November Prune Orchard Management Considerations

Clarissa Reyes, North Sacramento Valley Orchard System Staff Research Associate

Please note that the following are general recommendations intended to help you keep track of regular practices in a busy time; the optimal timing for management practices may vary based on specific location and conditions.

  • Plant new trees: Protect trees from sunburn and herbicides with white interior latex paint diluted 2:1 water to paint, plus tree wraps. If tree wraps are used without painting trees, the boxes should be flattened (◊ from the top, not □) to avoid “wrapper burn.” Research in almonds shows that white paint, alone, doesn’t protect young tree trunks from herbicide damage.
  • Irrigation: Check irrigation system for uniform distribution to prepare for heat or frost protection during bloom.
  • Weeds: Survey for weeds after the first rain to identify perennials, germinating winter annuals, and summer species that escaped the past season’s control tactics to inform next year’s control strategies. UC IPM provides a printable weed survey form (PDF).
  • Gophers: Manage gophers when populations are at their lowest. Trapping, fumigation and baiting can all be effectively utilized when soil is moist.
  • Potassium: Band potassium (K) in the soil, based on July leaf sample results, visual symptoms, and the amount of fruit harvested this year.
  • Pest Management: Sample dormant spurs to determine pest management needs for aphids, mites, and scale pests.
    • Aphid: If you have a history of aphid infestations, assume you have an annual problem and treat aphids between fall and leaf out.
    • San Jose Scale: Treat with oil, or for moderate to high infestations, oil with insect growth regulator (Centaur®, SeizeTM). Check with your PCA about using oil if the trees and/or soil are dry to avoid oil burn damage, especially to young shoots.
    • Peach Twig Borer (PTB): PTB can infect prunes. Dormant sprays of oil plus spinetoram (Delegate®), spinosad (EntrustTM, SuccessTM) or diflubenzuron (Dimilin®) will kill overwintering larvae without causing water quality issues—oil alone does not control peach twig borer. Managing PTB is part of a fruit brown rot control program as skin damage from worm feeding provides an avenue for disease infection
  • Cytospora: Prune to remove Cytospora and to manage next year’s crop:
    • Remove existing cytospora cankers and spore sources by cutting branches several inches to a foot below the symptoms and burn prunings (if permitted).
    • Consider your management goals: topping young vigorous trees before a big wind can reduce risk of blow-over, while long pruning can increase early yields in young prune plantings.
    • Prune early in the fall to allow cuts to harden off before seasonal rains. Protect fresh wounds from water-borne spores with a fungicide spray (Topsin-M® or Topsin-M® + Rally®).
  • Orchard Sanitation: Sanitize your orchard by removing fruit mummies and blighted shoots to remove disease inoculum. Remove bark damaged during harvest, and backhoe out diseased or dead trees to prepare for replants.

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