Australian grapevine yellows – Source, spread and control

In investigating the source and spread of AGY, none of more than 12,000 cuttings tested, transmitted disease. Surveys of >130 Chardonnay and Riesling vineyards and 50,000 Riverland, Riverina and Sunraysia vines showed levels of AGY ranged from 1-88% incidence with disease gradients found across vineyards near AGY-hot spots and wasteland vegetation where a native bluebush, ruby saltbush and climbing saltbush, tested PCR-positive for AGY. These are probably the primary hosts of disease. Intensive leafhopper trapping studies indicated that the green jassid and the common-brown leafhopper are prime candidate vectors. The prospects for further investigation are good.