Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 214

Family HIEROXESTIDAE

DESCRIPTION
Adult: 8-9 mm wingspan; fore wings shiny white
(often partly or entirely suffused with brown), marked
apically with a dark spot and by several black streaks
which extend through the fringe of cilia; hind wings
dark grey. Larva: up to 8 mm long; body green,
translucent and moniliform; head and legs brown.
Pupa: 3.5 mm long; light green, with yellowish-brown
wing cases.

Opogona sacchari (Bojer) ( 507 )
larva

sugar cane borer
This tropical species is a native of various African
offshore islands, including the Canary Islands,
Mauritius, St. Helena and the Seychelles, where it is a
pest of banana and sugar cane. Infestations also occur
on various plants imported into Europe as ornamentals,
including blue-stem yucca ( Yucca guatamalensis ),
Dracaena , Hibiscus and rubber plant ( Ficus elastica ).

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LIFE HISTORY
Adults occur in June and August, and from October
onwards, individuals of the autumn generation
hibernating under loose bark, amongst thatch and in out-
buildings. They reappear in the following April. Eggs
are usually laid singly on the underside of a leaf, and
hatch about two weeks later. Each larva then
commences to mine towards the upper surface and
eventually forms a very long, pale-coloured gallery.
This widens gradually throughout its length and
terminates in a distinct, elongate chamber. Feeding is
completed in three or four weeks. The larva then
emerges and wanders about on the foliage for a few
hours before beginning to spin a slight, 6-7 mm long,
hammock-like cocoon, attached by strands of silk to a
leaf or rough bark. Pupation then takes place, and the
adult moth appears about two weeks later. There are
usually three generations each year.

DESCRIPTION
Adult: 20-28 mm wingspan; fore wings lanceolate,
pale ochreous suffused with brown and blackish brown;
hind wings brownish and shiny. Larva: up to 25 mm
long; whitish, with small yellowish pinacula; head
chestnut-brown; prothoracic and anal plates brown.

LIFE HISTORY
Larvae burrow into the stems of host plants, forming
extensive, silk-lined, frass-filled galleries. Fully grown
individuals pupate close to the surface, and the pupae
protrude from the galleries following emergence of the
adult moths. Infested plants imported into greenhouses
in northern Europe usually produce moths in the winter
months, but such insects are unable to survive the winter
outdoors.

DAMAGE
The mines disfigure the foliage and, if numerous, cause
distortion and premature death of infested leaves. On
some hosts, notably snowy mespilus, infested leaves
become greatly discoloured, particularly where the
gallery isolates a section of the leaf blade. On cherry
laurel the leaf tissue often splits along the length of the
mine; portions of the leaf blade may also fall away to
leave rounded or irregular holes.

DAMAGE
The stems of infested plants are riddled with galleries,
spoiling the appearance of ornamentals, reducing vigour
and, sometimes, causing death of plants.

507

507 Sugar cane borer ( Opogona sacchari ) damage to stem of
Dracaena .