Vascular Streak Dieback disease of cocoa (II) Diagnosis on cutting

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Diagnosis to identify VSD fungus (Oncobasidium theobromae) on cocoa plants is indispensable. An experiment to identify the fungus on cuttings derived from infected twig and leaves has been rarried out at hte Research Institute for Estate Crops in Jember, Indonesia. The results showed that the VSD fungus could be identified only on cuttings prepared from infected twig. The mycelium grew out from the injured parts, i.e. leaf scar and cut sides of twigs and leaves. The fungus has covered all of the cuttings on the third day of incubation. The growth of fungus on leaf cuttings was slower than that on twig cuttings with trimmed leaves. It is concluded that cuttings prepared from infected twig could be used to identify O. Theobromae. Sri Sukamto, Yohanes Djoko Junianto; Balai Penelitian Perkebunan Jember