Thread: Borers and grubs

Originally Posted by funkychicken

Does anyone know the particular names of all the different borers? At work we get a few different types:

Big segmented white ones. 4" long x 3/4" diameter. Spots on each section. Eats all through a log, favours blue gum and grey gum. I've never seen them in blackbutt. (I found a live one today, never seen one that wasn't in half before)

Short segmented white ones. 25-35mm long, 10-3mm diameter (they taper) black nibblers on the big end. Burrows between the bark and sapwood, leaving obvious trails. Favours Spotted gum, probably blackbutt too. Nutty taste

Six legged black things. 15-25mm long. They've got yellow antennae and can fly. I've never seen them boring but they hang around the logs at work.

Tiny little things. They make 1-2mm dia holes and leave powder in their wake. They might be powder post beetles.

The first ones could be any of a number of moth larvae and sound quite similar to those which attack kurrajong trees and eventually cause their death.

The short, tapered, segmented white ones would more than likely be Longicorn beetle larvaeand the six legged black things are the mature insect.

and last but not least is the "powderpost" or lyctus borer.

Another to look out for is the ambrosia beetle of which in Australia few timbers are immune to attack.

another to keep an eye out for is sirex wasps. they only seem to infest conifers but if any are found the affected timber should be burned ASAP

funky,any chance of a few pics if you get time? trav seems to know what your'e talking about but apart from the lyctid borer or powder post borer (the small one) which i get alot of. i'd love to see a pic of the others so i could positively id them. regards charlsie

I can try, it's not often I find ones I haven't already lopped in half.

I was only thinking about pics yesterday - I saw the mature longicorn beetle out at Maryborough on a job. I can probably get some of it's larvae later today?

I've read the powder post and ambrosia leave very similar small holes in the sapwood, but the ambrosia stains the edges of the pin holes black, just a tidbit - not sure if everyone knows, might help in an ID to stop the little buggers

I call the big spotted ones '12 gauge grubs' - never seen more than a nasty stain on some timber from where one met a saw blade tho'. Now I know what the thing looks like that makes 12 gauge sized holes in the logs.

Originally Posted by bsrlee

I call the big spotted ones '12 gauge grubs' - never seen more than a nasty stain on some timber from where one met a saw blade tho'. Now I know what the thing looks like that makes 12 gauge sized holes in the logs.

I am led to believe that they are actually the larvae of one of australias large moths, and may spend upwards of 3 or 4 years as a larvae inside the tree only to turn into a moth breed and die within a matter of a couple of days.

some info regarding the aforementioned insects

Ambrosia beetles. Also known as pin hole or shot hole borers. These belong to 3 distinct families of wood boring insects, varying from minute insects 1/8 th of an inch to over 1 inch long. These borers occur in all tropical regions, and in Australia few timbers are immune to the attack.
attack ceases when timber starts to dry as neither the larvae or mature adult can survive in dry wood. they prefer pored or "hard" woods.
Some of the species lay their eggs in cracks in the bark and wood and the larvae bores the hole while other species the adult beetle bores a hole to the heart of the tree and deposits its eggs. While excavating the tunnels or galleries the female infects the walls with a fungus which grows into the "ambrosia" which feeds the larvae. This fungus is believed responsible for the staining seen around the tunnels. Flight holes average 1/16th of an inch in diameter (roughly 1.5 mm)

Lyctus borer. Also known as powder post borer
The lyctus borer is one of the commonest borers which attack SEASONED HARDWOOD timber throughout the world. It is so common in Australia that little or next to no unprotected susceptible timber escapes attack within the first year or two of service.
The lyctus only attacks the sapwood of pored timbers. True pines, firs and spruces are never attacked. They require a timber which is high in starch and with a fairly large pore size.
The larvae are small creamy coloured grubs, which may live in the sapwood for up to 18 months. the mature beetle is dark brown in colour and about 3/16th of an inch or roughly 5 mm long (look similar to a barley bug if you know what they are but dark brown!) and seldom live for more than a few weeks.
The most typical characteristic is the abundant fine powdery frass which is tightly packed into the network of tunnels. the tunnels are unstained and run in the direction of the grain, as opposed to ambrosias which are stained and run across the grain.

Longicorn beetles, also called jewel beetles and wood moths
The larvae bore holes into both sapwood and true woodof forest trees and green logs usually only pored woods. The insects lay their eggs in cracks or crevices in the bark of living trees or green logs. They may live inside the log for several years prior to emerging as a mature insect. If the timber from an infected tree is allowed to dry naturally some of the insects may complete their life cycle and emerge from the dry timber.
Damage consists of 1/4 to 3/8 inch holes or tunnels generally across the grain. Treatment of infested timber is quite unnecessary as there is no risk of re infestation

This is info from a book called "woodwork in theory and practice" by John A Walton

I will try to get a pic of a longicorn larvae and mature insect for you all in the next few days, I dig them out and feed them to the Cat it loves them. I have seen a heap of the mature beetles in the timber I used to make my front fence.

The large grub could be the larvea of a cossid wood moth. Have a look at,
http://www.museum.wa.gov.au/collecti...Giantmoths.pdf
Jim

Originally Posted by Travis Edwards

The first ones could be any of a number of moth larvae and sound quite similar to those which attack kurrajong trees and eventually cause their death.

The short, tapered, segmented white ones would more than likely be Longicorn beetle larvaeand the six legged black things are the mature insect.

and last but not least is the "powderpost" or lyctus borer.

Another to look out for is the ambrosia beetle of which in Australia few timbers are immune to attack.

another to keep an eye out for is sirex wasps. they only seem to infest conifers but if any are found the affected timber should be burned ASAP

A lot of Longicorn borers up this way [Kyogle] Travis, one the old timers call the "one inch grub" - reason being the holes were almost exactly 1"...I've measured 'em, mostly about 15/16ths, often with the remains of the borer dead further down in the log, sometimes killed by the "kena"...red gummy juice the gumtree releases to murder the intruder I'm guessing. [hence "bloodwood" etc. ]
Some smaller Longicorns too. They used to get into our acacias when I taught Hort out in the desert [Tennant Creek] with the mob. Give you a nasty nip if you let 'em. They enter near a fork and make their way up the centre of the branch. The adults, [beetles] are actually quite beautiful.... if you can separate this idea from the idea that they really chew up your timber!

Ps the larvae go very well on the barbie...nutty & nutricious. Cant eat the head 'tho.

Fer what it's worth....

richie

Originally Posted by richie47

A lot of Longicorn borers up this way [Kyogle] Travis, one the old timers call the "one inch grub" - reason being the holes were almost exactly 1"...I've measured 'em, mostly about 15/16ths, often with the remains of the borer dead further down in the log, sometimes killed by the "kena"...red gummy juice the gumtree releases to murder the intruder I'm guessing. [hence "bloodwood" etc. ]
Some smaller Longicorns too. They used to get into our acacias when I taught Hort out in the desert [Tennant Creek] with the mob. Give you a nasty nip if you let 'em. They enter near a fork and make their way up the centre of the branch. The adults, [beetles] are actually quite beautiful.... if you can separate this idea from the idea that they really chew up your timber!

Ps the larvae go very well on the barbie...nutty & nutricious. Cant eat the head 'tho.

Fer what it's worth....

richie

The cat doesn't seem to mind the head...lol

i ger teh big one all the time ill take some pics next time. got a heap in some logs that came in from out at warick.

i just call tehm f@rk!nb@$####. but i call a lot of things that.

Yup,
they sure can eat mate. stuff up nice slabs too.
You wouldn't mind if it was pine...

Pulled a dozen whole ones (and lots of halves) off the outside of the blackbutt flitch boards I cut yesterday when I cleaned up the last of the logs at home before the Lucas went to it's new home today. They were the tapered type ones up to about and inch and a half long and live just under the bark in the swan river blackbutt. My chooks loved them.

Geese Mike, I'm super bummed mate Can't ya retire now, and keep the mill?

When we attacked some old red gum sleepers there were heaps of grubs a bit longer than your thumb but about that thickness.

When I threw them into the chooks they basically looked at them, then me as if to say "Well get me a knife and fork and then I'll tuck into it."

They looked a lot like giant forms of the christmas beetle larvae,

R