PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Scientific name
A native moth (Maroga melanostigma, Order
Lepidoptera). Synonym Crytophasa melanostigma.
Other borers may also attack shrubs, trees, vines
(page 79) including:
Order Lepidoptera
Family Oecophoridae, eg fruit-tree borer
Family Cossidae (wood moths)
Family Hepialidae (ghost moths)
Order Coleoptera (page 99)
Family Cerambycidae (longicorn beetles) (page 111)
Family Curculionidae (weevils)
Family Bostrichidae (auger beetles)
Family Platypodidae (ambrosia beetles,pinhole borers)
Family Scolytidae (bark beetles)
Order Hymenoptera
Family Siricidae (wood wasps, eg sirex wasp, page 116)
Host range
Ornamental trees, eg black wattle (Acacia
decurrens), banksia, flowering Prunus spp., elm,
plane, willow, Pistacia spp., crepe myrtle and
jacaranda, eucalypt, grevillea, hakea, NSW
Christmas bush (Ceratopetalum gummiferum),
Cassinia, Helichrysum (shrubby species),
Leptospermum, melaleuca, Prostanthera.
Fruit trees, eg stone fruits, especially cherry,
peach, nectarine, plum, prune, also apple, pear,
raspberry.
Fruit-tree borer
The most easily controlled ‘borer’
Description & damage
Moths (adults) are satiny-white and 35-60 mm
across their outspread wings. The upper surface of
the abdomen is black, with an orange-colored
fringe of hairs, and a thick tuft at the tip. Moths are
nocturnal and rarely seen. Caterpillars (larvae)
are fleshy, brownish-red, sparsely hairy and up to
50 mm long and feed in the phloem-cambium
region. During the day the caterpillars hide in the
tunnel and come out to feed at night on callus
tissue which grows around tunnel entrances.
Caterpillars sometimes take leaves into their
tunnels for food.
Trunks and branches. Although this is
probably the most frequently noticed borer, many
other borers cause more serious damage. Tunnels
are vertical, short (only 8-10 cm deep) and are
usually made in the forks of trees or between main
branches. Damaged areas and tunnel entrances are
neatly covered with chewed wood, bark, webbing
and droppings which protect caterpillars from
predators, eg ants. Some trees, eg cherry, ooze gum
from damaged areas.
Attacks weaken branches and may ringbark and
kill smaller branches or small trees and allow
entry of wood rot fungi.
Branches may also be completely ringbarked or
severely weakened in the crotches. Damaged
branches, stems or canes may break.
Productivity of commercial crops such as
prunes may be affected.
Diagnostics.
Fruit-tree borer tunnels only 8-10 cm deep.
Can be mistaken on some hosts with damage
caused by other moth borers, eg wood moth
damage on wattles, which are also covered with
webbing, chewed wood but the larvae and the
tunnels they make are much larger in diameter.
Do not confuse with beetle borers (pages 103, 111).
It is often necessary to seek diagnostic assistance
(page xiv).
Fig. 66. Fruit-tree borer (Maroga melanostigma).
Left top: Adult moth (natural size). Left lower: Caterpillar
(up to 50 mm long). Right: Branch showing webbed material
covering tunnel entrance, when webbed material is removed
the damage is apparent (see page 30 for internal damage).
Photo NSW Dept of Industry and Investment.
96 Insects and allied pests - Lepidoptera (butterflies, moths)