General situation After a slow, late start to the season, summer has finally arrived and is staying. Northern counties will see temperatures building over the next few days and settling into an extended period with 100+ highs. All that heat will really accelerate thrips development and increase their activity.
Thrips generations and TSWV We have extended the population projection out to September 1. It looks as though generation 4 adults probably peaked a few days ago. Generation 5 adults should peak around July 26, with generation 6 following in mid August. Based on recent scouting, thrips numbers have been low until now, but TSWV is relatively easy to find in crops across the northern counties, albeit at relatively low incidence. Testing of samples has shown that the strains of the virus now present in the region are all resistance-breaking strains, so varieties with the SW-5 gene will need protection in situations where thrips pressure is high.
In normal seasons most of the crop would be far enough along that our main concern would be generation 4, but there are quite a few late-planted fields and generations 5 and 6 could bring in TSWV before these crops are big enough to shrug off virus strikes. Late-planted crops might require additional protection this year, particularly in locations with a history of TSWV damage.