For most older groves, bud break should be considered as the stage when green tissue is readily visible on the dominant variety. Most growers modify the standard program to best fill their individual needs. The fungicides commonly used to control scab and most other diseases do not control powdery mildew or zonate leafspot. These diseases occur occasionally and require special control measures. Regular scouting can aid a grower in knowing if and when these measures are needed.
Pecan varieties vary greatly in their susceptibility to scab.
Historically, the general trend has been for varieties regarded as scab resistant to become susceptible with the passage of time. Many growers spray varieties believed to be scab resistant much less than varieties known to be scab susceptible. Orchard scouting can inform a grower if the disease control program used on a variety believed to be scab resistant is adequate. Stuart is the leading pecan variety in Georgia. It has been considered more or less scab resistant for many years.