Virus surveys of lettuce crops and management of lettuce bigvein disease in New Zealand

Abstract

Virus surveys of lettuce crops over the past three seasons have confirmed that a number of virus diseases can threaten production Lettuce bigvein disease (LBVD) caused by Mirafiori lettuce bigvein virus (MLBVV) usually in combination with Lettuce bigvein virus (LBVV) was the most widespread virus disease of lettuce over the survey period Other viruses present include Lettuce necrotic yellows virus (LNYV) Beet western yellows virus (BWYV) Cucumber mosaic virus (CMV) and Lettuce mosaic virus (LMV) The surveys have not detected Tomato spotted wilt virus (TSWV) or Tobacco necrosis virus (TNV) Control of Olpidium brassicae the fungal vector of LBVD is an important factor in disease management This paper outlines survey results and describes experiments using fungicides to control this disease