Box sucker

Box hedges and topiary are often fed upon by box sucker, any leaf distortion caused is superficial.

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Box sucker damage. Credit: RHS/Science.

Quick facts

Common name Box sucker
Scientific name Psylla buxi
Plants affected Buxus sempervirens
Main symptoms In spring a white waxy substance produced by flattened pale green insects can be evident. Leaves at the shoot tip are cupped
Most active April–early June

What is box sucker?

The psyllids or plant suckers are a group of sap sucking true bugs (Hemiptera). There are more than 40 species found in Britain. A gallery and more information on these species can be found at British Bugs. 

Box sucker feeds at the shoot tips of box plants in spring, damage is usually minor and can be tolerated.

Box can is host to several invertebrate species suffer from a number of other problems.

Symptoms

  • In spring a white waxy substance covering a droplet of liquid, excreted by box sucker nymphs often spills from the cupped leaves, leaving white waxy smears on foliage
  • In April to May flattened, pale green, wingless nymphs live among the leaves at the shoot tips
  • New shoot extension in spring can be stunted and the cupped leaves at the shoot tips produce a cabbage-like appearance

Control

Damage from this insect is superficial and control is not usually necessary on established box hedges or topiary plants that are going to be clipped.

Non-pesticide control

  • Often suckers do not affect the growth or vigour of plants and so can be tolerated
  • Regular clipping removes affected parts of the plant
  • Encourage predators and other natural enemies of suckers, in the garden, such as birds, ladybirds, wasps and ground beetles.

 

Pesticide control

  • Pesticides are not needed to control this insect it has little impact on the growth of host plants

 

Biology

  • Box sucker overwinters as eggs on its host plant. These hatch in spring when new growth begins 
  • The nymphs suck the plant's sap and secrete chemicals that stunt new growth and distort the leaf shape, although this damage is not usually serious 
  • The nymphs excrete a sugary liquid called honeydew that is coated with a white waxy secretion from their bodies
  • Yellowish brown winged adults, 2-3mm long (1/8in), develop in May to June
  • No further damage occurs after June

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