Lindcove Research and Extension Center
University of California
Lindcove Research and Extension Center

California Red Scale Degree Days

California red scale Degree Days

Pheromone traps are used to monitor California red scale (CRS) male flight activity. Following the biofix (first male flight) degree days (DD) are used to predict when the crawler emergence or when next generation flight takes place. Degree days for CRS are heat units accumulated above the lower developmental threshold (LDT) of CRS.

LDT for California red scale = 53 F

Degree days from Biofix to crawler emergence = 550 DD

Degree days for the second generation flight = 1100 DD

Degree Days for the second generation crawler = 1650 DD

Degree days for the 3rd generation flight = 2200 DD

Degree days for the third generation crawler = 2750 DD. 

Higher average daily temperatures mean faster accumulation of degree days, hence faster development of insects. 

This page updates current degree days for Kern, Tulare, Fresno, and Madera counties. 


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