Pear Psylla Degree Days (updated weekly on Friday)
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 | |
---|---|---|---|---|---|---|---|
Feb 3 | 7 | 39 | 120 | 0 | 8 | 12 | 6 |
Feb 10 | 16 | 61 | 152 | 0 | 13 | 25 | 16 |
Feb 17 | 26 | 78 | 169 | 0 | 19 | 43 | 27 |
Feb 24 | 48 | 99 | 186 | 3 | 31 | 66 | 48 |
Mar 3 | 52 | 101 | 194 | 4 | 33 | 77 | 56 |
Mar 10 | 53 | 107 | 205 | 5 | 33 | 83 | 56 |
Mar 17 | 70 | 128 | 243 | 14 | 43 | 108 | 74 |
Mar 24 | 111 | 167 | 280 | 48 | 74 | 152 | 116 |
Mar 31 | 150 | 196 | 301 | 80 | 103 | 182 | 157 |
Apr 7 | 182 | 223 | 337 | 104 | 123 | 219 | 190 |
Apr 14 | 230 | 265 | 397 | 146 | 158 | 272 | 241 |
Apr 21 | 269 | 298 | 444 | 180 | 185 | 313 | 284 |
Apr 28 | 376 | 409 | 573 | 273 | 281 | 424 | 401 |
May 5 | 540 | 527 | 678 | 452 | 432 | 576 | 576 |
May 12 | 664 | 647 | 767 | 567 | 536 | 697 | 712 |
May 19 | 863 | 857 | 961 | 763 | 724 | 915 | 919 |
May 26 | 1024 | 1001 | 1102 | 930 | 874 | 1090 | 1101 |
Jun 2 | 1202 | 1145 | 1250 | 1093 | 1023 | 1260 | 1306 |
Jun 9 | 1401 | 1316 | 1441 | 1289 | 1200 | 1474 | 1524 |
Jun 16 | 1592 | 1479 | 1620 | 1472 | 1371 | 1665 | 1736 |
Jun 23 | 1739 | 1608 | 1756 | 1604 | 1493 | 1805 | 1902 |
Jun 30 | 1962 | 1807 | 1953 | 1816 | 1696 | 2028 | 2142 |
Jul 7 | 2181 | 2020 | 2173 | 2034 | 1906 | 2254 | 2376 |
Jul 14 | 2412 | 2220 | 2384 | 2258 | 2113 | 2491 | 2625 |
Jul 21 | 2642 | 2440 | 2614 | 2485 | 2328 | 2718 | 2873 |
Jul 28 | 2863 | 2641 | 2830 | 2698 | 2523 | 2946 | 3110 |
Aug 4 | 3088 | 2840 | 3047 | 2914 | 2726 | 3155 | 3357 |
Aug 11 | 3308 | 3051 | 3267 | 3135 | 2926 | 3378 | 3598 |
Aug 18 | 3557 | 3292 | 3513 | 3386 | 3161 | 3617 | 3860 |
Aug 25 | 3735 | 3477 | 3720 | 3566 | 3325 | 3801 | 4054 |
Sep 1 | 3936 | 3667 | 3899 | 3764 | 3517 | 4002 | 4264 |
Sep 8 | 4124 | 3827 | 4073 | 3953 | 3690 | 4179 | 4472 |
Sep 15 | 4314 | 4014 | 4264 | 4129 | 3866 | 4368 | 4675 |
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.