Watermelon chlorotic stunt begomovirus: addition to the EPPO Alert List
Watermelon chlorotic stunt begomovirus was first reported in 1986 from Yemen on watermelon (Citrullus lanatus) crops. Symptoms are characterized by yellow veins, chlorotic mottling, severe stunting of young leaves, and drastically reduced fruit yield. The disease occurred wherever watermelon was grown and incidence of up to 90-100 % was reported. It was showed that Bemisia tabaci (EPPO A2 quarantine pest) biotype B can transmit the virus. Between 1993 and 1996, severe outbreaks caused by watermelon chlorotic stunt begomovirus were reported in the cucurbit-growing regions of Central and Eastern Sudan on watermelons and melons (Cucumis melo). Additional field observations carried out in Sudan from 1995 to 1997 confirmed that watermelon chlorotic stunt begomovirus causes considerable losses in commercial melon crops. A similar situation was observed in southern provinces of Iran (Bushehr, Hormouzgan, Sistan-Balouchistan). The genomes of two isolates of watermelon chlorotic stunt begomovirus from Sudan and Iran were cloned and sequenced. These geographically distant isolates from Africa and the Near East shared a very high overall sequence similarity and their capsid proteins were identical. It is felt that considering the wide distribution of watermelon chlorotic stunt begomovirus throughout the Near East and the established populations of B. tabaci in the Mediterranean Basin, particular attention should be given to this virus.
Watermelon chlorotic stunt begomovirus
Why: This virus came to our attention because it causes a serious disease of cucurbits in Iran, Sudan and Yemen.
Where: Africa: Sudan. Asia: Iran, Yemen.
On which plants: Watermelons (Citrullus lanatus), melons (Cucumis melo). It can also be found on: snake cucumber (Cucumis melo var. flexuosus), Cucurbita moschata, wild cucurbits: Citrullus colocynthis and Cucumis melo var. agrestis.
Damage: Symptoms are characterized by yellow veins, chlorotic mottling, severe stunting of young leaves, and drastically reduced fruit yield. High disease incidence (up to 100%) and severe losses are reported in countries where the disease is present.
Transmission: Bemisia tabaci biotype B.
Pathway: Infected cucurbit plants for planting, fruits?, viruliferous B. tabaci from countries where watermelon chlorotic stunt begomovirus occurs.
Possible risks: Cucurbits are important crops in the EPPO region. Melons and watermelons are particularly important for southern Europe. The insect vector B. tabaci is widespread.
EPPO RS 2000/159
Panel review date - Entry date 2000-10
Bedford, I.D.; Briddon, R.W.; Jones, P.; Alkaff, N.; Markham, P.G. (1994) Differentiation of three whitefly-transmitted geminiviruses from the Republic of Yemen. European Journal of Plant Pathology, 100(3-4), 243-257.
Dafalla, G.A.; Lecoq, H.; Kheyr-Pour, A.; Gronenborn, B. (1994) Disease and pest outbreaks. Sudan. A whitefly-transmitted geminivirus associated with yellowing disease of watermelons in Sudan. Arab and Near East Plant Protection Newsletter, no. 19, p 39.
Kheyr-Pour, A.; Bananej, K.; Dafalla, G.A.; Caciagli, P.; Noris, E.; Ahoonmanesh, A.; Lecoq, H.; Gronenborn, B. (2000) Watermelon chlorotic stunt virus from the Sudan and Iran: sequence comparisons and identification of a whitefly-transmission determinant. Phytopathology, 90(6), 629-635.