The incidence of dothistroma blight [Dothistroma septospora (Doroguin) Morelet] throughout the world during the last fifteen years is reviewed with particular reference to its economic effects.

Impact of the disease has been generally slight in the northern hemisphere, with most severe effects localised in nursery and ornamental stocks in parts of the USA and Canada. In Central and East Africa and New Zealand chronic defoliation has caused serious loss of increment in young Pinus radiata; in Chile outbreaks have been acute and of short duration, causing only slight yield loss.

Economic control has been obtained by a well organised copper fungicide spray programme in New Zealand, but this means has proved impracticable in Africa. Experience gained in New Zealand will be valuable when similar problems arise in industrial forest plantations in the future.