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TNFP0919-tim-hearden-roundup1_BT_Edits.JPG Tim Hearden
A shaker works an almond orchard near Red Bluff, Calif., in 2018. Walnut harvest is beginning in many areas in California.

Roundup: Harvests in full swing as NOW sanitation begins

Almond harvest ongoing; walnut, pistachio shakers get started.

While almond orchards continue harvest operations in the San Joaquin Valley, Sacramento Valley almond producers are getting into full harvest swing. Walnut harvest is also beginning in many areas and pistachio shakers are rolling into orchards as well.

Very early reports on almond yields seem to indicate California producers will exceed USDA’s latest estimate of 2.2 billion pounds this year. For walnuts and pistachio producers, many industry and agricultural economists in California agree it is still too early in the harvest season to accurately estimate final production levels, though USDA estimates walnut production could be down by as much as 7 percent.

Regardless whether yields are better or worse this year compared to last or whether production ends up larger or smaller, the following days and weeks represents the coup de grâce, or final chapter of the 2019 crop year and all hands are on deck. When the shaking, vacuuming and raking end, post-harvest efforts begin including orchard sanitation.

As one orchard producer put it, “this time of year represents the culmination of a long year of hard work.” With so many challenges like changes in the environment, trade issues and marketing obstacles farmers are facing, here’s hoping this harvest season will be a profitable one for California’s dedicated family of nut producers.

A warning about shaking

David Doll, in the Aug 20 issue of The Almond Doctor Newsletter, warns “shaker damage is commonly observed across orchard operations. This damage occurs when the force of the shaker is greater than the strength of the bark, causing it to tear away from the tree. The obvious damage not only impacts tree vigor, but also provides an opportunity for infection by wood canker fungi which can kill the tree. If the shake is properly timed and executed, shaker damage can be greatly reduced (and even eliminated) within an orchard.”

Doll warned that a common misconception is that trees that are kept too wet during the harvest period will be damaged by the harvesting process. But, he says, the facts fail to support this idea.

“Based on the lack of direct effect of moisture status on tree bark strength, it is thought that the damage observed in wet areas of the orchards is most likely due to the delays in ripening. Research has found that decreased water stress (Goldhamer and colleagues, 2006) and high nitrogen status (Saa and colleagues, 2016) both delay ripening. These trees, when shaken at the same time as the rest of the field, are often shaken harder to remove the nuts that aren’t ready to harvest,” Doll noted.

Read the informative issue here.   

A farmer’s work is rarely done

While harvest efforts continue in the orchard, there are plenty of other tasks awaiting in the wings. In a University of California Cooperative Extension (UCCE) article titled “Fall and Winter Management Consideration” published this month with contributions from, in part, Emily Symmes, UCCE IPM Advisor in the Sacramento Valley and Katherine Jarvis-Shean, UCCE Orchard Advisor for Solano and Yolo Counties, early harvest, as possible, can help reduce quality losses due to naval orangeworm (NOW), mold development, and darkening kernel color.

“At harvest, the objective is to shake what you can pick up that same day…(walnut) quality declines most rapidly during the first nine hours after shaking,” they advise.

The advisors also suggest collecting ground samples during harvest which make it easier to distinguish sources of damage in greater detail than is provided on grade sheets. A sampling protocol and damage identification guide is available at:

Post-harvest management

Following harvest operations, the advisors suggest operators should immediately begin orchard cleaning operations.

“Once harvest is complete, ensure that hullers, dryers, and areas surrounding orchards are cleared of nuts that may be harboring moth larvae. Sanitize orchards as part of your NOW management program by shaking/hand poling, blowing berms, and then flail mowing mummies prior to next season. Remember that walnut mummies on the orchard floor (middles and tree rows) provide overwintering survival sites for NOW, so even if you have few mummies remaining in the trees, blowing and destroying mummies on the ground helps reduce carry-over NOW populations,” Symmes noted.

If cover cropping is desired, they should be planted as soon in the fall as sanitation efforts are wrapping up. And if pruning or hedging is planned this year, aim for as early in fall as possible and when weather is forecast to be dry to avoid infection.

Finally, in this issue, according to American Pistachio Growers, researchers at Universitat Rovira i Virgili, Reus, Spain, Institute of Health Pere Virgili, CIBER, discovered that eating just a handful of pistachios as part of their diet can positively affect cellular aging and longevity.

As a result of poor lifestyle choices and eating habits, especially for those with metabolic conditions, researchers say such as prediabetes, the rate of oxidative damage to DNA. Oxidative damage can be caused by unhealthy diets and exposure to tobacco smoke, exhaust fumes, UV from the sun and radiation. Consequently, the damage speeds up cellular aging, health span and telomere loss.

But according to the research, the daily consumption of pistachios can result in decreased DNA damage and the expression of telomere-related genes increased.

For more news on tree nuts as reported by growers and farm advisors, subscribe to the Tree Nut Farm Press e-newsletter.

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