Potato aphid
The potato aphid (Macrosiphum euphorbia) is a widely spread species in Europe. It is a cosmopolitan and polyphage. The pest is able to affect more than 200 species of plants (vegetable, ornamental-flower and industrial crops) from 20 families. It is an agent of more than 50 plant viruses (in particular the vectorial virus of potato). This pest is a not distinct-stage insect.
Biology. Life cycle
The wingless female is green, sometimes red. Its body is oblong-oval, spiky to a hind end. The body is 2.7–2.8 mm in length. The forehead is without a hillock. The inner edges of antenna hillocks are directed in front to different sides. The sappy tubules come out beyond the bounds of the body. They are pallid at the base and dark-brown on a top. The length of tubules is equal or almost equal to the width of the body. There is honeycomb structure on their tops. There is a dark-green strip along the body on the dorsal surface of an abdomen. There are 5–9 hairs on the 8th tergite and 6–12 on a caudicle (tail). There are 10 rinaria on the 3rd segment of the antennae. The winged female is 3.4 mm in length. There are no dark transversal strips on the abdomen.
Mode of life
The eggs overwinter on the shoots of cultivars and the wild species of roses. In April-May the larvae of a progenitress arise from them. The progenitress bears about 50 larvae of winged and wingedless migrants during for all her life. In the autumn the winged males and the sexuparae return on roses and dog roses where they reproduce amphigenous females. They lay the eggs, which stay to overwinter. In glass-covered ground this species multiplies parthenogenetically all the year.
Symptoms of injuries
The pest forms colonies, populates young shoots and the undersides of plant leaves. In the process of feeding the pest excretes toxins into a plant, which cause the disturbance of growth processes (the curl of leaves, crumpl and etc.). The yellow necrotic spots emerge on the injured leaves. It is possible withering. During the process of life activity the pests leave sugary excretions on a leaf (waste products). After that the sooty fungus develops on the leaves. The potato aphid is an agent of the various viruses of vegetable crops.
