Early symptoms of turnip mosaic include numerous, small, light green, circular and irregular lesions on leaves. Later symptoms include curvature of the midrib and asymmetrical distortion of the leaf blade. Lettuce infected early may be stunted. The disease is occasionally lethal.

COMMENTS ON THE DISEASE

Turnip mosaic susceptibility in lettuce is restricted to crisphead lettuce types with downy mildew progenies derived from P.I. 91532. Transmission is by many species of aphids in a nonpersistent manner. The virus is not seed transmitted. The virus has a wide host range in 20 plant families and is especially common in crucifers.

MANAGEMENT

Crisphead varieties such as Climax, Great Lakes, Merit, or Vanguard are resistant. Butterhead, leaf, or Romaine lettuce types are all resistant.

PUBLICATION

UC IPM Pest Management Guidelines: Lettuce
UC ANR Publication 3450
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
R. M. Davis, Plant Pathology, UC Davis

Top of page

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/r441101811.html revised: November 17, 2009. Contact webmaster.