TSWV Field Risk Index and Thrips Projections

Stanislaus

April 14, 2026 update

General background: Just like last year, we are a little slow getting off the mark with our updates this year. 

Thrips development: The first post winter generation adults peaked around March 11th (about 2 weeks earlier than 2025).  Peak egg hatch for generation 2 peaked around March 25th. Generation 2 adults peaked around April 10th.  Based on current development rates and projected temperatures, the third generation of adults should peak around May 18th. Unless there is evidence of TSWV in crops already, it is unlikely that treatment for thrips will be useful at this time until the third generation at the earliest.