General outlook  A week of 100+ F daily maximum temperatures and warm nights will give thrips development a boost over the next week.  A gradual return to mid 90's highs is expected by the second week of June.  The current mini heat wave won't be enough to cause any significant mortality in thrips.  Degree day accumulation for thrips this season is about two days behind last year and roughly 6 days ahead of the 30-year normal.

Population projections Generation 3 post winter adults peaked in the last day or so.  Generation 4 adults are currently projected to peak around June 19th.  These two generations are the first that are likely to have significant levels of TSWV in them, so any plans to apply insecticide specifically to control thrips and suppress TSWV should be scheduled sometime in soon.  We've seen some TSWV already in a few areas.  Levels are generally low (below 1%), but there are a couple of hot spots that show there has been some early secondary spread of the virus within the crop. Secondary spread would be indicated by seeing short runs of two or three plants with symptoms clustered together. Under these circumstances treatment to suppress further spread is recommended. If you are not seeing any signs of TSWV in your area you may want to consider delaying treatment and re-assessing the situation for generation 5.  If you want further advice on management options for your situation please contact your UCCE advisor.

We are now finding SW-5 resistance breaking strains routinely in Fresno and Kings counties.  These strains are now the dominant type in this region and relying on SW-5 resistance to avoid TSWV damage is not recommended.  SW-5 varieties that have other favorable agronomic characteristics can still be used as part of an IPM approach for disease control.

Please report any unusual virus-like symptoms to your local UCCE adviser.  In addition to TSWV there are a number of other viruses that might show up in tomato.  Most of these will have minimal effects on yield in processing crops, but we are always on the look out for reports of viruses to help get a complete picture of what's happening across the region.