Root rot disease of mangium (Acacia mangium willd.) in the Philippines
1999
Militante, Ernesto P. | Manalo, Mutya Q.
A new root rot disease of Acacia mangium Willd. was first observed in the industrial tree plantations in the provinces ofAgusan del Sur and Mindoro, Philippines. The disease is caused by a white rot fungus, Phellinus noxious (Corner) Cunn., that infects the roots of A. mangium. Trees infected with P. noxious may exhibit the following symptoms; yellowing of the leaves, premature leaf fall, thinning of the crown, stunted growth, and death of the tree. The decayed wood becomes mottled and fibrous in the advanced stage of disease development with dark zone lines and black specks. The cream to brown mycelialmatis confined only to the sapwood resulting in blockage of water and mineral nutrient transport from the roots to the leaves. Heavily infected trees are subject to windthrow during typhoons. The mortality ofA. mangium due to root rot disease ranges from 10 to 25% in 6 to 10 year-old trees. However, in two separate areas the majority of the trees were infected in I and 4 hectare plantations respectively.
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