PEST
 
   NAME
     Steelblue Sawfly
     Perga species
 
   ORDER
     Hymenoptera
 
   FAMILY
     Pergidae

Description of the Pest
Adult females are steel blue in colour, with yellow antennae and legs, growing up to 20mm long, with 40mm wingspans. The insect is called a “sawfly” because of the sawing action of the ovipositor. The yellowish-brown larvae have chewing mouth parts. 

The larvae are called “spitfires” because, when disturbed, they bend back their bodies and exude a strong, eucalyptus-scented liquid from their mouths. This exudate contains concentrated eucalyptus oil, which can cause severe eye irritation. The non-feeding adults are seldom seen. Sawflies have a complete metamorphosis, pupating in cocoons in the soil for months or years.
These insects have a Holometabolous life cycle, ie. When metamorphosis is observed during the pupal stage.

Appearance of the Pest
During the day, sawflies larva congregate in clusters, separating at night to travel and feed on the foliage of the host plant.

Period of Activity
Caterpillars appear in spring through summer.

Susceptible Plants
Eucalypts, especially E. camaldulensis, E. blakelyi, E. melliodora, and E. pauciflora and others.

Damage Caused
Generally the larva eats the surface of leaves when young, but as they develop they eat large pieces leaving only the mid rib. They tend to feed on the terminal shoots, and heavy infestations can defoliating young trees.

Cultural Control
Clustering larvae may be hosed or knocked from branches, falling to the ground where they can be squashed under foot or attacked by other predators. During the day when the larvae congregate they can be collected and disposed off. In small infestations they can be picked by hand and destroyed. 

Biological Control
The exudate causes most birds to avoid the larva, although cockatoos remove the head and oil gland prior to consumption. They are also eaten by lizards and frogs or attacked by parasitic wasps.

Chemical Control
Affected plants can be sprayed using Maldison or Carbaryl, this is only possible for small trees.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.