Insect Infection?? of Natives

Hi all


I have been steadily replanting trees on our small property east of Warwick for several years. In 2011, I started with some Forest Red Gum (Eucalyptus tereticornis) that I thought I would try to grow from seed.


The seedlings are now over 18months old and doing quite well. However... I have noticed that most of them have these "lumps". I figure they are some type of insect gall and they are about 6 to 7 mm across. Inside, there is a small white larva about 2 to 2.5 mm long.


I have also been growing Tallowwood (e.Microcorys) White Mahogany (e.Acmenoides) and Honey Box / Yellow Iron Bark (e.Melliodora), but these do not seem to be affected (or infected).


Should I be removing the galls (if thats what they are), or should I leave them alone?


Thanks
Darrell

If you leave them to mature then you will just get even more of what-ever-it-is laying their eggs on your trees, leading to more damage. Repeat until trees die.

Ideally you would take some samples to a expert in either insect pests or plant diseases - try State Forests or one of the 'Botanical Gardens' as they may have some idea what it is and what can be done about it. The solution may be as simple as spraying with an oil emulsion or water that has had old cigarette butts soaking in it for a few days (YUCK!)

Get onto it now while the freeloaders are likely dormant, once they hatch and spread it will be twice (or more) the work to get rid of them in the spring.

Try doing a "Google" for Psyllids & Galls. If you look under images you can then compare

HTH

Col

Guys


Thanks for the guidance. Here is a brief update.


I took the infected trees. With half of them, I cut off the limbs and leaves that had the galls. With the other half I sprayed them with a mixture of water, soap, and pyrethrum. While the "surgical" removal was quite quick and had the affect of pruning the tree, the spray also killed off the grub in the gall and didn't have the same effect on the size or shape of the tree.


I then took the trees that had not been infected, and regularly sprayed half of them with the above mixture (water, soap, pyrethrum). So far, only one has contracted a gall. Of the other half that have received no spray, most of the trees contracted the gall. So I now spray them all.


Still, I am a bit surprised that only the Forest Red Gum have been affected.


Darrell

In answer to your original question....(which I missed until now). These types of galls are not particulalry injurious to tree growth rates or long term health and usually decline in importance as the tree matures or as the canopy of neighbouring trees grow together. Species like E. tereticornis have been shown to be able to withstand repeated defoliations by insects without dying and usually outgrow the predations of the herbivores. Unlike stem boring moths combined with cockatoos that can knock over saplings by busting the trunk open to result in catastrophic loss in windy conditions, its probably not worth bothering too much about the gallers (or other leaf eaters).

Guys


It has been a long time - things don't happen very quick regarding tree growth, but I thought I would let you know what has happened, and just say that pampelmuse was spot on.


After reading the post, especially "These types of galls are not particularly injurious to tree growth rates or long term health", and "its probably not worth bothering too much about the gallers", I decided to let nature run its course. I stopped spraying and cutting.


We have had two good summers now and the trees look fine. Some of them got the galls again, but they (the galls, not the trees) disappeared. Some of the newer trees got the galls, but the galls then also disappeared.


So I have saved all the problems/issues regarding spraying, and the cutting was only knocking the tree back for no reason.


Nature - its a wonderful thing.


Thanks
darrell