- Author: Elizabeth E Grafton-Cardwell
Temperatures are finally starting to increase after the cold spell we had in February and the first flight biofix of California red scale occurred roughly the middle of March in the San Joaquin Valley. Degree days above the lower developmental threshold of 53oF are accumulating and have reached about 50 since March 16. When the environment accumulates 550 degree days, the first crawler generation will appear. See our California red scale degree day web site for more details. Remember that every orchard is a little different due to orientation and elevation. To obtain more precise information than our county averages, you should place temperature measuring instruments in your orchards. To learn more about treating for California red scale, see the UC IPM Guidelines for Citrus.