Pests Beneficial Organisms Insect-Transmitted Diseases Management Options Other Resources Contact a Specialist Green Peach Aphid Morphs of Aphids Each aphid species has both winged and wingless adult "morphs."   The winged and wingless morphs often look very different, as in these green peach aphids.   Aphids develop into winged adults in response to crowding and/or changes in host plant quality.   All aphids in potato fields are females. Aphids reproduce parthenogenetically, which means that each aphid is genetically identical to its mother — much like clones are genetically identical. Aphids give birth to live young, rather than laying eggs. This is one reason their numbers can grow so fast. The other main reason is that baby aphids are born pregnant! Many aphids prefer plant tissue that is starting to yellow — more nutrients are moving in the sap that the aphids eat. Potato aphid giving birth Baby green peach aphid.   Aphids are often parasitized by wasps whose larvae eat the aphid from the inside out. These dead aphids are called "mummies."   Green Peach Aphid (Myzus persicae — GPA) Biology & Management GPA is by far the most important aphid species in Washington potatoes. GPA is a very effective vector of potato viruses like PVY and leafroll virus. GPA usually becomes abundant in potato fields in July. GPA overwinters as eggs on peach trees or as nymphs and adults on weeds. Many insecticides are available that control GPA, but be aware that pyrethroid insecticides kill aphid predators and parasites, allowing aphids to flare.   Potato Aphid — Macrosiphum euphorbiae Most commonly found in potatoes very early in the season. Effective virus vector. Much larger than green peach aphid. Overwinters on weeds or as eggs on rose bushes and other plants. Potato aphid is often found on actively growing shoots. Like many aphids, potato aphid can be green or pink.