California Almonds: Your 6-Item Checklist For The Rest Of June

Almond nuts. ©Sara Savary, AgFax Media

#1. Include regulated deficit irrigation (RDI) in your game plan.

RDI induces moderate water stress in the orchard to reduce Rhizopus hull rot and promote earlier, more even hull split. As my old high school driver ed teacher told us, slow down into turns. The orchard is turning towards harvest as hulls split.

Ease off the “gas” of water and avoid nitrogen into this “turn” to manage hull rot and help hull split be more uniform. See the hull rot/irrigation article in this issue.

#2. Get ready for hull split.

Almonds become vulnerable to NOW feeding/damage once hull split begins. Closely monitor hull split in the upper SW side of Nonpareil (NP) trees on field edges as those exposed nuts usually split ahead of the rest of the orchard.

Depending on your location in the Sacramento Valley and specific orchard conditions, hull split may start as early as late June or as late as mid-July. Consider an edge spray once sound nuts in the edge NP trees reach Stage 2C of hull split (see photo below). The rest of the NP in the orchard should follow in roughly a week.

Depending on the pollinizer(s) used, growers and their PCAs should decide if the first hull split spray (at Stage 2C for NP) should be a full spray or just on the NP. See discussion in the NOW article in this newsletter.

#3. Monitor for mites.

Do so weekly in the orchard’s hot spots. Consider the presence of predators (sixspotted thrips and predator mites) in addition to the presence of spider mites when making treatment decisions.

UC IPM guidelines use treatment thresholds of spider mite presence on 50% of leaves when predators are present, but only 30% of leaves if predators are absent.

#4. Get ahead of ants.

Timely harvest (100% hull split throughout the orchard) means less NOW risk. However, it also means longer drying times on the orchard floor and a higher chance for ant damage – if protein feeding ants are present.

Survey ant colony concentration on the orchard floor 2 to 3 days after irrigation, counting active colonies in five 1,000 square foot areas (roughly a 5 x 6 tree rectangle). Confirm they are the undesirable (protein feeding) pavement or southern fire ants, not the harmless pyramid ants with the aid of these helpful photos.

Estimate potential harvest damage using the table in this ant management article and proceed based on your damage tolerance.

#5. Manage ground squirrels.

Ground squirrels switch from eating green vegetation to seeds and grains in late May. This means that June is the beginning of the window in which they will eat baited rodenticides. Test bait acceptance before use of rodenticide to avoid toxin shyness. For more on ground squirrel management, see groundsquirrelbmp.com.

#6. Closely manage in young trees.

As summer heats up, especially with potted trees, make sure water is wetting the rootzone. Here’s more on dealing with the challenge of irrigating potted trees.




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