San Jose Scale

I have seen some pretty impressive infestations of overwintering San Jose scale this spring. These infestations re-emphasize the importance of putting on a dormant oil spray each spring, as scales are one of the pests controlled by that application. SJS overwinters as an immature and is now at the point of maturing. Shortly after, they will mate and the females will begin giving birth to live young, known as crawlers. Other than a dormant oil spray, the crawler stage is the one we want to target for control. If you have overwintering scales, you can monitor for crawlers by wrapping a piece of black electrical tape around a branch near the overwintering scales with the sticky side out. When the crawlers become active, they will move around to look for a good place to settle down and feed and can be captured in the tape. Catching crawlers this way will signal you that the timing is right for an insecticide spray. See page 22 of the Midwest Fruit Pest Management Guide for insecticides recommended for scale control.