Dr. Lenny Wells edits and updates the Pecan Spray Guide every year and it is a great resource. It has insects in pecans and control measures including thresholds to know when to spray. Pecan disease control including the latest chemicals labeled. Commercial pecan weed control options and timing. Overall an excellent publication and you can download here. 2020 Commercial Pecan Spray Guide
Dr. Charles Graham with the Noble Research Institute was speaking about Pecan Diseases at the Comanche County Pecan Meeting in De Leon, Texas recently. It was a good presentation and as always Dr. Graham is a wealth of information.
BUT, he made one observation that I had never heard. ELAST (Dodine) Fungicide from Arysta LifeScience can control pecan scab overwintering on pecan bark. This is from some PhD research about Pecan Scab control on pecan bark.
Your first zinc spray should include a fungicide because they are effective early and usually inexpensive, but based on this research ELAST may be the right choice.