First Report of Cucurbit Aphid-borne Yellows Luteovirus in Lebanon

Recently, Lecoq et al (1992) reported a new yellowing disease of cucurbits in France caused by cucurbit aphid-borne yellows luteovirus (CABYV) (1). Yellowing of older leaves of cucurbits has been observed in Lebanon for the past few years. Transmission tests showed that the disease incitant could be transmitted by Aphis gossypii in a persistent, circulative manner from muskmelon plants (Cucumis melo) to cucumber (C. sativus), muskmelon (C. melo), and squash (Cucurbita pepo) plants. Extracts from these plants reacted positively in enzyme-linked immunosorbent assays (ELISAs) with an antiserum prepared to a French isolate of CABYV. Surveys conducted in 1995 and 1996 showed that CABYV was widely distributed in the major cucurbit-growing areas along the Lebanese coast from north to south, and in the Beqaa plain. It was detected year round, alone or in mixed infections with mosaic-inducing viruses. The highest frequencies were recorded between May and October. CABYV and zucchini yellow mosaic potyvirus (ZYMV) were the most commonly detected viruses in outdoor cucurbits, including squash, cucumber, and melon. However, in protected cultivations (plastic tunnels), only a small proportion of cucumber plants showing similar yellowing symptoms reacted positively with CABYV antiserum in ELISAs, suggesting another cause to account for these symptoms. Reference: (1) H. Lecoq et al. Plant Pathol. 41:479, 1992.