How to Manage Pests

UC Pest Management Guidelines


Green Peach Aphid

Scientific name: Myzus persicae

(Reviewed 12/09, updated 11/12, pesticides updated 6/16)

In this Guideline:


Green peach aphid is among the most common aphid species found on peppers. It may be present at any time throughout the year but is most common from March through May and September through November. Generally its color is pale green, although at times individuals may be present that are pinkish. During cool weather, individuals are usually more deeply pigmented. Both winged and wingless forms of the green peach aphid have prominent cornicles on the abdomen that are markedly swollen and clublike in appearance. The frontal tubercles at the base of the antennae are very prominent and are convergent. Winged forms of the green peach aphid have a distinct dark patch near the tip of the abdomen; wingless forms lack this dark patch.


The green peach aphid transmits a number of destructive viruses in pepper including pepper potyviruses and cucumber mosaic cucumovirus. In addition, it can also damage the plant by sucking plant sap. Damaging levels are characterized by large numbers of aphids found on the underside of leaves. Extensive feeding causes plants to turn yellow and the leaves to curl downward and inward from the edges. Honeydew produced by the aphids can be a problem, especially on fresh market peppers. Aphid damage is most prominent on newer, younger leaves in the center of the plant.


Biological and cultural controls can be useful for limiting damage from this aphid. For instance, removing old crop debris from the field will reduce sources of virus and thereby its transmission by aphids, and using reflective mulches early in the season will repel aphids from young plants. Heavy infestations on seedling and young plants may require treatment with insecticides.

Biological Control

The green peach aphid is attacked by a number of common predators, including lacewings, lady beetles, syrphid flies, and parasites, including the parasitic wasps Lysiphlebus testaceipes, Aphidius matricariae, Aphelinus semiflavus, and Diaeretiella rapae, and is susceptible to the fungus disease, Entomophthora spp., that commonly attacks aphids. Aphid sampling should always include an evaluation of the presence and activity of natural enemies.

Cultural Control

An important factor in reducing virus spread is good field sanitation, especially the chopping or discing of crop debris immediately after harvest and destruction of alternate host plants. While field sanitation helps control the incidence and spread of viruses transmitted by green peach aphid, it does little to control the aphid itself. The spread of the virus within a geographical area can be reduced by not planting peppers near other pepper fields.

If peppers are planted near large areas of rangeland, it may not be possible to prevent the influx of green peach aphid. Studies have shown, however, that aluminum foil or silver reflective plastic mulches can be effective in repelling aphids from plants.

Organically Acceptable Methods

Biological and cultural controls and sprays of insecticidal soap or pyrethrin are acceptable for use on organically certified crops.

Monitoring and Treatment Decisions

Set out sticky traps before planting and check traps weekly for green peach aphids, along with thrips, tomato psyllid, and whiteflies. Be sure to replace traps as needed. When aphids are observed on traps, start monitoring pepper plants to determine population levels. Treatment thresholds for green peach aphid are not well established. Heavy populations can do extensive damage, particularly on seedlings or young plants. If seedlings or young plants show signs of stress because of aphid feeding, consider an insecticide application. If green peach aphids have been a problem in the past, apply imidacloprid at planting.

Common name Amount per acre** REI‡ PHI‡
(Example trade name)   (hours) (days)

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
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. Not all registered pesticides are listed. Always read the label of the product being used.
  (Fulfill) 2.75 oz 12 0
  COMMENTS: Can be applied either by soil or drip applications.    
  (Movento) 4.0–5.0 fl oz 24 1
  (Admire Pro –soil) 7–14 fl oz 12 21
  COMMENTS: Apply as a soil application according to label directions. Do not apply to vegetables grown for seeds. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Admire Pro –foliar) 1.3–2.2 fl oz 12 0
  COMMENTS: Apply as a foliar application according to label directions. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Actara) 2.0–3.0 oz 12 0
  COMMENTS: Do not exceed 0.172 lb a.i./acre per season. Thorough coverage is important. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Assail 70WP) 0.8–1.7 oz 12 7
  COMMENTS: Do not make more than 4 applications per season or exceed 0.3 lb a.i./acre per season. Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Dimethoate 400) 0.5–0.6 pt 48 0
  (Dimethoate E267) 0.75–1 pt 48 0
  COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Lannate SP) 0.5–1 lb 48 3
  COMMENTS: Apply in sufficient water (5–15 gal/acre by air) to obtain thorough coverage. Apply at 5- to 7-day intervals or as needed. Do not use if psyllids are present. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
  (Beleaf 50SG) 2.8–4.28 oz 12 0
  (PyGanic 1.4EC) 16 oz 12 0
  COMMENTS: Begin applications when insects first appear; do not wait until the plants are heavily infested. Apply by ground sprayer in sufficient water for thorough coverage of the plants. Apply at intervals of 7 days or less. Repeat as necessary to maintain control.
  (M-Pede) 2.5 oz/gal water 12 0
  MODE OF ACTION: A contact fungicide with smothering and barrier effects.
  COMMENTS: Only gives partial control (about 50%) and may cause phytotoxicity. Apply when aphids first appear or when damage first occurs. Spray to wet all infested plant surfaces. Repeat at weekly to biweekly intervals. Rotate sprays or rinse foliage to avoid more than 3 consecutive sprays.
** See label for dilution rates.
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 are assigned by IRAC (Insecticide Resistance Action Committee).



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Peppers
UC ANR Publication 3460

Insects and Mites

E. T. Natwick, UC Cooperative Extension, Imperial County
J. T. Trumble, Entomology, UC Riverside
J. Aguiar, UC Cooperative Extension, Riverside County

Acknowledgment for contributions to Insects and Mites:
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey County
R. L. Coviello, UC Cooperative Extension, Fresno County
C. F. Fouche, UC Cooperative Extension, San Joaquin County
C. G. Summers, Kearney Agricultural Center, Parlier

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