CRS degree day updates 2026

Biofix: March 1, 2026. 

First generation crawler emergence: April 15, 2026

Second generation flight: Expect by May 25, 2026

As of May 17, 2026, Fresno County has accumulated approximately 996 degree days (base 53°F) since the March 1 biofix for California red scale. This indicates that second generation males are expected to begin fligh and continue, as the population DD is close to ~1100 DD threshold for second genration flight. The second generation crawlers is expected near 1650 DD (mid-to late June). Orchards using mating disruption should ensure dispensers are installed before the second flight (~May 25) to ensure effective population suppression. Management should follow UC IPM guidelines, with field-by-field monitoring due to variability in microclimate and pest development across Fresno County orchards.

For more information on DD on previous seasons and 30-year average data, 

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