May 25 Update
Weather outlook: After further atypical cool, showery weather over the last week or so, the forecast for the next ten days shows a more settled period of dry weather with partial cloud cover and daytime highs gradually increasing towards 90F. Thrips population development can be expected to be steady over this period.
Thrips population timings: In our last update on 4/16 we projected Generation 3 adults to peak on June 5th and Generation 4 to peak on June 29th. Despite the period of cool weather projections for eastern San Joaquin county have remained more or less unchanged: Generation 3 is projected to peak on June 5th (as before) and Generation 4 on June 30th (one day later than last update). We are still not hearing reports of any TSWV in the area, and together with the delay in thrips development, the overall risk level in the upper San Joaquin Valley is low. Depending on crop development stage we recommend targeting either Generation 3 or Generation 4 for any intended thrips treatments. Later planted crops may still be at early, vulnerable growth stages as Generations 3 and 4 emerge; stay on top of the situation and check in with your UCCE adviser to find out if TSWV is being reported as the season progresses.