Gene Miyao, UCCE Farm Advisor for processing tomatoes in the Sacramento Valley, said he has seen at least a few occurrences of Race 3 Fusarium wilt in processing tomato fields this year.

While most popular canning tomato varieties have resistance to Race 1 and Race 2 Fusarium wilt, few have resistance to the newer Race 3, and those that do are not commercially popular, Miyao said. Fusarium wilt pathogens are long-lived in the soil and often remain when growers rotate back to tomatoes after two or three years.

“It is very important growers know how to recognize this soil-borne pathogen,” he said. “They also need to be aware of the problem where it exists so that in succeeding years they can think about whether the severity warrants switching to an R3 resistant variety that might not be as productive or familiar to the grower or processor.”

There are no management or control measures for Fusarium wilt. Growers should take care not to potentially spread the pathogen from one infected field to another. This is becoming more a problem as larger growers transfer cultivating and harvesting equipment from one field to another across a broad geographical area.

Larger growers farming multiple areas and custom harvest operations must be especially diligent about spreading the pathogen across a broad region, Miyao said.