University of California
The California Backyard Orchard
California red scale takes flight
The first flight of male California red scale was detected the week of March 14 in Tulare County. My web site provides degree day calculations (both current and 30 year averages) for projecting when the 1st generation of crawlers will appear. http://ucanr.org/sites/KACCitrusEntomology/Home/California_Red_Scale/Degree_Days_885/
Of course, monitoring your own orchards with pheromone traps, crawler tapes and/or temperature units is more accurate.