Two Acacia seed orchards, one each of A. mangium and A. auriculiformis, in Central Java have suffered high losses from root rot associated with a species of Ganoderma that is distinct from G. philippii, which causes extensive losses in A. mangium plantations in Sumatra and Kalimantan. Ganoderma steyaertanum was consistently isolated from roots of affected trees in the Javanese orchards and pathogenicity was confirmed by satisfying Koch's postulates. The mode of spread of the pathogen was examined by analysing the distribution of tree deaths in the A. mangium seed orchard and conducting somatic incompatibility tests among G. steyaertanum isolates from diseased trees. Spatial analyses indicate that, after an initially random disease distribution, the pattern of tree deaths was clustered. This is consistent with spore colonisation of thinned stumps followed by vegetative spread through root-to-root contact, as has been observed for other root pathogens such as Heterobasidion annosum. Somatic incompatibility tests demonstrated high genetic variability of the pathogen with root-to-root spread also confirmed.
Pinus merkusii, a multiuse tree, is cultivated at Indonesian Plantation. Pinus plantation have been threatened by rust/spot leaf disease. The pathogen has infected pinus seedlings at Perum Perhutani, BKPH Purworejo, KPH Kedu Selatan and cause high mortality. The aims of this research to identify pathogen causing rust/spot leaf thus information how to control can be observed. Pathogens were isolated from infected leaves, and grown on the potato dextrose agar (PDA) and observed macroscopis and microscopis and identified. The pathogens also were inoculated to healthy seedlings (Postulat Koch Test). The result shows that pathogen causing rust/spot leaf on seedlings pine is Pestalotia sp with characteristic white colony, hypha has aservuli with conidia that have 25 septums and at the edge, some structure looks like feather whipped 3-5. Potulat Koch test indicated that inoculated healthy seedling shows similar symptom with infected seedlings. Rust/spot leaf has similar sympto and sign. Spot or rust appear on leaves started from edge and spread to base. At first, spots were formed in small size and separate each other but they developed and became larger and wider and fused.
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