Katherine Jarvis-Shean, UCCE Orchard Advisor, Sacramento, Solano and Yolo Counties
Timely harvest is important for nut quality. Delaying harvest can darken pellicles, and encourage mold development and navel orangeworm. Walnut color quality decreases most rapidly in the first nine hours, so try to pick up the same day that nuts are shaken.
Collect a representative IPM evaluation sample from across each orchard block at harvest to assess your IPM program. Grade sheets won’t always give the detail necessary to decipher the source of damage and what needs to be changed to improve an IPM program. Compare what you see with photos and descriptions here.