CRS degree day updates 2026
Biofix: March 1, 2026; First generation crawler emergence: April 19, 2026; Second generation flight: May 24, 2026; Second geneation crawlers: 21 June; Third generation flight: 19 July
Third generation crawlers (anticipated): August 5.
As of July 26, 2026, Fresno County has accumulated approximately 2581 degree days (base 53°F) since the March 1 biofix for California red scale. This indicates that third generation flight has happened, and third generation crawlers will start emerging soon as the population DD is close to ~2750 DD. A fourth generation flight is expected near 3300 DD (mid-to late August). PCAs should plan to place the traps for fourth generation flight (as early as second week of August). If CRS is present on fruit, 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