Fruit rot of butternut squash (Cucurbita moschata Duch.) caused by Choanephora cucurbitarum in Sri Lanka

Butternut squash (Cucurbita moschata Duch.) is a fruit vegetable, and the hardy nature of fruit enables it resistant to many pests. However, flowers and young fruits are vulnerable to diseases. In the Northern Province of Sri Lanka, soft rot symptoms were noted in flowers and young fruits in some fields during Maha season in 2018. The fungus isolated from infected tissues produced cotton-like white mycelium and black spore masses on PDA. The internal transcribed spacer (ITS) section of the ribosomal DNA sequences was amplified using PCR, and the generated sequences had > 99 % similarity with the nucleotide sequences of Choanephora cucurbitarum in the BLAST search. In phylogenetic analysis, the isolates clustered in a clade of C. cucurbitarum with a high bootstrap value. Based on the results of morphological studies and the ITS region’s molecular analysis, the fungal identity was confirmed as C. cucurbitarum. The symptoms were reproduced in inoculation tests. The present findings confirm the first report of fruit rot of butternut squash caused by C. cucurbitarum in Sri Lanka. © 2021, Indian Phytopathological Society.