Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 130

Galerucella lineola (Fabricius) ( 272-275 )
Brown willow leaf beetle
An often common pest of willow ( Salix ); most
important in stool beds. Widely distributed in Europe.

They favour open, sunny situations and are often
numerous in willow beds and on young willow trees.
Eggs are laid on the shoot tips or on the upper surface of
the leaves, in groups of about 20-25, and hatch about a
week later. Larvae appear from about mid-May
onwards, feeding gregariously but later becoming
solitary. When fully fed, usually after about a month,
they enter the soil to pupate; new adults appear about a
week later. There are normally two generations
annually, with young adults of the final generation
appearing in the late summer, but the species is single
brooded in northern districts.

DESCRIPTION
Adult: 5-6 mm long; mainly yellowish brown, with
distinct black marks on the pronotum and shoulders of
the elytra; elytra of similar width throughout, with the
pubescence shiny and relatively closely set. Egg: 1mm
across; rounded, with a roughened surface; pale
brownish yellow. Larva: up to 8 mm long; head black;
body yellowish to black, with numerous black verrucae
and plates. Pupa: 4.5-5.5 mm long; yellow. DAMAGE

The larvae skeletonize the leaves, and also destroy the
buds and shoots, causing considerable damage on
heavily infested hosts.

LIFE HISTORY
Adults overwinter in the soil, under dead bark and in
various other places, and reappear in the following May.

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272 Brown willow leaf beetle ( Galerucella lineola ). 273 Eggs of brown willow leaf beetle ( Galerucella lineola ).

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274 Larva of brown willow leaf beetle ( Galerucella lineola ). 275 Pupa of brown willow leaf beetle ( Galerucella lineola ).