August Orchard Management Considerations

Franz Niederholzer, UCCE Orchard Advisor, Colusa, Sutter and Yuba Cos.
Katherine Jarvis-Shean, UCCE Orchard Advisor Yolo, Solano, & Sacramento Cos.
Luke Milliron, UCCE Orchard Advisor, Butte, Glenn and Tehama Cos.

August Orchard Management Considerations

  • Shake your Nonpareil when all nuts in the tree are at least at Stage 2C hull split (see photo below). This will reduce NOW damage as the female moths lay virtually no eggs on nuts on the orchard floor. Train shaker operators to clamp closer to the scaffold crotch, where possible, versus lower on the trunk. This delivers the best shake to the canopy and limits root damage.
  • Watch for rust in young orchards. Prevent early defoliation that can negatively affect flower bud formation for next year and delay nut drying. For more, see here.
  • Plan ahead to minimize dust at harvest. Consider steps like adjusting sweeper head heights, blower spout angles and fan speed. Find more suggestions here.
  • If you’re harvesting third or fourth leaf trees, keep an extra close eye on the shaker and its operator (walk behind the machine for a few rows on a regular basis). Bark slips easily in young trees and is an entry point for canker infections, considerably shortening the productive life of an orchard.
  • At harvest, collect nut samples for damage analysis. Gather at least 100 nuts per orchard after shaking, but before sweeping. Checking these samples immediately after Nonpareil harvest can inform NOW spray decisions for pollenizer varieties. If not checked immediately, freeze them for later. These samples will allow you to better understand damage results on your grade sheets and adapt IPM strategies for next year. Check out sampling and pest damage diagnosis help, including a handy damage comparison table with helpful photos.
  • Collect and submit hull samples at harvest for B analysis. Pull dry hulls randomly from windrows across a block. .
  • Manage post-harvest irrigation to minimize water stress. Water stress in late August to early October can interfere with flower bud development for the following spring. This can mean fewer flowers next February and fewer nuts next harvest. Defoliation reduces tree vigor by reducing sugar production. This is particularly important for orchards with a long window between harvest of Nonpareil and late pollenizers.
  • Assess hull rot and shaker damage post-harvest. Hull rot symptoms can be found here.
Stage 2C of hull split. When sound nuts in the SW corner of tree tops look like this, this is THE critical timing for insecticide for navel orangeworm and fungicide for Rhizopus hull rot. When all the trees in the orchard have all the nuts that look at least like this from top to bottom, the orchard should be ready to harvest.

Stage 2C of hull split. When sound nuts in the SW corner of tree tops look like this, this is THE critical timing for insecticide for navel orangeworm and fungicide for Rhizopus hull rot. When all the trees in the orchard have all the nuts that look at least like this from top to bottom, the orchard should be ready to harvest.

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