CRS degree day updates 2026

Biofix: March 1, 2026. 

As of April 24, 2026, Tulare County has accumulated approximately 738 degree days (base 53°F) since the March 1 biofix for California red scale. This indicates that first-generation crawlers are actively emerging and will continue over the coming period, as the population has passed the ~550 DD threshold for crawler emergence. This is a critical management window, as crawlers represent the most susceptible stage for control. Orchards should be closely monitored for white caps and crawler activity using regular scouting and tape traps, with treatment decisions based on confirmed field presence rather than degree days alone. The second male flight is expected around 1100 DD (~late May), with second-generation crawler emergence near 1650 DD (~early summer). For orchards using mating disruption, dispensers should be in place before the second flight (~May 25) to ensure effective suppression. All management decisions should follow UC IPM guidelines, with careful field-by-field monitoring due to variability in local conditions.

For more information on previous seasons DD and 30 year average, click here. 

Individual field conditions may vary. Monitor Individual fields. For treatment recommendations UCIPM Guidelines for citrus