What's eating the gum trees?

Quote:

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Originally Posted by Tote

Christmas beetles, they give some of the trees a real hammering.

Regards,
Tote

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Back in the early 1980s, eucalyptus die-back was a real problem in the New England area, around Murrumbateman, and in a lot of other places around Australia.

There were multiple causes and in many cases a combination of factors causing the problem.

One of the problems was Christmas beetles. It was generally considered that if the beetles stripped more than 50% of the leaves in two consecutive years, that would be enough to kill the tree.

When I was working on a farm near Boorowa, one of my jobs was to implement a trial scheme aimed at saving the trees. It involved drilling a hole about 1cm in diameter through the bark and into the sapwood. Concentrated Rogor was poured into the hole which was then sealed with putty.

The Rogor was carried into the leaves and beetles which ate the leaves were killed. Only a few of the trees in a clump needed to be treated to protect the clump.

The technique appeared to be successful and there was no indication of the trees suffering long term harm.

I used the same technique on a magnificent gum tree on my own place and once again it appeared to save the tree.


Since you said it was around Xmas, it could easily have been Christmas beetles.

There is a real problem with many types of Lerps attacking specific species of Eucalypts, Corymbias and Angophora species (Gum Trees) throughout Australia.

The problem seems to be greater following extended droughts and then getting rains which cause new growth on the trees which is then predated upon by the lerps. They suck the sap out of the tree and cause it decline in health.

I look after the trees in the Blacktown area and have taken out literally hundreds of trees which have succumbed to the pests.

I have attached a couple of articles on the problem.

[ame]http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0007/390283/Psyllids-Insect-Pests-of-Eucalypts.pdf[/ame]

Death and regeneration in Western Sydney | Brewongle Environmental Education Centre

OK so it is not just me.
I'm looking for something to manage the pests.

We grow timber and have to be careful the solution does not affect the timber. Apart from spraying, which would be difficult with the hight of our trees, I'm not sure what to do?

Maybe that technique that I described earlier whereby the insecticide is carried up to the leaves via the sapwood would be worth investigating.

Spraying would have been out of the question for the mature trees I was treating.

You would probably only have to treat a few trees to give the others a chance of surviving.

We have used IMIDACLOPRID in various forms and formulations. Silvashield can be used as a tree injection or Merit as a soil drench and foliar spray.

SilvaShield Injectable Tree Insecticide

Merit Turf and Ornamental Insecticide - Bayer

For best results I have used them in combination with a good success rate.

There is also a soil tablet called Confidor tablets

Yates Confidor Tablets Garden Insecticide - Yates products

all of these work but are not cheap.

Good luck

Bellbirds are apparently killing a lot of forest :o
This is because the bell miners exclude other birds and the leaf-eating insect populations get out of balance, and eventually if enough leaves are eaten, the trees become unhealthy and expire.
Tim Low - ABC Conversations with Richard Fidler

I contacted the ACT government about the dead branches overhanging the garden. The lads that came round to cut back the trees were saying it has been a perfect storm of Lerps and Christmas beatles.

I for one am fed up of sweeping up all the leaves. :(

Let's hope next year is better for the trees.