Thrips/TSWV Fresno
Article

Projections for early season high risk period

General situation After a dry and warmer weekend, the weather will return to a slightly cooler, unsettled pattern next week, with temperatures in the mid-to-high 70's and slight chance of  rain showers on several days.  This pattern will prolong the slow start to the season, with thrips developing relatively slowly at the forecast temperatures.  We have projected thrips development out to the end of June, based on current conditions. This takes in the first four generations of thrips and covers the period we would typically think of as the most critical for controlling thrips numbers.  Because we are projecting ahead by two to three months, based on relatively cool early season conditions, we can expect the projected dates for generations to peak to vary by a few days as we settle in to the summer season.

Specific details Generation 2 adults probably peaked a few days ago but a few will still be emerging.  Since there are no significant sources of TSWV this early in the season, thrips are not a risk at the moment.  We are expecting to see Generation 3 adult numbers peak around May 30th with Generation 4 peaking around June 22nd.  Given the slow start to the season, at this stage we would expect Generation 4 to be the key generation to target to suppress TSWV until the pre-flowering high risk period is past.  We will be actively monitoring the TSWV situation and will be posting updates, especially if anything happens to change our current advice.