Phytoparasitica (1998) 26, 165-166

Edna Tanne, Sigalit Orenstein, I. Sela, Tirza Zehavi and M. Klein (1998)
Epidemiology of grapevine yellows disease in Israel
Phytoparasitica 26 (2), 165-166
19th Congress of the Israeli Phytopathological Society, February 16-17, 1997, Bet Dagan, Israel, lecture
Abstract: Grapevines exhibiting yellows-resembling symptoms were observed on the Golan Heights, for the first time, about 7 years ago, in cv. 'Chardonnay'. The disease causes decline of the plants and has a severe impact on the quality and quantity of the yield of some varieties. The severe infection of the sensitive Chardonnay resulted in discontinuing its planting on the Golan Heights. Yellows diseases are caused by phytoplasmas (formerly called mycoplasma-like organisms, MLOs), which are now diagnosed mainly by molecular methods such as hybridization with a DNA probe or polymerase chain reaction (PCR). These organisms are present in the phloem tissue of plants and in insects which transmit the MLOs. Grapevine yellows disease spread in Israel in recent years to all viticultural areas of the country, and to various other varieties, including Chardonnay, 'Cabernet Sauvignon', 'Sauvignon Blanc', 'Merlot', 'Carignan' and 'French Colombard'. Phytoplasmas have also been detected in several rootstocks which were grafted with infected scions. PCR tests which were carried out with tissue originating from symptomatic and asymptomatic grapevines confirmed that phytoplasmas are associated with yellows diseased grapevines. Two different types of phytoplasma have been identified in grapevines in Israel using nested PCR, either as single or double infection. Transmission of the causative agent from grapevines to periwinkle by grafting was successful, resulting in the true-to-type transmission of the phytoplasma involved. Experiments to identify possible vectors were carried out in the north and center of the country. Yellow sticky traps were set up in different vineyards and suction traps were also used. In both geographical regions a leafhopper (Neoaliturus fenestratus) and a planthopper (Hyalestes obsolatus) were trapped. Molecular tests demonstrated the presence of phytoplasma in the insects; these insects are suspected as possible vectors of grapevine yellows in Israel. Efforts to prevent the spread of the disease in the vineyards included the use of pesticides to control insects. Application of Confidor (imidacloprid) to a vineyard on the Golan for three successive years did not prevent the spread of disease. In laboratory experiments the leafhopper Empoasca could survive for 7 h on a grapevine treated with Confidor. Experiments to use resistant rootstocks and various agrotechnical measures to control the disease are conducted.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
transmission/dispersal of plant diseases

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Neoaliturus fenestratus	Grapevine (Vitis)	Israel