Capsids

Key Points

  • Capsid infestations can cause potentially severe damage to many different fruit crops
  • For best results, control measures must be directed against young capsids
  • Lorsban WG should be applied at green cluster timing
  • Applications of Lorsban WG can control Capsids and many other fruit pests

Introduction

Many species of capsids appear on fruit crops, but the majority of these are beneficial as they prey on common pests such as Spider mites, Apple suckers and Leafhoppers. An occasional pest of apple crops is the Apple capsid — Plesiocoris rugicollis — but this rarely occurs at damaging levels in well-managed apple orchards. Of greater significance to UK fruit growers is the Common Green capsid — Lygocoris pabulinus — which is a common pest of cane and bush fruit crops. It can also colonise strawberry plants and, to a lesser extent, apple, pear and other tree fruits.

For both Apple capsid and Common Green capsid, the appearance of small brown spots, the result of a feeding puncture, are the first sign of attack. These are normally found on new, young leaves but shoot tips, flower buds and fruitlets will also be attacked. Injury to apple trees can be caused by either species but the Common Green capsid is more normally responsible for damage to all other susceptible fruit plants.

Damage from a feeding puncture leads to growth of deformed leaves, production of an excessive number of secondary shoots and fruits with irregular cork-like areas. In severe attacks fruits can become badly misshapen with little or no marketable value. Attacks on strawberry crops by the first generation of the Common Green capsid causes malformed fruits similar to those resulting from poor pollination.

Biology

Both species are bright green in colour and nymphs can only be distinguished from adults by their slightly smaller size and absence of wings. Mature adults grow to approximately 5mm and carry pale green wings with translucent tips. All growth stages are very active when disturbed, moving quickly around the leaf or taking flight in the case of adults.

Apple Capsid (Plesiocoris rugicollis)

The Apple capsid produces only one generation each year. Eggs are laid in crevices in the plant’s bark and hatch between mid-April, the green cluster stage, and early May. Young capsids feed on rosette leaves, causing the brown feeding marks, then move on to developing fruitlets and any new foliage. Adults live for 4 – 6 weeks around late May and mid-June, dying once eggs have been laid during late June and in to July. Apple capsids can also attack redcurrants, blackcurrants and gooseberries.

Common Green Capsid (Lygocoris pabulinus)

Unlike Apple capsid, the Common Green capsid has two generations each year. Eggs overwinter in bark crevices and hatch after mid-April through to mid-May, slightly later than for the Apple capsid. Around 50% of eggs have normally hatched by the beginning of the blossom period and hatching is complete by petal fall. The young shoot tips of cane and bush fruits are particularly susceptible to feeding by nymphs with rosette leaves, and then young shoots and fruitlets, attacked on apple and pear trees.

Infestation of fruit crops generally ends when adults of the first generation appear in June. A second generation is produced where these adults lay eggs on cane fruit crops. These eggs hatch after about two weeks. Other adults migrate to a wide range of other host plants where they lay eggs that give rise to a second generation of adults from mid-August onwards. These adults return to fruit trees and bushes to lay eggs that then overwinter.

Product Choice

Applications of Lorsban* WG (active ingredient chlorpyrifos) at the green cluster stage, i.e. the timing used for control of aphids and caterpillars, will control infestations of Capsids. 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.