Morphological and molecular characterization of Neoscytalidium isolates that cause canker and dieback in Eucalyptus and Chinaberry trees in Iraq

Abstract

Neoscytalidium Dimidiatum isolates are the most pathogens associated with sooty canker and dieback in the stem and twigs of Eucalyptus and Chinaberry trees in the Kurdistan region of Iraq. Young trees showed branch dieback and yellowing leaves. The symptoms were further developed to sooty canker and dieback appeared on the main branch and trunk. N. dimidiatum colonies on potato dextrose agar were dense white at first and became dark gray to black within seven to ten days. Arthric dark brown conidia (6.6x 4.3 µm) were observed in the chain of mycelium. The color of the colonies was white at the beginning, then eventually turned greenish in seven days, and finally became black. The fungus produced white to olivaceous aerial mycelium with chains of chlamydospores and arthroconidia. Conidia were initially hyaline, ellipsoidal to globose, 4.1-9.8 m × 2.8-3.5m, with muriform septa. The inoculated Eucalyptus and Chinaberry seedlings displayed necrosis streaks along with the barks and xylem of the inoculation points. Combined dataset of internal transcribed spacer (ITS), Nuclear Ribosomal Large Subunite (LSU), and Beta tublin 2a (Bt2a) using Maximum Likelihood and Maximum Parsimony analysis support the monophyletic on Neoscytalidium dimidiatum isolates from Iraq (N. hyalinum (No. B21), and Neoscytalidium novaehollandiae (No. B22)). This is the first time to report Neoscytalidium dimidiatum on Chinaberry in Iraq.

Keywords

• sooty canker
• neoscytalidium isolates
• n. dimidiatum
• phylogenetic lineages