PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Codling moth
An example of an internal-feeding caterpillar in fruit
The codling moth is the key pest of pome fruit in
eastern Australia. Unless effective control measures
are applied the total crop may be lost.
Scientific name
An introduced moth (Cydia pomonella, Order
Lepidoptera).
Host range
Ornamentals, eg crabapple.
Fruit and nuts, eg apple, pear, quince, nashi.
Also uncommonly, walnut, stone fruits,
persimmon, pomegranate and hawthorn.
Description & damage
Moths (adults) when at rest with wings folded
are brownish-gray in general appearance and about
12 mm long. On closer examination, the fore part
of the wing is found to be pale grayish-brown with
faint narrow cross stripes. The rest of the forewing
is dark chocolate brown. Metallic glints can be
seen in the color pattern when the moth is
examined under a hand lens. Caterpillars
(larvae) are 12-20 mm long when fully grown, are
cream to pinkish in colour with a brown head.
Cocoons are tough, white and stick firmly to the
bark of the fruit tree. Pupae are dark, orangebrown
and about 1 cm long.
Damage to fruit. Only the fruit are damaged.
In unprotected crops, caterpillars may tunnel into
50-100% of the fruit on a tree.
The tiny caterpillar enters the fruit mainly near
the calyx end. More damage occurs when they
leave to pupate. If the fruit is split open tunnels
are seen to run to the core and seeds on which
the caterpillar feeds. Caterpillars tend to be
cannibalistic so that usually only one caterpillar
is found in the center of each infested fruit.
When the caterpillar is fully grown, it tunnels to
the surface of the fruit and emerges through a
round exit hole.
Damage on the outside is visible as small holes
or punctures (Fig. 59). Later the holes become
more obvious and masses of black frass protrude
usually with gummy exudate.
Sometimes, ‘stings’ occur on the surface of the
fruit where a caterpillar has died after entering,
or failed to enter the fruit successfully.
Damaged fruit often drop prematurely.
Diagnostics.
Codling moth larvae are the only caterpillars
that commonly tunnel to the core of apples and
usually there is only one caterpillar per fruit.
Do not confuse with caterpillars of the oriental
fruit moth (OFM) which only rarely attack pome
fruits or with fruit fly maggots which are much
smaller and numerous.
Fig. 59. Codling moth (Cydia
pomonella). External signs of
attack by caterpillars PhotoNSW Dept of
Industry and Investment (W.G.Thwaite).
Fig. 60. Codling moth
(Cydia pomonella). PhotoNSW
Dept of Industry and Investment (E.H.Zeck).
1. Eggs (about x4).
2. Caterpillar (about x3).
3. Cocoon spun in crack in
bark cut open to show pupa.
4. Adult moths in resting position
(about x4).
Actual size
5. Eggs on leaf.
6. Cocoon showing empty pupal
skin from which a moth has
emerged.
7. Moths resting on leaf.
8. Apple showing damage
caused by the caterpillar
feeding inside
Insects and allied pests - Lepidoptera (butterflies, moths) 89