PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
ALLIED PESTS - Slaters, pillbugs, woodlice
Class Malacostraca, Order Isopoda
Scientific name
Slaters and pillbugs belong to the Class Malacostraca,
in the Phylum Arthropoda. Crabs, prawns and lobsters
which are seas dwellers also belong to this Class.
Slaters and pillbugs live on land, but breathe by
means of gills which must be kept moist. Pillbugs
are roughly similar in shape to slaters, but are able to
roll up into a tight ball when disturbed.
Common slater (Porcellio scaber) exotic
Common pillbug (Armadillidium vulgare)
Pest species are introduced, some native species are
considered to be endangered.
www.ento.csiro.au/education/allies/isopoda.html
Host range
Slaters and pillbugs are important in recycling
natural forests and vegetation. They mainly feed on
decaying organic matter, but may attack
seedlings, young tender plants, soft fruit like
tomatoes, ferns, young roots of orchids and other
plants in glasshouses, conservatories, old shaded
gardens and cause considerable damage.
Staghorns, in particular, are very susceptible to
attack as, in addition to providing food and shelter,
they provide attractive breeding places.
Description & damage
Adult slaters are gray-brown, oval, semiflattened
and commonly 9-15 mm long. They
have 2 prominent tail-like appendages. Slaters
have:
A bilaterally symmetrical body.
An exoskeleton (outer hard covering).
A segmented body, most 8 thorax and 6
abdominal segments.
Four or more pairs of jointed legs.
Two pairs antennae but 1 pair may be hard to
see.
Eyes usually on stalks.
Plant damage. Slaters are usually found
hiding during the day about the bases of plants,
under flower pots and stones, under damp leaves,
in compost heaps and in similar damp places. They
feed by chewing and may do considerable damage
to roots and tender growth near the ground of any
plant. May chew on soft leaves and strawberries in
contact with the ground. Because they come out to
feed at night, when the risk of dehydration is less,
they are not usually observed feeding. Pillbugs
damage plants in a similar manner to slaters but
mainly feed below ground. Mostly feed on organic
matter but give the perception that they feed on
roots.
Remember many slaters in a particular place are
not generally a cause for concern. Overall they
are more beneficial than harmful.
Slater
Pillbug
Diagnostics.
Slaters and pillbugs are easy to recognize, but
damage is more difficult to pinpoint.
Do not confuse the name pillbug with billbug.
Billbugs are weevils, the larvae of which feed on
rhizomes, stolons and crowns of turf grasses.
Slaters cannot roll up into a tight ball like
pillbugs.
A group of slaters.
Pillbugs can roll into a ball for defense.
Slaters cannot roll up into a tight ball.
Fig. 129. Slaters (various species) commonly 9-15 mm long. PhotoNSW Dept of Industry and Investment
212 Insects and allied pests - Slaters (Isopoda)