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Sunflowers Linked to Reduced Varroa Mite Infestations in Honey Bees

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A new study indicates a benefit to honey bees of local sunflower cropland. Even low levels of sunflower acreage nearby correlate with reduced Varroa mite infestation in managed colonies, researchers found, and supplemental sunflower pollen helps ward off the mites, as well. (Photo by Lillian Wong via FlickrCC BY-SA 2.0)

By Paige Embry

Paige Embry

Varroa destructor is aptly named. It is a parasitic mite of Asian honey bees (Apis cerana) that jumped to European honey bees (Apis mellifera) and then romped around most of the world, wreaking havoc.⁠ In 1987 it arrived in the United States,⁠ where it wins the dubious award of being the most problematic of the honey bee’s many pests and diseases.⁠

Scientists long thought that Varroa mites were tick-like—blood-suckers that transmitted diseases—and that the bulk of the harm they caused came from the diseases they spread. Even without spreading diseases, Varroa mites damage bees because they don’t actually eat replaceable hemolymph (a bee’s blood-equivalent); rather, they eat its fat body. It sounds benign because the name is misleading. A bee’s fat body is a bit like a human’s liver. It plays a role in the bee’s immune system and its ability to survive the winter and detox pesticides. Any method of lowering Varroa loads would be a huge boon to honey bees and their keepers.

new study published in December in the Journal of Economic Entomology provides early evidence that the humble sunflower (Helianthus annuus) may provide some relief from those fat body-destroying mites.

Evan Palmer-Young, Ph.D.

The pollen and nectar of sunflowers (and some other members of the Asteraceae family) are protein-poor and generally considered a subpar source of nutrition for bees. From an overall health perspective, however, sunflower pollen and nectar look like great food because they may help reduce parasites. Evan Palmer-Young, Ph.D., a postdoctoral fellow at the U.S. Department of Agriculture’s Bee Research Lab in Beltsville, Maryland, is lead author on the new study. Previous experiments on bumble bees had shown that sunflower pollen strongly reduced infections by a specific parasite, so, Palmer-Young says, “We wanted to see whether honey bees might derive similar, infection-reducing benefits from sunflowers.”

The study covers four different experiments that looked at two parasites and several viruses, but only two experiments showed significant results. The authors sum up their findings: “Although we did not find significant effects of sunflower pollen on endopasrasites [Nosema ceranae] or viruses in laboratory or field settings, sunflower pollen was associated with reduced levels of Varroa mites in honey bee colonies.”

In one experiment the scientists provided supplemental pollen (sunflower pollen, wildflower pollen, or artificial protein patties) to field colonies of honey bees in late summer when Varroa levels often begin to rise. The colonies given supplemental sunflower pollen saw a 2.75-fold diminishment in Varroa infestation levels relative to bees receiving artificial pollen patties. (The group receiving wildflower pollen had more mites than the ones fed sunflower pollen, but the difference was not statistically significant.)

Perhaps the most significant finding was from the experiment that looked at the association of Varroa mite infestation levels and sunflower crop acreage. The scientists found that honey bees located near sunflower cropland had lower mite levels—even when the total land cover by sunflowers was scant (a median of 0.32 percent). Their models predicted that each doubling of sunflower acreage within two miles of an apiary would lead to a 28 percent decrease in mite infestation. The researchers note that this pattern is a correlation, and some other factors related to having sunflowers in the vicinity—different management practices by beekeepers or pesticide exposure, for example—may be the cause for the lower mite loads. Nevertheless, Palmer-Young says a big takeaway from the work is, “that sunflowers appear to be protective against a major threat to honey bees (i.e., mites), whereas the amount of U.S. sunflower cropland is declining—potentially limiting bees’ access to sunflower-associated benefits.”

Total crop area devoted to sunflowers in the U.S. has decreased by 2 percent per year since 1980. The authors note that market and policy shifts that led to changes in agriculture in the Dakotas played a role in that decline. In the 1980s, low-quality farmland was converted to (flower-rich) grasslands as part of the Conservation Reserve Program (CRP)—a change likely beneficial to bees of all sorts. Post-2000, both sunflower crop area and CRP acreage were replaced by corn and soybeans. The authors note, “Between 2006 and 2016, 53 percent of CRP land surrounding existing North and South Dakota apiaries was converted to crop production, but only 8 percent was used for bee-friendly crops.” This area hosts 75 percent of U.S. sunflower acreage as well as 40 percent of U.S. honey bees during the summer.

The authors write that they don’t have enough evidence yet to recommend specific changes in land use, but Palmer-Young says, “If sunflowers are as big of a factor in mite infestation as indicated by our landscape-level correlations … having a few more acres of sunflower within a mile or two of apiaries could bring colonies below the infestation levels that require treatment of hives with acaracides (i.e., mite-controlling chemicals).”

Palmer-Young provided a poetic summary for the paper:

Fields of sunflower blooming in sight
yield for many a bee a delight.
But with bright yellow joy
Displaced by corn and soy,
Honey bees could lose balm for their mites.

In other words, if additional research supports sunflowers as an anti-parasitic for Varroa mites, don’t be surprised if beekeepers start tossing out sunflower seeds everywhere they go.

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Sunflower-Associated Reductions in Varroa Mite Infestation of Honey Bee Colonies

Journal of Economic Entomology

Paige Embry is a freelance science writer based in Seattle and author of Our Native Bees: North America’s Endangered Pollinators and the Fight to Save Them. Website: www.paigeembry.com.

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The correct identification of insect pests and their natural enemies is critical for developing sound and sustainable pest management strategies: this is particularly so for rice. In the 1960’s, a comprehensive rice insect pest and natural enemy collection was established at the International Rice Research Institute (IRRI) in the Philippines, with the aim of helping those in national rice research programs to identify rice arthropods. 

A similar project was begun in West Africa in 1990, establishing a rice insect and natural enemy collection at WARDA (West African Rice Development Association), which subsequently became AfricaRice.

Associated with both of these collections, dichotomous keys were developed and published in the following books on rice arthropods:
Biology and Management of Rice Insects,
edited by E. A. Heinrichs (1994) and published by IRRI, and 
Rice Feeding Insects and Selected Natural Enemies in West Africa, authored by E. A. Heinrichs and Alberto Barrion (2002).

While the printed versions of both books have been out-of-print for several years, a recent upgrade of the Lucid software program, which makes it possible to convert paper-based, dichotomous keys to interactive pathway keys, means that both keys are now freely available to use on the Internet, courtesy of IAPPS (International Association for the Plant Protection Scientists) at: http://www.plantprotection.org

 Adding arthropod images: Note that the IRRI key now includes a large number of color images of important insect pests and natural enemies. E.A. Heinrichs (eheinrichs2@unl.edu) would appreciate any good resolution images that colleagues would be willing to submit for adding to the key – with due acknowledgement

IRRI arthropod key

West African arthropod key

© Copyright International Association for the Plant Protection Sciences. All rights reserved 2022.

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Amped-Up Ants: Caterpillars’ Sugary Treats Earn Carpenter Ant Care

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A new study finds that larvae of the endangered butterfly Cyclargus thomasi bethunebakeri, often known as the Miami blue butterfly, survive in greater numbers when protected by Florida carpenter ants (Camponotus floridanus), which fend off predators in exchange for the caterpillars’ sugary secretions. Shown here are two Florida carpenter ants tending to a Miami blue butterfly caterpillar. (Photo by Geena M. Hill)

By Carolyn Bernhardt

Since the 1960s, researchers have observed ants providing protection to various insects, a phenomenon called myrmecophily. And by creating a mix of chemical, acoustic, and other cues, certain butterfly species have long found ways to become frequent beneficiaries of ants’ dedicated services.

In a recent study led by Geena M. Hill, a research biologist at the Florida Natural Areas Inventory at Florida State University, researchers tested whether the Florida carpenter ant (Camponotus floridanus) provides protection to the highly endangered butterfly Cyclargus thomasi bethunebakeri, often known as the Miami blue butterfly. Their results were published this week in the open-access Journal of Insect Science.

The butterfly Cyclargus thomasi bethunebakeri, often known as the Miami blue butterfly, has been a federally listed endangered species since 2012. (Photo by Geena M. Hill)

“We found that ants provide significant protection to Miami blue larvae, with later instar larvae receiving a higher level of protection due to differences in tending frequencies,” Hill says. The ants tended to the late instar larvae more than twice as much as they did early instar larvae.

Geena M. Hill, a research biologist at the Florida Natural Areas Inventory at Florida State University, conducts fieldwork in central Florida. (Photo by John Lampkin)

Previous studies conducted by study co-author Matthew D. Trager, Ph.D., forest planner at the U.S. Forest Service, have shown that ant tending has sex-dependent benefits for female Miami blue butterflies. Ant-tended female Miami blue larvae grow into larger pupae and lay more eggs as adults. So, in this latest study, Hill and team conducted a series of timed observational trials in the lab to assess larval survival and ant protection from insect predators.

Ants were incredibly effective protectors for the larvae, but they seemed to provide greater protection over later instar larvae. Hill says she isn’t totally certain why this is, but she has a hunch that certain butterfly life stages influence ant tending behavior while some more vulnerable life stages do not as effectively stimulate ants to protect the larvae. She says she suspects this could be because each time the larvae molt they might develop and produce more secretions that signal to ants to help them as they increase in size.

At certain developmental stages, each caterpillar has a nectary organ tucked neatly into a slit in its back and flanked by tentacle-like organs on either side. When this organ emerges, it secretes a sugary substance packed with amino acids and other nutrients for ants. Hill and her colleagues watched in the lab as the ants’ energy levels soared whenever predators approached after the ants had ingested the substance. “They were all amped up!” she says. The carpenter ants would even drum their antennae on the back of the caterpillar to request a helping.

A new study finds that larvae of the endangered butterfly Cyclargus thomasi bethunebakeri, often known as the Miami blue butterfly, survive in greater numbers when protected by Florida carpenter ants (Camponotus floridanus), which fend off predators in exchange for the caterpillars’ sugary secretions. (Video by Chris Johns and Geena M. Hill)

For the most part, Hill says she thinks the substance itself is enough motivation for the ants to protect the larvae from threats. However, it’s also possible that the chemical makeup of the secretions affects the dopamine levels in the ants. “We already know other species can trick the ants by using different chemicals,” she says. “So, it is interesting to think maybe they could have a chemical in the secretions that affects the dopamine levels [in the ants] and makes them more aggressive toward predators.”

Whatever the reason, this research shows that, for Miami blue butterfly caterpillars, Florida carpenter ants are effective protectors against attacks and help improve butterfly larvae survivorship. But while the Florida carpenter ant is the Miami blue’s most common associate, 16 other species of ants also tend the Miami blue caterpillars. Hill says she wants to test those other species to measure how effective each species is at promoting survival for the federally listed, critically endangered butterfly species. This information can help inform conservation efforts for rehabilitating the endangered Miami blue. “Hopefully with this work, we will see increases within the Miami blue population,” Hill says. “As our lab conducts butterfly releases, it will be important to select release sites that have Florida carpenter ants present.

While the Florida carpenter ant (Camponotus floridanus) is the most common associate with the endangered butterfly Cyclargus thomasi bethunebakeri, often known as the Miami blue butterfly, 16 other species of ants also tend the Miami blue caterpillars, such as Camponotus planatus, sometimes known as the compact carpenter ant, shown here. Geena M. Hill, a research biologist at the Florida Natural Areas Inventory at Florida State University, says she wants to test those other species to measure how effective each species is at promoting survival for the federally listed, critically endangered butterfly species. (Photo by Geena M. Hill)

Historically, the Miami blue was found throughout coastal Florida. But, with climate change and the effects of human-driven land development, the species’ numbers have long dwindled. “Predators are not the sole driver for the decline of the Miami blue, but with such low population numbers, they can have a big impact,” says Hill.

For a long time now, the Miami blue has been limited to a few islands in the Florida Keys. It mainly lives in the Key West National Wildlife Refuge. Still, over the last several decades, researchers have successfully reestablished the species into the ecosystem in Bahia Honda State Park—35 miles east of Key West and that much closer to mainland Florida. And work is underway to reintroduce the species in mainland Florida.

“Insect declines are being observed worldwide,” says Hill, “and it’s imperative to study these insects and their interactions so we best know how to protect them. There are so many species that will go extinct without us knowing. By protecting one species, we [could be] protecting others within the habitat as well.”

Read More

Protective Benefits of Tending Ants to a Critically Endangered Butterfly

Journal of Insect Science

Carolyn Bernhardt, M.A., is a freelance science writer and editor based in Portland, Oregon. Email: carolynbernhardt11@gmail.com.

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Entomologists issue warning about effects of climate change on insects

by University of Maryland

<img src="https://scx1.b-cdn.net/csz/news/800a/2022/entomologists-issue-wa-1.jpg&quot; alt="Entomologists issue warning about effects of climate change on insects" title="Climate change impacts on insects can be categorized into two major categories: Gradual long-term change and extreme events that will increase in frequency and severity, while interventions include formal mitigation of change through policy and public approaches which in turn help to reduce impacts in various ways. Credit: <i>Ecological Monographs
Climate change impacts on insects can be categorized into two major categories: Gradual long-term change and extreme events that will increase in frequency and severity, while interventions include formal mitigation of change through policy and public approaches which in turn help to reduce impacts in various ways. Credit: Ecological Monographs (2022). DOI: 10.1002/ecm.1553

In a new scientific review, a team of 70 scientists from 19 countries warned that if no steps are taken to shield insects from the consequences of climate change, it will “drastically reduce our ability to build a sustainable future based on healthy, functional ecosystems.”

Citing research from around the world, the team painted a bleak picture of the short- and long-term effects of climate change on insects, many of which have been in a state of decline for decades. Global warming and extreme weather events are already threatening some insects with extinction—and it will only get worse if current trends continue, scientists say. Some insects will be forced to move to cooler climes to survive, while others will face impacts to their fertility, life cycle and interactions with other species.

Such drastic disruptions to ecosystems could ultimately come back to bite people, explained Anahí Espíndola, an assistant professor of entomology at the University of Maryland and one of the paper’s co-authors.

“We need to realize, as humans, that we are one species out of millions of species, and there’s no reason for us to assume that we’re never going to go extinct,” Espíndola said. “These changes to insects can affect our species in pretty drastic ways.”

Insects play a central role in ecosystems by recycling nutrients and nourishing other organisms further up the food chain, including humans. In addition, much of the world’s food supply depends on pollinators like bees and butterflies, and healthy ecosystems help keep the number of pests and disease-carrying insects in check.

These are just a few of the ecosystem services that could be compromised by climate change, the team of scientists cautioned. Unlike mammals, many insects are ectotherms, which means they are unable to regulate their own body temperature. Because they are so dependent on external conditions, they may respond to climate change more acutely than other animals.

One way that insects cope with climate change is by shifting their range, or permanently relocating to places with lower temperatures. According to one study cited by Espíndola and other scientists, the ranges of nearly half of all insect species will diminish by 50% or more if the planet heats up 3.2°C. If warming is limited to 1.5°C—the goal of the global Paris Agreement on climate change—the ranges of 6% of insects will be affected.

Espíndola, who studies the ways in which species respond to environmental changes over time, contributed to the sections of the paper that address range shifts. She explained that drastic changes to a species’ range can jeopardize their genetic diversity, potentially hampering their ability to adapt and survive.

On the other hand, climate change may make some insects more pervasive—to the detriment of human health and agriculture. Global warming is expected to expand the geographical range of some disease vectors (such as mosquitoes) and crop-eating pests.

“Many pests are actually pretty generalist, so that means they are able to feed on many different types of plants,” Espíndola said. “And those are the insects that—based on the data—seem to be the least negatively affected by climate change.”

The team noted that the effects of climate change are often compounded by other human-caused impacts, such as habitat loss, pollution and the introduction of invasive species. Combined, these stressors make it more difficult for insects to adapt to changes in their environment.

Though these effects are already being felt by insects, it is not too late to take action. The paper outlined steps that policymakers and the public can take to protect insects and their habitats. Scientists recommended “transformative action” in six areas: phasing out fossil fuels, curbing air pollutants, restoring and permanently protecting ecosystems, promoting mostly plant-based diets, moving towards a circular economy and stabilizing the global human population.

The paper’s lead author, Jeffrey Harvey of the Netherlands Institute of Ecology (NIOO-KNAW) and Vrije Universiteit Amsterdam, said in a statement that urgent action is needed to protect insects and the ecosystems they support.

“Insects are tough little critters, and we should be relieved that there is still room to correct our mistakes,” Harvey said. “We really need to enact policies to stabilize the global climate. In the meantime, at both government and individual levels, we can all pitch in and make urban and rural landscapes more insect-friendly.”

The paper suggested ways that individuals can help, including managing public, private or urban gardens and other green spaces in a more ecologically-friendly way—for instance, incorporating native plants into the mix and avoiding pesticides and significant changes in land usage when possible.

Espíndola also stressed the value of encouraging neighbors, friends and family to take similar steps, explaining that it’s an easy yet effective way to amplify one’s impact.

“It is true that these small actions are very powerful,” Espíndola said. “They are even more powerful when they are not isolated.”

Their paper was published in Ecological Monographs.

More information: Jeffrey A. Harvey et al, Scientists’ warning on climate change and insects, Ecological Monographs (2022). DOI: 10.1002/ecm.1553

Provided by University of Maryland 


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We need to stop thinking of insects as ‘creepy crawlies’ and recognise their keystone role in ecosystems, say scientists

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“Coconut Leaf Wilt Disease could have been controlled sooner if there was cooperation”

Monday, December 5, 2022 – 01:00

Print Edition

Local

Priyan de Silva

Dr. Nayani Arachchige

Fourteen years after being first detected in Sri Lanka, over 340,000 coconut palms identified as diseased, over 313,000 coconut palms cut down and destroyed, and billions of rupees spent on disease control, coconut growers in the Southern Province continue to be plagued by the Weligama Coconut Leaf Wilt Disease (WCLWD)

Coconut Research Institute (CRI) Deputy Director (Research) Dr. Nayani Arachchige said that the CRI together with Coconut Cultivation Board (CCB) and other related stakeholders including law enforcement authorities have managed to contain the disease to the Southern Province and added that if the coconut growers and the community on the whole had been more cooperative, the disease could have been controlled sooner.

The Weligama Coconut leaf Wilt disease is caused by phytoplasmas and transmitted by infective insect vectors, vegetative propagation or grafting of infected planting material to healthy plants, by vascular connections made between infected and uninfected host plants by parasitic plants, and by seed or embryo transmission. Once infected, a coconut palm will die within two years. There is no known cure and cutting down infected trees and incinerating the crowns is the only practical solution to arrest the spread of the disease.

Dr. Arachchige said that at the initial stage of infection, a coconut tree would bear profusely and growers have second thoughts of cutting down the tree even after they have been noticed to do so by the authorities. The delay causes greater harm as more trees in the vicinity are prone to infection and was one reason that containing the disease has taken so long.

The WCLWD was first detected in the Weligama area in 2008, but had spread from Galle to Tangalle. To prevent the disease spreading further, the CRI demarcated a buffer zone three kilometres wide on either side of the A17 trunk road from Galle running through Angulugaha, Henegama, Akuressa, Kamburupitiya, Kirinda – Puhulwella, Hakmana, Walsmulla, Beliatta and ending in Tangalle.

The Government, by gazette notification No. 1542/7 of 24 March 2008, prohibited the transport of any palm species and their live parts out of the demarcated boundary. Although the prohibition was not strictly adhered to due to various restraints, it was fortunate that the disease did not spread to other coconut growing areas.

The Matara district where WCLWD was first detected has borne the brunt of the disease. Figures obtained from the Coconut Cultivation Board show that up to September 30, 2022, 313,857 diseased trees have been identified in the Matara district.

Growers who complied with the order given by the CCB authorities and cut down the diseased trees were paid Rupees 3,000 per tree more as an initiative to cut and destroy the tree rather than compensation as the cost incurred by a grower to tend to a plant until it starts bearing and the loss of produce is very much more.

Due to WCLWD and other factors such as eating of the coconut by Grizzled Giant Squirrels and the Toque macaque, the annual yield in the Matara district had dropped from 121 million nuts in 2011 to 96 million nuts in 2019 and to 73 million nuts in 2020.

Some growers have been compelled to destroy their whole plantation and plant alternate crops as provisions of the Plant Protection Act prohibits planting any type of palm trees in the areas where WCLWD has been detected.

According to the CCB, WCLWD could be fully eradicated in the near future if the growers and public were more cooperative and if the Government would continue to provide adequate funds.

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New Executive Board of the Entomological Federation of Latin America (FELA)

The Entomological Federation of Latin American (FELA) is integrated by nine entomological societies: Sociedad Entomológica de Brasil (SEB), Sociedad Entomológica Argentina (SEA), Sociedad Boliviana de Entomología (SBE), Sociedad Colombiana de Entomología (SOCOLEN), Sociedad Chilena de Entomología (SCHE), Sociedad Entomológica Ecuatoriana (SEE), Sociedad Mexicana de Entomología (SME), Sociedad Panameña de Entomología (SEPAM), and Sociedad Entomológica del Perú (SEP). During the XI Argentinian Congress of Entomology and the XII Latin American Congress of Entomology (La Plata, Buenos Aires, Argentina, October 24–28), FELA held its first ordinary assembly, where representatives of the member societies voted the new Executive Board. Welcomed members of the Board are Juana María Coronado Blanco (President), Bruno Zachrisson (Vice-President), Lucía Claps (Secretary), Norma Nolazco (Vocal), and María Stella Zerbino (Past President). The city of Uberlandia (Minas Gerais, Brazil) was designated to host the XIII Latin American Congress of Entomology (CLAE), that will be held in 2024.

New Executive Board of FELA: Bruno Zachrisson, Lucía Claps, Norma Nolazco, Juana María Coronado Blanco, and María Stella Zerbino.

Submitted by:

Dr. Nora Altier

IAPPS Coordinator Region XV, South America

E-mail: naltier@inia.org.uy

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Western Farmer-Stockman

Nate LongWFP-nate-log-juniper-control-web.jpg

Junipers on a hillside are controlled through chaining.

Large populations of the tree can negatively impact sage grouse habitat and diminish sustainability of grazing land.

Heather Smith Thomas | Jul 28, 2022

Farm Futures Summit and Boot Camp 2022

Western juniper is a native shrub that grows to tree size, thriving in the Great Basin, which spans most of Nevada, much of Oregon and Utah, and portions of California, Idaho, Wyoming, and Mexico.   

In recent decades, hardy junipers have been dominating vast areas, crowding out other plant species.  Large populations of juniper can negatively impact sage grouse habitat and diminish sustainability of grazing land.

The goal of many rangeland managers has been to restore ecologic balance.  Juniper removal on the Modoc National Forest in California, for instance, is part of an effort to improve sage grouse habitat, but there are many other ecological benefits resulting from removing the encroaching juniper stands.

These trees pull more water from the ground than the surrounding vegetation does, leaving less moisture for the other plants. With loss of understory vegetation in juniper woodlands, there is soil loss and erosion during intense rain storms. They outcompete most other plants; with their efficient root system they consume a lot of water that would have helped the survival of other plants.

Effect on watersheds has been noticed; with increased demand for water by juniper, combined with several years of drought in Northeast California, many springs and streams have dried up.

Removal projects

Kyle Sullivan, District Manager, Soil and Water Conservation District, Grant County, Ore., says there were government projects in earlier years to help ranchers remove juniper; there was funding for mechanical removal—sawing the trees, piling and burning them.  “Logging crews brought equipment to take out the trees, with hand-labor follow-up for the smaller trees,” Sullivan said.

Loggers piled the trees, and after they dried out the landowners burned the piles during winter when there was no risk of fire danger.

“Our Soil and Water Conservation District received grants to try to control juniper with herbicide.  A dozen years ago we did an experiment, cutting incisions into the trunk with a chain saw, then squirted herbicide into the trunk with a spray bottle. But juniper is so bushy that it is difficult to get to the base of the tree,” he said.

The crew tried different herbicides and different concentrations. It was effective for killing the trees, but the time and labor involved didn’t pencil out, economically.  The Forest Service preferred that method, however, because it left the dead trees standing and didn’t tear up the ground or disrupt surrounding vegetation.

A landowner might choose this method, to kill some of the larger trees and keep them from reproducing, but dead trees on the range might be fuel for wildfires.

“If standing trees are limbed high enough, a grass fire might quickly burn through underneath, but many junipers have low branches under the duff which could raise the fire higher off the ground and into the tree itself,” said Sullivan.

Junipers proliferate

“We left a few trees on the landscape to provide shade for livestock and wildlife, but they had to be trees with no berries (seeds).  Juniper trees have genders, and some can have both male and female characteristics.  If a tree isn’t producing berries it doesn’t spread seeds,” he explained.

“We also learned the importance of maintenance after trees are cut/piled/burned, because the seed source is still there.”  The seeds are viable for years, to produce new seedlings.  The problem will re-emerge if you don’t keep after it.

“After you cut them down you may get a new flush of young trees in 7 to 10 years, but you can do periodic controlled burning or remove the young ones, or use herbicide and eventually get rid of most of them.”            

Junipers are tough and hardy, with high survival rate.  If they take over a range or watershed, they can be detrimental.  “Research is still ongoing in central Oregon, looking at the effects of hydrology, and how a canopy of juniper can keep snow from coming to the ground.  This watershed study is providing new information; we realize what an aggressive root system they have.  If there is a high population of junipers, they have a negative effect on the watershed,” he said.

Herbicide pellets can be used for juniper control. Wilburn Ranches in Oregon started using chemical control of juniper invasions on their range pastures a few years ago, with good results. They took photos of trees afterward, showing how it killed them.

Label directions suggest putting one tablet on the ground in the drip zone of the juniper if it is 3 feet tall.  For every additional 3 feet, you add another tablet– up to about 10 feet of tree height.  The pellets can be applied when moisture is sufficient to dissolve them.  The smaller trees tend to die all at once and the larger ones die by degrees until they completely brown and dead.

Cost per tree for this method is lower than using chain saws or heavy equipment, but the herbicide pellets may need to be repeated every 3-4 years to keep juniper contained.  This is another option for people who don’t want to mechanically remove and then burn them.  Ranchers can hike around and distribute the pellets, or do it from horseback while checking cattle, tossing pellets around the outside edges of the junipers. 

Chains and excavators

Sullivan said one method still used in some parts of the West is chaining.  An old ship anchor chain (with huge, heavy links) is secured between two big Cat tractors to mow down the trees.  The heavy chain pulls on the trees and uproots them.

Another method is to tip the juniper tree over with the boom of an excavator.  The machine can then grab it, pick it up and shake the soil off the roots so the trees can be piled easier.  It costs more for this method but has the advantage of uprooting the trees without much damage to the surrounding terrain.  “A machine can also be used to pile them and clean up the area afterward.  This way you get some of the smaller branches that are underneath the soil; they pull up with the tree roots,” he said.

“This is probably one of the more expensive alternatives but leaves a cleaner site.  Depending on your goals, budget, and equipment, one method may be more attractive than another.”

In his region many ranchers use chain saws and cut down the larger trees, then go back later to get the little ones—and pile them all up with machines. 

“We try to keep abreast of research that keeps evolving on the impacts of these plants, and how to deal with them.  Oregon State University has published a number of guidelines with advice on managing western juniper,” Sullivan said.

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India’s Supreme Court mulls impact of green lighting GM crops on peasant woman farm laborers, who will no longer need to hand-weed

Krishnadas Rajagopal | Hindu | December 5, 2022

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Credit: Getty Images
Credit: Getty Images

The [Indian] Supreme Court on [November 30] expressed concern about the plight of thousands of women agricultural labourers in rural areas, traditionally engaged in de-weeding, who will be part of the human cost if the government permits the commercial cultivation of herbicide-tolerant crops such as GM mustard in India.

“In rural areas, women are experts in removing weeds. They are a part of the labour force in agriculture in India. It brings them employment…” Justice B.V. Nagarathna observed orally while hearing challenges against the environmental clearance given to genetically modified mustard by the government.

Justice Dinesh Maheshwari, the lead judge on the Bench, agreed that women were an integral part of the Indian agricultural landscape, from paddy fields to tea estates, across the country.

“They work in knee-deep water in the fields, bending the whole day and working,” Justice Nagarathna said.

Senior advocate Sanjay Parikh, for a petitioner, said the widespread use of herbicide-tolerant crops would encourage farmers to spray chemical weed-killers.

…“The Supreme Court’s own Technical Expert Committee [TEC] had said that these GM crops were not meant for agriculture in the Indian context. They may be suitable in the western context where there are large farms, but not here,” Mr. Parikh argued.

This is an excerpt. Read the original post here

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Climate change means farmers in West Africa need more ways to combat pests

by Loko Yêyinou Laura Estelle, The Conversation

worm on corn
Credit: Unsplash/CC0 Public Domain

The link between climate change and the spread of crop pests has been established by research and evidence.

Farmers are noticing the link themselves, alongside higher temperatures and greater variability in rainfall. All these changes are having an impact on harvests across Africa.

Changing conditions sometimes allow insects and diseases to spread and thrive in new places. The threat is greatest when there are no natural predators to keep pests in check, and when human control strategies are limited to the use of unsuitable synthetic insecticides.

Invasive pests can take hold in a new environment and cause very costly damage before national authorities and researchers are able to devise and fund ways to protect crops, harvests and livelihoods.

Early research into biological control methods (use of other organisms to control pests) shows promise for safeguarding harvests and food security. Rapid climate change, however, means researchers are racing against time to develop the full range of tools needed for a growing threat.

The most notable of recent invasive pests to arrive in Africa was the fall armyworm, which spread to the continent from the Americas in 2016.

Since then, 78 countries have reported the caterpillar, which attacks a range of crops including staples like maize and has caused an estimated US$9.4 billion in losses a year.

African farmers are still struggling to contain the larger grain borer, or Prostephanus truncatus Horn, which reached the continent in the 1970s. It can destroy up to 40% of stored maize in just four months. In Benin, it is a particular threat to cassava chips, and can cause losses of up to 50% in three months.

It’s expected that the larger grain borer will continue to spread as climatic conditions become more favorable. African countries urgently need more support and research into different control strategies, including the use of natural enemies, varietal resistance and biopesticides.

My research work is at the interface between plants, insects and genetics. It’s intended to contribute to more productive agriculture that respects the environment and human health by controlling insect pests with innovative biological methods.

For example, we have demonstrated that a species of insect called Alloeocranum biannulipes Montr. and Sign. eats some crop pests. Certain kinds of fungi (Metarhizium anisopliae and Beauveria bassiana), too, can kill these pests. They are potential biological control agents of the larger grain borer and other pests.

Improved pest control is especially important for women farmers, who make up a significant share of the agricultural workforce.

In Benin, for example, around 70% of production is carried out by women, yet high rates of illiteracy mean many are unable to read the labels of synthetic pesticides.

This can result in misuse or overuse of chemical crop protection products, which poses a risk to the health of the farmers applying the product and a risk of environmental pollution.

Moreover, the unsuitable and intensive use of synthetic insecticides could lead to the development of insecticide resistance and a proliferation of resistant insects.

Biological alternatives to the rescue

Various studies have shown that the use of the following biological alternatives would not only benefit food security but would also help farmers who have limited formal education:

  1. Natural predators like other insects can be effective in controlling pests. For example I found that the predator Alloeocranum biannulipes Montr. and Sign. is an effective biological control agent against a beetle called Dinoderus porcellus Lesne in stored yam chips and the larger grain borer in stored cassava chips. Under farm storage conditions, the release of this predator in infested yam chips significantly reduced the numbers of pests and the weight loss. In Benin, yams are a staple food and important cash crop. The tubers are dried into chips to prevent them from rotting.
  2. Strains of fungi such as Metarhizium anisopliae and Beauveria bassiana also showed their effectiveness as biological control agents against some pests. For example, isolate Bb115 of B. bassiana significantly reduced D. porcellus populations and weight loss of yam chips. The fungus also had an effect on the survival of an insect species, Helicoverpa armigera (Hübner), known as the cotton bollworm. It did this by invading the tissues of crop plants that the insect larva eats. The larvae then ate less of those plants.
  3. The use of botanical extracts and powdered plant parts is another biological alternative to the use of harmful synthetic pesticides. For example, I found that botanical extracts of plants grown in Benin, Bridelia ferruginea, Blighia sapida and Khaya senegalensis, have insecticidal, repellent and antifeedant activities against D. porcellus and can also be used in powder form to protect yam chips.
  4. My research also found that essential oils of certain leaves can be used as a natural way to stop D. porcellus feeding on yam chips.
  5. I’ve done research on varietal (genetic) resistance too and found five varieties of yam (Gaboubaba, Boniwouré, Alahina, Yakanougo and Wonmangou) were resistant to the D. porcellus beetle.

Next generation tools

To develop efficient integrated pest management strategies, researchers need support and funding. They need to test these potential biocontrol methods and their combinations with other eco-friendly methods in farm conditions.

Investing in further research would help to bolster the African Union’s 2021–2030 Strategy for Managing Invasive Species, and protect farmers, countries and economies from more devastating losses as climate change brings new threats.

Initiatives like the One Planet Fellowship, coordinated by African Women in Agricultural Research and Development, have helped further the research and leadership of early-career scientists in this area, where climate and gender overlap.

But much more is needed to unlock the full expertise of women and men across the continent to equip farmers with next generation tools for next generation threats.

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.


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Why African farmers should balance pesticides with other control methods

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University of Adelaide researchers developing gene drive technology to combat invasive mice

ABC Rural

 / By Dylan Smith and Brooke Neindorf

Posted Thu 10 Nov 2022 at 1:49amThursday 10 Nov 2022 at 1:49am, updated Thu 10 Nov 2022 at 3:32pmThursday 10 Nov 2022 at 3:32pm

five mice on top of each other
The technology aims to make future females of invasive mice species infertile.(Supplied: University of Adelaide)

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Researchers at the University of Adelaide have released their findings about the potential effectiveness of gene drive technology to control invasive mice.

Key points:

  • A South Australian research team identifies new technology it hopes will eventually curb mice numbers
  • Co-author Luke Gierus says the technology is the first feasible genetic biocontrol tool for invasive mammals
  • Researchers believe the technology can be developed to work against other invasive pests

The technology — named t-CRISPR — uses sophisticated computer modelling on laboratory mice.

DNA technology is used to make alterations to a female fertility gene and, once the population is saturated with the genetic modification, the females that are generated will be infertile.

Research paper co-first author and post-graduate student Luke Gierus said the technology was the first genetic biological control tool for invasive animals.

“So we can do an initial seeding of a couple hundred mice and that will be enough, in theory, to spread and eradicate an entire population,” he said.

“We’ve done some modelling in this paper and we’ve shown using this system we can release 256 mice into a population of 200,000 on an island and that would eradicate those 200,000 in about 25 years.”

person with facial hair in their mid 20's smiles at the camera
Paper co-author Luke Gierus says the technology has a long way to go but signs are promising.(Supplied: Luke Gierus)

The team has been undertaking the research for five years.

Mr Gierus said the next step would be to continue testing in laboratories before releasing mice onto islands where the team could safely monitor the effects.

He said the method was far more humane than other methods, such as baiting.

“It’s potentially a new tool that can either be used alongside the current technology or by itself,” Mr Gierus said.

“This is quite a revolutionary technology that gives us another way to try and control and suppress mice.”

Mice scramble over a white background
Invasive mouse species have caused millions of dollars in damages to crops in recent years.(ABC News Video)

Technology welcomed

CSIRO research officer and mouse expert Steve Henry said wiping out mice from agricultural systems would be a wonderful outcome but he could not see it happening any time soon.

“The farming community are fantastic in terms of their willingness to adopt new ideas, so while it’s really important to do this research, the time frame is long and we need to make sure we don’t say we have a solution that’s just around the corner.”

But Mr Henry believed the technology would be welcomed with open arms when it did arrive.

A man in a hat weights a mouse at the end of a string
CSIRO researcher Steve Henry says farmers are keen on innovative solutions.(ABC News: Alice Kenney)

“While we need to be focusing on the stuff that we can use to control mice now, we also need to be looking outside of the box in terms of these new technologies … into the future,” he said.

Mr Henry said that while he did not have extensive knowledge about the technology, it was exciting.

“The other thing that is really cool is you can make it so it doesn’t affect native rodent species as well,” he said.

Farmers group welcomes research

Grain Producers South Australia chief executive officer Brad Perry said introduced mouse species could severely damage crops and equipment, and recent plagues had been destructive.

“When it comes to pests and diseases in grain and agriculture more broadly, we need to be innovative and think outside the square on prevention measures,” Mr Perry said.

He said technology such as this could help farmers save money in the long run.

a mouse held by the back of its neck stares into the camera lense
Invasive mice species can have a devastating impact on crops.(Supplied: Michael Vincent)

“Grain producers currently manage populations by minimising the food source at harvest, and if populations require [it] zinc phosphide baits are used,” Mr Perry said.

“However, using baits adds to input costs, it is not always readily available and there are limited windows to when this is effective.”

Mr Perry said many farmers would be keen to see the technology in the near future.

“We are supportive of additional tools that help reduce introduced mouse populations — particularly when it involves local world-leading research at the University of Adelaide — which is targeted, reduces inputs and is sustainable.”

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Posted 10 Nov 202210 Nov 2022, updated 10 Nov 202210 Nov 2022

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Hi-tech farming robot sets about to weed parsnip field

The Robotti is an autonomous tractor which navigates with a satellite-guided accuracy of within 2 cm. It uses attachments for farm operations such as seeding, weeding and spraying. The Danish-built robot is being trialled at Frederick Hiam, a Brandon-based fresh produce business with farms in Suffolk and Cambridgeshire. The farms are growing root vegetables including parsnips, potatoes and onions.

Managing director Jamie Lockhart said he wanted to explore mechanised weeding as a way to reduce herbicide use within a ‘more preventative approach to weed control’. “We offered a 40-hectare block as part of the trial,” he said. “The Robotti has drilled [planted] the parsnips on this block and weeded them on several passes. Initially it was about getting confidence in the accuracy and reliability of a fully autonomous system. In this regard the machine hasn’t put a foot wrong and, on several occasions, we left the machine running all night whilst weeding, and the accuracy was perfect.”

Autonomous Agri Solutions will be demonstrating the Robotti machine at the Agri-Tech Week REAP Conference in Cambridgeshire on November 8, 2022.


Source: edp24.co.uk

Photo source: Agrointelli

Publication date: Wed 26 Oct 2022

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