First report of Watermelon crinkle leaf‐associated virus 1 (WCLaV‐1) on Cucurbita pepo in the United States

Zucchini (Cucurbita pepo) is widely grown in Florida and contributes to the US$35 million value production of all types squash state (United States Department Agriculture/ National Agricultural Statistics Service, 2021). In August 2022, zucchini (cv. Renegade) a commercial field North Florida, USA, showed pronounced chlorosis mild crinkle on leaves scattered areas (Fig. 1). The disease incidence was approximately 35%. One diseased leaf from each six plants were collected randomly for diagnosis; three 21-day-old (noted as Z272), 28-day-old Z273). All samples tested negative Cucumber mosaic virus, Squash virus yellow using ImmunoStrips (Agdia, USA). Subsequently, total plant RNA extracted Quick-RNA MiniPrep kit (Zymo Research, A conventional one-step RT-PCR (New England Biolabs, USA) used test primer pairs Cucurbit chlorotic yellows (CCYV; Jailani et al., 2022), Watermelon leaf-associated 1 2 (WCLaV-1 WCLaV-2; genus Coguvirus) (Hernandez 2021) (WMV-2; 5′-AAAGCTCCATACATAGCTGAGAC-3′/ 5′-CGGCCTTCATTTGTGCTATTG-3′). CCYV, WMV-2 WCLaV-2, but positive WCLaV-1 specific primers RNA-dependent polymerase (RdRP) region RNA-1 (Table To confirm detection WCLaV-1, RNA-2 primers, targeting coding regions movement protein (MP) nucleocapsid (NP), respectively, an assay 1, Hernandez sequences RdRP amplicon (881 bp) (GenBank Accession No. OP484885) had 99% nucleotide identity with isolates China (KY781184) USA (OL469153 OL469154). MP (538 (OP484884) shared nt Australian isolate S6 (ON934517) American “Turner” “Wilcox-02” (OM751929 OM751928). NP (786 (OP484883) Chinese KF-1 (KY781186) Wig-WM-D10 (MW559081). Both (Z272 Z273) similar results, therefore only sample Z272 submitted GenBank. results further confirmed by SYBR®-based real-time gene-specific (WCLaV-1FP/WCLaV-1RP) (Adeleke 2022). WCLaV-2 first reported watermelon (Xin 2017), followed America 2021), Brazil (Maeda 2022) Australia (Mulholland 2023). our knowledge, this report globally. mode transmission currently unknown. Studies understand potential vector seed should be conducted aid development best management practices. meantime, growers will have rely keeping pests crop under control, practicing tillage residues, removing weeds routinely general good