- Author: Neil McRoberts
General situation Thrips numbers have increased rapidly in the southern arm of the Central Valley and TSWV has been reported in all of the areas we monitor. The current risk in western San Joaquin county is lower than in other southern counties , but we think a precautionary approach is best. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.
If you are planning to use an insecticide program against thrips/TSWV this season, you should target the next generation of thrips (generation 3). If it is not possible to arrange for treatment in time to catch generation 3, target generation 4. Delaying treatment until later in the season will be much less effective at preventing damage from TSWV. Coordinated spraying across large areas has an additional effect on thrips populations because it makes it difficult for them to avoid treatment by migrating.
Generation 3 adults are projected to peak on May 28th. Sprays applied in the 14 day period before this peak date will check generation 3 and delay further population build-up and TSWV spread.
Generation 4 adults are projected to peak on June 22nd. Sprays applied in the 14 day period before this peak date will check generation 4 and delay further population build up and TSWV spread.