoring requires care in order not to miss early infestations that are hidden within the lettuce. This aphid has a tendency to disperse in the plant rather than forming colonies as green peach aphid does. Control of this aphid is difficult because of its rapid population growth combined with its preferred locations deep within the plant.
| 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. | ||||
| AT PLANTING | ||||
| A. | IMIDACLOPRID | |||
| (Admire) 2F | 10–24 fl oz | 12 | 45 | |
| MODE OF ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Soil application. Use at planting in fields that have a history of aphid infestations. The rate applied affects the length of control. Use higher rates where infestations occur later in crop development or where pest pressure is continuous. Do not apply more than 0.5 lb a.i./acre/year. Repeat applications of any neonicotinoid insecticide (acetamiprid-Assail or imidacloprid-Admire) can lead to resistance to all neonicotinoids. Alternate neonicotinoids with an insecticide that has a different mode of action to help delay the development of resistance. | ||||
| AFTER PLANTING | ||||
| A. | ACETAMIPRID | |||
| (Assail) 70WP | 0.8–1.2 oz | 12 | 7 | |
| MODE OF ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Thorough coverage is important. Do not make more than 5 applications/season. Repeat applications of any neonicotinoid insecticide (acetamiprid-Assail or imidacloprid-Admire) can lead to resistance to all neonicotinoids. Alternate neonicotinoids with an insecticide that has a different mode of action to help delay the development of resistance. | ||||
| B. | PYMETROZINE | |||
| (Fulfill) | 2.75 oz | 12 | 7 | |
| MODE OF ACTION: A pyridine azomethine (Group 9B)1 insecticide. | ||||
| COMMENTS: Thorough coverage is important. Do not exceed 5.5 oz/acre/season. Apply when aphids first appear before populations reach damaging levels. | ||||
| C. | OXAMYL* | |||
| (Vydate L) | 1–2 qt | 48 | 21 | |
| MODE OF ACTION GROUP NUMBER1: 1A | ||||
| COMMENTS: Do not apply more than 3 gal/acre/season. | ||||
| * | Permit required from county agricultural commissioner for purchase or use. |
| ‡ | 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 | Group numbers for insecticides and miticides are assigned by the Insecticide Resistance Action Committee (IRAC). Rotate pesticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. |