Agriculture Reference
In-Depth Information
Small Insect Orders
ORDER COLLEMBOLA (SPRINGTAILS)
Family HYPOGASTRURIDAE
Hypogastrura
spp.
Gunpowder-mites
houses, significant damage is sometimes noted
on cucumber, lettuce, tomato and various
ornamentals. Damage also occurs on outdoor
crops such as bean, carrot, celery, pea, potato
and sugar beet. The springtails form minute
pits in the roots, and damaged tissue soon turns
black; they may also attack the cotyledons
and hypocotyl, and sever the fine roots and
root hairs (see also damage caused by pygmy
mangold beetle,
Atomaria linearis,
p. 135). On
older plants, leaves in contact with the soil sur-
face may be pitted or skeletonized; such damage
is often noticed on lettuce and potato. Springtail
damage to the roots will also allow pathogenic
fungi to gain entry, increasing the significance of
attacks.
The so-called gunpowder-mites, which occasion-
ally cause damage in mushroom beds, are actu-
ally springtails. They breed continuously under
favourable conditions and vast numbers some-
times aggregate on the compost in mushroom
houses. The insects will then cause significant
damage by feeding on the fungal mycelium and
thus retarding growth. They may also attack
the sporopores, to form characteristically
dry
pits which lead to internal channels in the stipe
and cap (cf. damage caused by mould mite,
Tyrophagus putrescentiae,
p. 270); the pests are
especially destructive to button mushrooms and
often cause them to split open. Adults
(Fig. 178)
are minute (1.0-1.5mm long), bluish-black, pur-
plish or greenish-black, with a pale underside,
short, 4-segmented antennae and a short, 2-
segmented saltatory appendage.
BIOLOGY
These springtails, which lack a saltatory ap-
pendage and are unable to jump (cf. family
Sminthuridae, below), are often abundant in
wet, organic soils or compost. Development
from egg to adult extends over several months
but breeding is continuous, so long as conditions
remain favourable.
Family ONYCHIURIDAE
Onychiurus
spp.
White blind springtails
DESCRIPTION
Adult
up to 3 mm long, white, stout-bodied
with six abdominal segments;
head
large;
an-
tennae and legs
short;
saltatory appendage
absent.
Nymph
similar to adult but smaller.
Several species of
Onychiurus
are damaging to
cultivated plants. They attack the roots and
cause seedlings to collapse and die. In glass-
