Climate Change Prompts These Six Pests To Come And Eat Your Crops

As the environment changes, new and resurgent bugs are threatening our food supply. Climate Change Prompts These Six Pests To Come And Eat Your Crops

Climate change is opening up new habitats to old pests, transforming them from a mere nuisance into a growing menace and placing unprecedented threats on the global food supply. Here are six bugs to keep an eye on.

Fall Armyworm
Spodoptera Frugiperda

Found In: Africa, Australia, East And South Asia, And North And South America
Eats: Corn, Rice, Sorghum, Sugar Cane, Wheat

Native to tropical areas of the Western Hemisphere, this invasive species has spread rapidly, causing “major damage to economically important cultivated grasses,” according to CABI, the nonprofit Centre for Agriculture and Biosciences International. The pest infested about 15% of Zambia’s corn crop this year. It also contributed to a 4% decline in China’s corn harvest—a difference of about 11 million tons—sending prices skyrocketing and forcing the country to open its strategic stockpile, according to the U.S. Department of Agriculture.

Western Corn Rootworm
Diabrotica Virgifera Virgifera

Found In: Europe and North America
Eats: Corn

These insects are most destructive in the larval stage, when they burrow into and feed on plants’ roots. This makes their presence especially difficult to detect: A plant’s root structure may be almost destroyed, but aboveground it can still appear normal. A storm may easily knock over the stalks, as happened in the U.S. this summer, when high winds blew down stalks across millions of acres of Iowa corn. The rootworm is also increasingly resistant to genetic modifications in corn designed to thwart it, according to the University of Illinois’s Farmdoc data center.

Coffee Berry Borer
Hypothenemus hampei

Found In: Tropical Climates—I.E., Almost All Coffee-Producing Countries
Eats: Coffee

These tiny beetles make their home inside the fruit of coffee plants, eating them from the inside out. The bug used to stick around lower, warmer elevations, but rising temperatures have coaxed them higher uphill. That’s affecting the more expensive arabica coffee varietals, which prefer to grow on the slopes. Controlling the beetle population requires careful, labor-intensive monitoring. And farmers, who are already seeking higher ground because of climate change—coffee plants are particularly sensitive to temperatures—are running out of room.

Schistocerca Gregaria

Found In: Africa, Asia, And The Middle East; Plus A Few Cases In Europe
Eats: Pretty Much Anything

Desert Locust

This pest has a Biblical appetite. In the past year it’s ravaged crops in regions as far-flung as East Africa and northern India. Both outbreaks were made possible by warmer seas, which generate more hurricanes and typhoons, which in turn create the perfect breeding ground for locusts. Ample rains moisten the soil, helping eggs thrive and encouraging vegetation growth in typically arid regions. As the climate gets more volatile, locust swarms are expected to become both more frequent and more severe.

Soybean Gall Midge
Resseliella Maxima

Found In: U.S. Great Plains, Creeping Into The Midwest
Eats: Soybeans

This tiny up-and-comer has been appearing in soybean fields in Iowa, Minnesota, and Nebraska. Its larvae attack the stems of soy plants that are in flower. There’s no known effective defense. “Nothing was significant enough to suppress the larvae,” says Erin Hodgson, associate professor of entomology at Iowa State University. “Plants can experience straight-up death.”

Spotted Wing Drosophila
Drosophila Suzukii (Matsumura)

Found In: Asia Primarily, But Increasingly In The Americas And Europe
Eats: Summer Fruits, Such As Berries, Cherries, And Grapes

The flying pest’s small larvae feast on soft, expensive fruits, rendering them unsellable and costing farmers millions of dollars. Although it showed up in North America only a decade ago, it’s already wreaked havoc on U.S. berry farmers. Rising temperatures will expand the drosophila’s potential habitat, allowing it to push farther north each year.

Meet The New Climate Refugee In Town: Coyotes

As droughts and fires worsen, wild animals are migrating into cities. In Berkeley, California, some residents have had enough.

Amid the sylvan tranquility of the Berkeley hills neighborhood, an image of a snarling predator, fangs bared, stares down at passersby from atop a pole planted in the yard of a sprawling Tudor-style home. “Danger! “Coyotes!” the homemade placard warns.

It’s a sign of a growing climate-driven conflict. Drought and heat waves are not only fueling catastrophic wildfires in California’s wildland-urban interface, they’re also driving coyotes and other wildlife into the streets in search of food and water, according to scientists.

That’s triggering clashes among residents over an influx of four-footed climate refugees into the Berkeley hills and adjoining neighborhoods wedged between a vast regional park and San Francisco Bay.

Tracy Richardson says she and her partner put up the sign after a coyote crossed into their yard on an August Sunday morning and growled at them and their three cats. A week later, she says, a coyote snatched one of the felines and ran down the street. “Our cat was sitting like five feet from us and the coyote came up to get the cat,” says Richardson. “We’re doing this is to stop the inevitable, which is a human is going to get attacked.”

Attacks on people are rare. But with reports of coyotes roaming the hills and preying on pets multiplying as California’s record-breaking drought drags on, the response from some in this affluent, ecologically self-conscious enclave has become increasingly dark. “I am in favor of shooting the most dangerous coyotes,” one neighbor declared on Nextdoor in August while another wrote, “Would be nice to see coyotes eradicated from the city.”

Richardson has hired a trapper, who placed a cage on their property. No coyote has yet been caught.

Urban coyotes have established themselves as a permanent presence in cities nationwide over the past two decades. Climate change, however, is now pushing wildland animals — coyotes, bears, bobcats, feral pigs, elk — into residential areas where food and water are abundant.

“Most coyotes will try to stay away from folks as much as they possibly can, but as droughts and fires get worse, they will have no choice but to move into human settlements,” says Christopher Schell, an assistant professor at the University of California at Berkeley who studies urban coyotes. “That sets up the perfect storm for human-coyote conflict.”

As climate change alters the habitats and migration patterns of wildlife, those confrontations are likely to rise, scientists say, compelling a reassessment of how humans share a landscape they and their pets have long dominated.

“It’s just an incredibly unrealistic expectation to think that we’re going to be able to keep wildlife like coyotes out of cities,” says Morgan Farmer, a PhD student researching urban carnivores at the University of Wisconsin-Madison. “Our effort is better spent trying to understand how to coexist rather than to try and remove them.”

Tilden Regional Park is a 2,079-acre preserve of canyons, meadows, eucalyptus forests and oak and bay laurel woodlands that borders Berkeley and other East Bay cities. Nearby residents have long lived with wildlife. Families of deer amble down winding lanes, grazing on carefully cultivated gardens. Gray foxes perch on backyard fences, scouting for squirrels. And on occasion, a mountain lion will leave Tilden for dinner in town, chasing deer through hillside neighborhoods.

Encounters with coyotes tended to be fleeting, a shadowy shape caught in the corner of the eye or in the headlights of a car as the omnivores moved through the hills at dusk and dawn. During periodic droughts, though, daytime sightings become common as water and prey grow scarce in Tilden. Such contact – and the alarm it raises — was cyclical. As the rain inevitably returned after past droughts, so did some coyotes to the park.

Now, scorching heat waves and back-to-back droughts are upending that balance. California is in the second year of an extreme drought, and since October 2020, more than 1,000 acres of trees have died in East Bay regional parks. By fall, most of the parks’ ponds and streams had gone dry for the first time in memory, according to Doug Bell, wildlife program manager for the East Bay Regional Park District.

That in turn precipitated a fall in populations of rabbits, squirrels and other coyote chow. As water dries up, wild turkeys have descended into the flatlands, and residents have recently posted sightings of feral pigs roto-tilling lawns and bobcats bounding into backyards.

“It’s been mind-boggling and there probably has been a lot of movement of animals like bobcats and coyotes into the urban environment because we supply a lot of food, water and places for them to seek refuge,” says Bell, noting coyotes’ indiscriminate palate includes cats and other small mammals, fruit and just about anything edible that humans toss in the trash.

Across San Francisco Bay, the black bear population had been extinct in Marin County for 120 years with only rare sightings of individual animals over the decades. Then in May, a homeowner in the town of San Anselmo found a 200-to-300-pound bear clinging to an oak tree in her backyard, a block from downtown.

“There’s probably several bears in Marin County now,” says Stacy Martinelli, a wildlife biologist with the California Department of Fish and Wildlife, noting confirmed sightings over the summer.

In neighboring Sonoma County, a 500-pound black bear rambled around a neighborhood near downtown Petaluma last month before seeking refuge in a redwood tree.

Martinelli has received so many calls from Sonoma County residents about bears that she is helping lead a two-year genetic study of the population that could shed light on whether climate conditions are prompting migration to cities. She says Tule elk, which were not known to exist in Sonoma, have begun to show up in backyard gardens.

How many coyotes traverse East Bay neighborhoods is unknown, though Schell says planned research projects aim to pinpoint the population and its distribution. He says increased sightings of coyotes in part may be due to more people working from home and strolling their neighborhoods during the Covid-19 pandemic.

One indication of coyote numbers in the area comes from a 2017 study conducted by Farmer when she was a UC Berkeley student. She set up nine camera traps on trails in Tilden and captured images of coyotes over the course of a year. Farmer determined that the park is probably home to six to 10 coyotes; likely many more live in the vicinity and may pass through Tilden.

“There’s a lot of tension between people who are really concerned about the safety of their children or their pets and people who really value the animals and their place in nature,” says Farmer.

Those tensions have intensified in recent months, polarizing an otherwise politically homogenous community where Joe Biden received upwards of 95% of the presidential vote in 2020 and “Hate Has No Home Here” signs dot the yards of $1.8 million houses.

Residents routinely post photos of coyotes trotting down streets during the day on social media along with reports of cats killed by the animals. That’s generated hundreds of comments and petitions to local officials to reduce the animal’s numbers.

One neighbor called coyotes “a parasite on human beings” on Nextdoor in August, prompting another to respond, “Coyotes have been living and hunting here since before European colonization. Are you actually advocating for a mass extermination of a species?”

Gina Farr is an environmental educator and advisory board member at Project Coyote, a Marin County-based nonprofit that promotes co-existence with carnivores. She says such reactions express both an ancient fear of predators and a misunderstanding of coyote behavior in residential areas.

Wildlife experts say coyotes rarely attack people and incidents mostly happen when a coyote has become habituated to humans who feed the animals or give them easy access to food.

“Coyotes are simply being attracted by a resource that takes very few calories to obtain,” says Farr, noting that keeping cats inside, dogs on leashes and putting food and water out of reach will minimize negative interaction with coyotes.

Kensington resident Marilyn Stollon says she started a spreadsheet of sightings in three East Bay communities after a coyote jumped a fence and chased her cat through a neighbor’s yard. She says she’s so far this year recorded 102 coyote sightings and 21 cats killed.

“I do believe that once urban coyotes have been habituated and are rogue….it may signal that those few need to be removed,” Stollon said in an email, adding that she now keeps her cat inside.

Other factors may drive coyote conflicts. Schell says research shows that coyotes favor green spaces most often found in wealthier communities that may regard the incursion of such outsiders as a threat. “The historical and contemporary legacies of inequality shape how we perceive and treat coyotes and how folks view their ownership of the landscape,” he says. “That will only get worse as fire and drought get worse.”

To Farr, trying to wall off neighborhoods from animals people find problematic is “like digging a hole in the ocean” – there’s always another wave of wildlife to take their place.

“We live in a natural world,” she says, “and we can never sterilize nature around us.”

Updated: 8-8-2021

Invasive Insects And Plants Spread Northward

From tree-eating beetles to crop-smothering vines, pests once found only in more southerly latitudes are expanding their ranges, as climate change spurs warmer winters.

Chris Steigerwald saw the browning tops of the pitch pines and hiked toward them for a closer look. As he drew near, the New York forester said he saw tree trunks marked with hundreds of oozing, popcorn-like defects—evidence the trees were infested by a tiny beetle with a big appetite for pine.

“I never like finding the southern pine beetle because I know all these trees are going to die,” Mr. Steigerwald said of his July trek. But he is glad he spotted them: These beetles, “a pine tree predator,” he said, quickly spread if his team doesn’t catch them early.

Week after week, Mr. Steigerwald drives and hikes Long Island’s Central Pine Barrens, tags trees infested with the beetle and chainsaws them down.

Since the invasive insect was discovered on Long Island in 2014, the New York Department of Conservation reports that foresters have cut down more than 10,000 pines in the network of state and federal preserves there. Eradication is impossible, agency documents say; they can only hope to slow it down.

Just a few decades ago, it seemed unlikely that the southern pine beetle—a species native to the Southeastern U.S., Mexico and Central America—could make its way to New York. Today, invasive-species researchers say this beetle is one in a rising tide of plants and pests marching north.

Invasive species like the southern pine beetle, emerald ash borer and kudzu already cost the U.S. economy $120 billion a year in damage and removal costs, according to the U.S. Department of Agriculture. They choke crops, topple telephone poles, devalue timber and require extraordinary effort to beat back.

The Northeastern U.S. has long been vulnerable to invasive species because of its transportation hubs, through which travelers and goods inadvertently spread non-native species, and the hurricanes and other wind events that move seeds and insects up the Eastern Seaboard. Research also shows that state laws governing the sale of non-native plants in the region are inconsistent.

A body of evidence suggests that the problem here and nationwide is growing worse as a result of climate change—in particular, a warming of winter’s lowest temperatures. The coldest temperature of the year at some measurement sites in New York and New England has risen more than 6 degrees Fahrenheit since the 1960s, according to the most recent National Climate Assessment, a federal government report released in 2018.

“This is a massive change from an ecological perspective,” said Matt Ayres, a Dartmouth College entomologist whose work in the 1990s was among an early body of research suggesting rising temperatures could have profound impacts on invasive species.

Back then, his research team sought to understand why the southern pine beetle—an aggressive insect ubiquitous in the South—hadn’t yet invaded pine habitats in other parts of the country. They tested every barrier they could think of: Did habitat factors limit their food supply? Did summer warmth limit their breeding? The researchers determined that the factor limiting northward expansion of the beetle seemed to be the temperature on the coldest night of the year.

“Sitting in the laboratory watching the temperature of the beetle, it goes down, down, down, down, and then there’s a spike,” Dr. Ayres said, recalling their experiments. “That’s the heat of fusion the moment the fluids in the beetle crystallize.” At about 10 degrees Fahrenheit, it is the precise moment of its death. Beetles couldn’t thrive much farther than Delaware, his team surmised, because of the cold winters.

Based on regional temperature data, Dr. Ayres predicted in the 1990s that should the coldest night of the year warm up by 5 degrees, infestations could spread about 100 miles north to threaten pine ecosystems.

What they didn’t expect, Dr. Ayres said, was how fast the temperature shift would occur. By 2018, U.S. Forest Service researchers confirmed the southern pine beetle had reached as far as Connecticut and Rhode Island, a 140-mile expansion northward.

Carrie Brown-Lima, head of the New York Invasive Species Research Institute at Cornell University, said pests are now thriving here that she never thought could. “We really need to shift our thinking to understand that those rules don’t apply anymore,” she said. Otherwise, she added, “we’ll end up spending more money and having less impact” managing them.

Kudzu—a fast-growing vine already causing $100 million in annual damage to the agricultural and timber industries, power and railroad companies and public lands, according to plant researchers—has recently been found thriving along the Garden State Parkway by New Jersey invasive-species managers.

Hemlock woolly adelgid, a sap-sucking insect that the National Park Service says has destroyed up to 80% of the eastern hemlocks along the Blue Ridge Parkway in Appalachia, is now killing trees as far north as Maine and Nova Scotia, according to the Maine Forest Service and Canadian government.

The emerald ash borer, which according to the U.S. Forest Service has eaten its way from the Midwest to the Northeast doing nearly $12 billion in damage to U.S. ash trees since it arrived in 2002, is now moving deeper into Canada, according to scientists there.

Although climate change has given many invasives the opportunity to thrive in new places, it doesn’t make their arrival inevitable, said Bethany Bradley, plant ecologist and co-founder of the Northeast Regional Invasive Species and Climate Change Management Network of scientists, policy makers and natural-resource managers.

“The best management of an invasive species is to prevent it before it arrives,” she said, and one way to do so is targeting known pathways of introduction. For pests, that might mean regulating the use of solid wood shipping crates, a common vector for wood-boring insects. For plants, she said, the best tool is laws to prevent sales of ornamental plants known to harbor invasive pests or causing extensive damage themselves.

University of Massachusetts researchers Evelyn Beaury and Emily Fusco this year compiled regulations from every state and found that nationwide, banned-plant lists among neighboring states are often very different from each other. Some states, they found, have no regulations at all. “That automatically creates gaps across the country,” Ms. Beaury said.

Wayne Mezitt, chairman of Weston Nurseries and member of a group advising the commonwealth of Massachusetts on managing invasives, said that while nurseries don’t love regulation, most respond well to rules on invasive species.

His group is developing guidelines to inform state regulation, he said, and he’d like to see uniform invasiveness criteria nationwide that would ease confusion and create space for the industry to develop noninvasive versions of some species otherwise banned. “We want to do something that’s right for the future,” he said.

In Maine, state forest service entomologist Tom Schmeelk monitors southern pine beetle traps at 12 sites across the state, aiming to catch an invasion as early as possible.

He fears for the state’s red pines, an important source of extra income for rural families, and the pitch and jack pine forests along beaches that draw tourists to the coast. It is there that he expects the beetles will first arrive—somewhere like popular midcoast Popham Beach, he said, “traveling with the wind.”