Gall Rust Disease Epidemic on Falcataria moluccana in Indonesia and Malaysia

摘要

Gall rust disease caused by Uromycladium tepperianum (Sacc.) is one of the most destructive diseases on Falcataria moluccana in some part of the South East Asia region from 1990 up to now. The disease causing severe damage to all developmental stagesof the plant: from seedlings in the nurseries to mature trees in the field. Range of the symptoms includes development of chocolate brown, cauliflower-like or whip-like galls on stem, branch, petiole, shoot and pod (Rahayu et al. 2011). Objectives of this study were: to determine the status of gall rust disease in Malaysia, and Java Islands of Indonesia; to estimate the relationship between incidence of gall rust disease and environmental factors that may influence those phenomena at the sites and to predict the origin gall rust spore sources. Sampling intensity was 1% to 5% of the total area at each site. Three blocks, three replicates, three plots each with 10 trees were observed. In each site. More open site forest, flat topography, absence of fog,older age and lower altitude were significant local site conditions which could reduce gall rust disease incidence. However, high relative humidity and slower wind speed, are able to promote gall rust disease development. Based on the wind blew predominantly from the northeast, gall rust spores may spread from the north, probably from the Philippines, to Tawau-Malaysia, then to Celebes-Indonesia.