First report of cucurbit chlorotic yellows virus affecting squash and pumpkin in Florida, USA

A field survey was conducted in Florida during 2020-2021 in squash and pumpkin research fields to identify the viruses associated with leaf symptoms of yellowing, crumpling, and vein yellowing. The symptoms were similar to previously reported whitefly-transmitted viruses such as cucurbit leaf crumple virus (CuLCrV), cucurbit yellow stunting disorder virus (CYSDV), squash vein yellowing virus (SqVYV). Another potential virus of interest was the cucurbit chlorotic yellows virus (CCYV) that was recently reported on watermelon in Florida. Symptomatic leaves were tested by RT-PCR with coat protein (CP) gene-specific (GS) primers for CuLCrV, CYSDV, CCYV, and for SqVYV with a nuclear inclusion protein (NIa) GS primers. Amplification for CuLCrV, CYSDV, and CCYV were detected in squash and pumpkin samples. The CCYV amplicons were further sequenced and compared with available CCYV sequences. The NCBI BLAST analysis revealed similarities of the RdRP (100%), HSP70h (99.75%), and CP (99.75%) to the Shanghai CCYV isolate (RNA KY400636 and RNA2 KY400633). To our knowledge, this is the first report of CCYV on squash and pumpkin in Florida.