General outlook & thrips population
As planting wraps up, temperatures remain similar to long-term averages. Thrips population predictions are similar to last week’s update. Generation 2 adults peaked a couple weeks ago; generation three adults are predicted to peak 6/8.
The 3rd and 4th generations are considered to be a good target for sprays to processing tomato, as earlier generations of thrips are less likely to carry the virus and later generations are less likely to cause yield loss. Earlier sprays are recommended if you are in an area with high historic pressure or are currently seeing infections. If you are rotating several materials, this window is a good time to use more expensive but effective products (e.g. Radiant).
UC IPM has published an excellent brochure on recognizing and managing TSWV: https://ipm.ucanr.edu/legacy_assets/PDF/PMG/Tomato_Spotted_Wilt_Print.pdf
Local monitoring
We’re seeing high numbers of thrips on our yellow sticky cards, and I hear similar reports from others. I’m also starting to see some TSWV in more tomato and pepper fields around Yolo County. However, it has been at levels much less than 1%.
As always, feel free to contact me if you have a suspected infection you would like confirmed (Patricia; 530-219-5198)
Thrips caught as part of a monitoring effort funded by the California Tomato Research Institute and the California Pepper Commission. Each bar represents the average number of thrips caught on yellow sticky cards placed for two weeks at the field edge. Cards were collected 4/24 and 5/9. We will continue monitoring until early July.
