Tag: Agriculture

The Happy Nut: California’s Rise to Pistachio Power

Pistachios grow on a tree in the Central Valley (Photo: Erik Olsen)
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I just got back from a filming assignment in California’s Central Valley. That drive up I-5 and Highway 99 is always a strange kind of pleasure. After climbing over the Grapevine, the landscape suddenly flattens and opens into a vast plain where farmland and dry earth stretch endlessly in every direction. A pumpjack. A dairy farm. Bakersfield. There’s a mysterious, almost bleak beauty to it. Then come the long stretches where the view shifts from dust to trees: pistachio trees. Especially through the San Joaquin Valley, miles of low, gray-green orchards extend to the horizon. At various points, I busted out a drone and took a look, and as far as I could see, it was pistachio trees. A colorful cluster of pistachios hung from a branch and I picked on and peeled off the fruity outer layer. There was that familiar nut with the curved cracked opening. The smiling nut.

California now grows more pistachios than any place on Earth, generating nearly $3 billion in economic value in the state. Nearly every nut sold in the United States, and most shipped abroad, comes from orchards in the Central Valley. The state produces about 99 percent of America’s pistachios, and the U.S. itself accounts for roughly two-thirds of the global supply. And that all happened relatively quickly.

When the U.S. Department of Agriculture began searching for crops suited to the arid West in the early 1900s, the pistachio was an obvious choice. In 1929, a USDA plant explorer named William E. Whitehouse traveled through Persia collecting seeds. Most failed to germinate, but one, gathered near the city of Kerman, produced trees that thrived in California’s dry heat. The resulting Kerman cultivar, paired with a compatible male variety named Peters, became the foundation of the modern industry. Every commercial orchard in California today descends from those early seeds.

For decades, pistachios were sold mainly to immigrants from the Middle East and Mediterranean. It wasn’t until the 1970s that California growers, backed by UC Davis researchers and improved irrigation, began planting on a large scale. By the early 1980s, they had found their perfect home in the southern San Joaquin Valley—Kern, Tulare, Kings, Fresno, and Madera Counties—a region with crazy hot summers, crisp winters…according to researchers, the kind of stress the trees need to flourish.

Pistachio trees in the Central Valley of California (Photo: Erik Olsen)

Then came The Wonderful Company, founded in 1979 by Los Angeles billionaires Stewart and Lynda Resnick. From a handful of orchards, they built an empire of more than 125,000 acres, anchored by a vast processing plant in Lost Hills. Their bright-green “Wonderful Pistachios” bags and silly “Get Crackin’” ads turned what was once an exotic import into a billion-dollar staple.

But the company’s success is riddled with controversy. Mark Arax wrote a scathing piece a few years ago about the Resnicks in the (now, sadly defunct) California Sunday Magazine. The Resnicks have been criticized for their immense control over California’s water and agriculture, using their political influence and vast network of wells to secure resources that many see as public goods. Arax described how the couple transformed the arid west side of the San Joaquin Valley into a private agricultural empire, while smaller farmers struggled through droughts and groundwater depletion. “Most everything that can be touched in this corner of California belongs to Wonderful,” Arax writes. (Side note: Arax’s The Dreamt Land made our recent Ten Essential Books About California’s Nature, Science, and Sense of Place.)

And yes, pistachios have been immensely profitable for the Resnicks. Arax write: “All told, 36 men operating six machines will harvest the orchard in six days. Each tree produces 38 pounds of nuts. Typically, each pound sells wholesale for $4.25. The math works out to $162 a tree. The pistachio trees in Wonderful number 6 million. That’s a billion-dollar crop.”

Pistachios at golden hour. (Photo: Erik Olsen)

Alas, California’s pistachio boom carries contradictions. The crop is both water-hungry and drought-tolerant, a paradox in a state defined by water scarcity. Each pound of nuts requires around 1,400 gallons of water, less than almonds, but still a heavy draw from aquifers and canals. Pistachio trees can survive in poor, salty soils and endure dry years better than most crops, yet once established, they can’t be left unwatered without risking long-term damage. Growers call them a “forever crop.” Plant one, and you’re committed for decades.

The pistachio has reshaped the Central Valley’s landscape. Once a patchwork of row crops and grazing land, vast acres are now covered in pistachio orchards, the ones I was recently driving through.

Pretty much everyone growing anything in California – pistachios, almonds, strawberries (especially strawberries) – can thank the University of California at Davis for help in improving their crops and managing problems like climate change and pests. Davis is a HUGE agricultural school and has many programs to help California farmers.

UC Davis is one of the world’s leading research centers for nuts, especially pistachios, almonds, and walnuts. Scientists here study everything from drought-tolerant rootstocks to disease resistance and pollination, making it the quiet engine behind California’s multibillion-dollar nut industry. (Photo: Erik Olsen)

In the case of the pistachio, recent research at UC Davis has shed new light on the tree’s genetic makeup. Scientists there recently completed a detailed DNA map of the Kerman variety, unlocking the genetic controls of kernel size, flavor compounds, shell-splitting behaviour and climate resilience. The idea is to help growers by making pistachios adapt to hotter, drier conditions. UC Davis is now one of the world’s leading centers for pistachio and nut science.

Here’s something I’ll bet you didn’t know: pistachios can spontaneously combust. Pistachios are rich in unsaturated oils that can slowly oxidize, generating enough heat to ignite large piles if ventilation is poor. Shipping manuals classify them as a “spontaneous-combustion hazard”, a rare but real risk for warehouses and freighters hauling tons of California pistachios across the world. Encyclopedia Britannica notes they are often treated as “dangerous cargo” at sea.

Now, some pistachio biology: The pistachio is dioecious, meaning male and female flowers grow on separate trees. Almonds are not. Farmers plant one male for every eight to ten females, relying on wind for pollination. The trees follow an alternate-bearing cycle, heavy one season, light the next. They don’t produce a profitable crop for about seven years, but once mature, they can keep producing for half a century or more.

California grows nearly all of America’s pistachios, and most of them come from the empire built by Lynda and Stewart Resnick, the power couple behind the Wonderful Company. Their orchards stretch across hundreds of thousands of acres in the Central Valley, transforming a desert landscape into one of the most lucrative nut operations in the world.

Another strange quirk of pistachios is that they are green and, if you look closely, streaked with a faint violet hue. The green comes from chlorophyll, the same pigment that gives leaves their color, which in pistachios lingers unusually long into the nut’s maturity. Most seeds lose chlorophyll as they ripen, but pistachios retain it, especially in the outer layers of the kernel. The purple tint, meanwhile, comes from anthocyanins, antioxidant pigments also found in blueberries and grapes.

As I walked among the pistachio trees recently, I marveled at how alone I was on one of the dirt roads off Highway 99. Not a soul in sight, only the hum of irrigation pumps and the rattle of dry leaves in the breeze. I like to write about the things we all see and experience in California but rarely stop to look at closely. Pistachios are one of those things. If you’ve ever driven through the San Joaquin Valley, you’ve seen how the landscape stretches for miles in orderly rows of pistachio trees. It’s easy to forget, amid the fame of Silicon Valley and Hollywood, that so much of California’s wealth still comes from the land itself, from agriculture and other extractive industries. The pistachio boom is a story of astonishing scale, but it’s also riven with the contradictions and complexities of modern California itself, where innovation and exploitation often grow from the same soil.

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A Tiny California Seaweed Could Make a Big Dent in Livestock Methane

Flasks of Asparagopsis taxiformis growing at Scripps Institution of Oceanography. Researchers are studying this red seaweed for its potential to slash methane emissions from cattle when added in small amounts to their feed. (Photo: Erik Olsen)
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Inside a long, brightly lit basement lab at the Scripps Institution of Oceanography at UC San Diego, a large aquarium filled with live corals sits against the wall, the vibrant shapes and colors of the coral standing out against the otherwise plain white surroundings. Nearby, in a side alcove, dozens of glass flasks bubble with aerated water, each holding tiny crimson clusters of seaweed swirling in suspension, resembling miniature lava lamps. These fragile red fragments, born in California and raised under tightly controlled conditions, are part of a global effort to harness seaweed to fight climate change.

Cattle and other ruminant livestock are among the largest contributors to methane emissions worldwide, releasing vast amounts of the gas through digestion and eructation. Burps, not farts. The distinction is not especially important, but it matters because critics of climate science often mock the idea of “cow farts” driving climate change. In reality, the methane comes primarily from cow burps, not flatulence.

But I digress. 

Cattle at Harris Ranch in California’s Central Valley, one of the largest beef producers in the United States. Livestock operations like this are a major source of methane emissions, a greenhouse gas more than 80 times as potent as carbon dioxide over a 20-year period. (Photo: Erik Olsen)

Globally, livestock are responsible for roughly 14 percent of all human-induced greenhouse gases, with methane from cattle making up a significant portion of that total. The beef and dairy industries alone involve more than a billion head of cattle, producing meat and milk that fuel economies but also generating methane on a scale that rivals emissions from major industrial sectors. Because methane is so potent, trapping more than 80 times as much heat as carbon dioxide over a 20-year period, the livestock industry’s footprint has become a central focus for climate scientists searching for solutions. 

Enter Jennifer Smith and her colleagues at the Smith Lab at Scripps in beautiful La Jolla, California. Their team is tackling urgent environmental challenges, from understanding coral die-offs to developing strategies that reduce greenhouse gas emissions, among them, the cultivation of seaweed to curb methane from cattle.  

The seaweed species is Asparagopsis taxiformis. Native to tropical and warm temperate seas and found off the coast of California, in fact right here off the coast in San Diego, it produces natural compounds such as bromoform that interfere with the microbes in a cow’s stomach that generate methane gas, significantly reducing the production of methane and, of course, it’s exhalation by the animals we eat. It turns out the seaweed, when added to animal feed can be very effective:  

Asparagopsis taxiformis, commonly known as red sea plume, a tropical red algae being studied for its ability to cut methane emissions from cattle. (Photo: Wikipedia)

“You need to feed the cows only less than 1% of their diet with this red algae and it can reduce up to 99% of their methane emissions,” said Dr. Or Ben Zvi, an Israeli postdoctoral researcher at Scripps who studies both corals and seaweeds.

Trials in Australia, California, and other regions have shown just how potent this seaweed can be. As Dr. Ben Zvi indicated, even at tiny doses, fractions of a percent of a cow’s feed, other studies have shown that it can reduce methane by 30 to 90 percent, depending on conditions and preparation. Such results suggest enormous potential, but only if enough of the seaweed can be produced consistently and sustainably.

“At the moment it is quite labor intensive,” says Ben Zvi. “We’re developing workflows to create a more streamlined and cost-effective industry.”

Which explains to bubbling flasks around me now. 

Scripps Institution of Oceanography at UC San Diego (Photo: Erik Olsen)

The Smith lab here at Scripps studies every stage of the process, from identifying which strains of Asparagopsis thrive locally to testing how temperature, light, and carbon dioxide affect growth and bromoform content. Dr. Ben Zvi is focused on the life cycle and photosynthesis of the species, refining culture techniques that could make large-scale cultivation possible. At Scripps, environmental physiology experiments show that local strains grow best at 22 to 26 °C and respond well to elevated CO₂, information that could guide commercial farming in Southern California.

The challenges, however, are considerable. Wild harvesting cannot meet demand, and cultivating seaweed at scale requires reliable methods, stable yields, and affordable costs. Bromoform content varies widely depending on strain and growing conditions, so consistency remains an issue. Some trials have noted side effects such as reduced feed intake or excess mineral uptake, and long-term safety must be established since we’re talking about animals that we breed and raise to eat.

“It’s still a very young area, and we’re working on the legislation of it,” says Ben Zvi. “We need to make it legal to feed to a cow that eventually we either drink their milk or eat their meat. We need for it to be safe for human consumption.” 

Dr. Or Ben Zvi (Photo: Erik Olsen)

And, of course, large-scale aquaculture raises ecological questions, from nutrient demands and pollution to the fate of volatile compounds like bromoform.

To overcome these obstacles, collaborations are underway. UC San Diego and UC Davis have launched a pilot project under the UC Carbon Neutrality Initiative to test production methods and carbon benefits. In 2024, CH4 Global, a U.S.-based company with operations in New Zealand and Australia that develops seaweed feed supplements to cut livestock methane, partnered with Scripps to design cultivation systems that are efficient, inexpensive, and scalable. Within the Smith Lab, researchers are continuing to probe the biology of Asparagopsis, mapping its genetics, fine-tuning its culture, and testing ways to maximize both growth and methane-suppressing compounds.

At a time when university-based science faces immense pressures, the Smith Lab at Scripps provides a glimpse of research that is making a real impact. The coral tanks against the wall belong to another project at the lab, and we have another story coming soon about the research that readers will find very interesting, but the bubbling flasks in the alcove reveal how breakthroughs often start with small details. In this case, the discovery that a chemical in a widely available seaweed could have such a dramatic, and apparently harmless, effect on the methane that animals make in their guts. These modest but powerful steps are shaping solutions to global challenges, and California, with its wealth of scientific talent and institutions, remains at the forefront. It is one of many other stories we want to share, from inside the labs to the wide open spaces of the state’s natural landscapes. 

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How a Tiny Beetle Helped Save California

California’s citrus industry confronted a deadly challenge, leading to a groundbreaking innovation in pest control.

Cottony Cushion Scale (Public Domain)
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In the sun-drenched orchards of late 19th-century California, a crisis was unfolding that threatened to decimate the state’s burgeoning citrus industry. The culprit was a small sap-sucking insect native to Australia called the cottony cushion scale (Icerya purchasi). First identified in New Zealand in 1878, this pest had made its way to California by the early 1880s, wreaking havoc on citrus groves. The pest is believed to have arrived in the United States through the global trade of plants, a common vector for invasive species during the 19th century. As horticulture expanded globally, ornamental plants and crops were frequently shipped between countries without the quarantine measures we have today. Once established in the mild climate of California, the cottony cushion scale found ideal conditions to thrive, spreading rapidly and wreaking havoc on the citrus industry.

The cottony cushion scale infested trees with a vengeance, covering branches and leaves with a white, cotton-like secretion. This not only weakened the trees by extracting vital sap but also led to the growth of sooty mold on the honeydew excreted by the insects, further impairing photosynthesis. Growers employed various methods to combat the infestation, including washing trees with whale oil, applying blistering steam, and even detonating gunpowder in the orchards. Despite these efforts, the pest continued its relentless spread, causing citrus exports to plummet from 2,000 boxcars in 1887 to just 400 the following year. This decline translated to millions of dollars in lost revenue, threatening the livelihoods of countless farmers and jeopardizing the state’s citrus economy, which was valued at over $10 million annually (approx. $627 million in today’s dollars) during this period.

Orange and lemon groves, along with the home of citrus pioneer William Wolfskill, circa 1882. (California Historical Society)

In 1885, the independent growers across Southern California banded together in response to the insect invasion and the broader difficulties facing citrus growers at the time, forming the state’s first fruit cooperative, which would later become Sunkist. Despite their efforts, homemade mixtures of kerosene, acids, and other chemicals failed to halt the relentless spread of Icerya purchasi. The pests, with an endless supply of citrus trees to feed on, continued to multiply unchecked. New laws mandated growers to uproot and burn infected orange trees, but the devastation was widespread. By 1888, real estate values, which had soared by 600 percent since 1877, had plummeted.

Enter Charles Valentine Riley, the Chief Entomologist for the U.S. Department of Agriculture. A visionary in the field of entomology, Riley had previously attempted biological control by introducing predatory mites to combat grape phylloxera in France, albeit with limited success. Undeterred, he proposed a similar strategy for the cottony cushion scale crisis. In 1888, Riley dispatched his trusted colleague, a fellow entomologist named Albert Koebele, to Australia to identify natural enemies of the pest.

The cottony cushion scale infestations were so severe that citrus trees appeared as though they had been coated with artificial snow, resembling Christmas flocking. Fruit production sharply declined, and many trees succumbed to the damage. (UC Riverside)

Interestingly, Valentine resorted to subterfuge to send an entomologist to Australia despite Congress’s objections. Lawmakers had prohibited foreign travel by the Agriculture Department to curb Riley’s frequent European excursions. However, Riley, well-versed in navigating political obstacles, cleverly arranged for an entomologist to join a State Department delegation heading to an international exposition in Melbourne.

Charles Valentine Riley (Wikipedia)

Koebele’s expedition proved fruitful. He worked with Australian experts to locate the pest in its rare habitats along with its natural enemies, including a parasitic fly and approximately the Vedalia beetle. The vedalia beetle (Rodolia cardinalis) is a small ladybird with a voracious appetite for the cottony cushion scale. Koebele collected and shipped hundreds of these beetles back to California. Upon their release into infested orchards, the vedalia beetles rapidly established themselves, feasting on the scales and reproducing prolifically. Within months, the cottony cushion scale populations had diminished dramatically, and by 1890, the pest was largely under control across the state. This 1888-89 campaign marked the beginning of biological control in the United States, a strategy involving the introduction of natural predators to manage invasive pests.

In her 1962 classic Silent Spring, Rachel Carson described the Novius beetle’s work in California as “the world’s most famous and successful experiment in biological control.”

Novius ladybug devours an Icerya.  (UC Riverside)

This was far from the last time California employed such measures. It became a relatively common practice to introduce new species to control those that posed threats to the state’s economically vital crops, but not always successfully.

In the 1940s, California introduced parasitic wasps such as Trioxys pallidus to control the walnut aphid, a pest threatening the state’s walnut orchards. These tiny wasps laid their eggs inside the aphids, killing them and dramatically reducing infestations, saving the industry millions of dollars. Decades later, in the 1990s, the state faced an invasive glassy-winged sharpshooter, a pest that spread Pierce’s disease in grapevines. (Interesting fact: The glassy-winged sharpshooter drinks huge amounts of water and thus pees frequently, expelling as much as 300 times its own body weight in urine every day.) To combat this, scientists introduced Gonatocerus ashmeadi, a parasitic wasp that targets the pest’s eggs. This biological control effort helped protect California’s wine industry from devastating losses.

The Vedalia beetle (novius cardinalis) also known as the cardinal ladybird (Katja Schulz Wikipedia)

While the introduction of the vedalia beetle was highly effective and hailed as a groundbreaking success, biological control efforts are not without risks, often falling prey to the law of unintended consequences. Although no major ecological disruptions were recorded in the case of the cottony cushion scale, similar projects have shown how introducing foreign species can sometimes lead to unforeseen negative impacts. For example, the cane toad in Australia, introduced to combat beetles in sugarcane fields, became a notorious ecological disaster as it spread uncontrollably, preying on native species and disrupting ecosystems. Similarly, the mongoose introduced to control rats in sugarcane fields in Hawaii also turned predatory toward native birds. These examples highlight the need for meticulous study and monitoring when implementing biological control strategies. Today, regulatory frameworks require rigorous ecological assessments to minimize such risks.

The glassy-winged sharpshooter (Georgia Tech)

In the case of the Vedalia beetle, its precise and targeted predation led to a highly successful outcome in California. Citrus quickly became one of the state’s most dominant and profitable crops, helping to establish California as a leader in agricultural production—a position it continues to hold firmly today.

This groundbreaking use of biological control not only rescued California’s citrus industry but also established a global precedent for environmentally sustainable pest management. The success of the Vedalia beetle’s introduction showcased the power of natural predators in managing agricultural pests, offering an alternative to chemical pesticides. While pesticides remain widely used in California and across the world, this effort underscores the value of understanding ecological relationships, evolutionary biology, and the benefits of international scientific collaboration.

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The story of the Vedalia beetle and the cottony cushion scale highlights human ingenuity and the effectiveness of nature’s own checks and balances. It stands as an early example of integrated pest management, a method that continues to grow and adapt to meet modern agricultural challenges. This successful intervention underscores the importance of sustainable practices in protecting both our food systems and the environment.

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