Seeing where you’re at with scale management is important for Walnut growers this time of year and one common monitoring practice needs to start being done earlier than normal.
Scale treatments don’t need to be made every season which makes monitoring for populations even more important. March is a good time for growers to make delay dormant applications in Walnut orchards but many wait until crawlers emerge to see how much pressure there actually is. Area Integrated Pest Management Advisor Emily Symmes says monitoring for crawlers is effective but the practice might need to be done earlier to get a true representation of scale populations.
Symmes says tape tapes might also be a good idea every year to see how your scale management system is working.
More on tape traps
From the UC IPM website: Transparent double-sided sticky tape can be used to effectively time a foliar insecticide application. During the spring before crawlers begin to emerge, tightly encircle each of several scale-infested twigs or branches with transparent tape that is sticky on both sides, available at fabric or craft stores. Double over the loose end of the tape several times to make it easier to remove. Place a tag or flagging near each tape so you can readily find it. Change the tapes at weekly intervals. After removing the old tape, wrap the twig at the same location with fresh tape. Preserve the old sticky tapes by sandwiching them between a sheet of white paper and clear plastic. Label the tapes with the date, location, and host plant from which they were collected. Read more from the UC IPM website.