Fruit IPM Fact Sheet Fruit IPM Fact Sheet
Green Peach Aphid
Myzus Persicae (Sulzer)
Common Tree Fruit Pests, NCR 63. by: Angus Howitt, 1993.
Michigan State University
The green peach aphid is a native European pest. It was first described as a peach pest in Europe in 1761.
Life Stages
Egg: Eggs are shiny black, about 0.50 mm long and 0.25 mm wide.
Nymph: Young nymphs look yellowish green and have three darker green lines on the back of the abdomen.
Adult: Stem mothers,
which appear in the spring and fall, are deep pink. The adults developing from the stem
mothers are pear-shaped, about 1 to 5 mm long, and yellowish green with a median and two
lateral dark green stripes that pass over the abdomen. A pair of cylindrical cornicles are
present at the end of the abdomen.
Host Range:
The green peach aphid feeds on a variety of host plants, including peach, plum, apricot, cherry, ornamentals, vegetables and flowering plants.
Injury or Damage
Green peach aphids feed on leaves and
extract sap, causing the leaves to turn yellow and drop. Honeydew is excreted as a waste
product and acts as a foundation for a black, sooty fungus that causes smutting of leaves
and fruit. The green peach aphid transmits a variety of diseases on other crops,
particularly vegetables. It is not uncommon to find hundreds or even thousands of aphids
per tree.
Factors Affecting Abundance
Aphids have a high reproductive potential. Weather, including wind, rain and cool temperatures, regulates populations. A number of predators and a parasites, including ladybird beetles, lacewings, syrphid fly larvae and chalcid wasps, prey on them.
Life History
The green peach aphid has a complex life history, with five distinct morphological forms and two behavioral forms. This pest also needs to complete several generations during midsummer on host plants other than peach. As cold weather approaches in the fall, females fly to peaches and give birth to female nymphs. These females mate with males as they return from summer host plants and either lay eggs under peach buds or overwinter as adults without laying eggs. In the spring when the first peach leaves appear, the overwintering females establish themselves as stem mothers. This spring generation triggers two or three more generations or females on peach; the females give birth parthenogenetically to wingless young. By June, winged adults appear and the aphids leave the peach trees by July to migrate to other crops and weeds. Here, they complete several summer generations of their life cycle before returning to peach trees in the fall to lay eggs or overwinter as adults.
Monitoring
Aphids are a problem early in the season and remain on peaches for two or three generations-until about the middle June-before leaving for other crops. The aphids feed on the undersides of the leaves. In a block of peaches, select 10 spurs from each of five trees. Treatment is recommended if an average of one colony or more per tree is found.
Control
This pest is difficult to control because it has developed resistance to many pesticides. Encourage the buildup of predators and parasites. When using an effective pesticide, thorough coverage, particularly of the lower leaf surfaces, is necessary.
