Bay sucker

Bay sucker can spoil the appearance of a bay tree by causing discoloration and distortion of leaves at the shoot tips.

Bay sucker. RHS/Science.

Bay sucker. RHS/Science.

Quick facts

Common name Bay sucker
Scientific name Lauritrioza alacris
Plants affected Bay (Laurus nobilis)
Main symptoms Leaves develop curled leaf margins that are abnormally thickened and pale yellow. Greyish white insects may be seen under the curled leaf margin. Later the damaged parts of the leaf dry up and turn brown
Most active May to October

What is bay sucker?

Bay sucker is a small sap-sucking insect that attacks the foliage during the summer. It is the nymphs that cause most of the damage.


  • Bay tree leaves thicken, curl downwards at the margins and turn yellow; often only one half of the leaf is affected
  • The discoloured areas later dry up and become brown 
  • Small greyish white insects may be seen underneath or near the curled leaf margins
  • Whilst unsightly the long term health of the plant is usually unaffected


Bay sucker can affect the appearance of bay but does not usually reduce the vigour of bay plants.

Non-chemical control

  • For light infestations pick off and dispose of infested leaves
  • Badly affected shoots can be pruned out in winter. This will encourage new growth in the spring and may remove some overwintering adults

Chemical control

  • As most stages of this insect are hidden within curled leaves the contact action insecticides available for use on edible herbs are unlikely to have any effect on bay sucker
  • On bay treated as an ornamental products containing acetamiprid (e.g. Scots Bug Clear) may give some control
  • Do not spray near plants in flower due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener


Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)


The damage is caused by the nymphal stages of the bay sucker when they suck sap from the young leaves during the summer.

  • The winged adults are greenish brown and about 2mm long (less than 1/8in), and they overwinter in sheltered places
  • In April to May, adult bay suckers emerge and start to feed, causing the leaf margins to begin curling over. Eggs are laid under the curling leaf margins
  • The young nymphs are grey, flattened wingless insects, whose bodies are covered with a white fluffy material
  • Like the adults, the nymphs suck sap and increase the leaf curling and discoloration
  • Two or three overlapping generations occur between May and September

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