Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 275

Rhyacionia buoliana (Denis & Schiffermüller)
Pine shoot moth
An important forestry pest, especially on Austrian pine
( Pinus nigra var. nigra ), beach pine ( P. contorta ) and
Scots pine ( P. sylvestris ), and also damaging to
ornamentals. The fast-growing species bishop pine
( P. muricata ) and Monterey pine ( P. radiata ) are very
susceptible. Eurasiatic. Widely distributed in Europe,
and an introduced pest in North and South America.

Spilonota ocellana (Denis & Schiffermüller)
( 699-700 )
Bud moth
An often common pest of rosaceous trees and shrubs,
including ornamentals; various other trees, including
alder ( Alnus ), hazel ( Corylus ) and oak ( Quercus ), are
also suitable hosts. Larch ( Larix ) is attacked by a distinct
form - Spilonota ocellana laricana . Eurasiatic; also
present in North America. Widely distributed in Europe.

DESCRIPTION
Adult: 16-24 mm wingspan; fore wings mainly orange
or reddish orange, variably patterned with silvery-white
stripes and flecks; hind wings greyish brown to dark
brown. Larva: up to 18 mm long; body reddish brown,
with small brownish-black or black pinacula; head and
prothoracic plate brown or black; thoracic legs dark
brown; anal plate yellowish brown, mottled with dark
brown; no anal comb.

DESCRIPTION
Adult: 12-16 mm wingspan; fore wings whitish, more
or less suffused with grey, marked towards the apex
with metallic bluish grey and black, and each with a
dark, triangular dorsal spot and a blackish, angular basal
patch; hind wings dark grey. Egg: flat and more or less
circular; pale yellowish white. Larva: up to 12 mm
long; dark purplish brown, with lighter pinacula (larch-
feeding form light greyish brown, with indistinct
pinacula); head, prothoracic plate and anal plate shiny
black or blackish brown. Pupa: 6-7 mm long; brown,
with outline of wing cases distinctly darker than
abdomen; tip blunt.

LIFE HISTORY
Adults occur from late June to mid-August. Eggs are
laid singly or in small groups close to a whorl of young
buds, and hatch 2-3 weeks later. Each larva then tunnels
into the base of a needle, sheltered beneath an outer
covering of silk. After 1-2 weeks the larva bores into a
lateral bud to continue feeding. Resin soon exudes from
the damaged bud, and the larva incorporates this in the
walls of a protective silken tent spun amongst the
invaded whorl of buds. Larvae overwinter within
hollowed-out buds, and resume activity in the spring.
They then invade buds on the developing shoots, again
forming resinous, silken shelters. Larvae are fully
grown in June, and pupation takes place in the larval
habitation.

699

DAMAGE
Larvae cause death of buds, and damage is most
important if the main shoot is affected. Death of all buds
in the whorl results in the development of untidy
secondary growth from adventitious buds; if just the
leading shoot is killed, this is eventually replaced by one
of the laterals, with minimal distortion. However, if the
leading shoot is merely damaged superficially, it keels
over but then recovers, to produce a characteristic
'posthorn'-shaped deformation of the main stem. The
pest is a particular problem on young trees.

699 Bud moth ( Spilonota ocellana ).

700

700 Larva of bud moth ( Spilonota ocellana ).