Sunday, August 2, 2015

You Might Call It Summer Cleaning for Almond Growers

It’s hard to believe almond orchards across the Valley have gone from buds, to bloom to hullsplit.

For most growers, the time for the final payoff is approaching after enduring another dry winter, an early spring and an unusual summer marked by thunderstorms that brought nearly a half-inch of rain and slightly cooler than normal average high temperatures in July. (OK – a daily average of 95 degrees in July this year vs. the historical average of 98 is still hot.)
Growers are mowing weeds in the orchard margins.
While some growers on the warmer Westside of the Valley already started shaking nuts off their trees, most farmers elsewhere have been busy the past week doing final preparations for harvest, reports field scout Jenna Horine.

“Everyone is getting their orchards ready before harvest,” she says. The prep work varies from farm to farm.

Some orchards get final pre-harvest water.
Some growers are giving their trees one final drink of water – which means shaking will come one to four weeks later. As we mentioned earlier, growers need to let the ground firm up to prevent tree damage during mechanical shaking.

Other growers are cleaning up the orchard floor, getting rid of weeds, leaves and other orchard trash to make it easier to sweep up the fallen nuts from the ground. Jenna points out it’s too late to treat for ants. In general, you need treat for ants several weeks before harvest, she says.
Prepping the floor is important before harvest.

UC IPM says prepping the orchard floor before harvest “is important in an almond IPM program. Rapid and efficient nut pick-up after tree shaking reduces the time the nuts are exposed to pests such as ants”

 “Rapid pick-up and hulling or on-farm fumigations, prevents damage by navel orangeworm and peach twig borer. The ground should be smooth, dry, and free of weeds, ants, trash and other debris. Orchards that are regularly cultivated should be disked to break up clods and then rolled to make the surface smooth and firm,” UC IPM says.

In addition, UC says growers should take these steps before harvest:
  • Flail-mow weeds growing in between the trees close to the ground so that they will sufficiently decompose before harvest.
  • Make sure your last preharvest irrigation takes place 1 to 4 weeks before harvest, depending on the soil texture and depth.
  • Collect shaken nuts immediately after ground drying.
On the pest front, mites have been under control so far, Jenna says. Some orchards continue to have stink bugs around. Jenna talked to some growers about the problem. They’ll have to deal with these pests after harvest to avoid problems next season.

Meanwhile, Jenna can validate predictions of a smaller harvest due to the drought.

Kernels expect to be smaller because of the drougt.
The Almond Board of California forecasts production at 1.8 billion meat pounds, down 3.3 percent from 1.867 billion pounds in 2014. The yield comes even though nuts will be harvested from 890,000 bearing acres across the state, up from the record high of 880,000 predicted by the National Agricultural Statistics Service last year.

Jenna is seeing this first-hand. “The kernels are smaller across the board,” says Jenna, who routinely snatches a nut and cuts it open for a closer inspection during her scouting rounds. “You can’t have a record breaking harvest in a drought.”
We’ll second that.

Monday, July 27, 2015

Controlling Aphids Can Be a Sticky Issue for Growers

This time of year cotton fields start turning the corner from a sea of pink, yellow and white flowers to an ocean of lush green bolls. 
Here is a close-up photo of aphids. -- UC IPM Photo

Lurking in the background, though, are pests that can damage the crop and inflict economic pain. Field scout Carlos Silva reports cotton aphids are taking center stage on the pest front right now in a number of fields, particularly in the Firebaugh region of Fresno County.

About of third of the cotton plant leaves he has inspected are infested with aphids. “Growers are starting to think about how they may need to get rid of the pest,” Carlos says.

Aphids can be found throughout the season and cause different kinds of problems during the growth stage of the cotton plant. During the spring, heavy aphid populations can cause leaves to crinkle and stunt seedling growth.
Aphids are found on the back of a cotton plant leaf.

Carlos says growers need to be vigilant with their monitoring programs. UC IPM says it’s important for growers to be aware of both the number of aphids and the color of the pests. Small yellow aphids develop slowly from nymphs to adults and don’t produce many offspring. As a result, their populations don’t increase quickly. On the other hand, darker green and black aphids reproduce rapidly and their populations can explode.

Natural enemies such as parasitic wasps, minute pirate bugs, bigeyed bugs and green lacewings can help control aphids. “There are a lot of green lacewings in the fields,” Carlos says.

Honeydew residue creates a sheen on a cotton plant leaf.
However natural enemies won’t be enough to tackle a heavy aphid infestation. But chemical treatment isn’t a simple solution. Here’s what UC IPM says:
“Chemical management of cotton aphid can be extremely erratic and unpredictable. Part of the problem is that cotton aphid has developed resistance to many chemical classes, including organochlorine, organophosphate, carbamate, and pyrethroid insecticides. In addition, these broad-spectrum pesticides kill the natural enemies of the cotton aphid. Another resistance concern is with the neo-nicotinoid insecticides. Repeated applications of any neonicotinoids can result in resistance to all neo-nicotinoids.”

Parasitic wasps can help control aphids.  -- UC IPM photo
“To manage resistance, follow the basic principles of IPM: (1) spray only when pests reach economic thresholds; (2) start with the most selective pesticides and avoid pyrethroids early in the season in order to preserve natural enemies; (3) save the broad-spectrum pesticides for mid- to late-season aphid outbreaks; and (4) rotate insecticides that have a different mode of action group number if you have to spray more than once.” Go online to UC IPM’s cotton aphid management site to see a table that summaries insecticide resistance guidelines.

Overall, cotton development is progressing well. Growers are irrigating their fields for the third time this season. The plants are at about 12 to 13 fruiting branches.

In alfalfa, growers are preparing for another harvest. So far, it appears many growers have enough water available for another cutting.
Carlos reminds growers to continue leaving strips of uncut alfalfa to create a habitat for lygus bugs and keep them migrating to nearby cotton fields. “There still is a lot of lygus in the alfalfa fields,” he notes.

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.

Monday, July 13, 2015

Dusty Roads Might Stir Up Mite Trouble for Almond Trees

Every year, we talk about dusty roads and spider mites, especially during the hot summer months.

Kicking up dust will stir up mite populations.

These pests will reproduce quickly in hot weather and are most populous from June to September. Dusty conditions can trigger outbreaks.

To help control mites, growers should “apply water to pathways and other dusty areas at regular intervals,” UC IPM says. “Water- stressed trees and plants are less tolerant of spider mite damage. Be sure to provide adequate irrigation.”

Mites feed tree leaves and can lead to defoliation in the most severe situations. Major mite damage can cause a loss in yield.

Example of a web spinning mite issue.
Of course, keeping dust down on roads and providing trees and plants with enough water becomes a little problematic – and costly – for farmers during a severe drought. But growers have little choice because watering down roads and watering crops is matter of economic survival.

Field scout Jenna Horine sees out water trucks out regularly sprinkling H2O agua on dirt roads around melon fields bordering almond orchards. The melon harvest is in full swing, which means lots of trucks running in and out of the fields.

“It’s important to keep the dust down,” Jenna says. The recent heat wave was driving up mite numbers in the almond orchards. However, Jenna notes that most growers have applied miticides in their hullsplit treatments. That has kept mites under control for now.

Check beneficial populations before treatment.
Of  course, non-chemical, biological ways are effective in controlling mites too. UC IPM advisors point out growers could hold back on second miticide applications to give beneficial insects a chance to build their population to knock down mites. Under this approach, growers have to be comfortable enough to tolerate some amount of leaf damage to give beneficials enough time to gobble up the mite population. Yes, it’s a good practice to check on the beneficial insect population in the orchard before deciding to spray.

Cotton plants, too, can suffer mite damage – in which leaves turn yellow or red and then drop. This condition could hamper development of cotton squares and bolls, causing them to fall to the ground. Whole plants can become defoliated. Early plant and fruit development are when mites become the biggest threat.
Cotton fields are receiving the second irrigation of the season.

Field scout Carlos At the moment, Silva says lygus bugs have been in check in most fields. Plant development – around 10 to 11 fruiting branches – and fruit retention is good.
“Everything is growing quickly,” Carlos says, pointing out cotton plants are getting their second helping of irrigation water this season.

Field Day AlertDon't forget the summer Alfalfa Field Day on Wednesday from 10 a.m. to 12:30 p.m. at Bowles Farming at the intersection of Hereford Road and Bisignani Road in Los Banos. The speakers are UC IPM advisor Dr. Pete Goodell on insect management; UCCE Davis alfalfa extension specialist Dr. Dan Putman on current issues, including weeds, water quality and availability and summer retirement of alfalfa fields; Merced County Deputy Agricultural Commissioner Sean Runyon on an update of chlorpyrifos regulations; and Cannon Michael of Bowles Farming. Continuing education credits for farmers and PCAs, including 30 minutes of regulations, will be available. For more information contact Marcia Gibbs at (530) 370-5325 or