Bee researchers draft new weapon in fight against deadly varroa mite

Honeybees, worth almost $20 billion to American agriculture, are worth protecting — and a new biological weapon scientists discovered may help combat honeybees’ main enemy, aptly named the varroa destructor.

The varroa destructor is a parasitic mite responsible for decimating honeybee hives. Now, in an effort to save bee colonies, researchers are tapping into an unlikely ally: the bacteria that live in bees’ guts.

In a January 2020 experiment, scientists engineered gut bacteria that occurs naturally in bees. The results, they reported, were astounding — the mites died after ingesting the manipulated bacteria, while the bees’ own immune systems were strengthened.

Outside the lab, researchers say they hope the technique can be scaled up to rescue full colonies.

But there’s a long road ahead.

Since the 1940s, the number of hives in the U.S. has nose-dived from 6 million to 2.5 million. From 2018 to 2019 alone, U.S. beekeepers lost more than 40% of their colonies, according to the Bee Informed Partnership.

A combination of colony-killing foes are blamed, but researchers say varroa mites pose the greatest threat.

“Varroa mites are the worst,” said Laura Lavine, entomology department chair at Washington State University. “They’re the most imminent threat to beehives in North America today.”

The mites kill bees by feeding on their fat stores, said Tim Hiatt, a commercial beekeeper and member of the Washington State Beekeepers Association. They also carry the deadly “deformed wing” virus, which they transmit to bees.

To put this in human scale, molecular biology researcher Sean Leonard said to imagine a mammoth tick clinging to you and feeding off your body.

“It’s like having a giant tick the size of your face sucking your blood,” said Leonard.

Leonard is a graduate student at the University of Texas studying cell and molecular biology. He is part of the research team that discovered the potential solution to combating varroa mites.

Leonard and his colleagues engineered double-stranded RNA to use as ammunition against varroa mites and the virus they carry.

RNA, or ribonucleic acid, exists in all living cells. Its main role is to act as a messenger, carrying DNA’s protein-coding instructions to a cell’s reproduction machinery. But RNA can also be used to shut down invasive genetic materials.

The team of scientists at the University of Texas at Austin used two similar but distinct techniques, one for killing the mites and another for combating the virus.

To attack the virus, the scientists used a preventive technique similar to vaccination in human or animal medicine. Using double-stranded RNA, they introduced a small portion of the genome into the bee, which strengthened the bee’s immune system against the later invasion of a full-scale virus.

“If you could compare it, it’s almost like getting a vaccine,” said Leonard.

To kill the varroa destructors, the research team attacked the mites’ immune systems directly.

Leonard figured out how to genetically modify Snodgrassella alvi, one of the bacteria in a bee’s gut, so it would produce RNA that matched the genetic material he wanted to dismantle.

The team then put the engineered bacteria into sugar water and fed it to honeybees. Later, when the mites fed off the bees, they ate the engineered bacteria — and died. The mites, which were forced to dismember some of their own genes, had been tricked into killing themselves.

Mites were 70% more likely to die on treated bees, and bees infected with the virus were 36% more likely to survive, the team reported.

“When we got those results in, we definitely started to get excited,” said Leonard. “I think this is such a promising technology. But we don’t have a marketable product yet.”

The techniques, though exciting, won’t immediately be available to beekeepers.

Critics are concerned about the use of engineered bacteria outside the lab, since bacteria in the wild are not easy to contain. Leonard said caution is crucial, but because the bacteria are not known to exist outside bees’ guts, he is not worried about cross-species infection.

Experts agree that more experimental work needs to be done on hives in controlled settings before testing the effectiveness on a mass scale.

It will take time, research, industry partners and funding to make this work, said Leonard.

Through his research, Leonard has developed an appreciation for bees.

“I’ve come to love these fascinating creatures,” he said. “There’s something amazing about opening a hive and seeing thousands of bees crawling all over and working together.”

When he completes his Ph.D., Leonard said, he hopes to join the ranks of U.S. beekeepers — hopefully in a world with fewer threats from varroa mites.

Registration still open for Small Farms Conference

Registration for Oregon State University’s popular Small Farms Conference is still open.

The day-long event will be held Feb. 22, 2020, at OSU’s Corvallis campus at the LaSells Stewart Center and CH2M Hill Alumni Center.

“The Oregon Small Farms Conference is a daylong event geared toward farmers, agricultural professionals, food policy advocates, students and managers of farmers markets,” according to the event’s website.  “Twenty-seven educational sessions are offered on a variety of topics relevant to the Oregon small farmers. Speakers include farmers, OSU Extension faculty, agribusiness, and more.”

Registration through Feb. 7 is $85. Registration is not available at the door.

In addition to three seminar sessions, the conference includes a networking session, “Think With a Drink,” which will allow attendees to confer with other small farmers over beer, wine or cider.

For more information, go to the conference website.

The conference is sponsored by Northwest Farm Credit Services.

Asian giant hornet, a nemesis of honeybees, appears in Washington

BLAINE, Wash. — As if life wasn’t hard enough for the honeybee, things just got worse with the appearance of a new hornet that can decimate hives.

While honeybees in North America face many foes such as lethal varroa mites, a new nemesis buzzed onto the scene in Washington state — an invasive species capable of killing honeybee populations, reducing crop pollination and stinging humans.

The pest is the Asian giant hornet. According to entomologists, it is indigenous to Asia, where it has many names: commander wasp, yak-killer hornet and tiger head bee.

The hornets are distinguishable by their yellow heads, long bodies and three-inch wingspans.

The hornets prey on other insects, feeding pulped bugs to their larvae.

Where similar species of hornets are established in Europe, they have wiped out 30% of beehives, reduced honey production by two-thirds and dramatically slashed crop production due to lack of pollination, according to Washington State Department of Agriculture public engagement specialist Karla Salp.

A typical Asian giant hornet is five times the size of a honeybee and can kill up to 40 bees per minute, according to Tim Hiatt, a commercial beekeeper and member of the Washington State Beekeepers Association.

“No one knows what triggers it, but sometimes they literally go into slaughter phase, decapitating bee after bee and eating their bodies,” said Salp. “It takes 20 hornets to kill an entire hive in one to six hours.”

Probable sightings
The first Asian giant hornet sightings recorded in the U.S. were Dec. 8 by a resident of Blaine, Wash., just south of the state’s border with Canada. They had previously been confirmed at three sites in British Columbia.

Since then, WSDA has received 80 new sighting reports, three of which they deem probable. One was from a Bellingham beekeeper.

“Since these hornets are normally dormant in the winter, it’s unusual to find them active this time of year,” said Salp. “It’s probably because the winters are milder here, so they’re surviving better. It seems the Pacific Northwest is their ideal environment.”

Hitchhiking hornets
All it takes to establish a new colony is one mated female, said Salp. And to invade a new location, a queen hornet just needs to do a little hitchhiking.

“Honeybees are mobile,” said beekeeper Hiatt. Bees are shipped across the U.S. to pollinate crops. Three-quarters of all managed beehives are shipped to California in February to pollinate almonds.

At the border, California Border Protection Stations, or as Hiatt calls them, “bug stations,” inspect for pests. In summer, finding stowaway hornets would be easy, said Hiatt. But in winter, when hornets are dormant, finding one tucked inside a pallet is nearly impossible.

Experts say it will take everyone working together to stop the spread.

“This is a good citizen-scientist moment,” said Laura Lavine, chair of Washington State University’s entomology department. “Everyone can pitch in.”

If you’re a beekeeper
According to entomologists, Asian honeybees have developed natural defense instincts. When a hornet invades, honeybees clump together around the invader in tens or hundreds, creating a giant ball and suffocating their attacker.

North American honeybees, said Salp, appear not to have this instinct.

“I think there’s a need for panic,” said Lavine. “I’ve heard anecdotes of beekeepers in Asia standing around with badminton rackets, smacking the hornets to the ground and stomping them. I know that sounds totally insane, but that’s what it can come to.”

Hobby beekeepers, said Hiatt, should consider putting a so-called robbing screen, which hornets can’t enter but bees learn to navigate through, in front of beehives.

Robbing screens, however, aren’t feasible for commercial-size operations. Hiatt suggests all beekeepers restrict the entrance size of hives, making it harder for hornets to enter.

If you’re a farmer
Farmers, Hiatt said, should watch for the hornets, which nest in the ground.

However, he warned against flushing out any ground nest indiscriminately. He said some native bees nest in the ground — many of which pollinate crops, especially alfalfa.

Be alert
Experts say everyone should be alert — especially in port cities, where there is ongoing trade with Asia.

If you think you’ve found an Asian giant hornet, report it immediately to WSDA’s pest program via email at Send a photo if possible.

Put safety first. In Asia, according to Salp, dozens of people die annually from stumbling into hornet nests. If you get stung and have an allergic reaction, call 911 and get medical help.

Hemp attracts younger generation of farmers

Artist, sound engineer and adventure traveler Blu Fortner is adding “farmer” to his resume with his first commercial crop of hemp seed.

The Idaho native moved across the state line to Oregon five years ago in his pursuit of growing medicinal hemp.

His attraction was the plant’s potential to provide relief to people suffering from various ailments.

“I moved to Oregon because the laws here were more cannabis-friendly,” he said.

He started with a small, organic, medicinal grow but soon found there wasn’t a market for his production.

With his limited agricultural experience, he was fortunate to meet Clint Shock, a plant physiologist and agronomist. Shock, who was the director of Oregon State University’s Malheur Experiment Station, was interested in medicinal plants.

“I wanted to learn about non-cannabis medicinal plants, and he wanted to learn about hemp,” Fortner said.

It made for a good partnership, he said.

The two teamed up in a teacher-student relationship and did a four-plant, hemp test in Shock’s back yard last year. Three of the plants were successful females that produced high-level CBD oil.

CBD is a non-psychoactive compound in hemp thought by many to offer numerous health benefits.

This year, Fortner and Shock planted hemp in two fields and a total of 5 acres to produce feminized hemp seed for growers. They also partnered in a new business — Medicinal Botanical Seed.

If the crop is successful, they plan to expand production next year.

At 38, Fortner is one of a growing number of “brand new farmers” drawn to agriculture by the allure of hemp, a newly legal crop that produces CBD and a variety of other products ranging from the edible seeds to clothing material. Hemp production was legalized in the 2018 Farm Bill.

Both THC — the main psychoactive compound in marijuana, which is also thought to have health benefits — and CBD found in hemp have a lot of value, he said.

“But THC is limited by state and federal regulations, and CBD is legal nationally and internationally,” he said.

He thinks younger people’s attraction to hemp farming is connected to their belief that it should be legal. But it also provides a niche for farmers who don’t have a lot of resources when it comes to land, equipment and capital.

“For farming in general, there isn’t easy access. There are almost insurmountable hurdles for young farmers,” he said.

But with demand for hemp currently higher than the supply, a small-scale farmer can grow 1 acre and make a living, he said.

Legal boom
Michael Bowman — widely known as “Mr. Hemp” — has been a driving force in the legalization of hemp production in the U.S.

He’s farmed his entire life on the eastern plains of Colorado above the declining Ogallala Aquifer. Twenty years ago, he was researching crops that would use less water than corn and alfalfa.

“The hemp plant captured my attention and imagination,” he said, listing the plant’s other environmental benefits.

That started him on a path of advocacy, and he became the founding board chairman of the National Hemp Association.

The association had a state-by-state strategy to get hemp legalized and build support for federal legalization. It resulted in progress in the 2014 Farm Bill and victory in the 2018 Farm Bill.

The 2014 Farm Bill legalized hemp research in states where its production was allowed, and the 2018 Farm Bill took hemp off the controlled substance list and redefined it as an agricultural crop.

According to Vote Hemp, a nonprofit advocacy group, 46 states have now legalized hemp.

The 2018 Farm Bill also lifted restrictions on interstate commerce and lending by financial institutions and authorized crop insurance.

But the new rules guiding those issues won’t be in place until 2020, making 2019 the industry’s “teenage years,” Bowman said.

“It’s been a little awkward, but there’s been significant growth under that awkwardness, he said.

Since the passage of the 2018 Farm Bill, hemp cultivation in the U.S. has grown rapidly, according to Vote Hemp. The organization estimates 230,000 acres of hemp were planted in 2019 compared to 78,176 acres in 2018.

Moving the needle
The U.S. hemp industry is driven by CBD oil, both because of the potential profits and the current lack of infrastructure to produce other hemp products, Bowman said.

Economic models show a net return for growing hemp for CBD oil from $20,000 all the way up to $80,000 an acre for someone “who really knows what he’s doing,” he said.

“It gets a lot of farmers’ attention,” he said.

But contrary to what most people believe, it’s not an easy crop to grow for high production, he said.

“There’s certainly a community of first-timers that didn’t make any money,” he said.

There’s huge demand for hemp and CBD products, and the new legislation that legalized hemp farming has really opened up the market, Jessica Manly, communications director for National Young Farmers Coalition, said.

“I do think it’s something that’s attracting younger farmers,” she said.

From what she’s hearing, a lot of beginning farmers are becoming interested in growing hemp and some young farmers are experimenting with it on some of their land.

In addition, a lot of commodity farmers are transitioning their operations to hemp because prices are much higher than the crops they’ve been growing, she said. Many commodity crop prices have remained low in recent years.

There are some concerns, however, about regulation, permitting and interstate trade, she said.

“That’s still getting sorted out because it’s such a new industry,” she said.

There is also concern about whether this is a bubble that’s going to burst — whether demand will hold up over time or whether the market will be over-supplied, she said.

On the flip side, vegetable growers are worried about competition for land. Hemp growers might be able to pay more for land and crowd them out, which also raises a food security issue, she said.

“It’s definitely a concern,” she said.

Youthful appeal
The legalization of hemp farming has created a “hemp Wild West” that’s bringing new farmers and younger farmers into the industry, Bonny Jo Peterson, executive director of the Industrial Hemp Association of Washington, said.

She’s talked to several conventional farmers who say hemp is getting their children and grandchildren interested in farming.

Some who were looking to sell their operation because they had no interested successor now find they do have a succession plan, she said.

“Hemp is more exciting than corn or hay. A lot of millennials are jumping in full bore,” she said.

It’s something they find interesting. They see the potential hemp brings to the table when it comes to climate and the environment. On the CBD side, the attraction is its potential as an alternative medicine, she said.

The interest in hemp extends beyond the farming end of things. It’s also in processing, consulting, soils, pesticides and machinery, she said.

“Just about every aspect of agriculture is being tapped into for this new experience,” she said.

Peterson helped write the bill that fully authorized hemp production in Washington. Gov. Jay Inslee signed it into law last April.

The legislation spurred growth in the state’s industry from one grower with about 140 acres to more than 100 licensed businesses and about 7,000 licensed acres, she said.

The majority of those businesses are growers, and at least one-third are new farmers, she said.

Rural resurgence
Hemp is attractive for a lot of reasons, including its role in the country’s history and U.S. agriculture, Bowman, the Colorado advocate, said.

Hemp is used in more than 25,000 products, giving anyone with an imagination and an entrepreneurial spirit a “lane to swim in,” he said.

Growing crops like corn, soybeans, cotton and rice is robotic, he said.

“There’s nothing to tickle the right side of the brain, everything is prescribed,” he said.

Millennials and Generations X, Y and Z have little interest in systems like that, he said.

“The point of it is … the plant has come out of prohibition, and they want to show you what can be done,” he said.

Hemp is absolutely bringing young people into agriculture, he said. Colorado, for example, is seeing a tremendous number of young people entering the field, he said.

That includes people who don’t have an agricultural background and an influx of young people coming back to the farm and rural communities, he said.

“I’m really excited about that. We are seeing a resurgence, and it’s all due to the plant,” he said.

But it’s going to take leadership to keep that momentum going, he said. People who see the opportunity, embrace it and develop policy to support it are going to do well and “create an ecosystem of bringing kids back” to agriculture, he said.

At 60, he’s about the average age of U.S. farmers today. The industry needs a younger generation to take up the reins, he said.

“This is our one chance, generational chance, to reset the clock,” he said.

Researchers use tiny wasp to control stinkbugs

CORVALLIS, Ore. — The samurai wasp may be small, but it is a mighty assassin of one of Oregon agriculture’s most detested pests — the brown marmorated stinkbug.

No bigger than a pinhead, the tiny wasp lays its eggs inside the eggs of stinkbugs, killing the host when they hatch. Stinkbugs first arrived in Oregon in 2004 and are a scourge to farmers, damaging high-value crops including wine grapes, blueberries, cherries and hazelnuts.

Researchers know the samurai wasp can be an effective biological control for stinkbugs. A new study from Oregon State University goes a step farther, describing how farmers can integrate the wasp as part of an overall management strategy.

David Lowenstein, an entomologist and postdoctoral research associate at OSU, led the study, which focuses on the impacts of different insecticides on wasp survival. His results found that some chemicals were highly lethal to the wasp, while others were more suitable.

The study was published recently in the Journal of Economic Entomology. Funding came from the Oregon Hazelnut Commission, Oregon Raspberry and Blackberry Commission and the USDA Specialty Crop Research Initiative, which is assisting more than 50 researchers across the U.S. studying ways to defeat the stinkbug.

Like the stinkbug, the samurai wasp is native to east Asia. It was discovered in 2016 in the Willamette Valley, and since then OSU has bred colonies of the wasp in Corvallis and at the North Willamette Research and Extension Center in Aurora, Ore., to distribute to commercial orchards.

“They are not available commercially,” Lowenstein said. “We’re the sole group that is rearing the parasitoid and trying to get it established in different parts of the state.”

However, Lowenstein said it does no good to distribute the wasps while farmers are spraying certain types of insecticides to control other pests.

For the study, Lowenstein tested the effects of nine insecticides on samurai wasps in lab and field trials. He said neonicotinoids and pyrethroids were “fairly toxic” to the wasps, while diamide insecticides were less toxic.

One reason for this is because diamide insecticides specifically target sucking and chewing insects such as filbertworm larvae in hazelnut trees, while neonicotinoids and pyrethroids are “broad-spectrum” insecticides, Lowenstein said.

“The application of this work is that, for someone who wants to benefit from biological control from the samurai wasp, first they’re going to have to time it around when they apply insecticides,” he said. “We don’t expect chemical insecticide use is going to go away. It’s just how can you integrate them together.”

Lowenstein also suggested that orchards maintain natural areas around the property where samurai wasps can retreat during crop spraying.

Stinkbugs are found in 24 of Oregon’s 36 counties. OSU has already distributed samurai wasps at 63 locations across the state for bio-control.

The wasps are not harmful to humans and do not sting people, Lowenstein said.

“There’s no way you are going to confuse this with a yellowjacket,” he said. “If you have a samurai wasp on your property you won’t even know it’s there unless you are seeing its effect, which is less stinkbugs.”

Washington’s Small Acreage Expo planned

The 14th annual Small Acreage Expo will  be on April 13 at the 78th Street Heritage Farm in Vancouver.

The Small Acreage Expo is sponsored by the WSU Clark County Extension. Pre-registration is $15 and runs until 2:30pm on Friday, April 12. Register by April 12 to include a free lunch with registration. Late registration price is $25 and can be paid on arrival. For more information and to see an event program, go to the event’s website.

The farm is located at  1919 NE 78th St., Vancouver, Wash.

The expo allows participants to choose from various workshops covering land management, grazing, weeds, composting and other topics. An open house during the lunch hour will allow participants to meet and learn more about local agencies that serve the public as well as ask questions to local vendors participating in the event.

Sessions include:

Session A (9am-10:15am):
– Managing Grazing for Sustainable Pastures with Gary Fredricks, WSU Cowlitz County Extension
– Maintaining a Healthy Well with Drake Amundson, Clark County Public Health
– Native Vegetation Landscaping with Brad Mead, Clark County Public Utilities

Session B (10:30am-11:45am):
– Weed’em and Reap with Kara Hauge, Clark County Vegetation Management
– Septic Inspection* with Sean Hawes, Clark County Public Health
-Heritage Farm Tour with Joe Zimmerman, Clark County Public Works

Session C (12:45pm-2:00pm):
– Composting Manure with Doug Stienbarger, WSU Clark County Extension
– Advanced Septic System Maintenance with Sean Hawes, Clark County Public Health
– Heritage Farm Tour with Joe Zimmerman, Clark County Public Works

Session D (2:15pm-3:30):
– Improving Drainage with Grant Johnson, Grant Johnson Drainage
– Sustainable Living for Small Farms with Eric Lambert, Clark County Public Works
– Tractor Safety with Joe Zimmerman, Clark County Public Works

*Gravity fed systems only

Researcher identifies new weapons against slugs

Essential oils from thyme and spearmint are proving lethal to crop-damaging slugs without the toxicity to humans, animals or the environment that chemical solutions can present.

An added advantage of these oils is the rapid mortality they cause in slugs, whereas the most common chemical molluscicide used by Oregon farmers, metaldehyde, simply causes them to stop feeding, said Rory McDonnell, Oregon State University’s slug specialist.

“The oils were essentially just as effective as metaldehyde in killing grey field slugs,” the worst culprits in Oregon grass seed fields, McDonnell said during the Oregon Seed League’s annual meeting, held in Salem, Ore., on Dec. 10-11.

Thyme and spearmint oils achieved 100 percent mortality at a concentration of just 0.25 percent, most likely through direct contact with slugs — though it’s possible their volatile emissions could also serve as repellents for the pest, McDonnell said.

Because they’re natural compounds, these oils would be exempt from the U.S. Environmental Protection Agency’s registration and residue tolerance regulations for conventional pesticides, he said.

Before they could be commercialized as biological pesticides, data would need to be submitted to the Oregon Department of Agriculture proving they’re not toxic to humans or non-target organisms, though this should be a big obstacle, McDonnell said.

“I’ll eat my hat if it’s toxic,” he said.

McDonnell was hired by OSU in 2016 after Oregon farmers told the university’s leaders that more research was needed to fight slugs, which have become increasingly destructive in recent years.

Another positive development from McDonnell’s research is the discovery of a nematode that’s naturally parasitic to grey field slugs — phasmarhabditis hermaphrodita — on OSU’s campus in Corvallis, Ore.

The location if the discovery was ironic given that McDonnell had traveled thousands of miles around the state searching for the species, which is native to Europe and used in slug control there.

“The darn thing was a stone’s throw from my office,” he said.

Since then, McDonnell has discovered two other nematode species in Oregon that show promise as biological control agents.

In the United Kingdom, the phasmarhabditis hermaphrodita nematode is sold as a commercial biopesticide that’s been shown to reduce slug damage in winter wheat by 85 percent, he said.

The nematode finds a hole in the back of a slug’s head, then vomits up a bacterial soup that’s toxic to the gastropod. As the slug’s body decomposes, the nematode’s offspring feed on its corpse.

The BASF chemical company also markets the nematode in Europe, producing it in enormous vats through a secret process, McDonnell said.

Before the nematode can be commercialized in the U.S., BASF or another pesticide manufacturer would need to demonstrate to USDA that it’s not harmful to other species, such as the native banana slug.

“I think that would be a major stumbling block,” he said.

Apple, pear growers struggle with fire blight

YAKIMA, Wash. — Fire blight, a bacteria that kills apple and pear trees, has been an accelerating problem the last three springs in Central Washington orchards.

Growers say last June was the worst month. They cut infected limbs and whole trees and burned them. An East Wenatchee agricultural consultant, Nick Stephens, in June said it was the worst he’d seen in 28 years and orchards young and old were in grave danger.

Six months later, Dec. 4, at the Washington State Tree Fruit Association annual meeting in Yakima, Tianna DuPont, Washington State University tree fruit specialist, said everyone knows it was a “hard year” for fire blight, but “we don’t know how hard or how much it cost us.”

A show of hands of a couple hundred growers in the session showed about half dealt with fire blight this year.

Sarah Kostick, a WSU horticultural doctoral candidate, talked about her studies in 2016 and 2017, the first on some cultivars.

“Most apple cultivars are susceptible to some extent to fire blight. It’s difficult to compare studies because of different methods used,” she said.

Kostick and her team inoculated up to 30 shoots per tree on numerous varieties for two years and added other methods to create a multiple matrix survey.

The results show Jonathan, Granny Smith, Gala, Honeycrisp, Cripps Pink, Jonagold, Golden Pinova and McIntosh are highly susceptible to fire flight. Fuji, Cosmic Crisp, Delicious and Rome Beauty were moderately susceptible and Aurora Golden Gala, Empire and Enterprise were of low susceptibility.

Gennaro Fazio, research geneticist at USDA ARS in Geneva, N.Y., said rootstock can become infected in bark wounds at the base or from infection at the top of the tree that spreads to the bottom. He talked about fire blight field trials in Geneva rootstock and said many new varieties, including Jazz and Envy, are sensitive to fire blight.

“Cosmic Crisp (the new Washington state variety) is moderately sensitive, but that’s still sensitive so it’s a concern,” Fazio said.

Fire blight can stay subdued in a tree for a long time and it’s hard to get rid of, he said.

Kerik Cox, associate professor at Cornell University, talked about assessing and minimizing the threat of fire blight following mechanical thinning and hedging and said hedging can be used to remove fire blight.

He also talked about calcium and biological treatments at pink stage of bloom.

Kari Peter, research pathologist at Pennsylvania State University, said fire blight has been a significant challenge in young, high-density and older large-tree apple orchards in that state. She talked about low rate calcium applications.

Fire blight overwinters in trees and reactivates in oozing cankers around blossom time. It is acerbated by extreme heat followed quickly by rain during bloom. It attracts flies and other insects that spread it to blossoms. Within a week or two, infection is ahead of portions of trees that show withering.

Antibiotics, copper fungicides, lime sulfur, other minerals and biological controls are applied before, during and after bloom but at best are 80 percent effective, growers have said.

Feared plant pathogens pop up in Western Washington

Black leg and black rot, plant diseases that Washington agricultural officials have long been on-guard for to protect the vegetable and oil seed industries, appeared this month in Western Washington in separate incidents.

Seeds from an organic radish farm in Island County tested positive for black leg, according to the state Department of Agriculture. Meanwhile, black rot appeared on leaves of a brassica crop in Skagit County.

It’s unknown how either disease was introduced, Washington State University plant pathologist Lindsey du Toit said. Growers in both places reported the pathogens, helping efforts to contain them, she said.

“Both have the same repercussions for the seed industry,” du Toit said. “I was pleased to see there wasn’t an attempt to cover it up.”

Black leg is a fungal disease that infects cruciferous crops such as canola, broccoli and cabbage. An outbreak of black leg in the Midwest and eastern U.S. in the 1970s was traced to Northwest-produced seeds, devastating Western Washington’s vegetable seed industry. It had not been detected in Western Washington in recent years, according to the agriculture department.

Black rot is a bacterial disease. According to the American Phytopathological Society, black rot “must be considered the most important disease worldwide of vegetable brassicas.”

To guard against both, the agriculture department requires crucifer seeds planted in Island County and five other Western Washington counties to be tested and treated for black leg and black rot. The department extended the requirement to 20 Eastern Washington counties in 2015 after black leg was found in canola fields in Oregon and Northern Idaho.

In Island and Skagit counties, the farmers planted seeds that had been tested, du Toit said. Seeds, however, are destroyed during the test, so samples from seed lots are screened.

Du Toit said she examined plant matter that she collected from the field in Island County, but did not find black leg. The seeds had been harvested about a month earlier, and the disease was discovered in testing at Iowa State University.

Black leg and black rot can be spread in the rain or by wind. The crop in Skagit County will have to be destroyed, du Toit said.

The Oregon Department of Agriculture mandated statewide testing for black leg in 2015 after an outbreak in the Willamette Valley.

The five other Western Washington counties in the quarantine area are Clallam, Lewis, Skagit, Snohomish and Whatcom. The quarantine also covers all of Eastern Washington.

Saturated steam an organic weed killer

The Steam Weeder looks like a vacuum cleaner and sounds like an espresso machine, with a long hose and nozzle attached to a tractor-mounted boiler that superheats water up to 250 degrees.

Erik Augerson, a graduate research assistant for Oregon State University, recently demonstrated how the technology works during Blueberry Field Day at the North Willamette Research and Extension Center, steaming along rows of organic blueberries to control field bindweed.

As a weed management tool, Augerson said the Steam Weeder has shown promise, especially for organic growers. The saturated steam kills weeds by bursting plant cells, without frying woody mulch like flame weeding does.

Augerson, who is earning his master’s degree from OSU in horticulture, is part of a research team trying to develop a season-long organic weed management program for small berry growers, using steam in combination with other mechanical treatments and certified organic sprays.

“The organic berry industry in Oregon is having a lot of trouble determining what the best and most cost-effective form of weed management is for their systems,” Augerson told the Capital Press. “We’re just trying to increase the growers’ toolbox.”

The project is supported in part by a $500,000 grant from the USDA Organic Transitions Program, with additional funding from the OSU Agriculture Research Foundation and Northwest Center for Small Fruits Research.

Jeremy Winer, managing director of Weedtechnics, the Australian company that manufactures the Steam Weeder, was also on hand at Blueberry Field Day to meet with growers and answer questions about the product.

According to Winer, the Steam Weeder superheats water and flashes it into saturated steam within the nozzle system. It sprays 2.5 gallons per minute, penetrating 1 inch deep into the soil.

“It’s not actually boiling, but it’s superheated,” Winer explained. “It explodes the (weed) cells.”

OSU purchased the Steam Weeder over the winter, and field trials began about a month and a half ago. While they are still collecting data, Augerson said the technology could be another option for organic growers.

“We know that it can kill weeds, and that it works from a management standpoint,” Augerson said. “I think it has a lot of promise.

Depending on the size and model, Steam Weeders cost between $16,000 and $30,000. Augerson said the value for small farmers is in decreased need for manual labor controlling weeds, allowing them to put their workers to better use.

“There is a lack of farm labor, and it is decreasing,” Augerson said. “We want to make it so farmers can utilize their labor in different ways.”

Augerson said they will need at least two years of data before they can start writing a comprehensive, full-season weed management program for organic berries.