Selecting Tomatoes for Disease Resistance

By Carla Resnick, Butte County Master Gardener, April 25, 2014

Having healthy plants will go far toward good tomato crops.  Choose from tomato varieties that have been developed for disease resistance.  Tomatoes are susceptible to several disorders that can significantly diminish yield or even destroy an entire tomato crop, but many hybrid tomato varieties are resistant to them.  The disease identification codes (shown below) are usually marked on the plant label or seed packet following the tomato's cultivar name.

• A     Alternaria stem canker
• F     Fusarium wilt
• FF   Fusarium races 1 and 2
• FFF  Fusarium races 1, 2 and 3
• N     Nematodes
• T     Tobacco mosaic virus (TMV)
• St    Stemphylium gray leaf spot
• V     Verticillium wilt

Using this code system, it can easily be determined that a tomato type marked VFNT is resistant to Verticillium, Fusarium, nematodes, and TMV.  Note that “resistance” is not equivalent to “immunity.”  In areas where these problems have occurred in the past, even disease-resistant varieties may encounter some difficulty attaining full growth and production.  For that reason, it is recommended that home gardeners follow a crop rotation schedule and avoid planting tomatoes or other members of the nightshade (Solanaceae) family in the same location more than two years consecutively.

For further information, see University of California Agriculture and Natural Resources (UC ANR) Publication 8159:  “Growing Tomatoes in the Home Garden.”

http://anrcatalog.ucdavis.edu/pdf/8159.pdf