Citrus burrowing grub (?) (forum)

Kathy starts with ...
Hello do you recognise this creature (picture 1)?
Its behaviour was a bit like longicorn beetles in that it ring barked the citrus tree (you can see the ring barking in photo 2 - it's painted black - see below).
BUT unlike what I can read about longicorn beetles a grub came out of the hole in the tree each night/early morning to feed on the bark (maybe this grub created the ring barking and then I sealed it using a plant sealer to discourage it - maybe it did??. I could tell the grub came out for each morning there would be a web with frass over the hole - I'd destroy that =- but it was back the next morning.
So I thought of how to kill it:
1. the painting with a sealer was the first effort - no luck.
2. Then I made a mixture of hand cream and eucalyptus oil and put that around the hole and the bark where there was evidence of its eating each night.
Sadly for the grub, the mixture killed it (see picture 2 of it poking out of its hole). The grub is about 1.5 centimeters long (maybe longer when alive) with a hard black head and about 13 rings in its body.
What is the grub?
Is there a better way of getting rid of it than by killing it in what may have been a gruesome way for it (i.e. a quicker way of death)?
Would it have harmed the tree?
Thanks a lot
kathy
Pictures - Click to enlarge

Picture: 1
Picture: 2

Time: 13th October 2011 10:37am

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Original Post was last edited: 13th October 2011 7:30pm

About the Author kathyturner
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Mike says...
You can't quite see it well enough to identify it.Cossid and ghost moths have large boring larva but most of the time it is longicorns and several other families of beetles.Hook them out of their trails near saw dust piles with bent wire or dig them out.The trees usually recover well unless there is secondary fungal attack.

Time: 13th October 2011 7:50pm

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Kathy says...
YEs Mike - it seems it must be one of the longicorn beetles manifestations (just because of the ring barking) - but I cannot find any reference to longicorn grubs feeding each night on the bark near their exit holes - or of them covering the hole each night when they return to the tree with webbing.
The only reference I can find to a caterpillar emerging at night and eating bark is this from the DPI Victoria:

The fruit tree borer Maroga melanostigma and vine borer Echiomima sp. are moths, of which the caterpillar stages bore relatively shallow tunnels into grapevine spurs. The caterpillars emerge at night to feed on the bark around the tunnel entrance. The feeding area becomes covered with webbing and frass.

BUT I don't see any reference to these as ring barking the tree so precisely.
?????????
IF it just ate the bark around it's hole - then I would have just let it carry on with its life cycle - it was only because I thought it was a type of creature that ate through the tree killing it, that I killed it. That's why I'd like to know.
That's good the tree should live - it is looking quite healthy now - so maybe YES it will be okay.
Kathy

Time: 14th October 2011 8:15am

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Original Post was last edited: 14th October 2011 9:31am

About the Author kathyturner
Malecy, Qld
#UserID: 5954
Posts: 43
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