California Almonds: Here’s Your Post-Harvest Checklist

Photo: Almond Board of California

Post-harvest orchard clean-up/monitoring

Survey orchard for mummy nuts.

If more than 2 nuts per tree remain, plan to knock off and destroy mummies by February 1st to reduce navel orangeworm. Nuts stuck to the tree well after harvest may indicate hull rot or excessive boron. If hull rot is indicated, make a note to revise/reevaluate irrigation and nitrogen management practices in May and/or June to help manage hull rot next year. If you’d like more information on symptoms and signs of hull rot visit: ucanr.edu/agriculture/almond/hull-rot/

Prune out damaged branches,

Remember: avoid pruning immediately prior to rainfall event. This is especially true in young orchards. Disease spores are spread in rain events and pruning wounds are a key entry-point for these infections. Recent research has found that Topsin-M is a highly effective pruning wound protectant against several canker pathogens including Cytospora and Botryosphaeriaceae (“Bot”)

Scout for weeds after the first fall rains.

Look for late summer weeds that escaped this year’s control and winter annual weeds that are just emerging. UC IPM has a late fall weed survey form (ipm.ucanr.edu/PMG/C003/almond-fallweed.pdf) that can help. The UC Weed ID Tool (weedid.wisc.edu/ca/weedid.php) may also help. See article in this newsletter for more information.

Winter weed control.

Pre-emergence herbicide (combined with a post-emergence burn-down material, if winter weeds have already germinated) should be applied shortly before a moderate rain event (0.25”) to move material into the soil. Avoid application prior to a large rain event (> 1”), which can move the product too deep into the soil for good weed control. Avoid spraying root/trunk sucker leaves with any spray containing systemic herbicides such as glyphosate (Roundup, etc.), since those herbicides can enter the tree and cause damage next

Pest & Disease

Sanitize your orchard, if needed.

If you find more than 2 mummy nuts/tree when doing the mummy survey mentioned above, sanitize your orchard by shaking all trees/all varieties later in the fall or winter to get mummies out of the trees. If shaking doesn’t get mummy numbers down to 2 nuts per tree or less, use a hand crew (polling crew) to get to the mummy target you are using. [In the central and southern San Joaquin Valley where NOW pressure is very high, the target is 1 mummy for every 5 trees.] This is a critical step to managing worms next year in your orchard.

Check mummy infestation.

Once the mummies are on the ground, check 20 per block for live The higher the number, the more the pressure should be next year. The % infested mummy number is part of the information you and your PCA will need to help keep damage as low as possible next year.

Check dormant spurs

Check for scale, mite eggs and scab sometime between mid-November and mid- January. For more information on sampling visit: ucanr.edu/PMG/r3900211.html.

Watch for shot hole fruiting structures in leaf lesions.

Do this after fall rains begin. If fruiting structures producing spores are present in leaf lesions in the fall, there is a greater risk of shot hole development the following spring. A foliar zinc sulfate nutritional spray applied in early November may hasten leaf fall and reduce shot hole inoculum. For more information on shot hole symptoms and signs visit: ucanr.edu/PMG/r3100211.html.

Nutrition

Consider a fall nutrient spray.

Both boron (B) and zinc (Zn) can be absorbed into leaves and translocated within almond trees. Check hull sample B results and July Zn leaf levels to help determine if a foliar spray of either or both nutrients is needed.

Consider planting a cover crop.

The objectives include improving soil, providin pollen to bees, and/or reducing  runoff. Get it in the ground by the end of October for best stand establishment. Here’s information on cover crop seed selection.

Apply banded potassium to the soil if that’s in your plan.

For every 1,000 lbs of almond kernels harvested there are 80 lbs of potassium removed from the orchard or captured in new growth. For more information, see the article in this


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