Thread: Help! What's eating it?

Move House Quick !

A few things I need to ask my good Man of green,

#1 Are you positive they wern't already there as you very detailed shot indicates to me from the sharp edges this was cut already containing the hole?

#2 are these holes anywhere near the sap region of the slab?

#3 have you gently blown into the smaller end of the two holes to check (A) they are actually the 2 ends of the same tunnel & (B) a grub or beetle isn't still there as this makes Id'ing heaps easier?

#4 If you are able to could you tell which end of the hole would've been closer to the base of the tree? (I'd almost bet a leftie the 10mm end is)

some more pix and investigation and lets see if you actually have a problem. or not

Pretty odd getting holes that big in an imported, seasoned timber—being jelutong I assume it's imported. Whatever the borer/beetle it's the sort that normally attacks standing or unseasoned timber. Don't know of anything that size that attacks seasoned timber.

Thanks Bruce and Rusty

Bruce

1 Only one hole existed when the slab was sliced down (into 2), now there are several

2 I would have to sand one end of the slab to check the growth rings, but I do know the slab is at least 10-15 year old, should have minimal moisture

3 The holes go right through the timber at different angles, indicating they don't follow the grain. The photo shows the solid material I removed from the holes. It was like removing the loose timber from the centre of a knot

4 Sorry, no idea - never been able to fathom how to read grain direction

Rusty

Either it's a small insect that goes round and round to remove the central core, or something larger that may leave the solid waste core (being much darker, probably the latter). Some of the holes appear larger because of the angle of entry. The removed plugs are oval and approx 8mm at the widest point. The timber was stacked against a slab of Cinnamon Wood - it obviously didn't fancy that timber, turned around and re-entered the Jelutong

Tikki :confused:

Tikki, I'm going to mull it over and check some references out tomorrow, I was leaning towards anomium borer or the smaller wood grub, maybe even lyctus type, but what you said pretty well rules them out. Being well seasoned timber and an exotic means I might actually have to do some homework cause it's bugging me now On the other hand, there are some very experienced well informed heads around here and the odds are they will more of an idea than me.

As your uninvited guests sound like they are still in residence the easiest way to identify them would be to see them. You could try injecting something offensive but not necessarily lethal (diluted turps perhaps or English beer) into one of the holes. Take cover at a safe distance and see what comes out.

By the size of the holes, a shotgun might be more in order

Originally Posted by E. maculata

I was leaning towards anomium borer or the smaller wood grub,

G'day Bruce.
Remember I was telling you about Okum's Razor??
First thought, best thought, correct thought???

I would tend to agree with your above statement.
Hooroo.
Regards, Trevor
Grafton

Okay I'm leaning towards "anomium" see following excerpt from one of my text books....
Insects
The two groups of insects that worry timber users the most are borers and termites. Some species of borers attack only living trees, others are found more in green timber, and some prefer dry timber in a building. Termites will attack wood in any form, although some timbers are naturally resistant because of their silica content or other chemical deposits.

Since termites and borers can have such a serious effect on the strength of timber, there are specific building regulations designed to minimise the chance of particular types of attack. The regulations vary from one region to another, and also from state to state, depending on the likelihood of attack occurring in that area. We’ll discuss some of these regulations in this section.

Borers
Borers are beetles which at some stage of their development bore into wood for food or shelter. They pass through four stages: egg, larva, pupa and adult. With most borers, the major damage is done by the larvae, or grub, when it tunnels through the timber to access food. Generally speaking, the only damage they cause as adult beetles is when they bore an exit hole through to the surface so they can fly away and look for a mate.

Lyctid borers
Lyctid borers attack only the sapwood of particular hardwood species. They never attack the heartwood. The female beetles lay their eggs beneath the surface of the wood by inserting their ovipositor into the pores. If the pores of a particular species are too small for the ovipositor, then that species is immune from attack. If there isn’t enough starch in the sapwood to sustain the larva, then the attack will be very limited. Because softwoods don’t contain pores, they are all immune from attack.
The NSW Timber Marketing Act requires that framing timber containing lyctid susceptible sapwood must contain no more than 25% sapwood, measured around the perimeter of the piece. This means that if the timber is attacked after it has been installed in a structure, the damage done will be limited and won’t unduly affect the strength of the piece. In Queensland, the Timber Utilisation Marketing Act prohibits any lyctid susceptible sapwood in framing material. This is also the case with flooring timbers in both states—there must be no susceptible sapwood at all in a piece.

Sawmills therefore have two choices: they can either cut the sapwood out before they sell the material, or they can treat it with preservative chemicals so that it’s no longer susceptible to attack. Two common treatments used are boron and copper-chrome-arsenic (CCA) (see Section 4 for more on these treatments)

Anobium borers
The most common type of anobium borer in Australia is the furniture beetle. This beetle prefers damp, humid conditions and is a particular problem in old furniture, especially pianos and other articles with plywood backing made from softwood veneers. It’s also known to attack baltic pine flooring in houses with poor sub-floor ventilation.
In Queensland, the hoop pine borer, also from the anobium family, is sometimes found in timbers such as hoop and kauri pine.

Pinhole borers
Pin hole borers are also called ambrosia borers, because when the female lays its eggs, it bores into the wood, deposits the eggs, and then coats the walls of the hole with ambrosia fungi to provide a food source for the larvae when they hatch. This is why the holes generally have a characteristic blackish stain around them when the timber is sawn.

As their name implies, pinhole borer holes are generally long, straight and small in diameter, and tend to run at right angles to the direction of the grain. They only attack tress and freshly felled logs, since the ambrosia fungi need a high moisture content to survive.

Longicorn borers
Longicorns are also a forest problem, rather than a dry timber problem. They generally attack hardwoods, and drill oval shaped holes up to 10 mm in diameter, although sometimes the holes can be larger. Longicorns include the witchetty grub varieties.

Other forest borers
Some of the other borers that occur in forests are:
• jewel beetles, which attack unhealthy or fire-damaged cypress pine trees
• auger beetles, also known as bostrychids, which generally attack only the sapwood of hardwoods
• sirex wood wasps, which were a potentially serious problem in plantation pines in Victoria several years ago, but have now been brought under control.
I'm going with the anomium.

Whatever it is it would probably make good bait for a nice Murray Cod.

So could these cause a problem like that,

Originally Posted by echnidna

So could these cause a problem like that,

More Murray Cod bait.

Originally Posted by Barry_White

More Murray Cod bait.

Trouble is grubs like this are easy enough to get but there aint no cod in our local rivers and lakes.

A good handful, what do you guys find them in? I know Yellow belly(golden perch) like them too, not bad fried up on barbeque either (so I'm told )
Those grubs are tough suckers up here they eat high silica hardwoods and the causarinas (oaky type) mostly.