Pear Sucker

Key Points

  • Pear sucker infestations have become increasingly common over recent years
  • The presence of honeydew and secondary sooty mould infection are characteristic of attack
  • Lorsban WG should be applied when infestation occurs
  • Applications of Lorsban WG can control Pear sucker and many other fruit pests

Introduction

Pear sucker (Psylla pyricola) infestations have become more common in recent years with some pear orchards carrying large, established populations. The adoption of integrated control programs, incorporating the use of effective insecticide treatments, is very important as a means of reducing the damage this pest can cause.

Feeding by Pear sucker nymphs occurs in the spring on developing leaf and blossom trusses and continues through the summer on leaves. Heavy infestations can cause complete kill of developing blossoms. A secondary symptom of Pear sucker attack is the development of sooty moulds in the honeydew secreted by the nymphs. This leads to blackened shoots and foliage, sometimes affecting the fruit as well.

Biology

Unlike Apple suckers, which overwinter as eggs, Pear suckers 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.

Egg hatch normally 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. Honeydew deposits are found on the underside of leaves where nymphs are present.

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.

Product Choice

Applications of Lorsban* WG (active ingredient chlorpyrifos) when populations of Pear sucker are detected at potentially damaging levels will control this pest. Do not apply to crops in flower or to those in which bees are actively foraging. Do not make applications when flowering weeds are present.

Pear suckers resistant to one or more groups of insecticides are widespread. Where strains resistant to products containing organophosphorus insecticides occur Lorsban WG is unlikely to give satisfactory control. Where repeat treatments are necessary use different active ingredients.