The Structural Conservation of Panel Paintings

information has been published concerning these wood-destroying insects

in buildings and other wood products. For discussions of termite biology

and attack, see Creffield (1991), Hickin (1975), and Moore (1979).

Successful control offungi and insects requires knowledge of the biologi-

cal agents that can cause deterioration, as well as the ability to diagnose

the existing damage adequately. Once this information is available, much

can be gleaned from existing literature about the nature of the attack and

its effects on the wood.

A clean, pest-free environment with RH control ofless than 60% is

essential to prevent damage by fungi and insects. Reducing wood moisture

halts decay activities by fungi but does not eradicate the fungus or the

reproductive structures that produced it. A change in moisture and return

to more favorable conditions for fungal growth can result in renewed

growth of the dormant fungus or facilitate new infestations. An inspection

progr am and the eradication of established insect infestations from wooden

objects are necessary to prevent future damage. Although effective control

procedures for insects are available that utilize fumigants, heat, freezing

temperatures, or insecticides (Edwards, Bell, and King 1981; Hickin 1978;

Nesheim 1984; Robinson 1988), these methods may not be ideally suited for

Control of Fungi

and Insects

A G  W D C  M  I 65

Table 2 Summary of wood-boring-insect damage to wood

Insect Wood Distinguishing characteristics

Common furniture Sapwood of softwoods and hardwoods; Meandering tunnels 1–2 mm in diameter, often in direction of grain,
beetle, Anobium may attack heartwood if fungal decay filled with frass consisting of oval pellets and wood powder.
is present.

Lyctus Sapwood of hardwoods with large vessels, Damage in sapwood with high starch content. Circular tunnels 1–2 mm
powderpost beetle such as oak and elm. in diameter, usually parallel to grain, filled with fine powder.

Bostrychid Sapwood of tropical timbers. Convoluted tunnels 3–6 mm in diameter, packed with fine powder.
powderpost beetle

Wood-boring weevil Decayed softwoods and hardwoods. Tunnels 1 mm in diameter, oriented in direction of grain, with fine,
granular powder.

Ptilinus beetle Sapwood of hardwoods. Meandering tunnels 1–2 mm in diameter, packed with fine bore dust.

Death watch beetle Sapwood and heartwood of decayed hardwoods. Tunnels variable in diameter from 0.5–3 mm, randomly oriented
but common in direction of grain; bore dust consists offine,
disk-shaped pellets.

Ambrosia beetle, Standing trees or cut green timber; does not Main tunnel 1–2 mm in diameter at right angles to grain with short
pinhole borer infest timber that has been dried. lateral tunnels originating from it; wood is darkly stained by fungi
around tunnels; no bore dust in tunnels.

Bark beetle Bark of hardwoods and softwoods. Insects tunnel through bark and cause scoring of wood surfaces beneath
bark and phloem; only found on fresh wood with bark.

Dermestid beetle Damage to dry animal material (leather, fur, Short tunnels free from bore dust in wood adjacent to animal material;
etc.); wood damaged only when in contact circular holes 3–4 mm in diameter and up to 10 mm long.
with a food source.

Buprestid beetle, Standing dead or recently cut logs; rare in dry Large tunnels 7–8 mm in diameter, with oval emergence holes; large
jewel beetle timbers. cylindrical frass pellets make up bore dust. Larvae have large flat heads.

House longhorn beetle, Sapwood of softwoods. Tunnels 6–10 mm in diameter with similar-sized oval emergence holes;
cerambycid beetle bore dust contains cylindrical pellets with fragments of wood; most of
the sapwood may be consumed, with just a thin veneer of surface
wood left.