The colour pyei variable, ranging between orange-red and black, the thorax having whitish longitudinal stripes on its upper surface. Orchard Pest Management Online. The secretions cause spots on the fruits which lower their value. Sucking of larvae and adults, when populations are high, can produce pustules on branchlets and spots on leaves. From Wikipedia, the free encyclopedia. The excess honeydew produced by the insects coats the leaves, covering up the stomataand encourages the growth pyrii sooty mould.
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The colour is variable, ranging between orange-red and black, the thorax having whitish longitudinal stripes on its upper surface.
The wings are transparent, with dark veins and sometimes a smoky appearance near the base. Later instar nymphs are purplish-brown or reddish-brown, with white longitudinal stripes and black patches; the developing wing-pads each bear a single knobbed bristle.
The younger nymphs are yellowish with red-purple eyes. In spring it leaves diapause , and the female starts laying eggs round the base of the swelling buds. Later in the summer, the eggs are laid beside the midribs of the leaves, on the petioles and on the flower buds. The nymphs moult five times, and both nymphs and adults insert their mouthparts deep into the phloem tissue to suck the sap, secreting the excess fluid as honeydew.
The predators included the predatory bugs Anthocoris nemoralis and Deraeocoris spp. The wasp Trechnites psyllae was the main parasitoid. The excess honeydew produced by the insects coats the leaves, covering up the stomata , and encourages the growth of sooty mould. The size of fruit is decreased and tree growth is diminished.
Failure of nutrients to be translocated downwards can cause root starvation, with trees either declining slowly or suffering from sudden collapse. Trees grafted onto Pyrus pyrifolia or Pyrus ussuriensis rootstocks are more susceptible to this disease than those on Pyrus communis.
Cacopsylla pyri (Linnaeus, 1758)
CACOPSYLLA PYRI PDF
EPPO Global Database