General Situation  After the wet winter and extended cool spring, the annual summer weather pattern finally seems to have established itself. Temperatures for the next 10 days will see daily maximum values in the mid to high 80'sF, reaching the mid 90's by the first few days of June.  Planting has been happening rapidly over the last 2-3 weeks and crops will pull away quickly with settled warm conditions.

Thrips and TSWV We have had a few sporadic thrips detections but no TSWV so far in Fresno county.  There's a wide range of crop growth stages in the main planting areas, from stuff that has only gone in the ground in the last 7-10 days, up to crops that are bushing out well, and flowering is underway.  The low thrips numbers and lack of TSWV is all good, but we are concerned that the late planting times will mean that the pre-flowiering high risk period for TSWV will be extended this year.  We are predicting that Generation 3 adults will peak around June 3 and Generation 4 adults will peak around June 25.  Given the slow start and low leves of TSWV so far, unless there is a local source of TSWV, Generation 4 seems the more likely source for any significant chance for TSWV to spread around, and the more likely to pay off in terms of investment in thrips control.  Contact your local UCCE adviser if you want to discuss options specific to your situation.

Resistance breaking TSWV Remember reistance breaking strains of TSWV are now widespread in the San Joaquin Valley, so varieties carrying the SW-5 resistance won't necessarily stand up on their own without thrips management if there are local sources of TSWV.  At locations with a history of TSWV it's probably better to treat SW-5 varieties the same way as varieties without the resistance gene.