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California Almonds: A Big Crop Begins Splitting – AgFax

June 27, 2020June 27, 2020
By Owen Taylor and Jenny Holtermann

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Here is this week’s issue of AgFax Tree Crops.
Our thanks to BASF and its California team for sponsoring this coverage.
Got questions or comments? Let us know.

Owen Taylor, Editor

Jenny Holtermann, Contributing Editor

OVERVIEW

Almond hull split is upon us, and the first sprays will start over the next week. Edge sprays have been going out in places.

After a run of mild weather, a hotter pattern continues, with triple-digit highs expected through much of our coverage area.

With more heat, people in the field expect pest populations to build. Miticides will likely go into plenty of tanks as hull split sprays start up.

This will be a big almond crop, which presents its own set of challenges. Growers have already spent plenty of time and money propping up branches that were weighted down by a heavy nut load. Harvest also will take longer because more nuts will be on the ground, and those delays will give ants more time to damage almonds. See related comments by Kris Tollerup.

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CROP REPORTS

Franz Niederholzer, UC Farm Advisor, Colusa, Sutter and Yuba Counties

“Almond hull split is closing in on us fast. Edge trees on the south side of Nickels Soils Lab orchards show splits beginning on blank nuts and on sound nuts in a few weak trees.

“We’ll spray outside borders as early as this weekend. We’ll check both outside nuts on orchard edge trees and tree top nuts within the orchard, then decide whether to spray the whole orchard or make another edge application.

“A number of small blocks and some unsprayed trees are in the vicinity of the lab, and we’re finding more NOW damage than I’d like to see, despite a mating disruption program all season in all blocks. Last year, we generally detected lower damage in the blocks where we went with NOW mating disruption and higher levels in the blocks without it.

“Air-blast sprayers began making applications on edges in the Arbuckle area this week. That area, which is west of Interstate 5, has a rockier soil type, and both bloom and hull split historically start there first compared to the rest of the North State.

“One experienced PCA expects most growers to start their first hull split sprays in the first week of July, and a miticide will probably be included in many hull split sprays. But if trees are still pretty clean, mite-wise, some growers may wait until later in the hull split window to apply a miticide.

“Using a March 13 biofix, the NOW degree-day accumulation at Nickels reached 1050 last weekend, meaning the second-generation flight should have begun. We noted a slight uptick in egg trap counts late last week.

“Walnuts are progressing well, and this looks to be a good crop. Sunscreen applications go on as nuts get heavier and the temperatures warrant sunburn reduction.

“Fruit bins are starting to go out in cling peach orchards along the Feather River growing region, and harvest will begin soon in the early varieties.”

Tony Touma, PCA, Bio Ag Consulting, Bakersfield

“All almond growers have their hull split spray recommendations. They are buying material and getting ready for the applications. Within the last two days, we have started to see edges and borders of fields begin to split. With an early bloom this year, we anticipated hull split to lean on the early side, but we are running 4 to 5 days behind where we thought we would be.

“We simply didn’t get the heat days we expect earlier in May and June. Due to lower almond prices, a few growers told me they will only apply one hull split spray this year. “Insect pressure tends to be lower when stretched over the large almond crop we are expecting . If any pests flare up, we suggest two hull split sprays. Growers will begin their hull split sprays around 1% to 5% splits.

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“Most growers also will include a miticide. Mites have started showing up in the last week as temperatures increased.

“In the last few weeks, stink bugs and leaffooted bugs have still been around. The numbers remain low, but they haven’t gone away all season. Rust didn’t seem to advance after the spray early in the season. Alternaria is increasing daily, and growers with a history of disease pressure will include a fungicide in the hull split spray.

“Growers continue to irrigate and are finishing their ant bait spreading.

“Pistachios remain healthy in our area. A few blocks have mealybug showing up again behind a spray. We had to come back with an additional spray in areas with historical mealybug issues.

“Alfalfa has been mostly clean this season. We have not seen aphid or worm issues so far this year. We did deal with a lygus infestation in cotton three weeks ago and had to spray a couple of times. The large migration did go away, and we were able to control the damage. Fields look clean now.”

Doug Elrich, PCA, Big Valley Ag, Gridley

“Hull split is approaching next week. A few splits are turning up here and there in stressed areas. We expect hull split to begin in our area around July 4, although a lot can change in the coming week.

“We continue to monitor mites. Populations have been building the last couple of weeks with the higher temperatures. This year, mites were slow to start, and those cooler temperature swings allowed beneficials to keep spider mites in check.

“Growers will likely include a miticide with the hull split spray. About 75% of my growers haven’t applied a miticide this season, so adding one to the hull split spray will be needed to make it through the rest of the season.

“Growers applied fungicides with the last rains in May. Disease pressure remains low, and we haven’t seen any flare-ups since then. Growers are spraying weeds and mowing as they prepare orchards for harvest.

“With this high heat, walnut growers are applying sunscreen on their orchards. With certain varieties like Hartley, leaves provide minimal shade for the nuts, so they’re particularly exposed to the sun.

“We caught a few codling moths last week, enough to set a biofix for the 2A flight. This week, the trap counts jumped significantly compared to last week’s numbers. Growers have been spraying for codling moths and including a miticide, and most added a fungicide for botryosphaeria.

“Fertilizer applications continue as growers feed a large crop. We have been monitoring husk fly traps for three weeks and have hardly caught any, but we expect to find more in hot spot areas over the next couple of weeks as temperatures rise. We’re still monitoring navel orangeworm in walnuts to track their life cycle.

Almonds in early split.
Photo: ©2020 Jenny Holtermann

“With this high heat, irrigation is critical. Tomorrow (6/26) will be the hottest day this week, with 104 in the forecast. Over the weekend, we will dip into the low 90s, then head into triple digits again.”

Kris E. Tollerup, IPM Cooperative Extension Advisor, Kearney AREC, Parlier

“Almond hull split is gearing up, and growers are preparing for hull split sprays. Continue to monitor mites.

“In cases where processors reported black spot damage in the past, we suspect that this was caused by late feeding by leaffooted bugs. The most serious cases appear along riparian areas. Leaffooted bugs try to feed on the nut in the late season, although they can’t get through the hull. But they leave a black stain on the pellicle, the brown skin of the almond.

“This year, ant damage could be a more important factor than usual. This is a big crop, estimated at 3 billion pounds. With the large crop, it will take longer to harvest, so almonds might remain on orchard floors longer than usual, which means prolonged exposure to ants. Their damage, in turn, can cause quality downgrades, something processors stress.

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“With that in mind, be diligent with ant management. If you’re stockpiling nuts on-farm, closely monitor for ant activity in areas surrounding stockpiles as well as the edges of the piles.”

Aaron Beene, PCA, Simplot Grower Solutions, Merced

“In almonds, we are starting to see blanks splitting along the edges of the orchards, and I suspect more will show up next week. A week after the blanks split, the true nuts will start to split, and growers are looking to start hull split spraying around July 6 to July 8.

“Navel orangeworm and peach twig borer trap counts are beginning to increase with this heat. However, egg counts on traps will decrease over the next couple of weeks as adults begin to lay on split nuts.

“The majority of our blocks are clean in terms of disease. Because it wasn’t raining after petal fall, some growers decided they wouldn’t make that fungicide application at 2 to 5 weeks post-petal fall. Now, heavy rust and scab are developing in those orchards.

“This has been a low mite year for our area. However, as soon as growers begin deficit irrigation after hull split, we could see that change, and growers will add a miticide to their hull split sprays as a precaution.

“This year, weeds are in a heavy growth pattern from the cool spring, and we could see an uptick in mite pressure due to the climate the vegetation builds in these areas. Weeds are growing swiftly, causing growers to hit hard with weed spraying. Growers are knocking down the initial growth now and returning once more before harvest to clean the orchard floors.

“Ant populations are increasing rapidly. The majority of growers made an ant bait application three weeks ago, but orchards will require an additional round of ant bait before harvest.

“We are starting to take tissue samples to ensure a good handle on nutrient status. With the high yields projected this year, we don’t want growers to fall behind on nutrients.

“Growers are fully irrigating to maintain adequate moisture in the soil profile. They anticipate that when hull split starts, they’ll cut back on irrigation, and we want the profiles filled by then.”

Nick Groenenberg, Independent PCA, Hanford

“We are closely monitoring for hull split. You can find just a few blanks beginning to split. Select growers are doing a few border sprays where needed. With these high temperatures, we expected more splits by now, but that hasn’t pushed the almonds to that point yet.

“Growers plan to start hull split sprays towards the end of next week at the earliest, but the following week will more likely be when most make their first applications. Last year, hull split sprays began around July 10, but we look to be a couple of days off that.

“Growers see little disease pressure yet. No significant mite issues have developed, either, although that can change as temperatures rise.

“In pistachio, we’re monitoring for navel orangeworm. Most fields have mating disruption puffers, and we will hold off spraying until 2200 degree days and skip the one timed for 1700. That would put the application in the third or fourth week of July.

“Scouting continues for mealybug in pistachios. The next generation hasn’t had time to cycle through yet. Growers sprayed towards the end of May, and some fields will likely need another application.

“Growers are applying herbicides where needed and are still fertilizing. Nut fill will begin in July and the trees will need another round of nitrogen then.

“ Tomato harvest will begin at the earliest near July 6, with more growers closer starting on July 10. In alfalfa and tomatoes, worm pressure has been light this year. Corn is growing well and is receiving a mite spray where needed.”