INTEGRATED MANAGEMENT OF DENDROCTONUS-MICANS IN THE UK

Great spruce bark beetle, Dendroctonus micans, first discovered in the UK in 1982, has been the subject of an integrated pest management (IPM) programme developed by the Forestry Commission. The programme is based on a combination of forest management practice, including sanitation felling and restriction of transport of infested spruce, and biological control through introduction, rearing and release of the exotic predatory beetle, Rhizophagus grandis. Five phases in the development of the IPM programme are recognised and described, although all are interrelated: (i) initial survey and sanitation felling reduced numbers below critical levels; (ii) initial forest management strategy was to introduce a scheduled area restricting movement of infested spruce to approved mills; (iii) introduction and release of R. grandis through an inoculative release strategy; (iv) refinements to forest management to reduce further accidental spread and to monitor natural spread of Dendroctonus micans; (v) assessment of the impact of R. grandis using a range of criteria. Populations of Dendroctonus micans are now at low levels and there is strong evidence that R. grandis has established well, is spreading and is an important factor in regulating the bark beetle populations.