PEST
 
   NAME
     Gall Wasp (General)
     Various Gall Wasp  
Species
   ORDER
     Hymenoptera

Description of the Pest
Generally there is many species of small wasps 3mm to 5mm long that form galls with there larvae feeding on the tissue inside the gall. The adult is normally black or brown and not commonly seen. It lays its eggs in the soft tissue of a plant; normally the leaf where the white legless larva develop.
Unlike Coccid galls, Wasp galls contain many maggot-like larvae that develop together up to 4mm long. The galls are normally colourful in tones of red, which contrasts with the surrounding green of the leaf.

Life Cycle
These insects have a Holometabolous life cycle, ie. When metamorphosis is observed during the pupal stage.
Certain species only have one generation each year. 
  
Appearance of the Pest
The wasp lays its eggs during spring after emerging from a previous season’s gall in which the larvae pupated. It normally infests the same plant or one near by due to its poor flying capabilities. Some species can lay up to 120 eggs within 24 hours of leaving the gall. It can also be transported to other areas physically, as in contaminated stock or on cut plant material.
Vacated galls are peppered with small holes and become entry points for other diseases. 

Period of Activity
Throughout summer the larvae grows and affects the surrounding cell walls of the plant, creating galls in which they live. 

Damage Caused
The wasp infects many parts of the plant, twigs, fruit stalks, leaf veins including the underside, and other soft wooded areas causing weakness in the plant. Normally small infestations will not harm the tree but may look unsightly.

Susceptible Plants
A wide range of plants are attacked including Quercus species, Eucalyptus species and all citrus varieties including common lemon and grapefruit.

Control
During late winter cut off and burn the infested parts. Avoid distributing and dispose of infested stock. There is no chemical control that is effective.