Agriculture Reference
In-Depth Information
Fig. 178
A gunpowder-mite,
Hypogastrura
sp. (x35).
Fig. 179
Lucerne-flea,
Sminthurus viridis
(x20).
Family SMINTHURIDAE
Bourletiella hortensis
(Fitch)
Garden springtail
black, yellowish-bordered eyes;
antennae
long
and geniculate;
abdomen
globular, with a small,
tube-like ventral sucker and a forked saltatory
appendage.
Infestations of this generally common springtail
occur mainly on wet, acid soils. The insects make
small pits in the cotyledons and hypocotyl of
seedlings of various plants; feeding damage may
also occur on young leaves. Attacks, which are
usually of greatest significance before July, occur
both in the open and in glasshouses. Outdoor
crops affected include beet, mangold, potato and
radish; this springtail is also a serious seedling
pest in conifer nurseries.
Sminthurus viridis
(L.)
Lucerne-flea
Although associated mainly with clover and lu-
cerne, this widely distributed springtail also oc-
curs on various other crops, including cereals,
cucumber, grasses and lettuce. Damage is usually
limited to the production of small holes in the
cotyledons of seedlings but is sometimes
more extensive; leaves of young plants may then
become skeletonized. Although reported as an
important pest in Australia, the lucerne-flea is
usually of little or no economic significance in
Europe.
BIOLOGY
This species inhabits the soil surface and, al-
though breeding throughout the year, is usually
most numerous from late April to the end of
June. Eggs are deposited in small groups in the
soil, up to 100 eggs being laid by each female.
The rate of nymphal development varies accord-
ing to conditions and may be protracted but,
under favourable conditions, the adult stage is
usually attained within 2-3 months.
BIOLOGY
This species breeds continuously whilst condi-
tions are favourable, eggs being deposited in the
soil in batches of up to 60. The eggs hatch within
a few days but hatching may be delayed in dry
conditions. The nymphs feed for 1-3 months
before becoming adults.
DESCRIPTION
Adult
1.5 mm long, mainly black to dark green
but often spotted with white;
head
large, with
