Natural Nicotine Heals Honey Bees

January 23, 2017

NEONICOTINOID INSECTICIDES (e.g. thiamethoxam, imidacloprid, clothianidin) developed at Bayer Japan as safer alternatives (e.g. to human spray applicators) to the natural nicotine once widely used by farmers and gardeners, is now suspected of contributing to honey bee health problems like learning disorders and colony collapse. In contrast, natural nicotine, found in honey produced by bees working tobacco fields, as well as in pollen, nectar, leaves and other plant parts, is a nutrient and medicine helping to heal weak honey bee colonies, said Susan Nicolson of South Africa’s University of Pretoria at “Entomology Without Borders,” a joint meeting of the International Congress of Entomology (ICE) and the Entomological Society of America (ESA) in Orlando, FL.

Natural nicotine, even if produced organically in a sustainable recycling sort of way from tobacco waste products, is mostly shunned in organic farming and gardening. “Over 120 million sites will be returned on a web search on tobacco, but most will not be associated with plant science,” wrote USDA-ARS researcher T.C. Tso in Tobacco Research and Its Relevance to Science, Medicine and Industry. “Many plant scientists in academic institutions cannot obtain grant support for projects using tobacco as a research tool. Some even have to avoid tobacco because of the applying of ‘political correctness’ to academic research. The tobacco plant has served as a valuable tool since the dawn of plant and biological sciences, so it is indeed a great loss to scientific progress that a research tool already invested with so many resources and about which there is such abundant knowledge and such great potential for new advancement is now being wasted.”

Honey bees readily consume bitter alkaloids such as nicotine mixed in sugary plant nectars. Adult honey bees excel at detoxifying alkaloids such as nicotine, which should not be surprising, as survival depends on it. Younger, larval honey bees have fewer enzymes to detoxify nicotine, but also survive quite well even when their royal jelly contains high levels of nicotine. Honey bees and insects immune to nicotine, such as green peach (peach-potato) aphids, transform nicotine into less toxic butanoic acid. A knotty question naturally arises: If natural nicotine heals honey bees, why are synthetic neonicotinoids so terribly different? Are natural compounds like nicotine inherently more beneficial and their synthetic analogs (e.g. neonicotinoids) inherently bad, perhaps due to subtle differences in molecular structure? If bees and other pollinators are a major concern, perhaps natural product restrictions on nicotine need to be relaxed to provide competition to the synthetic neonicotinoids.

“Alkaloids, especially in the nicotine family, have been the main focus of tobacco research because alkaloids are the characteristic product of tobacco,” writes Tso. Dozens of other tobacco molecules are relatively overlooked, including sugar compounds providing least-toxic botanical insect and mite control. Anabasine (neonicotine), an alkaloid found in tobacco and other plants, has also been widely used as a natural insecticide. Strangely enough, anabasine is also an insect attractant and a poison gland product of Aphaenogaster ants. In a strange urban twist to the wild bird practice of lining nests with medicinal herbs emitting essential oils counteracting parasites: Researchers in Mexico discovered urban birds lining nests with cigarette butts to similar advantage. In times past, organic gardeners soaked cigarette butts in water to get a nicotine spray brew. Historically, most commercial nicotine insecticide used on farms and gardens was a sustainable tobacco waste extract.

There are 60-80 described tobacco or Nicotiana species, some available in seed catalogs and grown as ornamentals. Most Nicotiana species grow wild in the Americas, with some in Australia and Africa. “Tobacco plants are easy to grow and have a short growing period,” writes Tso. “Each tobacco plant may produce 14 g or about 150,000 seeds which may provide seedlings for 2 to 5 acres (1–3 ha) of field tobacco, depending on the type.” In Europe, oil extracted from tobacco seeds is being explored for an alternative bio-diesel fuel industry, with dry leftovers as animal feed.

Native American Nicotiana species are being integrated into China’s ancient agricultural interplanting tradition. When tobacco is interplanted in vineyard rows, tobacco roots and grape roots intermingle. Perhaps some sort of biological soil fumigation occurs. Whatever the mechanism, vineyards are cleansed of soil-dwelling phylloxera aphids, a pest that almost destroyed wine grape growing in France in the 1800s and is still a worldwide problem. According to the journal Chinese Tobacco Science, intercropping tobacco with sweet potato also alleviates soil and other pest problems, maximizing profits per unit area of land. Burley tobacco is intercropped with cabbage and other vegetable crops, according to the Journal of Yangtze University (Natural Science Edition).

Neonicotinoids are soluble in water and absorbed systemically by plants, and some are sprayed on urban lawns and landscapes. However, over 80% of synthetic neonicotinoids are applied to seeds prior to planting hundreds of millions of acres of corn, soybean, sunflowers and other crops. In Canada’s Ontario and Quebec provinces, 100% of corn seed is treated with neonicotinoids, said Nadejda Tsvetkov of Toronto’s York University at “Entomology Without Borders.” Though neonicotinoids were seldom found in corn pollen samples, somehow, perhaps by water transport, neonicotinoids are finding their way into clover and willow tree pollen far from corn fields.

“For a lot of farmers it is hard to get seeds untreated, especially corn,” as commercial seed is routinely treated with neonicotinoids regardless of need, said the University of Maryland’s Aditi Dubey at “Entomology Without Borders. In Maryland and other mid-Atlantic USA states where low pest pressures are the norm, neonicotinoid seed treatments are both unneeded and counterproductive. In 3-year Maryland rotations with double-cropped soybeans, winter wheat and corn, sowing seeds treated with thiamethoxam or imidacloprid reduced beneficial predatory ground beetles and increased slug damage to crops. Mid-Atlantic USA farmers typically apply 4 unnecessary prophylactic seed treatments every 3 years. Besides reduced biocontrol and more pest damage, soil accumulation over time is a disturbing agro-ecosystem possibility.

Alternative seed treatments include natural plant hormones such as salicylic acid and methyl jasmonate, which induce a natural immunity called induced systemic acquired resistance (SAR). Crops such as lettuce and argula (rocket) grown from seed treated with salicylic acid and methyl jasmonate also release volatile gases repelling pests such as sweet potato whitefly, a major worldwide pest, said Ben-Gurion University’s Mengqi Zhang at “Entomology Without Borders,” a gathering of 6,682 delegates from 102 countries. Numerous botanical materials and microbes have also been investigated around the world as alternative seed treatments.

A proactive approach to honey bee and bumble bee health includes a diversified landscape sown with herbs and medicinal botanicals for self-medication, not just natural nicotine from tobacco nectar or other sources. Thymol, an essential oil found in thyme and many other plants, is already sprayed in hives by beekeepers to combat Varroa mites. At “Entomology Without Borders,” North Carolina State University’s Rebecca Irwin reported laboratory choice tests where bumble bees rejected nicotine. In field tests, bumble bees were given a choice of different colored flowers each with a different botanical such as thymol, nicotine, anabasine and caffeine. Bumble bees only selected flowers with thymol to self-medicate. Interestingly, thymol and other herbal essential oils also synergize nicotine, boosting effectiveness against disease pathogens and perhaps also minimizing the likelihood of colony collapse.

Landscapes and hedgerows sown with medicinal plants such as thyme, sunflower and foxglove minimize bumble bee disease transmission, said Lynn Adler of the University of Massachusetts, Amherst. The current USA farm bill will actually pay farmers to plant bee-friendly sunflower edges or hedgerows around canola fields. Antimicrobial and medicinal honeys derived from sunflower, bay laurel (Laurus nobilis), black locust, etc., also effectively combat bee diseases like chalkbrood and foulbrood, said Silvio Erler of Martin-Luther-Universität in Halle, Germany at “Entomology Without Borders.”

Bee pharmacology is also useful in human medicine. In Oaxaca, Mexico gangrene is stopped and wounds are healed by combining maggot therapy and honey, reported Alicia Munoz. Maggot therapy uses sterilized (germ-free) green bottle fly maggots to disinfect and cleanse wounds by eating unhealthy tissues and secreting antibiotics, allowing healthy pink tissue to grow back under honey-soaked gauze. This cost-effective approach reduces hospital stays, lowers morbidity and can eliminate the need for surgery. It may sound yucky, but for diabetics and patients with bed sores or wounds where surgery is medically impossible, a few maggots and a little honey is preferable to amputating wounded or infected limbs.

Cancer-fighting bee propolis products were touched upon at “Entomology Without Borders” by Chanpen Chanchao of Chulalongkorn University in Bangkok, Thailand, where hives of stingless bees are reared like conventional honey bees. Cardol, a major component of propolis from the Indonesian stingless bee, Trigona incisa, causes early cancer cell death by disrupting mitochondrial membranes and “producing intracellular reactive oxygen species (ROS).” ROS are essential to energy, immunity, detoxification, chemical signaling, fighting chronic and degenerative diseases, etc. Cardol “had a strong antiproliferative activity against SW620 colorectal adenocarcinoma,” killing colon cancer cells within 2 hours, followed by complete cell necrosis within 24 hours. Thus, cardol is an “alternative antiproliferative agent against colon cancer.”

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Insect Perceptions, Irrelevant or Important

February 23, 2016

“IT WAS THE BUTTERFLIES, my people say, who brought the first human babies to their feet,” writes Canadian Richard Wagamese in “Butterflies Teachings,” an essay touching on “what’s called Enendamowin, or Ojibway worldview” in his brilliant collection, One Native Life. “Before that, the New Ones sat in innocence beneath a tree, watching the world around them with wonder. But Creator had planned more for them. Their destiny called for them to move throughout the world. These human babies were meant to walk upon their two legs, and as long as they sat under that tree their destiny could not be fulfilled…The air seemed to tremble with butterflies. The human babies were entranced. Each time they tried to snare a handful of colour, the cloud drifted away. They stretched their arms higher. They thrust out their hands. But it was to no avail. When the butterflies danced just out of reach a final time, the New Ones lurched to their feet and raced after them across the meadow. The Animal People celebrated quietly, then returned to their dens and burrows and nests. The human babies never caught those butterflies, but they kept on running, right into the face of their destiny…”

Quite a different worldview from Prague and Eastern Europe, where Franz Kafka’s famous novel Metamorphosis begins: “As Gregor Samsa awoke one morning from uneasy dreams he found himself transformed in his bed into a gigantic insect.” According to the “wall notes” in the exhibit “Disguise: Masks & Global African Art” at the Fowler Museum at UCLA, Kafka’s words inspired South Africa artist Walter Oltmann. Among neon masks, dancing mask videos and sculptured African animals wearing masks are Oltmann’s large anodized aluminum and brass wire caterpillars in the midst of “transformation and change” (metamorphosis) and fashion sketches titled “Beetles & Suits.” The suit coats are gracefully curving, shell-like beetle elytra (outer wing covers) fashionably topped off with the latest antennae, and looking both business-like and sci-fi out of Star Wars or Star Trek at the same time. I can easily imagine a cell phone age makeover of The Beatles’ Sgt. Pepper’s Lonely Hearts Club Band regalia and long hair with “beetle suits” and high-fashion antennae. Perhaps too much entomology affects the psyche. Oltmann writes that “spending an inordinate amount of time on making something that is usually considered insignificant like an insect, does make us look differently at them.” He says it “speaks of neither this nor that,” but I’m not so sure.

Insect observations appear in haiku by Japanese master Matsuo Basho, whom I think of as the late 1600s slightly more refined counterpart of 20th century Los Angeles poet Charles Bukowski, who was too busy with “other interests” to notice beetles, flies, mosquitoes and roadside weeds. In Moon Woke Me Up Nine Times: Selected Haiku of Basho, translator David Young writes: “Odd numbers predominate; a dance is occurring, and each third of the poem is a turn, a gesture, a refining or revelation… The poem seems to end almost as soon as it has begun, a small flash of lightning…A more literal version of the haiku cited (below) would be something like: What can save your life? / one leaf, with an insect / sleeping on its journey… the journey, which refers to a Chinese story that Basho’s readers would know but that is largely meaningless to English readers…‘Basho mash-ups,’ I have sometimes called my versions”:

One insect
asleep on a leaf
can save your life

Perhaps Basho was thinking of medicinal silkworms slumbering on mulberry leaves, or perhaps his mind was journeying among high mountains where ghost moths metamorphose with fungi into plant-animal hybrids that have been used in Asian medicine for centuries. David Young says about haiku: “They love to startle, first the writer and then the reader. As though a hummingbird were to land suddenly on your resting arm. It is the way the world so often surprises us.”

A haiku by Los Angeleno Mark Jun Poulos, whose observation of the seemingly mundane urban habitat nagged at me long after I thought I had dismissed its ordinary elements from consciousness:

restroom sink-—
ladybug cooling off
in a drop of water

What nagged at me was water, a vital ingredient of life, which as hard sprays of rain washes away pesky mites and aphids that are ladybug prey. Water (H2O) is also a missing ingredient in most ecological studies of interplanting, a habitat diversity strategy designed to boost populations of lady beetles and other beneficial insects providing natural pest control. Australian grape vineyards and California lettuce fields have had some success interplanting blooming rows of sweet alyssum to provide pollen, nectar and alternative prey for ladybugs, lacewings, hover flies and other beneficial species consuming aphids and other pests. Sweet alyssum is also host to micro-wasps helping Michigan asparagus growers by parasitizing leafmining pest insects, Amanda Buchanan of Michigan State University reported at the Entomological Society of America (ESA) annual meeting in Minneapolis. But if habitats are missing water, then perhaps lady beetles, which do not puncture plants to drink fluid, will leave to find restroom sinks, puddles or other water sources. Perhaps, like providing water bowls for pets, something similar needs to be researched as part of biological control habitat alternatives. Though I would draw the line at alcoholic drinks, except perhaps beer in snail and slug traps. Another urban haiku observation by Mark Jun Poulos:

sultry afternoon—
wasp hovers over a whiskey bottle
held by a drunk bum

Ethanol or ethyl alcohol, by percentage the main chemical component of distilled whiskey, should not be abused, nor perhaps should it be so heavily subsidized as a biofuel, as that incentive exacerbates huge landscape changes measurable as reduced biodiversity. At Synergies in Science, a rare Minneapolis gathering of the ESA, American Society of Agronomy, Crop Science Society of America and Soil Science Society of America, the diminishing biodiversity of a Midwest USA with 21% less wheat, 16% less hay and much more GMO corn to distill into ethanol motor fuels was as hard to ignore as a drunk with a whiskey bottle on an urban bench. Jonathan Lundgren of the USDA-ARS in Brookings, South Dakota said we need to get away from our “very pest-centric approach” and adopt a more holistic biological network approach. Instead of a Midwest saturated with pesticides to grow GMO corn to distill into fuel tank ethanol, something as seemingly simple as adding biodiversity via cover crops amongst the corn rows could produce enough soil biocontrol of corn rootworm to eliminate wasteful neonicotinoid seed treatments whose honey bee and beneficial insect friendliness is being hotly debated. Karen Friley of Kentucky State University reported at the ESA that something as seemingly simple as native plant border rows around sweet corn fields “provide microclimates in the form of moderated temperatures, which offer shelter” for numerous natural enemies controlling corn pests.

Curiously enough, ethanol (alcohol) like that in whiskey bottles and vehicle fuels also attracts pine beetles and ambrosia beetles considered destructive forest, landscape, street tree and nursery pests. Perhaps more curiously, the very trees being attacked are producing the ethanol and releasing it into the atmosphere when stressed (e.g. by drought or flood), decaying or dying. Trees may look perfectly healthy on the outside, but inside the tree is another story, because ethanol emissions are signs of sickliness and ill health. Chemical ecologist Christopher Ranger of the USDA-ARS in Wooster, Ohio said it is a real problem, for example, when nursery seedlings are used to replant spruce forests or with dogwoods, magnolias, pines, etc. in nurseries, backyards, along streets, etc. It is definitely ecology, as the ethanol is luring in the beetles to help “recycle” the trees back into the soil as nutrients.

I liked Ranger’s reasoning: Find the tree equivalent of driver breathalyzer tests as a beetle-attack early warning system. SCRAM wrist bracelets worn by offenders for transdermal drug and alcohol detection were tested, but were not sensitive enough; taking a week to detect low tree ethanol exhalations, whereas beetles detect a few parts per million of alcohol and get to trees almost on day one. The solution was a portable ethanol monitoring device with a detector tube and a plunger to pull in air samples; developed using Japan’s Gas Tech industrial gas leak detection technology for quick detection of “inebriated” trees.

So, which is more startling and surprising: art, haiku or entomology?

Strange brew: September 17, 2015 daylight turning to dark, caught in one of those infamous, almost proverbial L.A. traffic jams at a freeway underpass on Church Lane transitioning from Sunset Blvd to Sepulveda Pass on my way past the Getty Museum to Mulholland Drive, listening to the Moody Blues Live at Red Rocks, going nowhere. Haiku and fireflies flashing internally, and externally the blinking side turn lites and red back brake lights suddenly and surprisingly metmorphosed into synchronous fireflies, albeit of a mechanical or robotic nature:

Tail and Turn Lights
Flashing like Synchronous Fireflies
In the Los Angeles Traffic Jam

 


Organic Dairies Suck Flies (CowVac)

December 5, 2014

Rest assured, a CowVac is not a veterinary vaccine of some sort that magically provides insect control or renders cows autistic. Rather, it is about producing organic milk and organic milk products like butter and yogurt. A CowVac is a suction or vacuum device incorporated into a larger trapping apparatus that removes blood-sucking flies that can be an even worse livestock plague than mosquitoes or ticks. Besides being bad economics (too expensive), pesticides repeatedly applied at ever higher doses quickly select for pesticide-resistant biting flies; i.e the flies become immune. Which is not to say that insects will not develop some ingenious solution, like holding on tighter, to avoid being sucked up by strong suction. But at least development of stronger suction devices and better ways to knock insects off animals would not add pesticide residues to the environment, food chain and human diets. A human equivalent, awaiting invention, would be an enclosure of some sort designed to knockoff and suck up (vacuum off) bed bugs before they bite (see previous blog, on bed bug desperation time innovative research).

“Seven years in the making: The Cow-Vac removes horn flies from dairy cattle” was the title of a special display at a members symposium “Honoring the Career and Contributions of Veterinary Entomologist Donald A. Rutz” at the Entomological Society of America (ESA) annual meeting in the beer brewing capital of the world, Portland, Oregon. On its web site, the Center for Environmental Farming Systems (CEFS) at North Carolina State University (NCSU) in Raleigh reports: “This innovative solution is now part of routine cattle management at the CEFS Dairy Unit and has allowed the herd to be insecticide-free for 5 years.” In other words, this “alternative fly management system” designed by Steve Denning and D. Wes Watson demonstrated “the feasibility of producing organic milk.”

“The trap removed between 1.3 and 2.5 million flies annually from the research station cattle,” Denning and Watson reported to the ESA in Portland. “Prior to the installation of the trap in 2007, the cattle routinely had horn fly populations above 1000 flies per animal and would require insecticide applications for horn fly control. With a vacuum trap in place, dairy cattle at CEFS have not required or have been treated with an insecticide.” With each of the thousand horn flies sucking blood 10-12 times per day, the blood loss and associated problems were huge (USA estimated losses are over $2.26 billion per year), and organic animal agriculture was considered questionable.

“The first walk-through pasture fly trap consisted of a covered structure designed to brush flies from the animals as they passed through, with the fleeing flies captured in the screened hollow walls,” reported Denning and Watson at the ESA meeting in Portland. “Modifications to the Bruce trap have been introduced over the years. These modified traps employ the same basic mode of action; curtains to dislodge flies and light, either natural or fluorescent, to attract flies to a cage, or bug zapper. In addition to curtains, the CowVac uses air pressure to dislodge flies, and vacuum to capture flies, trapping them in a chamber until death.” So far, the Animal Rights movement has yet to recognize a right to food (animal blood, in this case) for biting flies (also animals); and the flies die a natural death from lack of animal blood as a food source. Cruelty to animals (flies), perhaps; and fodder for an ethics debate. But if you want organic milk, butter, meat, yogurt, etc…

There are YouTube videos on the vacuum trap, and the Northeast Organic Dairy Producers Alliance has an in-depth article on the CowVac and its development by fly biocontrol specialist Tom Spalding of Spalding Labs: “…the Horn Fly is very tough to control. It’s resistant to most every chemical control. It only reproduces in cow pastures, which means there is always productive breeding material available as no one cleans up pasture pats…For the past 16 years, North Carolina State University entomologists, Dr. Wes Watson and Steve Denning, have been researching IPM practices for pest fly control for commercial livestock and poultry operations…They have seen it all, testing at least 100’s of products…repellent on most and only a few animals with pesticide, to using electric traps, light traps, walk thru traps, feed thru products, ear tags, oilers, you name it…in 2006 as Steve was watching flies get scrapped off cows going thru a walk in trap, and then following the cow out the exit and getting right back on, he had an AH HA moment of “let’s see if we could vacuum up those little buggers”…Organic Valley heard about this unit and they sponsored a test, placing 6 units on North Carolina dairies in 2012…we made a trip to Raleigh, NC to see it. I knew from our efforts using Fly Predators to control Horn Flies that this little insect was a big deal. It took a lot of work as you had to put the Fly Predators in the pastures where the cows has just been and that only worked for those doing intensive grazing. Harrowing or running a screen drag over the pastures made a big difference too, but all those things took more time than most dairymen had. If this vac thing worked it would solve a horrible problem every grazier has…We agreed to license the technology from NC State and so began the redesign for production and optimization. This is the second unlikely alignment of the stars. I run a beneficial insect company, but I’m a mechanical engineer (ME) by schooling and in the 30 years prior had started a number of high tech companies…we refined the airflow on real animals. While the simulated cow got us very close to optimized performance, we actually were blowing too much air…”


Whole Hog Into Debugging Michigan Apples

April 9, 2014

FROM TIME to TIME over the course of the centuries, agriculture seems to reinvent itself, and if anything modern agriculture based on the industrial model seems to be unconsciously integrating the higher animals back into the fruit tree groves, at least among those Michigan entomologists and farmers who appreciate the overlooked virtues of the hog as a faithful human servant at the beck and command of its handlers for hunting down pests that have become resistant to pesticides and difficult to control even with the latest pheromone mating disruption technologies. To those combating or hunting down feral pigs and wild boar disrupting native ecosystems and rooting up farm crops, turning pigs loose in apple, cherry, pear and other fruit tree orchards is likely to seem a heretical notion belonging to renegade rednecks or radical hippie farmers from the counterculture past stuck in a continuous time-warp loop with Spock and the characters from Star Trek.

One of the advantages of attending Entomological Society of America meetings is being able to follow themes like “livestock-crop reintegration,” which Ceres Trust Research Grants have been funding for Michigan State University entomologists like Krista Buehrer and Matthew Grieshop. Basically, organic hogs provide organic fruit orchards control of weeds and insect pests like plum curculio (Conotrachelus nenuphar), codling moth (Cydia pomonella) and Oriental fruit moth (Grapholita molesta). “The rotation of hogs through different pastures and orchards with supplemental nutrition sources” is also “a method of livestock-crop integration that avoids the problem of adhering to National Organic Policy (NOP) and Good Agricultural Practices (GAP) policies restricting the application of manure prior to harvest,” wrote Buehrer in “Graduate Student Final Report – Ceres Trust Research Grant.”

Rotating organic hogs through organic fruit orchards to clean out weeds and insect pests hidden inside fallen fruits, traces its roots to Charles Valentine Riley, who pioneered modern biological control in the orange orchards of Los Angeles, California. In his 1871 “Third Annual Report on the Noxious, Beneficial and other Insects of the State of Missouri,” Riley said that for apple curculio “the only real remedy is the destruction of infested fruit.” In 1890, writing in the Iowa Agricultural Experiment Station Bulletin, C.P. Gillette suggested grazing orchards with sheep or hogs to eat the insect-infested “windfallen fruit” on the orchard floor and thereby reduce pest populations.

From the 1800s into the Roaring Twenties, Iowa apple growers could not get rid of apple curculios by shaking the trees, cultivating the soil, pruning, or spraying arsenic pesticides, leading B.B. Fulton in 1925 and 1926 to test hog grazing on the “Apple Grove Orchards south of Mitchellville, Iowa.” Writing in the Journal of Agricultural Research in 1928, Fulton said: “The experiments with pasturing pigs were successful from a business standpoint. A cost account kept for the two years showed that this method of control was more than economical, for it actually netted a profit. In 1925 each pig returned a net profit of $10 above cost and feed and in 1926 a net profit of $7.65…five pigs per acre can, if properly handled, clean up the early dropped apples in an orchard and thus control the apple curculio. The critical time for such control, as shown by the seasonal history data, is from the middle of June until about the middle of July. Pigs weighing about 100 pounds are the best size for this purpose since they do not tramp down the low branches. They do not feed from the trees…”

Krista Buehrer told the 2012 ESA Annual meeting in Austin, Texas that weekly rotations (June-August) of grazing hogs eating dropped fruit (containing pests inside) on the orchard floor produced marketable organic hogs and reduced pests without harming earthworms or beneficial insects (e.g. lady beetles, lacewings, ground beetles, spiders, parasitoid wasps, tachinid flies, syrphid flies, dolichopodid flies, ants). ““There were 3 control plots and 3 hog grazed plots,” said Buehrer. “Grazed plots were bordered by electric fencing to prevent hogs from escaping. Twenty-four Berkshire hogs were rotated through each grazed plot twice. In 2012, they were in each plot for 1.5 weeks per rotation, for a total of 3 weeks per grazed plot. In 2013 they were in each plot for 1 week per rotation, for a total of 2 weeks per grazed plot. Hogs ranged from 50-90 lbs (23-41 kg) each.”

Hog grazing really only scratches the surface of changing fruit orchard floor management, which includes cover crops, living mulches, composts, etc. Perhaps it is more a case of everything old becoming new again, as grazing by cattle, sheep, goats, wild pigs and boar are considered part of traditional European agroforestry systems.


Fireflies in Tennessee: Tourism, Light Shows & Algorithms

January 25, 2013

A TRUISM IN TRAVEL is that on your first trip to a destination you learn what you should have done or gone to see. Sometimes you get back to do or see it, and sometimes you don’t. It is even more difficult, for scientific research as well as travel, to be there to witness rare, occasional or brief seasonal events in the life of a plant, animal or region. For example, I was in New Zealand the wrong season, and missed their famous glowworm (firefly) caves. Too much is happening and the world is too big to see or do everything; and some things are out of our vision, anyway; being too big or too small, too distant, or in the ultraviolet, infrared or some other electromagnetic frequency beyond our immediate sensory perception.

Viewing firefly (aka glowworm; lightning bug, firefly beetle, hotaru) photonic light displays at their rhythmically flashing best means being in the right place at the right time. Many of the world’s 2,000 known fireflies species lack the night fire, and are rather anonymous. Some glow as eggs and larvae (presumably to ward off predators), and as adults (advertising for mates). But most of the year, even the best flashers remain hidden (often as eggs, larvae or pupae) in the soil. More rarely, some esteemed Asian species have underwater larval life stages living in rivers, streams, wetlands and rice paddies and providing biocontrol of freshwater snails. The genji-botaru and heike-botaru fireflies (hotaru), celebrated since the 8th century in Japanese poetry (e.g. Man’yoshu) as early-summer “little lights darting about in the night,” are also icons of water purity.

Enchanting traveler’s tales involve the synchronous rhythmic flashing of many thousands, perhaps millions, of fireflies as far as the eye can see across the landscape. “Over the past four hundred years many anecdotal accounts of synchronous flashing of myriads of fireflies in trees in Southeast Asia have been scattered through travel books,” wrote pioneering firefly scientist, John Buck, who got started wondering about fireflies as a kid and advanced his studies working with his wife, Elisabeth, during summer vacations from his main work at the National Institutes of Health. “Pride of place in antiquity passes from Kaempfer’s (1727 Dutch physician’s book: The History of Japan (With a Description of the Kingdom of Siam)) description of synchronized flashing at the classic locality, the banks of the Chao Phraya (Meinam) River in Thailand, to Hakluyt’s (1589 book: A Selection of the Principal Voyages, Traffiques and Discoveries of the English Nation) account of what was probably the same phenomenon, as seen by Sir Francis Drake’s 1577 expedition: ‘a certaine little Island to the Southwards of Celebes…Among these trees, night by night, through the whole land, did shew themselves an infinite swarme of fiery worms flying in the ayre…make such a shew of light, as if every twigge or tree had been a burning candle.’”

Synchronized firefly flashing was late being recognized in the Americas. “Early in this century sightings of synchrony among flying fireflies in American meadows began to appear,” wrote John Buck in 1988. “No reasonable explanation of the behavior was offered: in fact a strong aura of incredulity or even mysticism pervaded the subject.” Indeed, when John Buck started studying fireflies in earnest in the 1930s: “The fast film, laboratory oscilloscope and image-intensifier that would eventually confirm and dissect synchrony were, like the jet airplane…still in the future…Today the phenomena has been photographed, charted, and videotaped…”

“The modern study of synchrony in fireflies dates from 1968, when John and Elisabeth Buck used cine photography and photometry to demonstrate that a certain number of Southeast Asian firefly species flash in rhythmic synchrony,” wrote Jonathan Copeland and Andrew Moiseff, who “used videography, photometry, computer-shaped LED flash, and flash entrainment experiments” in their own studies of flash rhythms in the synchronous firefly, Photinus carolinus, a popular tourist attraction in Tennessee’s Great Smoky Mountains National Park.

When the Entomological Society of America (ESA) met for its annual meeting in Knoxville, TN, in November (2012), the synchronous fireflies famous for what locals call “The Light Show” were slumbering about 50 miles away in the former logging town of Elkmont, which was swallowed up (residents sent packing) into Great Smoky Mountains National Park. “Huge numbers of male fireflies flash synchronously, dazzling the human spectators and drawing female P. carolinus for the purpose of mating,” wrote Lynn Faust of the Great Smoky Mountains Conservation Association, a former Elkmont resident, who along with local volunteers have collected 20 years of firefly data; aided by Paul Weston (Charles Sturt University, New South Wales, Australia) and other scientists.

“The display lasts only several days to slightly over a week, which means that the ability to predict its occurrence is of critical importance to the National Park Service, which organizes shuttle buses to ferry visitors from parking areas to the ecologically sensitive areas where the fireflies put on their display,” Faust and Weston told the ESA annual meeting. For the 10-day peak Light Show display, there have been up to 26,000 tourists. “Predicting the timing of this natural phenomenon is of equal importance to the researchers and naturalists who study its annual occurrence.”

In his Newbery Medal winning book (1989), Joyful Noise: Poems for Two Voices, poet and children’s book author, Paul Fleischman, calls fireflies: “…glowing insect calligraphers practicing penmanship…Six-legged scribblers of vanishing messages, fleeting graffiti…Fine artists in flight adding dabs of light, Signing the June nights as if they were paintings…” A description hard to top, even with the many fine firefly night light paintings from light shows around the world displayed on photographs on the Internet and in YouTube videos.

“The synchronous firefly Photinus carolinus (Green) of the moist cove hardwood forests of the Great Smoky Mountains National Park attracts much public attention during its spectacular month-long mating display known as The Light Show,” writes Lynn Faust in the Florida Entomologist. Besides the human tourist hordes, predatory biocontrol species also seem attracted to The Light Show: “Orb-weaving spiders (Araneidae) prey on P. carolinus. Late at night, after all courtship flashing had ceased, often the only lights visible were the rhythmic distress flashes or the steady glow of fireflies caught in webs. In addition, harvestmen (Phalangiidae) often were seen carrying glowing pupae, adult fireflies, or only the still glowing firefly lantern…local Photuris fireflies readily eat captive P. carolinus and regularly fly and signal within the dense display areas of male P. carolinus… Phorid flies (Apocephalus antennatus Malloch) parasitize Photinus fireflies by ovipositing eggs within the firefly’s body…” So, with the risk of being eaten by predators and becoming part of the greater ecological food chain during the short performance season, the life of an adult firefly Light Show performer must be as tough as it is brief.

Over the past two decades, lifelong firefly-enthusiast Faust and the Great Smoky Mountains Conservation Association volunteers collected data on “four landmark phenological events,” namely: 1) male emergence (date on which first flashing male fireflies are observed); 2) “good” display (date synchronized flashing by males is seen over wide areas; not just isolated patches); 3) female emergence (date of first female flashing in response to males; doublet flashes in leaf litter or low vegetation); and 4) peak display (final night of maximum male flashing displays; determined in retrospect, usually after a sudden fading out of The Light Show).

“A degree-day model based on a base temperature of 50 F (10 C) and a seasonal starting date of March 1 has resulted in remarkably accurate predictions of four landmark phenological events for Photinus carolinus,” Faust and Weston told the ESA. “This predictive ability has proven very helpful for timing research visits to field sites, and will be a valuable tool for the National Park Service when scheduling visits of thousands of visitors to the Smokies Mountain National Park to witness the Light Show.” The better the prediction of when “The Light Show” will occur, the more likely researchers, tourists and travelers will come away satisfied; versus feeling like they missed out.

“The Light Show is the name given by locals in the Smoky Mountains to the annual synchronous display of male P. Carolinus,” Faust and Weston told the ESA. “The males produce a string of about 6 flashes over 3-4 seconds, then remain dark for 6-15 seconds. Remarkably, these fireflies synchronize their flashes and dark intervals with those of their neighbors, which leads to visually striking displays stretching as far as the eye can see into the wooded hillsides and glens of the Smoky Mountains. The display can last for 2 hours or more on peak nights.”

The mathematics or calculations behind degree days (aka day-degrees, growing degree days, heat sums, thermal units, threshold temperatures) can be a bit tedious, but degree days are basically just a way of calculating the impact of temperature on a life process (or physiology). Degree days are used in botany, horticulture and agriculture to predict a range of phenomena, including flowering times, as higher temperatures mean plant enzymes are more active. Insects are also temperature-dependent creatures. Thus, degree-day models work to predict firefly adult emergence and light show times. Similarly, degree-day models can help time pest control actions by predicting the egg hatch of the codling moth, the proverbial worm inside the apple.

Raymond Bonhomme nicely sums up the agriculture origins of the degree-day concept: “The ‘degree-day’ unit stems mainly from the relationship between development rate and temperature. It was Re´aumur (1735) who first laid the basis of this notion: ‘The same grains are harvested in very different climates; it would be interesting to compare the sums of heat degrees over the months during which wheat does most of its growing and reaches complete maturity in hot countries, like Spain or Africa … in temperate countries, like France … and in the colder countries of the North,’ (original text in Old French: Durand, 1969). Even if the exact vocabulary was not correct (what is a sum of heat degrees?), the concept of a relationship between the development rate of crops (here the sowing to maturity period) and temperature was born. Hundreds of works have set about using, proving, or even disproving this idea…”

Degree days are only a warm-up exercise for mathematicians and computer scientists studying the synchronous rhythms and periodicities of fireflies. Indeed, synchronous flashing in fireflies may have similarities to other physiological events, like the human heartbeat (cellular coordination) or the schooling and swarming behaviors of fish and birds. No doubt some envision coordinating the actions of armies of drones or robots, though the Ant Colony Optimization (ACO) or Particle Swarm Optimization (PSO) algorithms might be better for that. Rather than being the dark warlike side of the light show, this work could also do great good in helping fight diseases involving coordination at the cellular or other levels, aiding theatrical productions or designing swarms of robotic devices for hazardous situations like fighting toxic disasters.

“Rhythmic communal synchronization occurs in body movements and sound production of a few insects and other arthropods,” wrote John Buck in 1988. “It is also typical of many human activities—e.g., dancing, the spontaneous rhythmic applause clapping by Russian opera, ballet and circus audiences and, notably, music. Even conducted orchestral music involves a large element of mutual cueing between performers.”

Hearing about the Firefly Algorithm, the mental lights flashed that it was perhaps created by Rufus T. Firefly, President of the bankrupt country of Freedonia, played by Groucho Marx in the 1933 USA movie, Duck Soup. But the Firefly Algorithm (FA) and the Improved Firefly Algorithm (IFA) are being studied by computer scientists and mathematicians trying to solve difficult optimization problems like “the famous economic emissions load dispatch optimization problem,” which is “one of the key problems in power system operation and planning in which a direct solution cannot be found.”

The Firefly Algorithm, developed in 2007 by Cambridge University’s Xin-She Yang, is simply a set of rules or problem-solving steps, in this case inspired by nature and programmed for computers based in part on the details of flashing firefly lights, an insect social or swarm activity. “Although the real purpose and the details of this complex biochemical process of producing this flashing light is still a debating issue in the scientific community, many researchers believe that it helps fireflies for finding mates, protecting themselves from their predators and attracting their potential prey, said Theofanis Apostolopoulos and Aristidis Vlachos of the University of Piraeus (Greece) in the International Journal of Combinatorics. “In the firefly algorithm, the objective function of a given optimization problem is associated with this flashing light or light intensity which helps the swarm of fireflies to move to brighter and more attractive locations in order to obtain efficient optimal solutions.”

Besides energy conservation algorithms for heating, ventilation and cooling (HVAC) systems, understanding firefly light production is a path to more energy-efficient household and industrial lighting. “The firefly produces its narrow-spectrum 560 nanometer light just like a chemical laser, but with even greater control,” writes Extreme Tech columnist, John Hewitt. “Understanding firefly scales as tiny prisms that change the way light impinges on an interface and creates new sharp-edged channels through which light can diffuse lets us make LEDs more efficient.” Indeed, mimicking firefly light transmission can boost light production from GaN (Gallium Nitride) LEDs by 55%.

As the Ohio State Parks web site notes in their succinct discussion of firefly bioluminescence chemicals, luciferin and luciferase: “Scientists are still not sure exactly how fireflies control their lights, but they have found many important uses for the chemicals luciferin and luciferase. Since living cells have ATP and oxygen, researchers can add luciferin and luciferase to detect harmful bacteria in food, milk or water. The two chemicals are also used for special electronic detectors used in spacecraft to look for earth-life forms in outer space! Luciferin and luciferase are also being used in research on human diseases such as cancer, multiple sclerosis, cystic fibrosis, and heart disease. Firefly technology has also been used to produce safer, cold light for flashlights, flares and holiday lights.”

This is only the tip of the iceberg in innovation from studying fireflies. Just something to think about next time you are out watching fireflies, whether in your backyard, the Great Smoky Mountains or anywhere else on the planet.


Doggone Birds (Fruit Protection)

September 13, 2012

Many bird species provide biocontrol by eating a wide range of insect pests, and are worth encouraging for controlling flies, mosquitoes, locusts, caterpillars, ticks, rodents and other pests around homes, forests, farms and gardens. Other bird species are considered pestiferous when feeding on our food plants, and can be repelled in various ways, including by loud noises, eyespot balloons, reflecting tape, scarecrows and scare devices, sensor networks and dogs.

Among the beneficial birds when they are not causing damage to utility poles or annoying people with their racket are woodpeckers. Personally, I like hearing woodpeckers working urban and forest trees, and was heartened to learn from Michigan State University’s Andrew Tluczek’s presentation to the Entomological Society of America (ESA) annual meeting that: “Woodpecker predation has caused up to 90% mortality of emerald ash borer (Agrilus planipennis) larvae in some sites.”

A 2006 tick control article in BioScience magazine devoted considerable discussion to birds for tick biocontrol. In Africa, birds known as oxpeckers (Buphagus spp.) provide biocontrol of ticks on mammals by consuming hundreds of adult ticks or thousands of nymphal ticks per day. Free-ranging guinea fowl experimentally tested around New York (USA) lawns reduced adult blacklegged tick numbers; but unfortunately the smaller nymph stage blacklegged ticks transmitting Lyme disease apparently were missed and not stopped very well.

The list of bird benefits for biocontrol, like barn owls for rodent biocontrol in Israel, Palestine, Malaysia and elsewhere could go on and on.

“Bird damage situations throughout the world are similar, involving many of the same crops and genera of birds,” wrote John W. De Grazio a few decades ago in the <em>Proceedings of the 8th Vertebrate Pest Conference. Seed-eating red-winged blackbirds, ring-necked pheasants, sparrows, crows, doves, parrots, munias, queleas, weavers and waterfowl are sometimes pests of corn, rice, wheat, sorghum, sunflowers, almonds, pecans, peanuts, etc. Starlings, sparrows, finches, grackles, robins, parakeets, etc. consume grapes, blueberries, and other fruit in yards, vineyards and orchards.

Dogs are used in pest control for sniffing out termites and bed bugs, and the natural proclivity of some dog breeds to chase birds can be harnessed to keep birds from destroying fruit in orchards and vineyards. In researching a grant proposal to travel to and write about Japan, which I failed miserably to qualify for, my Internet research for the proposal took me to the Japanese Journal of Farm Work Research. Being one of a select 4% of the USA population to have worked in agriculture, the journal title intrigued me enough to browse through several years of tables of contents, where I came across an intriguing article title: “Protection of Citrus From Bird Damage by a Dog.”

Not reading Japanese, I had to rely on the visual diagrams and English summary by researchers Hiromichi Ichinokiyama and Masami Takeuchi at the Kinan Fruits Tree Laboratory and Mie Prefectural Science and Technology Promotion Center:

“Effectiveness of a dog (Canus lupus familiaris) for protecting citrus fruits from bird damage was investigated using a citrus orchard (5.8 a in area) in the harvest season. In Experiment 1, a Border collie shepherd (male) was tied to a wire extended along one side of the square orchard to allow him to run along the inner side of the orchard. This watchdog system was effective in reducing fruit damage by birds (mainly brown-eared bulbul) only in the citrus tree row nearest to the dog runway.”

However, the researchers had better success letting the dog run free in the orchard:

“In Experiment 2, the orchard was enclosed with a tall chain-link fence and the same dog was allowed to move freely in the orchard. In this case, he persevered in chasing birds until they flew away from the orchard. This watchdog system effectively reduced bird damage to citrus fruits all over the orchard, resulting in an increase in crop yield…Further study is needed on the optimum number of dogs released per unit orchard area and the effectiveness of the watchdog system in case when this bird control system is spread to all orchards in the citrus-growing area.”

Like Richard Feynman’s Nontoxic Ant Ferry, dogs chasing birds away from trees laden with fruit or nuts is more a proof-of-concept awaiting further development than a fully developed technology you can order on the Internet.

Thank you to the organizations and people who created and are advancing the Internet, as even finding this sort of information would have been nearly impossible a few decades ago. Amazing how this high-tech infrastructure can advance low-tech solutions like the old-fashioned four-legged, tail-wagging dog as a bird-chaser in service of better fruit harvests.


Carbon Dioxide Gas Combats Bed Bugs

July 24, 2012

CARBON DIOXIDE GAS, an essential nutrient for photosynthesis and the human and animal food chain consuming green plants, can also play a key role in bed bug control. As an attractant, carbon dioxide (CO2) is useful for monitoring and trapping bed bugs and other vampire-like blood-suckers attracted to the gas, including ticks, mosquitoes, and assorted biting flies. Carbon dioxide gas, which has been used to fumigate everything from stored grain and food products to freight containers, museum collections, and hotel and motel rooms, can also be used to fumigate clothing, furnishings, books, electronics, and other bed bug-infested items.

Carbon, carbon dioxide, and the carbon cycle are integral to our very existence on planet Earth. “The carbon of the Earth comes in several forms,” writes University of Cambridge chemist John Emsley in his fascinating Oxford University Press book, Nature’s Building Blocks (An A-Z Guide to the Elements). “Most of what we eat –carbohydrates, fats, proteins and fibre – is made up of compounds of carbon…most ingested carbon compounds are oxidized to release the energy they contain, and then we breathe out the carbon as carbon dioxide. This joins the other carbon dioxide in the atmosphere, from where it will again be extracted by plants and become part of the carbon cycle of nature…The cycle rules the tempo of life on Earth and turns over 200 billion tonnes of carbon each year…In this way carbon is passed up the various food chains, with each recipient releasing some as carbon dioxide, until most carbon is back where it started.”

Does this mean that using carbon dioxide for bed bug control is environmentally acceptable, since it is kind of a “miracle of life” gas behind photosynthesis and plant life? Or is carbon dioxide really more the evil greenhouse or global-warming gas causing global climatic havoc and deserving of punishment via carbon taxes and elimination from the atmosphere via geological carbon sequestration (storage) schemes? Perhaps we should offset carbon dioxide releases for bed bug pest control with offsetting carbon dioxide injections into greenhouses, where elevated CO2 levels increase yields of greenhouse roses, tomatoes, cucumbers, peppers and other crops.

“Carbon is probably the most important element from an environmental point of view,” writes Emsley in Nature’s Building Blocks. “The Earth’s early atmosphere may have contained a lot of carbon dioxide and methane, but once life evolved that began to change. Today, there is very little of these gases and a lot of oxygen instead, thanks chiefly to the action of plants which convert carbon dioxide and water into carbohydrate and oxygen by photosynthesis. The Earth’s atmosphere contains an ever-increasing concentration of carbon dioxide and carbon monoxide, from fossil fuel burning, and of methane, from paddy fields and cows. Human contributions to these sources are still minor compared with natural sources: most carbon dioxide comes from plants, microbes and animals, while methane is given off by swamps, marshes and termite mounds.”

Obviously best to avoid bed bug infestations, and not have to think about remedies like carbon dioxide trapping or fumigations. Italian chemist Primo Levi makes the most persuasive literary argument: “Carbon dioxide, that is, the aerial form of carbon…this gas which constitutes the raw material of life, the permanent store upon which all that grows draws, and the ultimate destiny of all flesh, is not one of the principal components of air but rather a ridiculous remnant, an ‘impurity,’ thirty times less abundant than argon, which nobody even notices. The air contains 0.03 percent; if Italy was air, the only Italians fit to build life would be, for example, the 15,000 inhabitants of Milazzo in the province of Messina. This, on the human scale, is ironic acrobatics, a juggler’s trick, an incomprehensible display of omnipotence-arrogance, since from this ever renewed impurity of the air we come, we animals and we plants, and we the human species, with our four billion discordant opinions, our millenniums of history…”

Bed bugs concern themselves little with environmental correctness, and just tune into characteristics like the heat and carbon dioxide released by metabolizing warm-blooded meal hosts like humans, poultry, rodents, rabbits, etc. A flush from a CO2 cartridge is enough to flush bed bugs from their harborages or hiding places onto a bed in search of a meal. But more naturally, bed bugs follow CO2 gradients to locate live hosts for their blood meals.

“Carbon dioxide has been shown by several researchers to be the most effective attractant for bed bugs,” University of Florida-Gainesville entomologist Philip Koehler told a recent Entomological Society of America (ESA) annual meeting. Humans produce about 700 mg (0.02 oz) of CO2 per minute. “Thus, detectors with very slow CO2 releases cannot compete with human hosts,” said Koehler. “A rapid CO2 release is a better mimic to the human breathing pattern. Detectors with fast CO2 release captured about 4x more bed bugs than detectors with slow release.”

Trapping or monitoring bed bugs with CO2 is complicated by the fact that at different times in the life cycle bed bugs seek out hosts (releasing CO2) for blood meals when hungry; and then when well-fed, instead of CO2 bed bugs seek shelter in groups or cracks and crevices. So although CO2 is the better lure for hungry bed bugs, bed bugs that have fed have different needs and respond to different lures.

A commercial product, FMC’s Verifi(TM) trap, is a dual-action detector combining “fast CO2 generation with liquid kairomone and pheromone lures to attract both host-seeking bed bugs and aggregation-seeking bed bugs,” Koehler told the ESA. Carbon dioxide and the kairomone lure blood-seeking bed bugs into a pitfall part of the trap from which there is no escape. A pheromone lures harborage- or aggregation-seeking bed bugs seeking shelter in cracks and crevices into another part of the trap.

“An inexpensive detector that can be left in place and routinely serviced is needed to aid pest management professionals,” Ohio State University’s Susan Jones told the ESA. “Rutger’s do-it-yourself dry ice (frozen CO2) traps are a cheap and effective method for overnight surveys of potentially infested habitations.” An experiment in a 13-story high-rise apartment building in Columbus, Ohio compared (see You Tube video) 3 Verifi(TM) bed bug detectors per room with 1 CO2-generating dry ice trap per room and canine (dog) detection teams (2 dogs/room; same handler).

Verifi(TM) traps detected bed bugs in 11 of 17 infested rooms in the first 24 hours; and in 14 of 17 infested rooms within a week. Dry ice traps had similar efficacy. Dogs detected bed bugs in 19 rooms, including 3 rooms where neither visual inspections nor dry ice or Verifi(TM) traps detected anything. But the dogs were also not perfect, as each dog also missed 1 room rated positive for bed bugs. So the quest to capture bed bugs with carbon dioxide and other lures goes on.

Human ingenuity seems almost unlimited when it comes to traps. Carbon dioxide, heat and other attractants are all being tested with traps as varied as Susan McKnight Inc.’s Climbup bed bug trap and pitfall traps made from inverted dog bowls painted black on the outside. Rutgers’ Narinderpal Singh tested CO2, heat, and lures such as nonanol, octanol, 1-octen-3-ol, coriander, and spearmint with inverted dog bowl pitfall traps. CO2 had an additive effect with multiple-component lures in inverted dog bowl traps, and may be developed into an inexpensive monitoring system for detecting low levels of bed bugs. Trials with baited traps are continuing.

Both carbon dioxide and ozone show fumigant potential against bed bugs. Purdue University’s Kurt Saltzmann told the ESA of “Two devices capable of delivering ozone to laboratory fumigation chambers.” One device delivered a short exposure to high ozone levels, and the other long exposure to low ozone levels. “Preliminary experiments showed that adult male bed bugs were susceptible to relatively short periods of ozone exposure when high concentrations of ozone were used,” said Saltzmann. “100% mortality was achieved when bed bugs were exposed to 1800 ppm ozone for 150 minutes.” Low ozone fumigation is also being tested with 1-2% hydrogen peroxide for up to 72 hours.

Carbon dioxide (CO2) is used by libraries, museums, and others as an insect-killing fumigant. Indeed, dry ice (frozen CO2) to release CO2 gas is cheaper than washing and drying fabrics to kill bed bugs, Rutgers University’s Changlu Wang told the ESA. At an 80% concentration, CO2 kills all bed bug eggs in 24 hours (eggs are the toughest bed bug life stage to kill). A 50% CO2 concentration for 8 hours is sufficient to kill bed bug nymphs (immatures) and adults.

Wang’s CO2 fumigations involved filling Husky garbage bags 90% full of items such as mattress covers and fabrics, leaving little room for air. Then the bags were sealed with dry ice inside for several hours. Books, electronics, toys and other items damaged by heat treatments might benefit from the low temperatures created by dry ice treatments. However, for safety reasons Wang recommends wearing gloves and turning on fans for ventilation when opening many bags filled with carbon dioxide gas (fumigant).