New romaine lettuce lines launched
Tuesday, January 18, 2011 - 11:34
in Biology & Nature
California and Arizona, the two largest lettuce-producing states, account for more than 95% of the lettuce grown in the United States. Since the early 1990s, the states' lettuce crops have been subject to "dieback", a disease indicated by symptoms including mottling, yellowing, and death of older leaves, and stunting and eventual death of lettuce plants. Dieback disease, caused by two soil-borne viruses, affects romaine and leaf-type lettuce, often leading to crop loss of 60% or more. Most disturbing is the news that the virus is not effectively reduced using either chemical treatment or rotation with nonhost crops, and the virus can live on in infested soil.