CRS degree day updates 2026
Biofix: March 1, 2026
First gen crawler emergence: April 12, 2026
Second generation flight: May 15, 2026
Third generation flight: July 5, 2026
Third generation crawlers: July 26, 2026
Fourth flight (anticipated): August 11, 2026
As of July 26, 2026, Tulare County has accumulated approximately 2936 degree days (base 53°F) since the March 1 biofix for California red scale. indicating that third generation crawlers have already emerged, around ~2750 DD threshold. This year's third flights comes ~2-3 weeks earlier than previous seasons, strongly indicating that the fourth generation flight ~3300 DD will be prior it it has ever been, initiating on August 11. Fourth generation flights are indicator for how the population has stayed this season and prepare for the next season. PCAs can put out traps to monitor for the 4th flight. Fifth flight is expected by October first week. Management should be based on confirmed field presence rather than degree days alone; if CRS are detected on fruit, a well-timed treatment targeting this stage is warranted, following UC IPM guidelines, with emphasis on good coverage and resistance management.
Fourth flight can be expected to emerge as early as first week of August, with fourth generation crawler hatch following soon after expeted by 8/21. A fifth generation is likely to complete this season if weather remains favorable through October for CRS.
For more information on previous seasons DD and 30 year average.
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Individual field conditions may vary. Monitor Individual fields. For treatment recommendations UCIPM Guidelines for citrus