Pheromone traps: An effective synthetic female pheromone lure is available for monitoring the 4-5 flights of California red scale. See the California red scale degree day calculations page for San Joaquin Valley flights.
Scale crawler tapes: Double sticky tape is wrapped around one year-old twigs next to female scales. Crawlers emerge from under the females and become stuck on the edge of the tape as they move to the ends of the branch. Each week the tape is replaced and examined for scale crawlers. Crawler emergence is an ideal time for treatment with most insecticides.
Population Sampling: All pheromone trapping and crawler tape monitoring should be followed up with a fruit sample. Walk the orchard at monthly intervals and assess the number of fruit with scales. Recheck the bins of fruit for scale damage during harvest because then you can see the fruit that is in the tops of the trees.