Dothistroma needle blight (Dothistroma septospora)

Symptoms of damage

The initial symptom of dothistroma needle blight infection is minute resin drops from the needles. A small red-brown band of dying tissue develops, above which the needle dies. A black fruiting body forms within the red-brown band on the needle. Defoliation generally commences in the lower crown and spreads upwards
(see images).

Young radiata pine plantations (up to 12 years of age) appear to be most vulnerable, with resistance to the disease generally developing after this age.

Symptoms of needle damage	Foliage loss in radiata pine

Conditions conducive to outbreak

The development and spread of the fungus is favoured by conditions of high humidity. Consequently,outbreaks in Victoria generally occur in regions where annual rainfall exceeds 1100mm and within sites that have impeded air drainage such as valleys and some plateaus.

The most likely period of damage in Victoria is August to November – dry, hot summers inhibit disease development.

Method of dispersal

Windborne spores.

Distribution in Victoria

Statewide, except for the north-west and far south-west.

Control

The disease can be controlled with a correctly-timed application of copper fungicides and/or the use of tolerant genetic stock in areas prone to disease development.

Movement of host materials

There are restrictions on the movement of dothistroma needle blight host materials (including Pinus seedlings and cuttings) into South Australia.

For certification or more information about these restrictions, please email DPI on
market.access@dpi.vic.gov.au