A few thoughts from Dr. Lenny Wells on Pecan Scab:
For many growers, this post is stating the obvious, but its just a reminder to not to be caught off guard following our dry weather through June. We are currently in a highly critical period for scab protection. The nuts are sizing very rapidly at the moment and within just a few days of spraying there will be a lot of unprotected tissue exposed. We are having the worst weather possible for this right now with many locations receiving rainfall late each evening, which keeps the nuts wet all night.
This is THE most critical time to protect the nuts from scab. Hopefully, you were able to save some money early by skipping some sprays when the weather was dry and pressure was low. That time is past. Rotating Miravis Top with Ealst/Tin will offer the best scab protection available through the nut sizing period. With the rain we are seeing, you should tighten to 7-10 day spray intervals on susceptible varieties. A surfactant applied with Miravis Top (Group 3 + Group 7 fungicides) or with materials like the Group 3 + Group 11 mixtures can help under these conditions. No surfactant is necessary with Elast because it has surfactant activity itself.