Monday, July 20, 2015

There’s Something Shaky about the Almond Harvest

It is shake and bake time.

That’s right. Field scout Jenna Horine is reporting the first sightings of almond growers shaking nuts off the trees. The fresh almonds will be baking on the ground a few days before being swept up and collected.

It’s not our imagination. The start of the almond harvest has been getting a little earlier and earlier in recent years, thanks to the dry winters we have been experiencing across the Golden “Brown” State the past four years. The almond season has been getting a jumpstart during the drought.

Almond tree shaking is starting to  occur on the  westside.
Jenna says her records indicate the first shaking in the northern San Joaquin Valley took place around July 25 last year. She expects more growers to start knocking nuts off the trees this week.

The early shaking occurred on the westside, which is normally warmer and drier end of the Valley. The soft shell nonpareil variety is the first to develop and be harvested. Commercially, they are the most versatile and widely used almonds because the skins can be easily removed and the smooth kernels “allow for easy, blemish-free processing,” according to the Almond Board of California.
Later in the season, growers will go back into the orchard and shake trees with the hard shell varieties such as the butte and mission. Jenna says the hullsplit is still a ways off for these varieties.

Ending irrigation two weeks before shaking protects trees.
David Doll, the almond expert and pomologist with UC Cooperative Extension in Merced County, reminds growers to stop irrigating about two weeks before harvest to prevent tree damage due to shaking. Damage to the bark is the most common problem from mechanical shaking.
To determine when to start harvest, growers can hit a tree limb to see how easily the nuts come off. Then test shake a few more trees. When 99 percent of the nuts are shaken from the test trees then the time is right to start shaking the entire orchard.

Fallen nuts aren't left too long on the orchard floor.
Mechanical shaking should be started when the interior of the orchard is at about 95 to 99 percent hullsplit. Another factor to determine harvest timing is the need to avoid navel orangeworm damage to the nuts on the tree and ant damage on the ground. The longer the nuts are in the orchard the more likely there will be pest damage.

Usually, the nuts on the ground are hullable within two weeks. Jenna says growers often will remove the nuts from the orchard floor rapidly for pest and disease management purposes.

Meanwhile, Jenna says she has spotted stink bugs in some orchards. Areas near heavily traveled dirt roads are grappling with mites. Overall, though, pest pressures appear under control for growers.

In other crops, field scout Carlos Silva says alfalfa growers should be harvesting again over the next couple weeks. Weevil counts are up in some fields, but still under the threshold to consider treatment. But growers need to keep a close eye on weevils to keep them in check.
Fruit retention has been good in cotton fields.

Cotton plants are developing nicely, averaging about 11 fruiting branches. Fruit retention ranges from 65 to 70 percent. That’s a good rate. Anything below a 55 percent retention rate could be troublesome. Check out UC IPM’s online publication about fruit retention and lygus monitoring.

Carlos points out he is snagging two to four lygus bugs per 50 sweeps of his sweep net, which about half the rate for growers to start considering treatment. Again, a regular monitoring program is important.

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