Welcome to the web resource for integrated management of Western Flower Thrips and Tomato Spotted Wilt Virus in the California Central Valley.
The site contains two tools to help in disease risk management: There is a Field Risk Index tool which uses simple information about field locations, land use, and agronomy to calculate a risk category for tomato crops. This tool can be used before planting or early in the season to get a heads up about the general risk to a crop from TSWV.
The second tool is a thrips population projection model. This is driven by degree-day accumulation at several locations in in the Central Valley and lets us make projections about the time when thrips generations are hatching, developing, and adult numbers are peaking. We use this information to issue regular updates and provide broad guidelines for timing insecticide sprays to keep thrips numbers low enough to prevent TSWV from spreading.
The research behind these tools was supported by the California Tomato Research Institute (CTRI), the California Pepper Commission (Calpepper), and the California Leafy Greens Research Board (Calgreens).
Thrips projection areas in California
As the season progresses we will update the map with information on thrips and TSWV levels. The risk is low in northern counties and for peppers in the Gilroy/Holister area. In Fresno Co and northern Kings Co TSWV has been reported and there is evidence of infection by resistance breaking strains. In these areas the risk level is high. In remaining areas the risk level is now moderate. Read the updates for specific areas for more information or contact your local UCCE adviser.