2026 5th Report—

Warm temperatures over the past week have accelerated thrips generations slightly from last update. The fourth generation will be hatching soon. This is a good window to spray, particularly in more recently planted fields and if you are seeing active spread.  After fruits have begun to ripen and vine growth has slowed, additional infections will likely not affect yields. 

Field observations 

We have been seeing many more thrips over the past few weeks, especially in fields near Cache Creek west of I-505. I’ve also been getting reports of TSWV in Yolo and Colusa tomato fields. In the pepper and tomato fields we are monitoring near Cache Creek, we have also seen more TSWV infections . In general, there seems to be more TSWV in 2026 than I have seen for the past two years. However, I have not yet seen any fields approaching the levels we observed in some fields in 2023. 

Image

Figure 1. Yellow sticky card outside a pepper field bordering Cache Creek. Cards placed near flowering mustard appear to have especially large thrips numbers. 

If you see TSWV symptoms spreading rapidly in a field, or would like a diagnosis confirmed, please contact Patricia Lazicki (palazicki@ucanr.edu; cell (530) 219-5198