Agriculture Reference
In-Depth Information
but later becoming reddish-orange.
Larva
up to
12 mm long;
body
mainly greyish to pale ochre-
ous;
pinacula, prothoracic plate and anal plate
slightly darker than the body.
Pupa
7 mm long,
reddish-brown.
plum sawfly,
Hoplocampa flava
(p. 251) wet,
brown larval frass accumulates within the fruit
and is not ejected from the feeding gallery during
larval development. This pest is of particular im-
portance in years when fruit set is light and in
conditions favourable for development of a no-
ticeable second generation. Second-generation
or late-developing larvae are a particular prob-
lem as they often occur inside harvested fruits.
Even very small numbers of infested fruits may
be sufficient for processors to reject crops at the
factory.
Cnephasia incertana
(Treitschke)
Light grey tortrix moth
This species is essentially similar in habits and
appearance to
Cnephasia asseclana
(p. 215) but
the adults have slightly narrower, usually paler,
forewings
(Fig. 288b);
the larvae lack an anal
comb and are usually paler in colour; the pupae
are dull black and the spines on the cremaster
do not terminate in strongly thickened hooks.
The larvae are polyphagous and damage a wide
range of crops, including bean, clover, pea and
strawberry.
BIOLOGY
Moths are most numerous from mid-June to
mid-July, but may occur at any time from the end
of May to September. Eggs are laid singly on
developing fruitlets. The eggs hatch in about 2
weeks and the young larvae then burrow into the
flesh to begin feeding. Larval development lasts
for approximately 5 weeks. Fully fed individuals
vacate the fruits from late July or early August
onwards. They then spin cocoons in sheltered
positions on the bark of host trees, overwinter
and pupate in the spring. Under favourable con-
ditions, early-developing larvae may pupate im-
mediately and give rise to a partial second
generation of adults in August or September.
Second-generation larvae complete their devel-
opment in the autumn.
Cnephasia pasiuana
(Hiibner)
This often common species is associated with
Ranunculus
and various kinds of Asteraceae.
Although not usually of pest status, larval infes-
tations are sometimes found on sunflower crops
in May and June. Adults, that occur in June and
July, are similar to those of
Cnephasia asseclana
(p. 215) but usually distinguished by the less
strong and more uniform markings on the
forewings and the relatively broad median fascia.
Larvae (up to 14 mm long) are mainly yellowish-
brown to greenish-grey, with black pinacula, a
pale yellowish-brown (black-marked) head, a
yellowish-brown (black-speckled) prothoracic
plate and a black anal comb.
DESCRIPTION
Adult
11-15 mm wingspan;
forewings
dull pur-
plish-grey, with darker but obscure markings,
and irregularly suffused with ash-grey;
hindwings
brownish-grey
(Fig. 290). Egg
0.7 x 0.6mm,
Cydia funebrana
(Treitschke)
Plum fruit moth
This insect is a widely distributed and locally
common pest of damson and plum; infestations
are often also abundant on
Prunus spinosa.
The
larvae, known as 'red plum maggots', feed singly
within the flesh of developing fruits, and often
cause premature ripening and fruit drop. Unlike
fruitlets attacked by larvae of the fruitlet-mining
tortrix moth,
Pammene rhediella
(p. 222) and
Fig. 290
Plum fruit moth,
Cydia funebrana
(x6).
