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Ministry of Agriculture, Food and Rural Affairs

Green Peach Aphid

Green peach aphid in terminal Winged adults Green peach aphid adults
Click to enlarge.

Beginner

This pest affects:

Scientific Name
Myzus persicae

Identification
Adults

  • 1.2 to 2.5 mm long
  • Egg-shaped
  • Body has cornicles that are highly swollen toward the tips
  • Bases of the antennae have prominent, inwardly directed tubercles
  • Wingless adults are light green and almost translucent
  • Winged adults have a black or dark brown head and thorax and a dark dorsal patch in the center of the abdomen

Nymphs

  • Slender and a pinkish color at first
  • Becomes a yellowish-green color with three indefinite darker green stripes on the back of the abdomen
  • Resemble wingless adults in colour but are smaller

Damage

  • Aphids feed primarily on the underside of leaves
  • Leaves curl tightly, yellow and drop prematurely
  • Young shoots stop growing
  • Flowers and fruitlets may not develop or may drop
  • Nectarine fruit may be deformed, bumpy and streaked with russet
  • When abundant, aphids excrete large amounts of honeydew which supports the growth of a black sooty fungus that causes spotting of leaves and fruit

Often Confused With
Other aphid species

Period of Activity
Aphids are active all season long and in the orchard from bud break to terminal bud set. They move to summer hosts and return to the orchard in the fall.

Scouting Notes
Trees should be inspected weekly from the delayed dormant stage until the terminals harden off.

Begin monitoring at the delayed-dormant stage. Young aphids are easy to detect on the outside of open buds at this time. Examine several buds on 20 trees from throughout an orchard to determine the number infested by aphids. As soon as flowers open, aphids crawl inside and are more difficult to detect.

Inspect the underside of leaves of at least 10 trees per block from petal fall until about a month after shuck fall. Flower parts and developing fruit should also be inspected, but aphids are likely to be more abundant on leaves.  Monitor for the presence of predators in aphid colonies: lady bird beetles and their larvae, syrphid (hover) flies, lacewing larvae.  Nectarines should be monitored intensively and have a lower threshold.

Use of mating disruption technology to control OFM may increase risk of GPA infestation - intensive monitoring necessary, but increased GPA activity may be balanced by increased predator activity.

Threshold
30% of terminals infested or 20 colonies per tree for peaches.

10% of terminals infested or 5–10 colonies per tree for nectarines, young, non-bearing peach trees and mature peach trees under water stress.

 

Advanced

This pest affects:

Scientific Name
Myzus persicae

Identification
Adults

  • 1.2 to 2.5 mm long
  • Egg-shaped
  • Body has cornicles that are highly swollen toward the tips
  • Bases of the antennae have prominent, inwardly directed tubercles
  • Wingless adults are light green and almost translucent
  • Winged adults have a black or dark brown head and thorax and a dark dorsal patch in the center of the abdomen

Nymphs

  • Slender and a pinkish color at first
  • Becomes a yellowish-green color with three indefinite darker green stripes on the back of the abdomen
  • Resemble wingless adults in colour but are smaller

Damage

  • Aphids feed primarily on the underside of leaves
  • Leaves curl tightly, yellow and drop prematurely
  • Young shoots stop growing
  • Flowers and fruitlets may not develop or may drop
  • Nectarine fruit may be deformed, bumpy and streaked with russet
  • When abundant, aphids excrete large amounts of honeydew which supports the growth of a black sooty fungus that causes spotting of leaves and fruit

Often Confused With
Other aphid species

Biology
Green peach aphid feeds on mainly peach; however, apricot, plum, cherry and other trees may be attacked. Green peach aphid also feed on a wide variety of vegetable and floricultural crops.

GPA overwinters as eggs laid in bud axils and bark crevices on twigs of peach. They hatch just before bud break. Emerging nymphs begin feeding at once on opening buds, unfolding blossoms, and tender twigs and leaves. The nymphs develop into wingless females, which produce live young without mating. The aphids feed on the underside of the leaves. As the population increases, the leaves curl. After 2 or 3 generations, winged forms are produced, which migrate to summer hosts such as broadleaf weeds and other crop plants, where several generations are produced. In the fall at the onset of cold temperatures, winged aphids return to peach and other stone fruits and give birth to nymphs. These develop into egg-laying females, which mate with males and lay overwintering eggs.

The green peach aphid is one of several aphids that can transmit plum pox virus.

Period of Activity
Aphids are active all season long and in the orchard from bud break to terminal bud set. They move to summer hosts and return to the orchard in the fall.

Scouting Notes
Trees should be inspected weekly from the delayed dormant stage until the terminals harden off.

Begin monitoring at the delayed-dormant stage. Young aphids are easy to detect on the outside of open buds at this time. Examine several buds on 20 trees from throughout an orchard to determine the number infested by aphids. As soon as flowers open, aphids crawl inside and are more difficult to detect.

Inspect the underside of leaves of at least 10 trees per block from petal fall until about a month after shuck fall. Flower parts and developing fruit should also be inspected, but aphids are likely to be more abundant on leaves.  Monitor for the presence of predators in aphid colonies: lady bird beetles and their larvae, syrphid (hover) flies, lacewing larvae.  Nectarines should be monitored intensively and have a lower threshold.

Use of mating disruption technology to control OFM may increase risk of GPA infestation - intensive monitoring necessary, but increased GPA activity may be balanced by increased predator activity.

Threshold
30% of terminals infested or 20 colonies per tree for peaches.

10% of terminals infested or 5–10 colonies per tree for nectarines, young, non-bearing peach trees and mature peach trees under water stress.

Management Notes
Dormant oil application before bud burst may provide adequate control when applied in sufficient water to ensure thorough coverage. GPA are most susceptible just after hatching and before they have crawled into opening buds and flowers, just as buds are beginning to open. Dilute sprays, assuring good coverage, have provided good control during this period. After aphids have become protected by entering flowers or are concealed in curled leaves, chemical control is difficult. Postbloom insecticide sprays for aphids, Oriental fruit moth or other pests can kill predators, disrupting biological control, which in many orchards can suppress populations below damaging levels.

Preserve the many predatory insects that feed on aphids by avoiding use of harmful chemicals where possible. Early season establishment of lady beetles, lacewings, syrphid flies, soldier beetles and predaceous bugs is important for successful biological control. On all crops except nectarine, natural enemies will often suppress green peach aphid populations below damaging levels.

Management with insecticides - Insecticides are used to control green peach aphid in many commercial peach and nectarine orchards. See OMAFRA Publication 360, Fruit Crop Protection Guide.

Chapter 5 - Peach Calendar : Recommendations for OFM Petal fall to shuck, shuck split to shuck fall, second cover, third cover and prepick.

Do not spray aphicides in an attempt to control disease spread (e.g. PPV) - aphicides can actually increase the rate of disease transmission by aphids. Oil sprays will reduce the transmission of PPV by green peach aphid.

Information included above excerpted from;