Pear sucker

Pear sucker (Psylla pyricola) also called Pear Psylla can be a major pest for orchards, but is less common in gardens. The nymphs appears in the spring on developing leaf and blossom trusses later in the summer they move to the leaves. Where the presence of honeydew and secondary sooty mould infection are characteristic of attack. Heavy infestations can cause complete kill of developing blossoms.
Unlike Apple suckers, which overwinter as eggs, Pear suckers, which has a black spot on the inside edge of the forewing and are about 3mm long, overwinter as adults. They are similar in appearance to adult Apple suckers, being brown-black in colour, but only grow to about 2mm in length. Eggs are straw-coloured initially, gradually turning orange, and are smaller than those laid by Apple suckers. Egg laying occurs between late February and full blossom on to spurs and shoots. Normally egg hatching starts at the bud burst stage and is complete by the end of flowering. Newly-hatched nymphs have distinctive red eyes and an orange-yellow body that darkens with age. These nymphs mature to produce the first summer generation of adults and lay eggs along the midrib of leaves.
Pear suckers normally have three generations each year with peak adult populations being present in early June, Late July and mid-October. Even small numbers surviving winter can produce very large populations by the end of summer.
Another problem with this pest is the transmition of viruses which can cause the tree to decline in vigour and fruit production.