Lerps and Galls

​Thinking that lerps were all leaf sucking insects that hid under translucent shell-shaped cases, I googled lerp to find that this refers to the sugary case, and not the insect beneath that is called a psyllid; and that psyllids also cause galls. Adult psyllids look a bit like  small cicadas but are related to aphids and scale insects.
​Galls develop when leaves are sucked by the juveniles, which meta morphose into adults that erupt out of the gall (remember the movie ‘Alien’?). Click here for more psyllid information.​

Red galls as they mature

intact and erupted galls on lerp mallee

psyllids from lerp gall and from a lerp

​​A couple of months I noticed that some mallees near the Foxes Lair entry track had distorted leaves that were covered with lumpy galls. The mallee is Eucalyptus intrasylvatica, a hybrid derived from E. incrassata that is also called lerp mallee
​There is a significant lerp infestation on Foxes Lair wandoos at the moment.

Sugary lerps and ants attending psyllids about to fly off

Lerp above and psyllid below

In October I saw a Honey Myrtle/ Hypocalymma angustifolium plant that was flowering but also appeared to have seed pods. The 'pods' were galls containing a nightmarish looking little critter.

Some manna wattles on the Banksia walk are so heavily infested with galls that they appear to be festooned with round fruits like berries or nuts.
When I opened a few to have a look, I found maggots instead of psyllids. The maggots are larvae of the gall-midge (in actual fact a Cecidomyidae fly) that produces saliva, which forces acacias to produce gall cells. These have replaced flowers making the plant look like it has fruit.

Manna wattle galls

Fly maggot in split gall

Fly gall affected Acacia lasiocalyx flowers

Eucalyptus macrandra in the arboretum has branches severely affected by a galls on leaves and flowers that contain a small grub like those in acacia galls

Severely deformed twig

Gall infested leaf

Maggot in gall

Strange horned galls on a eucalypt