Description of the Pest
Overwintering eggs are found on twigs of the previous season's growth and on fruit spurs. They are identical in appearance to rosy apple aphid eggs: shiny, black, and football shaped. Newly hatched apple aphids are dark green. Mature aphids on apple foliage in spring and summer have a bright, yellow-green abdomen with darker green lateral spots.
Damage
Green apple aphids infest succulent terminal growth and when infestations are severe will also be found on fruits. High populations on young trees may seriously retard normal growth and result in irregular shoot growth. On bearing trees, heavy infestations of aphids may cover the fruit and foliage with honeydew on which a black, sooty mold develops. The mold can hinder leaf function and lower fruit grade.
Management
Green apple aphid feeds on both apple and pear trees and occasionally on hawthorn, loquat, pyracantha, and quince; apple, however, is the preferred host. Although green apple aphid is subject to wide fluctuations in abundance, it generally occurs yearly in most apple orchards. Natural enemies often control this aphid.
Biological Control
There are many natural enemies which feed on aphids. Among the most important are lady beetles, green lacewings, brown lacewings, and syrphid fly larvae.
Organically Acceptable Methods
Biological controls and sprays of insecticidal soap, approved narrow range oils, and azadirachtin (Neemix) are organically acceptable.
Monitoring and Treatment Decisions
A delayed dormant spray of oil will prevent early injury and should eliminate the need for further sprays.
If more than 45% of the tree's shoots are infested during the summer, assess the abundance of predators. Treatment may be warranted if 60% or more of the tree's terminals are infested. Spring treatments may also be necessary for young trees with severe infestations.
| Common name | Amount per acre** | 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. | |||||
| DELAYED DORMANT (Preferred timing) | |||||
| A. | DORMANT FLOWABLE EMULSION OIL | 4–6 gal | 1–1.5 gal | 12 | 0 |
| MODE-OF-ACTION: Contact including smothering and barrier effects. | |||||
| COMMENTS: Apply at delayed dormant to silver tip stage. | |||||
| FOLIAGE SPRAY | |||||
| A. | SPIROTETRAMAT | ||||
| (Movento) | 6–9 fl oz | 24 | 7 | ||
| MODE-OF-ACTION GROUP NUMBER1: 23 | |||||
| COMMENTS: Do not apply until after petal fall. Allow 14 days between applications. Maximum is 25 fl oz/acre (0.4 lb a.i./acre) per crop per season. | |||||
| B. | IMIDACLOPRID | ||||
| (Admire Pro) | 2.8 oz | 12 | 7 | ||
| MODE-OF-ACTION GROUP NUMBER1: 4A | |||||
| COMMENTS: Provides good control. Allow 10 days between applications. Repeat applications of any neonicotinoid insecticide (acetamiprid-Assail and imidacloprid-Admire Pro) 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. To help prevent development of resistance, do not use for both codling moth and aphid control. Highly toxic to bees. 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 ingredients or using more than one application method in the same season. |
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| C. | CLOTHIANIDIN | ||||
| (Belay) | 4–6 fl oz | 12 | 7 | ||
| MODE-OF-ACTION GROUP NUMBER1: 4A | |||||
| COMMENTS: Toxic to bees. 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 ingredients or using more than one application method in the same season. |
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| D. | ACETAMIPRID | ||||
| (Assail 70 WP) | 1.1–1.7 oz | 12 | 7 | ||
| MODE-OF-ACTION GROUP NUMBER1: 4A | |||||
| COMMENTS: May cause outbreaks of mites, especially in orchards with chronic mite problems; addition of 1% oil (volume by volume) and limiting applications to a single application may help mitigate mite problems. Repeat applications of any neonicotinoid insecticide (acetamiprid-Assail and imidacloprid-Admire Pro) 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. To help prevent development of resistance, do not use for both codling moth and aphid control. Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | |||||
| E. | DIAZINON* | ||||
| (Diazinon 50W) | 4 lb | 1 lb | 4 days | 21 | |
| MODE-OF-ACTION GROUP NUMBER1: 1B | |||||
| COMMENTS: Applications made during the foliage season are harmful to beneficials. 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. | |||||
| F. | INSECTICIDAL SOAP# | Label rates | 12 | 0 | |
| (M-Pede) | |||||
| MODE OF ACTION: A contact insecticide with smothering and barrier effects. | |||||
| COMMENTS: More than 1 application may be necessary because this material has little residual action. | |||||
| G. | NARROW RANGE OIL# | ||||
| (JMS Stylet Oil, Omni) | Label rates | See label | 0 | ||
| MODE OF ACTION: Contact including smothering and barrier effects. | |||||
| COMMENTS: Apply as soon as colonies are found and reapply at 7- to 10-day intervals as long as active colonies are found. | |||||
| H. | NARROW RANGE OIL# | ||||
| (JMS Stylet Oil, Omni) | Label rates | See label | 0 | ||
| MODE OF ACTION: Contact including smothering and barrier effects. | |||||
| . . . PLUS . . . | |||||
| AZADIRACHTIN# | |||||
| (Neemix 4.5) | Label rates | 4 | 0 | ||
| MODE-OF-ACTION GROUP NUMBER1: un | |||||
| COMMENTS: Apply as soon as colonies are found and reapply at 7- to 10-day intervals as long as active colonies are found. Azadirachtin without oil is not effective in controlling this pest. | |||||
| ** | For dilute application, rate is per 100 gal water to be applied in 300 to 500 gal water/acre, according to label; for concentrate applications, use 80 to 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. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| # | Acceptable for use on organically grown produce. |
| 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 ("un"=unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee). |