Over four years, 86 expert authors from 49 countries gathered the latest scientific evidence and Indigenous and local knowledge on invasive alien species. The report draws on more than 13,000 references, including governmental reports. We were among the authors. Here are some of the key insights for Australia and Aotearoa New Zealand.
Over four years, 86 expert authors from 49 countries gathered the latest scientific evidence and Indigenous and local knowledge on invasive alien species. The report draws on more than 13,000 references, including governmental reports. We were among the authors. Here are some of the key insights for Australia and Aotearoa New Zealand.
Corteva launches breakthrough innovation to control crop-damaging nematodes, protect soil health
Indianapolis, Indiana, USA September 13, 2023
Award-winning chemistry Reklemel™ active is latest addition to company’s portfolio of sustainable innovation
Plant-parasitic nematodes are microscopic organisms found in soil that feed on the roots of plants. Because they are notoriously difficult for farmers to identify and control, plant-parasitic nematodes represent a significant constraint to the delivery of global food security, causing damage estimated at or exceeding $80 billion per year.1
To address this significant, global challenge, Corteva (NYSE: CTVA) has launched Reklemel™ active, a new nematicide to help protect a wide variety of food and row crops from plant-parasitic nematode damage without disrupting the healthy balance of beneficial organisms in soil. Reklemel active was discovered and developed by Corteva and is the result of more than a decade of research and investment.
“The future of global farming – and our ability to feed a growing population – rests on innovation. Reklemel demonstrates how Corteva deploys innovation to help farmers meet critical challenges to feed the world,” said Robert King, Executive Vice President, Crop Protection Business, Corteva Agriscience.
Reklemel received a Reduced Risk designation from the U.S. Environmental Protection Agency (EPA) due to the product’s ability to selectively target plant-parasitic nematodes, its lower use rates than older nematicides, and its highly favorable environmental and toxicological profile as compared to alternatives. Reklemel is one of the first new active ingredients to be registered under EPA’s updated policy incorporating Endangered Species Act assessments into the pesticide registration process.
Reklemel also received the National Association of Manufacturers’ Sustainability and the Circular Economy Award in recognition that it, through lower use-rates, enables the potential to avoid more than 500M Kg of CO2 – equivalent emissions over the next five years.2
Salibro™ nematicide with Reklemel™ active will be available in the United States, India and Mexico beginning in late 2023, and is currently available for sale in Canada and Australia. Additional registrations are planned globally, including in the European Union, subject to regulatory approvals.
Reklemel is the latest advance brought to market by Corteva to help farmers increase yields, meet climate and other challenges, and ultimately strengthen global food security. Corteva invests nearly $4 million every single day in research and development. In 2022, the company launched more than 180 new crop protection products globally and advanced nine new active ingredients in its R&D pipeline.
Reklemel active can be applied pre-plant, at-plant or in-crop and protects a wide range of annual and perennial crop groups, including fruiting vegetables, cucurbits, root and tuber vegetables, fruits and nuts, field row crops, small fruits, and berries. Farmers who use Reklemel active in combination with cultural, mechanical, and biological management practices as part of an Integrated Pest Management strategy can increase yield potential and reduce quality losses associated with plant-parasitic nematode damage, reduce environmental impact compared to many alternative nematicides, and help preserve beneficial organisms critical to soil health.
Reklemel is one of the first new active ingredients to be registered under EPA’s updated policy incorporating Endangered Species Act assessments into the pesticide registration process. As part of these assessments, EPA evaluates the potential effects of labeled uses of a pesticide on listed species and their habitats, and initiates ESA consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, as appropriate. EPA’s work to establish and implement this new process is an important step toward regulatory certainty for farmers and others who rely on important pesticide technology, while also helping protect listed species and their habitats.
Plant viruses in the agriculture sector cause billions of dollars in losses each year. Farmers may now have a new tool in tracking these diseases.
Scientists with the Arkansas Clean Plant Center at the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, have developed a protocol that speeds up the process, lowers the cost and improves the accuracy of detecting plant viruses.
Ioannis Tzanetakis, director of the Arkansas Clean Plant Center and professor of plant virology, said a major bottleneck in detecting pathogens is the availability of positive controls to confirm a diagnosis. A positive control is a specimen known to contain the pathogen in question. Acquiring positive controls can be problematic, and their maintenance is expensive, and without them, a test cannot be validated, he said.
“This is a clear case of necessity being the mother of invention,” Tzanetakis said. “We had a new plant virus in Europe but nothing here to compare it to. What is unique about our approach is that because we are using a ‘sister’ virus as the surrogate, everything that we do pretty much mimics a natural infection and we do not need to import the infected material.”
Plant viruses cause billions of dollars of losses in agricultural crops worldwide, affecting the yield and quality of agricultural products, according to the U.S. Department of Agriculture. The emergence of novel viruses or variants through genetic evolution and spillover from reservoir host species, changes in agricultural practices, mixed infections with disease synergism, and impacts from global warming pose continuous challenges for the management of epidemics resulting from emerging plant virus diseases, the USDA reported.
The USDA has strict restrictions on the movement of plant material from outside the country, Tzanetakis said. And while there are permits for laboratories to conduct diagnostics with diseased material, the process is lengthy. So, what’s a scientist to do when time is of the essence in obtaining a positive control? Mimic it, said Tzanetakis.
A benefit of the patent-pending process, Tzanetakis noted, is that it can tell if the virus is from an unintentional contamination.
The Clean Plant Center works with plant material from all over the world, making sure plants are free from viruses. The scientists at the center provide virus “clean-up” and testing making sure that plant material is the best quality possible before providing it to nurseries, breeding companies and growers.
The Clean Plant Center receives plant samples from breeders, nurseries and growers to test for the presence of viruses. If scientists detect a potential virus, they must validate the detection by comparing the viral material from the plant with something that is known to contain the virus — either a “true” positive control or an “artificial” control. Normally, the Clean Plant Center obtains an artificial piece of DNA with the virus sequence as a positive control to amplify using polymerase chain reaction, also known as PCR, and compare to their diagnostics. But that process has major drawbacks, Tzanetakis said.
The center’s patent-pending protocol for virus-mimicking artificial positive controls, or ViMAPCs, creates an artificial positive control that acts like the target virus and allows for validation through what is considered a natural infection. Tzanetakis said for the “sister virus” to better imitate natural infection, it must belong to the same genus as the target virus.
“The virus-mimicking artificial positive control allows the center to create an artificial positive control that not only mimics the titre and tropism of the target virus, but also is cheap and rapid compared to the currently available artificial positive controls,” said Shivani Singh, a co-inventor of the technology and program associate for the center.
Titre is the concentration of a substance in solution – in this case the concentration of virus in the plant – and tropism refers to the distribution of the virus within the plant. A positive control considered to have a “natural infection” allows for a more accurate comparison to the diagnostic than a synthetic piece of DNA, Tzanetakis added.
“With just a piece of DNA, you don’t really know if the virus you are testing for has the same titre in the tissue,” Tzanetakis explained. “Some viruses hide in the roots, and they are barely detectable in the leaves and vice versa. We have developed a protocol that is as close to natural infection as you can get unless you have the actual infection of the target virus.”
The protocol was also designed so the ViMAPC control is easily differentiated from a true infection.
“The way that we use this protocol, we can easily identify if a positive result is due to an infection in the plant or a lab-based contamination from our controls, because the controls always have a different size than what the targets will be,” Tzanetakis said, referring to gel electrophoresis, which separates DNA by size.
The newly developed approach takes less than five days to implement whereas alternatives normally take several weeks. The strategy, Tzanetakis said, is straightforward and can be done by laboratories that use polymerase chain reaction-based diagnostics. The process could also have the potential to accurately confirm viruses that impact humans, he said.
Tzanetakis said they use widely available viruses as surrogates to the ones they are targeting, and the protocol limits the need to move viral tissue across international borders.
The Department of Industry, Tourism and Trade has increased plant surveillance after a confirmed sample of the papaya mealybug was found in the Darwin region.
The suspected Paracoccus marginatus was discovered after the Plant Biosecurity team received a call from a concerned resident in Parap last week, who identified a cluster of white coloured insects on their papaya plants.
There are many species of mealybug including a native Australian species which can appear to be similar in appearance. To confirm whether the retrieved sample was Paracoccus marginatus, the insects were subject to further testing, which subsequently came back positive this week.
Additional surveillance has since identified infestations at residential properties in Parap, the Narrows and Winnellie.
The papaya mealybug appears as a cluster of white ‘cotton-like’ mass, usually found on the fruit or underside of the leaves of affected plants.
Although the papaya mealybug does not pose a threat to humans or animals, affected plants may appear deformed, wilted and the papaya fruit likely to remain hard and bitter, with the papaya, hibiscus and frangipani species particularly susceptible.
Surveillance and testing has been ramped up across the Top End. The Plant Biosecurity team will continue surveillance activities and the public is requested to not move suspected infected plants, plant cutting or fruit from their gardens.
The team will work closely with residents and industry during the surveillance period.
Residents of the Darwin region are advised to check plants on their properties and report anything unusual to the Exotic Plant Pest Hotline on 1800 084 881.
During this time, the public are requested to not take cuttings from plants such as hibiscus, frangipani and papaya and to refrain from purchasing plants from uncertified sources.
/Public Release. This material from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style and length. Mirage.News does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s).View in full here.
Many gardeners will tell you that aphids are the bane of their existence. According to a new study from the University of Florida, these tiny pests also pose problems for the iconic monarch butterfly. The study found that when oleander aphids infested tropical milkweed — a nonnative milkweed species commonly used across southern portions of the U.S. stretching from California to Florida — the butterflies laid fewer eggs on the plants, and caterpillars developing on those plants were slower to mature.
Monarch butterflies depend on milkweed and its close relatives to complete their life cycle. The study’s findings suggest that when aphids attack tropical milkweed, they compromise this monarch resource.
“Around the country, efforts are underway to plant milkweed in urban areas to support monarch populations. We know that aphids and similar insect pests commonly reach high densities on plants, including milkweed, in urban settings. Our study helps us better understand how such pest outbreaks may affect monarch survival on the most
common ornamental milkweed species produced and planted in the South,” said Adam Dale, senior author of the study and an associate professor in the UF/IFAS entomology and nematology department.
Throughout the southern U.S., tropical milkweed is commonly used both to attract and support monarchs and as an ornamental plant, and many nurseries and big box stories carry it. However, milkweed often harbors oleander aphids, a type of aphid that goes after oleander and milkweed plants. Oleander aphids suck the sap out of the plants, stunting them and leaving behind a moldy residue.
“It’s long been known that oleander aphids flock to milkweed, especially in nurseries and urban areas, and that led us to wonder if and how that affected the monarchs who used these plants,” said Bernie Mach, first author of the study and a postdoctoral researcher in the UF/IFAS entomology and nematology department.
While the study did not investigate exactly why aphid-infested plants are poorer hosts for monarchs, the scientists say that past research on how aphids affect tropical milkweed, combined with their findings, offers some clues.
“Milkweed defends itself against pests with chemical compounds in its sap called cardenolides — this chemical is actually what makes monarch butterflies toxic to certain predators,” Mach explained. “Tropical milkweed has particularly high levels of cardenolides that ramp up even more when it is attacked by large infestations of oleander aphids. We think that these ramped up levels may deter monarchs from laying eggs on these plants and also affect their caterpillars.”
However, one point is clear: Aphid-free tropical milkweed appears to give monarchs a better chance at success.
In the study, the researchers grew tropical milkweed in a nursery setting, introducing aphids to one group of plants while keeping another group aphid-free. The researchers released monarch butterflies around each group of plants, then counted the eggs the butterflies laid on the plants. The butterflies laid three times as many eggs on aphid-free plants as they did on aphid-infested plants.
The researchers also monitored the development of the caterpillars that hatched out of those eggs. At the end of the experiment, caterpillars on aphid-free plants ate twice as much leaf material as caterpillars on aphid-infested plants. All caterpillars on aphid-free plants grew to full size, while most of those on the aphid-infested plants lagged behind or died.
For home gardeners in the southern U.S. who want to conserve monarch butterflies through landscaping, the authors note that native milkweed species like swamp milkweed have lower cardenolide levels, and other research has shown that monarchs do well on these plants even when aphid levels are high. For those who want to use tropical milkweed as a way to help monarch butterflies, the researchers share a simple but effective way to control oleander aphids: insecticidal soap.
“Spraying the aphids directly with insecticidal soap — while avoiding monarch caterpillars and butterflies — is an effective way to keep oleander aphids down and help tropical milkweed stay in better shape,” Mach said.
However, insecticidal soap isn’t always a feasible option in a nursery where growers are trying to keep hundreds or thousands of plants aphid-free, Dale said. In the next phase of this research, Dale and Mach will investigate pest management options that keep aphids at low levels and aren’t harmful to monarch butterflies.
Southeast Asian fern-feeding larva or caterpillar. (Photo by John Goolsby, ARS)USDA Research Identifies Moths that Slow the Spread of Invasive FernFor media inquiries contact: Autumn Canaday, (202) 669-5480
July 27, 2023The invasive Old World Climbing Fern was introduced to Florida’s ecosystem from southeast Asia around 1965. It soon dominated the state’s native vegetation, infesting more than 100,000 acres in a short amount of time. The fern spreads quickly and has destroyed numerous native plant populations, smothering trees and shrubs with vines that can grow up to 90 feet in length. You’ll now find this invasive fern throughout south and central Florida, specifically in wetlands and other habitats like the Everglades tree islands, bald cypress domes, and sawgrass prairies.USDA-Agricultural Research Service (ARS) and the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australian Biological Control Laboratory (ABCL), scientists began to search for a way to solve this agricultural challenge and soon found an answer to slow the fern’s spread.ARS and ABCL researchers collected, identified, and tested caterpillars feeding on the Old World climbing fern in its native habitat. One species of fern-feeding snout moth, Neomusotima conspurcatalis, commonly known as the Brown lygodium moth,is a member of the subfamily of Musotiminae and has been a successful deterrent to this invasive fern. The Musotiminae belongs to the Crambidae family that have protruding labial palpi, or “noses,” giving the family the common name of “snout moths.” Most of the moths that ARS researchers discovered in southeast Asia were snout moths, which at that time, belonged to a subfamily that had not been studied by the Agency. “Early detection of potential invasive species is crucial so USDA can quickly implement strategies that protect U.S. agriculture, forestry, and the environment,” said ARS researcher Alma Solis. “This study led to the discovery of a number of new fern-feeding species and the identity of their caterpillars, which were previously unknown to science.”ARS researchers studied the snout moth’s external wing patterns, dissected its insides, specifically the genitalia and wings, and compared it to other southeast Asian moth species. All of the snout moth’s immature stages, including larvae, and pupae, had never been seen before and were considered new to science. The research team also compiled a chart to compare adult and immature morphologies, host plants, and geographic distribution of the fern-feeding species. The findings permitted ARS to create criteria for biological control workers across the globe to distinguish Musotiminae species in their own countries or eco-systems. The snout moth was later introduced to Florida and slowed the spread of the Old World Climbing Fern with their eating habits.ARS researchers, and research partners for the state of Florida, continue to study the interactions of snout moths with parasites, predators, and fungi. Together they are working together to deter the spread of this invasive fern throughout the nation and protect America’s native vegetation.The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.
Many cereal crops, such as wheat and barley, are prey to devastating fungal diseases caused by infection with so-called grass powdery mildews. A key battleground between the plants and the powdery mildews is the interaction between plant immune receptors and pathogen effectors, molecules which are delivered into host cells by pathogens to establish infection.
These effectors and immune receptors are locked in a molecular arms race in which the fungus needs to continuously adapt its effector repertoire to avoid recognition by adapted immune receptors and maintain virulence activity.
However, the structures and functions of these numerous effectors—which can run into the hundreds for individual fungal lineages—remain incompletely characterized.
Now, scientists from Germany, Switzerland and China led by Paul Schulze-Lefert, director at the Max Planck Institute for Plant Breeding Research in Cologne and Jijie Chai who holds positions at Westlake University, Hangzhou and Tsinghua University, both in China, have reported the structures of several powdery mildew effectors from different subfamilies.
These structures show how effectors adopt a common structural scaffold with some local variations that allow them to evade recognition by immune receptors. Their findings are published in the Proceedings of the National Academy of Sciences.
Using X-ray crystallography, a technique that allows scientists to deduce the positions of atoms in a molecule based on electron density, first authors Yu Cao and Florian Kümmel and colleagues acquired structures for five different effectors from two different powdery mildews that infect barley and wheat. Strikingly, although the similarity between the effectors was very low at the level of DNA sequence, they were all found to adopt a common structural fold, known as RALPH after RNase-like proteins associated with haustoria.
Analysis of these structures revealed that they are indeed similar to that of RNase proteins, enzymes that bind to, and break down RNA molecules. Intriguingly, however, these effectors do not possess any RNase activity. Instead, the authors suggest that this common fold RALPH framework may be important for critical processes related to infection, such as assembly into functional effectors and the ability to cross biological membranes. The local structural changes in the RALPH scaffold may explain why the effectors can associate with different host proteins to allow infection.
Armed with an understanding of the structural template of a RALPH effector, the researchers then set out to determine whether they could engineer recognition between immune receptors and effectors in instances where effector divergence had led to immune escape.
Strikingly, they found that six amino acid substitutions were sufficient to turn a sequence-diverged effector into one that was recognized by a specific immune receptor. Analysis of further effector-receptor pairs allowed the authors to conclude that each immune receptor detects largely distinct patches on the surface of its corresponding effector.
“It is one of the eureka moments of science when, in evolution, the molecular arms race between plants and pathogens can be explained by local structural changes within a shared three-dimensional protein architecture,” says Paul Schulze-Lefert.
More information: Yu Cao et al, Structural polymorphisms within a common powdery mildew effector scaffold as a driver of coevolution with cereal immune receptors, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2307604120
A study of managed bumble bees and honey bees on a blueberry farm finds that most of the pollen they collect comes from other plants, suggesting that supplementing crops with a diversity of nearby plant types makes for healthier bees. Shown here are honey bee hives near blueberry fields. (Photo by Kelsey Graham, Ph.D.)
By Andrew Porterfield
Managed bees provide a critical service to crop growers, providing pollination as the bees search for nectar and pollen for their own needs. But many crops cannot provide for all the nutritional needs of bees. In those cases, bees begin searching for alternative sources of food.
This means that beekeepers and farmers may need to find ways to provide alternate food sources for their bees—while the bees will still be attracted to crop pollen and nectar, it won’t be an exclusive relationship. But, in turn, the bees will likely be healthier. To find out how managed honey bees (Apis mellifera) and bumble bees (Bombus impatiens) seek out a balanced diet, a group of researchers from Michigan State University looked at pollination and feeding behavior of bees around blueberry crops in that state.
The team, led by Kelsey Graham, Ph.D., a research associate at Michigan State’s Entomology Department at the time of the study and now at the U.S. Department of Agriculture’s Agricultural Research Service, determined what plants managed honey bees and bumble bees visited during high bush blueberry pollination season. They found that the most pollen collected was from plants other than blueberries, even though the blueberry bushes were the most abundant resources during the study. They also found that honey bee and bumble bee collection behavior varied a lot. Their results were published in July in Environmental Entomology.
In 2018 and 2019, the team collected pollen from bee colonies at 14 blueberry farms in Michigan. At each field, they used a 10-frame pollen trap immediately before the start of blueberry blooming (in early or mid-May) and collected samples through the end of the bloom (early to mid-June). At the same time, the researchers placed bumble bee colonies at the margin of each site, far enough away from the honey bee colonies to prevent raiding and robbing. The team used microscopes to identify the plant sources of the pollen.
Perhaps typical for them, bumble bees collected pollen from a wider range of plant species than did honey bees. Honey bees collected 21 pollen types in both 2018 and 2019. Bumble bees, however, collected 29 types in 2018 and 52 pollen types in 2019.
Surprisingly, common buckthorn (Rhamnus cathartica), an invasive species native to Europe and Asia, was one of the most abundant pollens collected by both types of bees. Willow (Salix spp.) was another. “Collection is likely from an invasive species in this area of Michigan, though there are some native species they could be visiting,” says Graham. “I think it surprises people to find out that blueberry pollen was not a dominant pollen collected by honey bees. While honey bees still provide pollination services for this crop through some pollen collection and nectar visits, it’s not a preferred pollen type.”
Although blueberry is a pollen-dependent crop that relies on managed and wild bees to yield fruit, blueberry pollen is not particularly nutritious for bees. Pollen provides proteins, fats, sterols, and micronutrients to support adult bee and brood health. However, the protein content of blueberry pollen is 13.9 percent, too low to sustain a healthy honey bee colony.
Therefore, bees will forage for other nutritional resources. Meanwhile, otherstudies have shown that a diversity of pollinators can improve pollination services for plants.
Graham and her team also studied whether landscape diversity influenced foraging behavior, but it appeared to have no effect on the diversity of pollen the bees collected. In other words, bees sought out a multitude of pollen types, even if they had to go further to find it. “This definitely suggests that honey bees and bumble bees are making foraging decisions based on floral characteristics and nutrition rather than just what they come across in the landscape,” Graham says.
The potential downside, though, to a predominantly crop landscape is that, as at least one other study has shown, the additional energy expended to collect pollen from other plants may reduce brood production.
“It’s somewhat rare that a single pollen source can fulfill all macro and micro nutritional requirements,” Graham says. “So, in landscapes where the crop is the primary plant available, supplemental plants through pollinator plantings or preserving natural habitats near farms can provide a large benefit to bees.”
Andrew Porterfield is a writer, editor, and communications consultant for academic institutions, companies, and nonprofits in the life sciences. He is based in Camarillo, California. Follow him on Twitter at @AMPorterfield or visit his Facebook page.
Sizes vary, but a sprayer drone can typically apply a 10′ to 40′ swath, depending on the wingspan, with bigger drones covering up to 50 acres an hour.(Bryan Young)
Squinting through the morning sun, Jesse Patrick watches the top of his corn crop whip in the downdraft of a large spray drone pipping fungicides into the canopy.“The drone is only putting out 2 gal. an acre, but the thing that surprised me was the swath and amount of downdraft coming off of it even flying 15′ above the corn,” Patrick recalls.This seventh-generation farmer, who grows soybeans, corn, wheat, hay and sorghum, is used to battling weeds and disease in his heavy Georgia clay soils about an hour east of Atlanta. Treating those yield robbers with a drone, however, is new.
“When the drone lands, you pull the battery out, fill it up, put in a new battery and the whole thing takes about 15 seconds,” Patrick says. “It’s a pretty well-oiled machine.”Drone-driven sprayers are popping up across the country as better batteries, longer flight times and bigger machines make it possible to spray sizable acreage in a timely manner.“There’s a 10-gal. tank so every 5 acres he has to come back to refill,” Patrick explains. “We knocked out 150 acres in about four to six hours.”
Does it Work?
While farmers such as Patrick find the technology useful, especially for spot spraying and targeting fields in less-than-ideal conditions, weed scientists are buzzing with more caution.“We [weed scientists] are very sensitive about the resistance issue we have in weeds to herbicides, and as I’ve heard about using drones for applications, I wonder who’s testing it,” says Bryan Young, a weed scientist at Purdue University. “I wondered if we are going to generate more resistance, if this is a sub-optimal application, and I wasn’t getting a lot of answers.”That kick-started a research project into drone sprayers and verifying the new application method is effective enough to do the job. Young has witnessed the potential benefits of sprayer drones; however, as with all new technology, he’s still quantifying and investigating the results.
“I was looking around for any guidelines on the best spray drone design in terms of nozzles and boom configuration,” Young says. “Frankly, to date, I can’t tell you where the industry is headed for sure or what is the best setup for herbicide application. This is an emerging technology for commercial applications in the U.S.”Drone operators often tout the strong down draft helping push product into the canopy, but then fly at higher elevations to maximize field coverage or spray swath. Young says these application methods are significantly different than traditional aerial applications, and it’s why he’s part of a working group looking into whether product labels should include separate drone application guidelines.“Right now, the U.S. EPA has left it up to each state to determine whether drones can be used for herbicide applications following the aerial component of the herbicide labels,” Young explains. “Not all states agree on that and not all countries agree.”Then there’s the question of drift. It’s still being investigated exactly how much different spraying with a drone is versus a ground-based sprayer or even by airplane.
Wind Tunnel Testing
“Underneath the drone’s propellers what would normally be a flat fan spraying from the nozzle, all of a sudden, [the pattern] starts to bend and oscillate,” explains Kyle Butz, a technical adviser with Spray Analytics.He’s been working with Sidaard Gunasekaran, a professor of mechanical and aerospace engineering at the University of Dayton, to test the effects of drone propellers on pesticide and herbicide application during flight. The two recently released their findings on droplet drift using the university’s low-speed wind tunnel.“I think Kyle and I both asked the same question: On what basis are they deciding where to put the nozzles?” Gunasekaran recounts. “It turns out, they just take an agriculture nozzle, stick it underneath the propeller and then go fly without understanding the aerodynamics or the right location for that nozzle.”In search of answers, Gunasekaran and Butz developed a test rig with two propellers, a spray nozzle and a measurement system. They confirmed the propellers do in fact pull droplets back into the down draft while blowing smaller droplets out away from the target zone.“If you have smaller droplets, called fines, which are anything under 140 microns, they are prone to drift,” Gunasekaran says.From a sprayer’s perspective, however, there’s always been a balancing act between droplet sizes and efficacy.“Ultimately, spray applications come down to, one, droplets have to be large enough to safely reach the target, and two, they have to be small enough to work the way they’re supposed to be working,” Butz explains.Their recommendation is to start with products less likely to drift and use a drone in scenarios or situations that are less sensitive.
A Tool Worth Trying
Like with all new technology, drone sprayers will no doubt have to earn their stripes. For farmers such as Patrick, it’s just another tool to deploy when the situation is right, such as when the aphids are going crazy on his sorghum but it just rained 2″ and he can’t run a sprayer.Today, he does not see this technology replacing the pre- or post-emerge passes on his operation.“However, at the end of the year, if you don’t want to run over a bunch of crops to spot spray, I think drone sprayers are definitely a tool we can use,” he says.“There’s a definite fit for these drones,” Young agrees. “It can allow us to be more timely with some of our pesticide applications and for us to be better stewards of pesticides.”
Posted31 Aug 2023 Originally published31 Aug 2023 OriginView original
Farmers use a natural extract from local trees to manage the pest sustainably
It was a sad day when Ali Abdoul from Al-Buniyah, Yemen turned the leaf of his sorghum crop and saw a worm. This loathed pest is not just any worm, it is the so-called Fall armyworm that attacks many crops, with a clear preference for maize, and ruins livelihoods in a growing number of countries worldwide.
This pest made its way to the Taiz Governorate in July 2018, adding additional misery to Yemeni farmers, who were already grappling with a litany of challenges.
“For us farmers, pests are a menace as they devour crops…. In Yemen, pesticides are now very costly. We sometimes have to sell some crops from the previous harvest to get money to buy pesticides and save the current crop,” said Ali.
Many other farmers in Yemen share Ali’s sentiments. About 70 percent of Yemenis live in rural areas and depend heavily on agriculture as a critical source of food and income. The eight-year conflict in the country has worsened the situation and the prices of farming inputs have shot up.
In addition to rising input costs, farmers have faced a shortage of critical agricultural necessities such as seeds and fertilizer, a sharp increase in the price of fuel and unpredictable weather patterns.
And now they had Fall armyworm.
Ali describes how farmers were desperate to manage the new pest and tried different control methods without success. Home mixtures weren’t effective, and chemical pesticides caused harm to the environment and agricultural soils.
It was at this time when they were still struggling with the new pest that Ali, together with other farmers, started attending farmer field schools (FFS) organized by the Food and Agriculture Organization of the United Nations (FAO).
“Two agricultural officers from FAO came and taught us to concoct natural insecticides using the mraemrah tree,garlic and hot pepper. The training we got through the farmer field school included how to crush, grind and filter the impurities and then spray the mixture on the crops,” said Ali.
The mraemrah tree, also known as Melia azedarach, chinaberry tree or bead tree, is commonly found in Yemen. It produces chemicals that can serve as a natural insecticide, hampering the growth and development of the Fall armyworm. Not only is the tree available locally, the biopesticide can be prepared directly in villages and in small quantities.
This pest control method was a traditional practice, but they had never tried it on the Fall armyworm. Ali and his fellow farmers were astounded by the results.
“Using biopesticides extracted from mraemrah was something new to us. After spraying, we found that the results were excellent. We were impressed, and we resolved that going forward, we will continue using the pesticide extracted from the mraemrah tree to manage Fall armyworm,” said Ali.
Ali added that the farmers realized that using the mixture was much cheaper than using chemicals and that it had no environmental impact.
“This biopesticide is helping us in a huge way. We were also taught that this type of pesticide is not harmful to human and animal health,” added Ali.
These biopesticides are not only safer for human health and the environment, they are also safer for beneficial insects like bees and other pollinators.
Through the FFS, FAO was able to train farmers on these methods of alternative pest control and other best agricultural practices. This learning environment allows farmers to practice, test and evaluate new sustainable methods and technologies by comparing the results of the demonstration plots with their conventional ones.
In addition, the FFS approach has significantly strengthened the social cohesion among Yemeni farmers, especially in the conflict areas, by helping them decide together as a group a plan of action for their fields instead of each deciding individually.
The FAO project has also provided monitoring equipment (including pheromone traps used to attract pests to a specific location) and smartphones offering the FAMEWS mobile application to collect, record and transmit data gathered from pheromone traps. FAO trained technical staff on the use of the mobile application to help in scouting for and monitoring the pest.
Worldwide, FAO promotes an integrated pest management approach that minimizes reliance on chemical pesticides and incorporates sustainable practices, such as regular monitoring for pests.
With support from FAO, the national authorities in Yemen have since built the capacity to identify, monitor and manage Fall armyworm. FAO is rolling out this training and encouraging the use of biopesticides in other countries struggling with this pest.