Get Cracking on a Second Look at Harvested Almonds

You can’t beat second opinions.

 That’s what field scout Jenna Mayfield offers every fall when she spends countless hours cracking hundreds of almond samples plucked from orchard floors at harvest time.

We call it crack-out.

Yes, this task calls for Jenna to meticulously crackone nut at a time as the pile of shells pile up.

She then carefully inspects each one, making a few notes from time to time. Jenna is looking for signs of pest damage to the kernels. These pests include navel orangeworm, ants and peach twig borer. The information is then passed along to almond growers participating in the San Joaquin Sustainable Farming Project.  Growers then can check the results against the grade sheetreceived from the huller.

Jenna lays out the almonds before cracking..

Ant damage to kernel. (UC IPM photos)

“It’s good for growers to have both reports. It’s like having a second opinion,” Jenna says.

For growers, it’s a good practice to inspect nut samples taken from the late summer harvest. This helps them map out pest management activities for the next season.

Navel orangeworm damage.

At harvest time, Jenna collects about 200 nuts from each variety in each orchard that she scouts during the season. She takes samples from three different blocks, usually where pest traps are placed during the season. The nuts are stored in a freezer and later taken out for crack-out in the fall.

Damage caused by peach twig borer.

By examining the kernel, you can determine what kind of pest damage you have, UC IPM advisors say. “Peach twig borer and navel orangeworm often infest the same nut, but navel orangeworm bores into the nut and peach twig borer does not. Therefore, navel orangeworm feeding masks that of peach twig borer,” according to UC IPM.

Here’s what to look for:

·         Naveloranageworm: Deep chewing into nut.

·         Ants: Scraping or peeling of kernel skin, deep hollowing of nut, "sawdust" present.

·         Shallow channels and surface grooves on the kernels

Jenna says her samples aren’t showing a lot of damage. “Everyone did a good job of pest management.” So far, she’s inspected more than half of her 5,000 samples. 

If the trend continues with the rest of Jenna’s crack-out, that will bode well on the pest front for growers next season.