Degree Day Calculations
Biofix: 1st male flight
Lower Developmental Threshold: 55oF (12.9oC)
Degree-Days to Complete a Generation: Every 580 degree days (F), citrus peelminer completes a generation. There are 7 potential flights in the San Joaquin Valley and 9 potential flights in the Coachella valley. Since the synthetic pheromone is not very attractive, we use the traps to find the first male flight biofix, and then calculate the timing of additional flights just by tracking intervals of 580 degree days.
In the San Joaquin Valley, the first two flights attack stone fruits and willows. The third flight attacks pummelos and grapefruit. It is not until the fourth flight that they begin to attack susceptible orange varieties. Hot summer temperatures tend to stop development of the peelminer in the summertime. See ANR Publication 8321: Citrus Leafminer and Citrus Peelminer for more detail.