Monday, August 14, 2017

Almond Growers Poised to Get Crackin’ on the Harvest and Taking Harvest Samples

The orchard is some 50 miles west of Fresno, 37 miles west of Raisin City and 20 miles southwest of Mendota. It borders the Westside Freeway, better known to most travelers as Interstate 5.

The locale also is the first almond orchard that field scout Jenna Mayfield spotted this season shaking nuts off the trees. “They usually are the first area to start harvesting almonds,” Jenna said, citing the combination of hot weather and a dry climate as reasons for the earlierharvest start than other areas in the Valley.

Westside almond orchards are the first to be harvested.
So we can officially say the almond harvest has begun. From now until early fall, growers will be busy shaking and sweeping in their orchards. More specifically, that’s shaking trees to knock off the nuts, letting them dry on the ground for about a week and then sweeping up the nuts to haul to the huller.

“It’s going to get busier for growers,” Jenna says.

You might liken the almond harvest as a marathon rather than a sprint. Because more than one variety of almonds is planted in orchards, growers will go in more than once to shake the trees. Of course, that means crews have to pick up the almonds more than once as well.

The soft shell varieties, especially nonpareils, ripen early and are the first to harvest. The hard shells such as Monterey ripen later and usually are harvested some40 to 60 days later. In fact, Jenna points out hulls of hard shell almonds aren’t even close to showing a sign of splitting.

Almonds drying on the ground are waiting to be gathered.
Right now, a number of growers are still wrapping up pre-harvest spraying, especially for mites. “The mite pressure is increasing,” Jenna notes.

Yes the to-do list is long for growers this time of year. “There are so many things to do,” Jenna says.

Foremost, according to UC Integrated Pest Management advisers, is moving to harvest as early as possible. As we mentioned earlier, almonds should be harvested when at least 95 percent of the hulls have split. The longer the nuts stay in the orchard the greater chance pests will move in and damage the crop.

While drying the nuts on the orchard floor is
important, it also is vital to pick them up as quickly as possible. “Ants are major pest threat

for nuts on the ground,” Jenna says.

Jenna also reminds growers to do one more task before gathering the nuts off the ground: Take nut samples. No, we’re not talking about Costco-like samples being handed out to snack on.

Almond kernels with NOW damage.
In this case, sampling involves collecting nuts from the ground and cracking them open to check for pest damage. A harvest sample lets growers assess the pest management program this season and lets them plan for next year. The results offer insights about damage from navel orangeworm, peach twig border, fruit moths or ants during the harvest process. The information also can be compared with numbers from the processor. Discrepancies could be costly for growers.

To collect samples, Jenna snatches up about 70 nuts from three different orchard locations, areas where pest traps have been placed. This lets her compare the damage with the pest information collected from the traps during the season. Later, she’ll crack each nut to inspect them for evidence of pests and pest damage and report the results to growers,

While Jenna and UC advisors regularly urge growers take samples, the practice isn’t widely practiced. Sampling, Jenna says, makes sense and will pay financial dividends in the long run
So let’s get cracking on those harvest samples.

Saturday, August 12, 2017

Cotton Aphid Population Explodes Seemingly Out of the Blue in Some Communities

It’s a funny thing about Mother Nature.

One day, everything is going just fine for farmers. A few days later it was another story.

Aphids are showing up in big numbers in some Valley fields.
Cotton field scout Damien Jelen offers a prime example how nature can throw a sudden curveball at farmers. After completing one of his scouting rounds in cotton, Damien noted aphid populations were under control. A few days later, “aphid numbers kind of exploded. They have become a problem,” he says.
The aphid issue appears most prevalent in the Mendota Firebaugh and Kerman areas of the Valley. It’s hard to say why the problem is concentrated in this region.

Experts say the higher populations often surface after heavy watering and fertilizer applications. That may be the case here because the outbreak surfaced a few days after irrigation, Damien says.Certainly, growers are less focused on the why and more focused on the how – like how am I going to stem the infestation. Damien points out the answer has been swift pest treatment. 

Cotton leaf curling is a sign of aphid damage.
Their reasoning: During mid-season, high aphid numbers – more than 50 per leaf – can shrink the size of bolls, stunt plant growth and cause more bolls to be shed from the plant, according to the University of California Integrated Pest Management.

Growers know they have a problem when leaves become cupped or crinkled and experience a build-up of honeydew and sooty mold. In extreme cases, the leaves will start falling off.
The cotton aphid is the most common aphid in California. They can emerge anytime during the season. Here how UC IPM describes the pest: 

Dark colored aphids can reproduce very quickly.
“Cotton aphid is highly variable in body size and color, and adults may be winged or wingless. Nymphs and adults of wingless cotton aphids vary in color from yellow to green to nearly black. The darker forms tend to be substantially larger. Nymphs that are developing into winged adults look very different from the nymphs developing into wingless adults: they bear small welts or protuberances on their bodies and may be covered with a coat of dusty-appearing whitish wax. Their body color is often greenish blue, or amber and blue.”

It’s important to determine the color of the bugs in the field. “The small yellow aphids develop slowly from newborn nymph to adult and do not produce many offspring; thus, their populations rarely increase rapidly. The larger, darker aphids (green and black) are quite different; they develop more rapidly, produce many more offspring in a rapid burst, and can generate rapid population growth rates,” UC IPM says.

The minute pirate bug is a natural enemy to aphids.
 Natural enemies such as minute pirate bugs, bigeyed bugs, green lacewings and damsel bugs can offer some biological control. But UC IPM notes that “although these natural enemies do provide some control, they generally are not able to strongly suppress aphid populations, or cause strong suppression after severe damage has occurred to the plant.”
Meanwhile on the almond front, field scout Jenna Mayfield says pest pressure is down in orchards.
Hulls continue to split and growers are treating for mites on the edge of the orchards where the pest often wind up after migrating from neighboring farms and dusty roads.“I haven’t seen any pest issues,” Jenna says. She also hasn’t seen any shakers rumbling through orchards. “Everyone is waiting to harvest.”
Growers are still waiting to shake their trees.

Monday, July 31, 2017

Cotton Plants Thrive in Warm Weather; However Very Hot Weather Is Another Story

It’s a good thing we had a tremendous rainy season. And our cotton growers aren’t dry land farmers like those in the Southwest.

Cotton plants thrive in warm climates. But hot, hot prolonged heat is another story.

That’s why field scout Damien Jelen reports seeing growers turning on the irrigation spigots and giving their cotton plants a healthy dose of H2O.  “They’re pushing water because of the heat,” he says.

Growers giving cotton a hefty dose of irrigation due to heat.
You might ask “if cotton likes warm climates, why are farmers rushing to irrigate their fields? 

First, let’s go through a brief science lesson. Cotton plants are about 10 degrees cooler than the air temperature. The reason is the plant features a natural air conditioner: Almost all the water taken in by the plant evaporates to provide cooling. During July, the amount of evaporative cooling from one acre of cotton equates to the same cooling produced by 50 to 100 home air conditioners.

A study in Arizona found the canopy temperature in well-watered cotton fields averaged 88 degrees on a day when the air temperature surged to a scorching 121 degrees. In contrast, poorly watered fields recorded a canopy temperature of 104. 

OK. So what does this mean?

Cotton is blooming.
Simply put, high temperatures combined with water stress can lead to smaller bolls, the loss of bolls and leaf damage. Leaf damage can cause cutout to take place too early or impact crop set. That’s not good.

As we close out the month, the National Weather Service says the average high temperature for July was 101.7 degrees for the Fresno region. The forecast for the start of a new month: More triple-digit weather for the foreseeable future. Yikes.

Good thing we’re no longer in a drought – or don’t dry land farm our cotton.

For now, the heat hasn’t triggered a serious pest infestation. “Pest pressure is down right now,” Damien says. It’s good that alfalfa growers, who have wrapped up another cutting for the season, are following best management practices and leaving strips of uncut alfalfa in their fields that neighbor cotton fields. That can keep pesky lygus bugs from migrating into cotton.

Almonds hulls continue to split as harvest season nears.
Meanwhile, field scout Jenna Mayfield says webspinning spider mites are becoming an issue for almonds. “A lot of growers have been treating for mites.” While mites won’t cause problems this year, the pests will cause the loss of leaves and hurt next season’s crop.

“They affect the set of the trees the following year,” Jenna says.

Right now, many orchards are around 50 percent hull split. In another couple weeks growers should start shaking off their nuts, signaling the start of harvest.

Jenna also notes a mysterious ailment is cropping in a few orchards. For some reason, the leaves are turning yellow and the trees are dying – on newly planted and established trees.“Something is going on and no one knows why. They can’t figure out why their trees are dying.”
Certainly, growers don’t want to replant trees if you’re not sure if the problem will show up again.

Stay tuned.

Monday, July 24, 2017

There’s Smoke and Fire in the Hot Air Across the Valley

Where there’s smoke, there’s fire.

Well, in this hot, dry post rainy season, this trite phrase is more than cliché around these parts.  In recent days, thick, brown choking smoke has enveloped the Valley.

Coupled with the summertime triple-digit temperatures, the smoky conditions make it tough for growers, farm-hands and others who earn a living working outdoors. It’s also rough for folks with respiratory conditions.

The fire: A massive, out of control blaze in Mariposa County, east of Merced, and other locales around the Golden Brown State.

“The smoke is really bad,” says almond field scout Jenna Mayfield. “It also has been really hot.”

The Fresno region, for instance, recorded triple-digit temperatures for 16-straight days this month, before dropping to 98 “cool” degrees last Wednesday. Ah, 100-degree weather returned over the weekend.

In almonds, there could be a different kind of fire smoldering in orchards: namely pests.

Peach twig borer numbers on the rise.

“Peach twig borer was getting a lot higher last week, more than previous weeks,” Jenna said. The spate of very hot weather triggered the uptick.  We’ll see how the numbers shape up this week.

Peach twig borer, or PTB, produce four generations each year. The larvae, or small caterpillars, damage the nuts as well as growing shoots. They cause shallow channels and surface groves. Sometimes, PTB damage can be masked by navel orangeworm damage. The reason: NOW will feed on earlier damage caused by PTB.

In some instances, growers have no other choice but to treat their orchards for the pests. Here are some monitoring tips from UC IPM:

Natural enemies can keep PTB larvae in check in the orchards.
  • Use past history, including results from harvest samples from the previous year, to determine if your orchard will require treatment.
  • Preferred treatment timing is during the dormant period (combined with oil sprays if there is concern for San Jose scale, European red mite, or brown almond mites) or at full bloom and petal fall (may be combined with bloomtime fungicide sprays, but check restrictions on compatibility).
Of course, exploring biological controls before determining whether to treat the orchard is a good management practice. PTB doesn’t have lots of friends – the pest boasts some 30 natural enemies.
Almond kernels damaged by PTB.
“In some years and orchards, these natural enemies destroy a significant portion of larvae, but they may not reduce twig borer populations below economically damaging levels. Ants also can be found preying on peach twig borer larvae.”

Right now, PTB isn’t a major threat as almond hulls begin to split. But, Jenna warns, “it’s something to look out for.”

Monday, July 17, 2017

Hull Split Timing Crucial for Harvesting Almonds Successfully

After months of watching their orchards go from bud to bloom to nut, the big moment has arrived for almond growers.

It’s hull split time. That means growers will start shaking the nuts off the trees soon.

Field scout Jenna Mayfield reports about 15 percent of hulls are split open in trees. Harvest starts when 95 to 100 of the hulls have split.
Unsplit almond stage. (UC IPM photos)
As we all know, of course, fruit – whether it’s a peach or an almond – doesn’t ripen uniformly. Oh, that would be too easy.

For almonds, hull split usually starts in the upper and outer sections of a tree in the southwest area – where it gets the most sun during the day. The nuts on the top of the tree are the least mature.

Initial separation of hull.
As a result, it’s important for growers to continue monitoring the progress of hull split to protect against pests. Jenna notes growers have been applying hull split sprays to combat bugs such as navel orangeworm (NOW). University of California Integrated Pest Management says NOW applications should be done during the start of hull split and the beginning of egg laying.

Hull at the deep "V" stage.
Peach twig borer and hull rot fungi are other concerns at hull split. Remember, the hulls provide a protective shell and after they split open the nuts are exposed to these bugs. It’s important to harvest the crop as soon as possible to limit pest exposure.
Split of ess than 3/8-inch.

Initial drying stage.
The first thing growers need to do is find out if hull split has started. Sometimes, it’s tricky to see through the foliage and branches. A handy trick is using a pole pruner to cut small branches from the top southwest section of five or six trees to see if hulls are starting to split.

Here are some other tips from UC IPM:
  • Continue monitoring trees until 95 to 100 percent of the fruit at eye level are visibly split.
        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.
    Complete drying stage of almond.
  • Harvest blocks with poorest sanitation first.
Historically, shaking starts in early to mid-August. But Jenna has seen in the past growers starting tree shaking as soon as July 25 in the Northern San Joaquin Valley.