July 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.

July Orchard Management Considerations

  • After 2 weeks of RDI beginning at early hull split, return the orchard to full ET irrigation until dry down for harvest.
  • Take leaf samples in July to measure nutrient status. Pull leaves from non-bearing spurs on representative trees across a block from one variety per sample. With differing croploads between varieties, nutrient levels may vary by variety and sampling each variety in a block should provide important information. Adjust your nutrient management plan for the rest of the season based on July leaf sample results.
  • Keep tracking NOW and PTB populations. If hull split didn’t occur in June, consider an edge spray once sound nuts in the edge Nonpareil (NP) trees reach Stage 2C of hull split (see photo below). Hull split in the rest of NP in the orchard should follow in roughly a week. Depending on the pollenizer(s) used, growers and their PCAs should decide if the first hull split spray (when 1% of nuts are at Stage 2C for NP) should be a full spray or just targeting NP. See discussion in the NOW article in this newsletter.
  • Spray a second hull split spray ahead of Nonpareil harvest if trap counts, current field checks, and/or past damage suggest a need.
  • Keep an eye on mites. Late season flare ups are expensive to control and hard to schedule by ground. Defoliation of mite damaged leaves at harvest can mean reduced flower numbers next year and slower nut drying on the orchard floor this year.
  • Preharvest interval (PHI) is based on shake date, not pickup date.
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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