Louis Nottingham and Robert Orpet wrote an article in the February 2021 edition of ‘Tree Fruit News’ reminding growers to start preparing dormant sprays of kaolin clay (Surround) to deter pear psylla colonization in the orchard. A dormant Surround spray will provide the first line of defense to keep psylla from entering your orchard. The optimal time to make this first Surround application depends on weather, but here is a good rule of thumb: if it is warm and dry enough for you to safely spray, go for it – psylla are probably colonizing your orchard!
Orpet and Nottingham article in ‘Fruit Matter’s Newsletter’ about potential for Surround applied in the fall for pear psylla management.
Kaolin clay (Surround WP) is a white sprayable powder that discourages pear psylla from laying eggs on pear trees by creating a physical barrier over the tree’s surface. If sprayed early in the season, the white coating could also deter psylla from colonizing orchards, possibly due to repellency of reflected UV light to insects. Kaolin is more persistent on trees than most insecticides, especially when used with a spreader-sticker (check labels for compatibility and mixing instructions), and it has low risk of harming natural enemies because it is non-toxic.