First record of watermelon crinkle leaf-associated virus 2 in Italy
Two recent articles report the first detections of watermelon crinkle leaf-associated viruses in Campania region (southern Italy). Watermelon crinkle leaf-associated virus 2 (Coguvirus henanense, WCLaV-2 – EPPO Alert List) was found in the field (Parella, 2025) and in commercial seeds, and watermelon crinkle leaf-associated virus 1 (WCLaV-1, Coguvirus citrulli– EPPO Alert List) was found in commercial seeds (Minutolo et al., 2024).
WCLaV-2 was first found in 2023 in Italy, on watermelon (Citrullus lanatus, cv. Samba) in a commercial field (about 4000 m2) in Eboli (Salerno province, Campania region, southern Italy). Foliar symptoms were observed on 100% of watermelon plants in this field, and included curling, wrinkling, yellow mottling and chlorosis. Certain watermelon fruits showed circular lesions and deformations. WCLaV-2 was identified through high-throughput sequencing and confirmed by RT-PCR.
This is the first record of WCLaV-2 in Italy, as well as in the EPPO region. Until then, this virus had been recorded only from China (Henan), and in a few states in the USA and Brazil.
The situation of WCLaV-2 in Italy can be described as: Present, restricted distribution (one field).
During the development of a RT-PCR test to detect coguviruses at the genus level, commercial seeds of various plant species bought in 2023 in several garden centres in Campania region (southern Italy) were grown to seedlings in pots in a greenhouse. Pooled leaf samples were tested by RT-PCR to detect the presence of coguviruses, and such samples from watermelon seedlings gave a positive result. Further tests were conducted to identify virus species and assess their prevalence in the positive seed lots. For watermelon, coguviruses were detected from 7 out of 16 seedlings of cv. Crimson Sweet (43.7 %) tested, 11 out of 19 (57.8 %) of cv. Sugar Baby, and 6 out of 13 (46.1 %) of cv. Tonda F1. No symptoms were observed on the seedlings, but the authors note that the young developmental stage is possibly not conducive to symptoms development. Further sequencing confirmed the presence of in the seeds of WCLaV-1 (cvs. Crimson Sweet and Sugar Baby) and WCLaV-2 (cv. Tonda F1).
Note from the EPPO Secretariat. WCLaV-1 has not been reported in the field in Italy to date. The origin of commercial watermelon seed found infected by WCLaV-1 in the present study is not known, and therefore the virus is not considered present in Italy in EPPO Global Database.
Sources
Parrella G (2025) First record of watermelon crinkle leaf-associated virus 2 infecting watermelon in open field in Italy. Plant Disease (early view). https://doi.org/10.1094/PDIS-02-25-0245-PDN
Minutolo M, Nicoloso V, Cinque M, Chiumenti M, Di Rauso Simeone G, Di Serio F, Alioto D, Navarro B (2024) A polyvalent tool for detecting Coguviruses in multiple hosts allowed the identification of a novel seed-transmitted coguvirus infecting Brassicaceae. Phytopathology 114, 823-831.