PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Oriental fruit moth, peach tip moth
An example of a tip or shoot boring caterpillar
Scientific name
Introduced moth (Grapholita molesta, Lepidoptera).
Widespread in southern Australia and coastal Qld.
Not known to occur in WA.
Host range
Fruit, eg mainly stone fruits, peach, nectarine, also
almond, apricot, plum and cherry and is becoming a
more serious pest of nashi, quince, apple and pear.
Ornamental varieties of these species.
Description & damage
Moths (adults) are mottled brown-grey and
6-7 mm long when at rest with wings folded. Males
are slightly smaller than females. When their wings
are outspread they measure about 13 mm across.
Moths are inactive during the day and are rarely
seen but during late afternoon on warm days they
can be seen in flight near the tree tops. Moths are
only active in dim light and when the temperature is
high enough probably above 18 o C. If these
conditions prevail mating followed by egg laying
will occur. Caterpillars (larvae) when fully grown
are nearly 12 mm long, creamy white or pale pink,
with a light brown head. They have a special
appendage, the anal comb, a toothed horny plate on
the last segment. Pupae are cocoons about 15 mm
long by 3 mm wide at the center.
Twigs/shoots. The caterpillar usually enters
the twig near the tip (and often through the petiole)
and tunnels downward for 7-10 cm causing the
twig to wilt, collapse, produce gum and die. An
individual larva may attack as many as 3 shoots
during a season. When older larvae move from one
twig to another, the point of entry into the shoots
may be at the axil of a leaf below the tip. Death of
the tip of a shoot may cause the buds below to
break dormancy and grow resulting in a rosette of
shoots. There may be severe damage to twigs.
Fruit. Later generations bore into the fruit as
well. Larvae may enter fruit either through the
stem of the fruit or where a leaf or small branch
touches the fruit (Fig. 63). Fruit can appear perfect
on the outside but when cut open numerous
feeding burrows can be seen. These tunnels may
be filled with brown particles of excreta, similar to
codling moth damage to apples.
General.
Populations which build up on growing
points in spring invade fruit later in the summer.
Damage to growing points is usually more
important in young trees which are being trained.
Up to 80% of the crop can be lost in some
untreated peach orchards and spread of brown
rot is enhanced especially during wet weather.
Diagnostics.
Limited host range.
Blackened shoot tips which may exude
blobs of gum are easy to recognize.
Fruit may also be attacked by other caterpillars,
eg budworms (Helicoverpa spp.), peach and
nectarines also by the yellow peach moth
and the orange fruitborer, depending on the
region. Rarely by codling moth. Expert assistance
may be required to differentiate some of these
pests. Do not confuse with fruit fly maggots which
are smaller (page 68).
Fig. 63. Oriental fruit moth (Grapholita molesta).
Peach fruit damaged by caterpillars. Note leaf stuck by
webbing to fruit and the small caterpillar on the surface.
Brown rot infection may develop around entrance holes.
PhotoCIT, Canberra (P.W.Unger).
Fig. 64. Oriental fruit moth
(Grapholita molesta). PhotoNSW
Dept of Industry and Investment (E.H.Zeck).
1. Eggs (x 10)
2. Caterpillars (x 8)
3. Pupa (x 8)
4. Moth (x 8)
5. Twig dieback caused by the
caterpillar feeding within tips
Insects and allied pests - Lepidoptera (butterflies, moths) 93