Monitor for Ants Before It's Time to Shake Almond Trees

With August around the corner and almonds are at hull split, it’s time for growers to start planning to do a little shake and bake in their orchards.

All almond varieties are at hull split in the Valley.

That’s shake as in shakin’ those nuts off trees. And that’s bake as in letting the fierce San Joaquin Valley sun dry those almonds on the ground.

To protect your crop on the ground, now is the final time to make sure those pesky ants scurrying about on the orchard floor are under control. A University of California study estimates a quick knock down of  the first ant infestation early on can save 140 pounds of nuts, based on an average yield of 2,000 pounds per acre.

Southern fire ants are known for their aggressive behavior.

The pavement ant and Southern fire ant will damage almonds drying on the ground by gnawing away at the kernel. UC almond experts point out ant populations may larger in orchards with drip and micro-sprinkler irrigation. Picking up the nuts off the ground as soon as possible after shaking can cut down on ant damage.

UC IPM says ant bait is the most effective. But it can take several weeks to take care of the whole colony. If a conventional spray is used, the application should be made two weeks before harvest. Read more about almond pest management guidelines for ants at UC IPM online.

Pavement ants are more laid back.

In addition to ants, our almond field scout Jenna Horine reminds growers to continue monitoring for navel orangeworm and peachtwig borer as well.

Meanwhile, field scout Carlos Silva reports alfalfa growers have completed their fourth cutting of the season. One even finished his fifth harvest. There isn’t a lot of bug activity in alfalfa after the cuttings.

In cotton, the plants are lush and full. We’re seeing up to 20 mainstem nodes. Many growers are irrigating their fields so it has been a little tough for Carlos to get into the fields with his sweep net. So far, the bad bugs seem to be under control.

Learning to Manage a Sticky Situation in Valley Cotton

Walking through a lush, field of cotton plants, you could feel something tacky on the rich green leaves.

You turn over a leaf for a closer inspection. On the back, you find a fair number of aphids feeding on the back of the leaf.

 In this San Joaquin Valley field, field scout Carlos Silva estimated finding aphids problems on some 40 percent of the leaves he inspected.

With cotton bolls in bloom and displaying a spectacular display of bright yellow and pink flowers, it is time for growers to pay special attention to aphids and whiteflies.

Aphids feeding on the back of a cotton plant leaf.

These pests can eventually affect the quality of the lint and be costly to producers and cotton ginners.

Here’s the problem: When aphids feed on the leaves, for example, they secrete a sticky honeydew-like substance that falls onto leaves and the other parts of the cotton plant. A fungus develops and leaves a black, sooty mold. The worry down the road is the honeydew will get onto the lint and result in economically damaging sticky cotton.

Yes, it’s not too early to be concerned about sticky cotton.  For generations, this issue has been haunting cotton growers across the globe.

A sticky honeydew-like substance coats the leaves.

Observations about pests and sticky cotton date back to the 1930s in India. Sticky cotton can cost growers 3 to 5 cents per pound in revenue annually, according to a 2007 USDA report. At the same time, managing these pests can be expensive.

For example, California cotton growers spent more than $220 million on pest control measures for whiteflies from 1992 to 2001, according to the USDA report written by E. Hequest of Texas Tech University, T.J. Henneberry of the USDA Arid Land Research Center in Arizona and R.L. Nichols, ag research director with Cotton Inc.

 “Cotton stickiness caused by excess sugars on the lint from the plant itself or from insects is a very serious program that affects all segments of the cotton industry. Stickiness is a worldwide contamination problem: Around one-fifth of the world production is affected to some degree,” the researchers point out.

Dirt will gets stuck on the sticky lint. - UC IPM photo

But controlling aphids and whiteflies isn’t a matter of simply spraying chemicals. The USDA report stresses a balanced integrated pest management approach. These pests “have demonstrated a penchant for development resistance to insecticides. Thus, resistance management principles must be integrated into the overall management programs for each of these pests or the risk of early loss modes of insecticide action will be increased.”

If you want to learn more, go to UC IPM online to read about monitoring aphids and whiteflies in cotton. Guess you can say there’s nothing sweet about sticky cotton.

A Farmer’s Life: Going from One Worry to Another

This time of year, it seems growers find a few extra gray hairs on their head and wrinkles on their forehead.

You might call it a case of “worry fever.” Day and night, growers worry about bugs, plant diseases, rising expenses and crop yields. The height of the summer season exacerbates this condition.

Take almond growers. Right now, says almond field scout Jenna Horine, growers are worried about mites flaring up in their orchards at the onset of hull split. And they are also concerned about navel orangeworm and peach twig borer, too.

How should they time hull split spraying? How can they protect pollinators? Should they turn to softer, more environmentally friendly materials? How effective are organic oils such as orange oil. Are there other options?

Watering heavily traveled dirt roads can help control mites.

Jenna says the answers aren’t always black and white. Many factors come into play. Growers should consider the surrounding environment, such as neighboring crops or dusty roads, she says. For example, spraying water on well-traveled dirt roads can control dust and prevent mites from being blown into the orchards. Or natural predators can help manage the pests and lessen the amount of chemical applications.

A good stress reliever is education. Yes, more growers have become better educated and understand the big picture about integrated pest management. They are asking more questions of the pest control advisors. And many are no longer just following what their neighbors are doing.

Rust can develop on leaves in humid regions. - UC IPM photo

 

 

 

 

 

What happens after mites are finally out of the picture this season? Well, the next worry for growers will be rust, a disease that can be triggered by the high humidity we have been experiencing in the Valley. Rust can cause leaves to fall and impact bloom the following year. Decisions, decisions.

Of course, almond growers don’t have a monopoly on crop worries. Cotton farmers are showing a few more gray hairs as they worry about plant getting overstressed by hot, dry conditions as well as emerging lygus          populations.

The extreme heat prompts growers to irrigate cotton again.

Field scout Carlos Silva says plant development and lygus are key concerns at this time.  The extreme heat prompted many growers to start the second irrigation of the growing season – this piggybacks the first irrigation just a couple weeks ago. While cotton can tolerate a certain amount of water stress, this prolonged heat wave has growers worried these conditions could slow plant growth and ultimately lower yields. 

 So far, lygus counts have been low. In fact, growers are finding pests to be under control at the moment. Of course, that’s not going to stop growers from worrying about their crop. Soon, they’ll be concerned about whiteflies and aphids and preventing sticky cotton.

If You Can’t Stand the Heat, Get Under Some Cool Shade and Drink Lots of Water

 Hot dogs and hamburgers weren’t the only things sizzling across the San Joaquin Valley over the holiday weekend.

A string of suffocating triple-digit temperatures beat down on the Valley. In fact, the Fresno area recorded its highest low temperature ever at a “cool” 80 degrees on the Fourth of July morning. In some parts of the region, highs topped 110 degrees, report field scouts Jenna Horine and Carlos Silva.

 

While 100-degree weather is common here – we average 36 days of triple-digit temperatures every year – this heat still takes your breath away, especially if you’re working outdoors. Weather forecasters called this heat wave extreme even by our standards. Forecasters say the string of consecutive 100-degree-plus days could finally be broken Satursday with the temperature dipping below triple digits (albeit 99 degrees) for the first time in over two weeks.

It was extreme enough to worry about the safety of field workers. Carlos tells us the farm where his father works as a foreman sent its workers went home early during the heat wave, calling it a day by 2 p.m.

Indeed, Carlos heads out to scout the cotton and alfalfa fields by 6 a.m., packing lots of water in an ice chest and wearing pants, a long sleeve shirt and floppy hat. He covers up to protect himself for the scorching sun. Jenna, too, sets out at 6 a.m. so she can wrap up her scouting in the almond orchards by 1 p.m. 

Yes, heat illness is a serious matter for farmers and ag workers. Every spring, Cal-OSHA works with farm community to sponsor training sessions about preparing for the hot summer months. State law entitles outdoor workers to have cool, fresh water as well as a shade area for hourly breaks.

The California Cotton Ginners and Growers Association offers a Heat Illness Prevention Program Tool Kit for farm supervisors to carry in their pickups. For more information, contact the association office at (559) 455-9272.

Another resource is heat illness compliance aids prepared the Ventura County Agricultural Association. You can access them online here. 

Meanwhile, this heat can be a double-edge sword for crops.

Cotton plants are growing well under the hot weather while pests are in check at the moment. The plants are at 15 to 18 main stem nodes with up to 10 fruiting branches. We’ll start looking at square retention rates soon. However, some growers are concerned the extreme heat could have an impact on yield. We will have to wait to see how that plays out as the season progresses.

Spider mites found on  a leaf.

The extreme heat at the onset of hull split presents some challenges for growers. In its latest monthly crop round-up for the region, Blue Diamond Almonds reported:  “Growers are monitoring soil moisture levels closely as they work to withhold irrigation to one-half of consumptive use for a two-week period in an effort to reduce the incidence of fungal hull rot infections, while not imposing undue stress on the trees. This delicate balance is made much more difficult by the heat wave currently enveloping the entire Central Valley.”

“Everybody is trying to keep up with the water because of the heat,” Jenna reports. Water-stressed orchards can trigger an explosion of spider mites. These pests will suck the cell content from leaves and ultimately can cause leaves to drop. A number of growers have been treating for mites. Some are applying orange oil, considered by UC IPM as one of the “organically acceptable ways of managing spider mites.” Check out UC IPM online for more about spider mites.

A tractor sprays for pests in a Valley almond orchard.