Monitor San Jose Scale—Bloom to Postbloom
The best time to assess the need for managing San Jose scale is during the dormant season. Dormant season is also the preferred timing for spray treatments. However, if a dormant spray was not applied and San Jose scale was a problem in your orchard in the previous season, or if the dormant treatment was not effective, a spray can be applied from late bloom to petal fall.
Use pheromone traps to time bloom treatments. These trap readings do not tell you if treatment is needed, but they help you to time treatment for best control in the spring. Use degree-days and pheromone traps to predict the crawler stage, and use sticky traps to confirm crawler activity.
When the traps begin to catch males consistently, start accumulating degree-days using a 51°F lower threshold and a 90°F upper threshold. If it is needed, apply a treatment for crawlers 600 to 700 DD after you catch the first males. Be aware that the traps may fail to catch any adults if the weather is cold, rainy, or windy.
To monitor for San Jose scale:
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