Ambrosia Beetle
Ambrosia beetles, also called pinhole borers, are small beetles about 3–5 mm in size. They have cylindrical bodies and are reddish brown to black in colour. They live in symbiosis with ambrosia fungi. They make tunnels in dead and living trees, then make fungal gardens as a source of food. They thrive in very moist conditions and are pests of freshly felled trees. They can be easily identified by the stains they leave on their flight holes, which degrades the quality of the appearance of timber but not the strength.
Biology and Behaviour of Common Species
Ambrosia beetles bore into freshly felled trees to lay their eggs, and leave fungal spores on the walls of the tunnels they made. The adults often die at the entrance of the tunnels as they protect their eggs from predators and block the tunnel holes from losing moisture. The fungi then grow spores that will serve as food for the larvae once they hatch as they do not feed on wood. The holes ambrosia beetles make are darkly stained because of fungi. Their life cycle is about 6–12 months but is longer is some species.
Austroplatypus incompertus, or the horizontal borer attacks injured trees and makes galleries in only one plane. It carries a fungus that degrades cellulose in a horizontal plane, causing fractures.
Other species of ambrosia beetles that can be found in Australia include Platypus australis, the polyphagous pinhole borer, Platypus subgranosus, the mountain pinhole borer, and Crossotarsus omnivorus, the omnivorous pinhole borer.
Treatment
Spraying logs at forest dumps or mills can prevent ambrosia beetle incidence. Once the logs are sawn and dried out, they lose moisture and become inhabitable for fungi and larvae. Therefore ambrosia beetles are no longer a problem and do not require treatment. However, strains they leave from flight holes can degrade wood’s appearance.
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