Water Management Crucial Before Almond Harvest

Water, water and more water.

That’s what field scout Jenna Mayfield sees in almond orchards throughout the Valley.

In fact, Jenna hasn’t stepped into many orchards lately because of the wet and muddy conditions.

Almond orchards are getting the last irrigation before harvest.

“Growers are doing a lot of work to prepare for hull split,” she says, pointing out that the start of harvest is just about a month away. “A lot of people are going to start managing their watering.”

Yes, timing the last pre-harvest irrigation is important, according to David Doll, University of California Cooperative Extension adviser and pomologist for Merced County. Of course, Dollis better known as the Almond Doctor among local farmers.

He points out that growers first need to set a target harvest date before mapping out their final watering schedule. The last irrigation should end about two weeks before the start of harvest activities to allow “dry down” of the trees to minimize bark damage from shaking. Also, trees could be damaged at the roots if the ground is too wet during shaking.

One thing to note is the dry down period depends on the type of soil in the orchard. Sand requires less time for the soil to dry out while clay needs more time.

Proper "dry out" of soil can avoid tree damage during shaking.

The reason is sandy soil has a lower water holding capacity. In that case, growers might need to irrigate between harvesting the different varieties in the orchard. In his Almond Doctor blog, Doll explains “proper water management between varieties is just as critical as water management before harvest because during this period the tree is developing the fruit bud for the coming season. Any moderate to severe water stress during this period will reduce the formation of fruit bud.”

When determining the harvest timing, growers should consider:

·         The need to avoid damage from ants or navel orangeworm.

·         The ability to remove the most nuts and maintain yield and quality.

·         Keeping tree damage at a minimum

·         Access to harvesting equipment

Growers should watch for spider mites.

 On the pest front, Jenna says the biggest worry is spider mites due to the heat wave. The pests have been dormant so far, but everyone is bracing for a potential outbreak.

The hot weather continues to drive up lygus populations in cotton fields. Field scout Damien Jelen has snagged as many as 9 to 12 lygus bugs per 50 passes of his sweep net – more than twice the treatment threshold for this time of year.

One grower already has treated for lygus. Damien says growers will continue to closely monitor for lygus – as well as the hot weather.

Prolonged Heat Wave Can Really Bug Valley's Crops

Summer is still two days away. But we’re certainly sending off spring with a bang.

It’s HOT, HOT, HOT in the Valley.

The sizzling temperatures we weathered over the weekend are predicted to continue throughout the week, reaching as high as 110 degrees. A week of triple-digit temperatures means things are getting quite buggy for crops, including almonds, alfalfa and cotton.

“Lygus is exploding,” alfalfa and cotton field scout Damien Jelen says.

As we mentioned last week, lygus bugs are a major threat to cotton. They can cause damage from early squaring through cutout and final boll set. The pest will pierce the squares and damage the tissue, eventually causing them to drop. If too many squares drop, the cotton plant will experience too much vegetative growth leading to tall spindly plants and a reduced yield.

Lygus bug damage in cotton. (University of Georgia photo)

In one cotton field, for example, Damien caught nine lygus after 50 passes of his sweep net. That’s not good because the treatment threshold through the end of this month is two lygus per 50 sweeps. The grower is going to have to closely monitor that field and make some hard decisions if the population densities remain high.

Cotton is in an important development period right now.  UC IPM notes: “Success in retaining early squares will greatly determine the final yield; therefore protecting cotton during the early square formation period (June) is critical. Protection during the early season is very complex. Factors such as lygus bug numbers, high susceptibility of cotton, and variability in sampling require the grower to be extremely vigilant and ready to act at an instant.”

If you want to read up on the topic, go to UC IPM online to learn about lygus pest management in cotton. Damien will continue to update us about the state of lygus in our fields.

Almond growers are adding lots of water due to the heat.

Meanwhile, almond field scout Jenna Mayfield reports the growers are keeping their orchards well hydrated. “Everyone is putting on a lot of water. They don’t want to stress the trees.”

Well-irrigated orchards are important for guarding against spider mites, which are a threat for almonds through August.  Mites flourish in warm weather and will hit water-stressed orchards.

“The conditions are ripe for mites,” Jenna says. She reminds growers dusty conditions can trigger mite outbreaks.  So it’s important to water down access roads and watch driving speeds to control dust, she says.

 

FIELD DAY: Don’t forget Tuesday’s  field day featuring alfalfa pest management tips and an update on pesticide regulatory issues. Sponsored by the San Joaquin Sustainable Farming Project, the free event will be  from 10 a.m. to 12:30 p.m. at Los 3 Pancho Restaurant, 2031 Blossom Street.  Merced County Assistant Agricultural Commissioner Yvette Pellman and Dr. Pete Goodell of UC IPM are the featured speakers. Growers will learn about non-fumigant VOC regulations, chlorphyrifos and worker protection as well as integrating multiple approaches to managing pests in alfalfa. The field day has been approved for continuing education credits. For more information, contact SJSFP Director Marcia Gibbs at (530) 5325 or Marcia@sustainablecotton.org

Don’t Leave Lygus Homeless: Build Them a ‘Home’ in Alfalfa

Alfalfa fields are starting to get another fresh cut.

Field scout Damien Jelen reports some alfalfa growers started to harvest their alfalfa field last week and others will follow suit this week. During his scouting rounds, he found an increase in beet armyworms and plenty of lygus bugs. In one alfalfa field, for example, he counted 40 lygus bugs per 50 passes of his sweep net.

Lgyus bugs abound in alfalfa this year.

You might recall UC IPM extension advisor Dr. Pete Goodell indicated early this spring he anticipated a big year for lygus populations because of the wet winter.

With the first squares emerging on cotton plants across the Valley, it’s time for farmers to start worrying about lygus invading their cotton fields. 

Alfalfa is a favorite habit for lygus. It’s time to remind alfalfa growers about the importance of leaving strips of uncut alfalfa in the fields, especially when there is cotton growing nearby. The strips will serve a habitat for lygus to stay in and keep them from fleeing to a cotton field, which is not their preferred home.

An uncut strip of alfalfa provides a habitat for lygus bugs.

Damien says growers seem to be getting that message. “I’ve seen growers leaving the strips out there.”

UC IPM points out that lygus bugs are a threat to cotton from the earliest squaring through final boll set. The pests pierce squares, which can shrivel, turn brown and drop to the ground. Losing too many squares will trigger vegetative growth in the plants and end up reducing yields.

Here are tips from UC IPM about strip cutting alfalfa for lygus management:

• Maintain nearby alfalfa fields in a fresh condition.
• Avoid cutting all alfalfa fields in an area within a short time period. Leave an uncut strip along the border between alfalfa and cotton to slow lygus migration.
• If lygus populations get very high, uncut strips of alfalfa may be treated with an insecticide if needed, but sprays should be avoided where possible to protect beneficial insects.

This practice should be followed for alfalfa fields that are within a two mile radius of a cotton.

 FIELD DAY: Speaking of alfalfa, we are spreading the word about a field day featuring alfalfa pest management tips and an update on pesticide regulatory issues. Sponsored by the San Joaquin Sustainable Farming Project, the free event will be Tuesday, June 20 from 10 a.m. to 12:30 p.m. at Los 3 Pancho Restaurant, 2031 Blossom Street.  Merced County Assistant Agricultural Commissioner Yvette Pellman and Dr. Pete Goodell of UC IPM are the featured speakers. Growers will learn about non-fumigant VOC regulations, chlorphyrifos and worker protection as well as integrating multiple approaches to pest management in alfalfa.  The field day has been approved for continuing education credits. For more information, contact SJSFP Director Marcia Gibbs at (530) 5325 or Marcia@sustainablecotton.org

It’s Time to Stomp Out Almond Pests Before They Flourish

Oh my, time sure does fly by.

It’s hard to believe growers will start harvesting almonds next month.  It’s even harder to believe that summer arrives in a couple weeks. Time sure does fly by.

As we prepare for hulls to start splitting open, growers are busy doing their prep work while  monitoring their orchards for pests.

Field scout Jenna Mayfield says growers have been busy working the ground between and around the rows of trees. “The winter rains really made the weeds grow this year. Everyone has been doing ground work. The first harvesting starts in six weeks for many growers.”

As weeding wraps up, growers need to keep an eye out for ants on the ground, Jenna says. “You want to get rid of the ants way before harvest.”

Indeed, farm advisers point out a large ant population can consume 1 to 2 percent of a crop in only four days. June is prime time to monitor for ants.

Red color identifies fire ants.

If ant problems exist, growers need to put out baitone month before harvest to maximize effectiveness on crop-damaging pavement and fire ants. Bait shouldn’t be used within 24 hours after irrigation or 48 hours before irrigation with sprinklers. Usually, you’ll find ants a problem around drip- or sprinkler-irrigated orchards.  Experts point out conventional insect sprays aren’t generally effective this time of year.

Pavement ants.

Here’s a cautionary note before going out to treat for ants. It’s important to understand there are good ants and bad ants and distinguish between the two types. A nifty trick is to put out potato chips or a hot dog – any brand will do – near the ant mound. If ants gobble up the tasty fare, it’s a safe bet the pests will feast on almond kernels as well.

If you don’t want to waste good food, try another trick: Stomp near the ant mound to rouse the ants out of their underground home. When they swarm out, check to see if the pests are red in color with a black rear end and if they bite. If they do, then it’s a sure sign they are fire ants.

Monitor for Navel orangeworm.

With summer around the corner, growers also need to monitor for early signs of hull split. It’s important to protect the crop from the second generation of navel orangeworm  (NOW) laying eggs. The first NOW treatment should be done before 1 percent hull split.

Now also is time to keep an eye for webspinning spider mites. This pest overwinters in the bark or under trash on the ground, In the spring they will migrate into the lower part of the almond trees. As the weather heats up, spider mite populations can explode during the summer months.

This is a web created by webspinning spider mites.

Spider mites will suck on the tree leaves. Webs will appear around the leaves and spurs. Eventually, the leaves will drop. A major mite infestation can lead to crop loss and reduced vegetative growth the following season.

Check out UC IPM for more information about managing spider mites and ants in almonds.


“It’s important to get pest problems under control before harvest,” Jenna says.