How to Manage Pests

UC Pest Management Guidelines


Big Vein

Pathogen: Mirafiori lettuce virus

(Reviewed 4/17, updated 4/17)

In this Guideline:

Symptoms AND SIGNS

Big vein disease causes the veins in leaves to become very enlarged and clear. Such deformities are easily seen if the leaf is examined with the light source behind it. The enlarged veins cause the rest of the leaf to be ruffled and malformed. Severely affected plants can be so deformed that they are unmarketable. Head lettuce varieties may even fail to form a head. However, infected plants showing less severe symptoms can still be harvested.

Comments on the Disease

The virus that causes big vein is soilborne and is introduced into lettuce plants by a soil fungus (Olpidium brassicae) that attaches itself to lettuce roots. Even though the virus is soilborne and therefore always present in infested fields, disease severity may vary greatly from season to season. Big vein is more prevalent and severe during cool spring weather.


Cultural Control

In fields having chronic and severe big vein histories, avoid planting susceptible cultivars during spring. Some big vein resistant cultivars are now available. Crop rotations are not effective in controlling big vein. No other control options are suggested.

Organically Acceptable Methods

Use cultural controls in an organically certified crop.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Lettuce
UC ANR Publication 3450


S. T. Koike, UC Cooperative Extension, Monterey County
T. Turini, UC Cooperative Extension, Fresno County

Acknowledgment for contributions to Diseases:
R. M. Davis, Plant Pathology, UC Davis

Top of page

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2017 The Regents of the University of California. All rights reserved.

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 our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   Contact webmaster.