Agriculture Reference
In-Depth Information
Family ARGIDAE
Family TENTHREDINIDAE
Arge pagana
(Panzer)
Ametastegia
glabrata
(Fallen)
Variable rose sawfly
Dock sawfly
This often abundant species, which is widely
distributed in continental Europe and in much
of southern Britain, is a destructive pest of
cultivated rose. The larvae cause exten-
sive skeletonization and defoliation that
affects the development and appearance of
bushes.
Dock sawfly is a widely distributed but minor
pest of fruit crops, especially apple and grape
vines. The larvae feed on various weeds and,
when fully grown, sometimes bore into mature
apple fruits; larvae may also bore into the pith of
shoots or branches of young fruit trees, vines and
other cultivated plants, often entering through
pruning cuts. Damage in apple fruits is character-
istic, and consists of a straight, often deep tunnel
(up to 5 cm long), surmounted by a red-ringed
entry hole about 2 mm in diameter; however, lar-
vae are rarely found inside damaged fruits. The
larvae have also been reported burrowing into
plastic irrigation pipes.
BIOLOGY
Adults occur from May onwards. Eggs are
deposited in rows within the young shoots
and flower stalks, the female's ovipositor leaving
long, characteristic scars. Larvae feed vora-
ciously on the expanded foliage from June
onwards. When fully fed, they pupate in the
soil, each in a double-walled cocoon; adults
emerge shortly afterwards. There are two
main generations annually, but larvae con-
tinue to be found on bushes well into the
autumn.
BIOLOGY
The larvae feed during the summer on the leaves
of weeds such as
Chenopodium, Polygonum
and
Rumex.
When fully fed, they usually pupate in
pithy or hollow stems of plants such as
Rubus,
but individuals may also bore into low-growing
branches of fruit trees. In autumn, fully fed lar-
vae in their search for overwintering sites may
also burrow into maturing apples; however, find-
ing them unsuitable, they soon leave for other
quarters. Two or three generations occur
throughout the summer.
DESCRIPTION
Adult
7-9 mm long, black with a mainly yellow
abdomen.
Larva
up to 25 mm long;
body
bluish-green, suffused with yellow dorsally;
pinacula
shiny black and arranged in distinct lon-
gitudinal and transverse rows;
head
black or yel-
lowish-orange;
thoracic legs
black;
abdominal
prolegs
five pairs present
(Plate 16c).
DESCRIPTION
Adult
5.5-8.0mm long and shiny purplish
bronzy-black;
legs
mainly red.
Larva
13-18 mm
long;
body
apple-green;
head
brownish;
abdomi-
nal prolegs
eight pairs present.
Arge
ochropus
(Gmelin in L.)
Large rose sawfly
This sawfly also infests rose but, at least in Brit-
ain, is usually less abundant than the previous
species, and often has just one generation annu-
ally. Adults are distinguished from those
oiArge
pagana
(above) by their yellow pronotum and
tegulae and partly yellow legs; pinacula on the
larvae of
A. ochropus
tend to be noticeably
larger than those of
A. pagana.
Athalia rosae
(L.)
Turnip sawfly
The turnip sawfly is a sporadically important pest
of radish and turnip; it also damages Chinese
leaf, mustard, oilseed rape and swede crops. Lar-
vae skeletonize the leaves of host plants, and
heavy infestations can be of considerable
