Infestation of regenerated stands of Karri (Eucalyptus diversicolor) by bullseye borer (Tryphocaria acanthocera,Cerambycidae) in Western Australia

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Abstract
Damage to even-aged regeneration of Karri by the indigenous bullseye borer beetle, first noted in 1967, caused serious concern in 1980 when first thinnings were harvested. The insect has a 2-year-life cycle, 18 months of which are occupied by the woodfeeding lavai stage. The borer occurs within the entire range of Karri forest. No damage was recorded in fully stocked stands younger than 14 years. Damage tended to be associated with the proximity of even-aged regrowth to old growth forest or non-clearfelled stands, and also with the unsuitability of sites for pure Karri, small coupe size, and drought (average annual rainfall for the period 1967–87 was about 10% less than in the preceding 21 year period (1946–66)). None of the infestations was linked to fire damage. Thinning regrowth stands of Karri may be a management option for reducing infestation by bullseye borer, but further research on the influence of site factors on Karri physiology and borer ecology is needed before this control measure can be prescribed.