Abstract:
Leaf spot (Corynespora cassiicola) and anthracnose (Colletotrichum orbiculare)
diseases are the most destructive diseases that infect cucumber in Taiwan.
Corynespora leaf spot is often confused with other foliar diseases such as
anthracnose and cannot be easily identified based on symptoms alone in the first
instance. The study focused on pathogen identification based on, combined
approach including symptoms on the plant, culture morphology, and molecular
identification. Infected cucumber leaves were collected to obtain 480 isolates and
their morphological characters were recorded. Molecular identification was done
using PCR with two universal primers (ITS1 and ITS4). The cultural characteristics
of isolates on potato dextrose agar (PDA) were occasionally similar to
Colletotrichum orbiculare. However, conidial morphology of isolates was more
similar to Corynespora cassiicola. National Centre for Biotechnology Information
(NCBI) database showed that all tested isolates corresponded to the genus
Corynespora.It is concluded that all of the isolates obtained from diseased tissues of
cucumber leaves in the study area (Pingtung farm) in Taiwan belonged to the
fungus Corynespora cassiicola.
