Description of the Pest
These aphids form colonies near the top of the root and at the base of the stems, as compared to aphids that feed on the foliage and are addressed separately in this publication. They occasionally form colonies on the root slightly below ground. All are similar in appearance, with the wingless forms being pale yellow to gray green and covered with a powdery wax.
The tulip bulb aphid is covered with a white waxy powder, while the wax covering the hawthorn parsley aphid is grayish white. The hawthorn carrot aphid is yellowish gray to greenish gray with a very light dusting of wax.
All three species, when present, are usually attended by ants. The presence of ants around the base of the plants is usually a good clue to the presence of these aphids.
Damage
These aphids occur infrequently and only occasionally cause injury. High numbers may stunt growth, but more serious is that the tops may be weakened by their feeding and break off during harvest, leaving the carrot in the ground.
Management
Biological Control
Because of their location near and below the soil line, predators and parasitoids have a difficult time finding these aphids. Ants that tend to aphids also discourage the activity of predators and parasites.
Cultural Control
Sanitation and crop rotation to nonhost crops are important in reducing the buildup of these aphids and their injury.
Organically Acceptable Methods
Use cultural controls in a certified organic crop.
Monitoring and Treatment Decisions
No treatment thresholds have been established for these aphids.
| 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, 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-foliar) | 1.2 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Thorough, uniform coverage is important for good control. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. If grown for seed, 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. | IMIDACLOPRID/BETA-CYFLUTHRIN | |||
| (Leverage 360) | 2.8 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A/3A | ||||
| COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. If grown for seed, 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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| C. | MALATHION | |||
| (Malathion 8 Aquamul) | 1–1.25 pt | 24 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 1B | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| D. | ZETA-CYPERMETHRIN | |||
| (Mustang) | 3.4–4.3 fl oz | 12 | 1 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| E. | THIAMETHOXAM | |||
| (Actara) | 1.5–3 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. If grown for seed, 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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| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without personal protective equipment. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of the 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. |