Management of Mycosphaerella leaf spot diseases in Australia

Abstract

Mycosphaerella musicola is the major leaf spot pathogen affecting banana in the tropics, whereas Mycosphaerella musae and M. musicola dominate in the sub-tropical areas of Australia. Control strategies include chemical and cultural practices. In tropical areas, sprays are applied at intervals of 10-14 days during the wet season and 21-28 days during the dry season. Annually, 18-24 protectant and systemic fungicide sprays are applied with petroleum oil (5L). Since the early 1980s, the banana industry has fought to exclude this disease from the production areas by monitoring and creating a barrier of resistant plant material. Black leaf streak disease has been detected in the Cape York area eight times in the past 20 years and was limited to a few plants and in all cases was successfully eradicated.
In April 2001, black leaf streak disease was identified in the main production area of North Queensland. An intensive survey (April-June) indicated the disease was restricted to the Tully area. Black leaf streak disease was found on 14 commercial properties and on 11 clumps of unmanaged plants. An eradication programme commenced in September 2001 across approximately 4500 ha of banana plants and involved deleafing commercial plantings to zero disease, weekly fungicide applications for six months and the destruction of all non-managed plants. Black leaf streak disease has not been detected on commercial plantations for eight months and on non-managed plants for four months. It was not detected in 1550 samples assessed during January to April 2002.