Pear Psylla Degree Days (updated weekly on Monday)

This page shows the cumulative pear psylla degree-days (DD) calculated by DAS at selected weather station locations across the Pacific North-West as part of the integrated pest management (IPM) program recently developer by the WSU Entomology Pear Extension and Research group at WSU-TFREC in Wenatchee, WA. The map below shows the most recently calculated cumulative DD values at each location.
The DAS calculated pear psylla degree-days, starting on the first week of February, will be available for free to the public for the 2023 season.

    Cashmere.N, WA Hood River, OR Medford, OR Omak, WA Peshastin.N, WA Wapato.W, WA Wenatchee, WA
Jan 30 7 39 105 0 8 12 6
Feb 6 12 47 133 0 11 15 11
Feb 13 21 71 163 0 16 34 21
Feb 20 45 96 181 2 30 63 46
Feb 27 48 99 192 3 31 68 49
Mar 6 53 103 195 4 33 79 56
Mar 13 57 112 226 7 35 93 61
Mar 20 86 149 262 27 54 128 91

Learn more about the newly developed pear psylla management guidelines and phenology model at WSU Extension.
Subscribe to DAS to get daily degree-days values, including estimated forecasts, for any weather locations across Washington, Oregon and Idaho, together with timed management guidelines and spray recommendations throughout the season.