Leaf spot and canker disease of Eucalyptus in nursery stage
Abstract
In Vietnam, several Eucalyptus species have been planted in large scale under about 170,000 hectares in 2015. The aim of this study is to evaluate morphological characteristics, symptoms, pathogenicity and to indentify the cause of leaf spot and canker of Eucalyptus spp. in nursery stage in Phu Tho province, Vietnam. The disease symptoms including staining of the vascular tissue, cankers and wilting on infected parts of the trees, or spots exuding in the leaves. The infected trees showed to be wilting symptom and died after ward. Pathogenicity of 10 isolates was varied and divided into 4 groups: weak (1 isolate), average (4 isolates), strong (3 isolates) and very strong (2 isolates). Fungal pathogen was identified by using molecular biology technique using ITS1 and ITS4 primers. The ITS sequence analysis of the two highly pathogenic isolates were compared with the reference sequence GU973522 (Cheewangkoon et al., 2010) and GU973519 (Lueangpraplut et al., 2013). Two isolates (PN3 and PN4) were indicated as Pseudoplagiostoma eucalypti, a serious pathogenic in eucalyptus plantation in Thailand. Therefore, it is necessary to study the effective management of this fungus in order to limit the spread of the disease in Vietnam.
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