In the Central and Western region of Uganda, farmers are busy with the first weeding of the season. As they head into their maize fields, they will be anxious to see just how the plants are growing — and how many have been affected by the Fall armyworm.
Farmers in Uganda have been dealing with the Fall armyworm infestation since last year. This invasive pest originally arrived in West Africa in 2016. Before then, the caterpillar was native to North and South America.
This hungry, hungry caterpillar is expected to cause more than $2-billion of damage to maize crops in Africa per year.
But farmers in the Central and Western regions have a new tool to help them manage this foreign invader: radio.
With our partners Radio Kitara and Radio Simba, we are on air again to talk about the Fall armyworm. As the farmers head into their fields this week, the radio shows are talking about how to identify the Fall armyworm, and particularly how it is distinctive from the African armyworm or other pests common to the region.
This is part of a 10-week radio campaign about the Fall armyworm, the second phase of our project that aired similar information over eight weeks from October to December.
After talking about identifying the Fall armyworm, farmers will learn how to monitor their fields and how manage the Fall armyworm if they do find the caterpillar has invaded. This includes using both biological and chemical methods of control, and the radio programs will also discuss the safe use of chemical pesticides.
Farmers are advised to monitor the damage in their fields and only use control methods when the damage is severe. This can be done by checking the damage on 10 consecutive plants in 10 areas of the field to estimate what percentage of plants have been affected.
Many farmers have chosen to handpick the larvae and eggs off maize plants, which can be an effective control method. The Fall armyworm multiplies quickly, laying up to 2,000 eggs in their lifetime. By destroying the eggs, the Fall armyworm population can be kept at bay.
The first Fall armyworm radio program was very popular with farmers. Nearly 6,000 interacted with the radio program, responding to poll questions during the project.
Charles Wandera is a farmer in Masindi district in Western region, Uganda. He tuned in to the first radio program on Radio Kitara. He told us, “All along we have been lacking information to fight the armyworm but from the time we got a chance with this project with Radio Kitara, we are getting information Mondays and Fridays. In a week, we are getting the information twice.”
With another growing season in full swing, we are back on air to support farmers and we expect that even more will tune in to this radio series to give themselves the best chance of a good maize harvest at the end of the season.
Harmless flies have evolved over millions of years to mimic the appearance of stinging insects, but new evidence suggests climate change is reducing the effectiveness of that disguise.
Many species have adopted a form of the yellow and black banding commonly seen on stinging insects, which predators such as birds and spiders have learnt to avoid, but now University of Leeds scientists say global warming may compromise that defence.
For the first time, researchers have shown that predators can learn during which seasons they should avoid eating yellow and black striped insects, based on when stinging insects are born and active.
They understand they can target them at other times because they will be non-stinging flies.
Dr Christopher Hassall from Leeds’ School of Biology, who led the study, says the Earth’s temperature is crucial to when insects emerge and, as it warms, stinging insects are emerging first.
The early bumblebee, a stinging insect. Photograph: Chris Hassall
“The patterns of hatching we have studied suggest that stinging insects are benefiting from climate change because they are born earlier each year.
“There is less randomness in the cycles than in the past, which benefits stinging insects the most, followed by predators who have learnt the seasons when they can eat or should avoid striped insects, but it helps the ‘mimics’ least.
“The time of year when they emerge shifts every year in response to spring weather, but their colours require many years for any change to occur. This means that predators have got wise to the trick.”
Dr Hassall said a small number of “mimic” flies have benefited because of earlier hatching, but for the majority, as the climate has warmed, they have lost out.
In the first part of the project, the researchers needed to understand how many flies were actually likely to be mimicking stinging insects, compared with those which just had a broadly similar appearance. To measure mimicry, the research team carried out a large “citizen science” project.
Recruiting people via Twitter, they created a website showing participants pictures of 42 different types of mimics, and 56 types of stinging insect, and used the human brain as a processing tool and the power of the crowd to generate data.
A hoverfly displaying yellow and black striping to deter predators. Picture: Chris Hassall
The team asked participants to rate how close in appearance the insects were and, out of 2,352 potential pairs, 30,000 rankings were submitted by participants during a year, resulting in 237 “high fidelity pairs” consisting of a mimic and a similar stinging insect.
The research team then examined long-term monitoring data stretching back over 50 years to identify those pairs whose historical spring appearance timing had been altered by climate change.
Gaming the species
Usually scientists study the behaviour of animals to predict human behaviour, but as part of this study, the researchers created a virtual reality computer game for people to play the role of a predator.
The game helped them to determine how successful predators were at telling the difference between harmless and stinging prey depending on the order of when the mimics or stinging insects appeared.
Using the game, the researchers tested whether different scenarios also affected how successful predators were in finding prey – when the stinging insects were born first, the mimics were born first, or when they appeared at random.
A honey bee displaying muted striping. Picture: Chris Hassall.
They found that predators could learn quickly when one prey type was presented first, but that randomness confused them. These results showed just how important it was who emerged first, and provided important information on how the mimics, stinging insects and predators might fare if that order was changed.
The game was played by 45 participants and the data gathered helped the research team to infer how the changes over time might affect the success of the mimics, stinging insects, and the predators.
Dr Hassall said the three elements of the study came together to show how climate change occurring over years or decades can influence evolutionary relationships that have taken millions of years to develop.
He explained the results indicated that mimics, models, and predators each experience different costs and benefits depending on whether the mimics or stinging insects occur first, or co-emerge, with the stinging insects benefiting most from appearing first presumably due to accelerated predator learning.
The full article, Climate-induced phenological shifts in a Batesian mimicry complex, is published in the PNAS journal.
Media contact: Peter Le Riche, University of Leeds press office. 0113 343 2049 or [email protected]
Top photo shows a hoverfly mimic. Picture: Chris Hassall.
Dr Hassall was supported by a Marie Curie International Incoming Fellowship within the European Community Framework Programme (EcoEvoMimic).
When humans experience stress, their inner turmoil may not be apparent to an outside observer. But many animals deal with stressful circumstances — overcrowded conditions, not enough food — by completely remodeling their bodies. These stress-induced forms, whether they offer a protective covering or more camouflaged coloration, can better withstand the challenge and help the animal survive until conditions improve.
Until now, it wasn’t clear what molecular trigger was pulled to allow this structural remodeling in times of stress. But researchers at the University of Illinois and the University of Pennsylvania have discovered the protein responsible in the roundworm C. elegans.
“We’re using a really simple animal system to understand basic biological questions that have implications not only for nematodes, including important crop parasites, but also for higher animals, including humans,” says Nathan Schroeder, assistant professor in the Department of Crop Sciences at U of I, and author of the new study published in Genetics.
When C. elegans larvae are stressed, they stop eating, their development halts, and they enter a stress-resistant stage known as dauer. In this form, their bodies become distinctly thinner and longer and develop an outer cuticle with ridges from tip to tail.
Schroeder and his team were investigating a protein called DEX-1 for an unrelated project when they noticed worms without the protein were “dumpy” in the dauer phase: they remained relatively short and round. Intrigued, the researchers decided to characterize the protein and its function in seam cells, the cells responsible for dauer remodeling.
“When we disrupted the DEX-1 protein, the seam cells did not remodel during dauer,” Schroeder says. “Seam cells have stem cell-like properties. We usually think about stem cells as controlling cell division, but we found that these cells are actually regulating their own shape through this protein, and that has an impact on overall body shape in response to stress.”
DEX-1 is an example of an extracellular matrix protein, a type that is extruded to form the mortar between cells. These proteins exist in every multicellular organism, not only keeping cells together but also facilitating interaction between cells. Not always in a good way; it turns out many extracellular matrix proteins, including a DEX-1 analogue, are associated with human diseases, such as metastatic breast cancer.
Schroeder says his group is interested in looking more closely at metastasis in cancers due to these proteins, but as a nematologist, he gets more excited about the prospect of understanding the basic biology and genetics of nematodes themselves, particularly parasitic species that affect crops.
“For many parasitic nematodes, when they’re ready to enter the infective stage, they have a similar process. Many of the genes regulating the decision to go into or come out of that infective stage also regulate the decision to enter dauer,” he says. “This research gives us insight into their biology and how they make these developmental decisions.”
Urgent planting of wildflowers will attract pollinators and boost farmers’ food crops, expert to tell UN
The collapse in bee populations can be reversed if countries adopt a new farmer-friendly strategy, the architect of a new masterplan for pollinators will tell the UN biodiversity conference this week.
Stefanie Christmann of the International Center for Agricultural Research in Dry Areas will present the results of a new study that shows substantial gains in income and biodiversity from devoting a quarter of cropland to flowering economic crops such as spices, oil seeds, medicinal and forage plants.
The UN conference is already debating new guidelines on pollinators that will recommend reducing and gradually phasing out the use of existing pesticides, but Christmann’s research suggests this can be done without financial pain or a loss of production.
The need for a change is increasingly evident. More than 80% of food crops require pollination but the populations of insects that do most of this work have collapsed. In Germany, this fall is by up to 75% over the past 25 years. Puerto Rico has seen an even sharper decline. Numbers are not available in most countries, but almost all report an alarming decline.
Government responses have varied widely. Earlier this year, Brazil, one of the world’s biggest food exporters, went backwards when pro-agribusiness congressmen voted to lift restrictions on pesticides forbidden in other countries.
But this policy is expensive and brings little or no income to farmers. Christmann has spent the past five years working on a different approach, which she calls “farming with alternative pollinators” with field trials in Uzbekistan and Morocco.
The essence of the technique is to devote one in every four cultivation strips to flowering crops, such as oil seeds and spices. In addition, she provides pollinators with cheap nesting support, such as old wood and beaten soil that ground nesting bees can burrow into. Sunflowers were also planted nearby as wind shelters.
“There is a very low barrier so anyone in even the poorest country can do this. There is no equipment, no technology and only a small investment in seeds. It is very easy. You can demonstrate how to do it with pictures sent on a cellphone.”
Compared with control fields of pure monocultures, “amazing” benefits for farmers and an increase in abundance and diversity of pollinators were found. Crops were pollinated more efficiently, there were fewer pests such as aphids and greenfly, and yields increased in quantity and quality.
In all four different climatic regions that she studied, the total income of farmers increased, though the benefits were most marked on degraded land and farms without honeybees. The biggest gains were in semi-arid climates, where pumpkin yields rose 561%, aubergine 364%, broad bean 177% and melons 56%. In areas with adequate rain, tomato harvests doubled and aubergine went up 250%. In mountain fields, courgette production tripled and pumpkins doubled.
In another study, which is funded by the German environment ministry, Christmann will test a five-year plan to move from work with small pilot projects to large scale producers by inserting flowering strips of canola and other marketable crops to break up monocultures.
She also hopes to see changes in national landscape policies. Working with tourist, agriculture and communication ministries, she aims to raise awareness of the economic benefits of wild pollinators and to encourage more planting of wildflowers, berry bushes and flowering trees.
“The entire environment would be richer, more beautiful and more resilient to climate change,” said the bee evangelist. “We would have many more insects, flowers and birds. And it would be far more self-sustaining. Even the poorest countries in the world could do this.”
As more countries appreciate the advantages, she hopes they will be willing to join the coalition of countries committed to reversing the decline in pollinators. Currently, there are only 24 countries in this “coalition of the willing”, mostly from Europe. Eventually, she hopes there will be enough support to multilateral environmental agreement on pollinators similar to the international convention on trade in endangered species. “I hope this week’s conference will be the first step to bringing a multilateral agreement into being because that’s what we need,” she says.
She expects resistance from agrichemical companies. “I think Monsanto won’t like this because they want to sell their pesticides and this approach reduces pests naturally,” she says.
Christmann is used to adversity. When she first suggested a focus on pollinators at the world agricultural conference in 2010, the delegates laughed at her. For many years, she struggled to gain funds and for two years she had to use her savings to finance her work on pollinator programmes.
Now she has the backing of the German government and a voice on the world stage, the only obstacle is time. “This cannot wait. The bees, flies and butterflies need urgent action. I’m 59 now and I want to to get them globally protected before I retire so I have to hurry,” she says.
The decline of pollinators will be highlighted in a new global report on genetic resources for food that will be released next year. Based on reports from governments across the world, the draft will show that even agriculture ministries – who have long resisted conservation action – are aware of the need for change.
“Countries are saying that we are using too many pesticides and the number of birds and bees is going down. We need to do something about it or our agricultural systems won’t work,” said Irene Hoffmann, who is leading the study for the Food and Agriculture Organisation. “It’s frustrating and sometimes it’s frightening. The situation is dire, but there are ways to solve it.”
A new study shows that several species of bats are giving Madagascar’s rice farmers a vital pest control service by feasting on plagues of insects. And this, a zoologist at the University of Cambridge believes, can ease the financial pressure on farmers to turn forest into fields.
There are few places in the world where relations between agriculture and conservation are more strained. Madagascar’s forests are being converted to agricultural land at a rate of one per cent every year and much of this destruction is fuelled by the cultivation of the country’s main staple crop: rice.
A key reason for this is that insect pests are destroying vast quantities of rice, leading local subsistence farmers to destroy even more forest to create new paddies. The result is devastating habitat and biodiversity loss on the island. But not all species are suffering. In fact, some of the island’s insectivorous bats are thriving, and this has important implications for farmers and conservationists alike.
Co-leading an international team of scientists, Ricardo Rocha from the University of Cambridge’s Zoology department Conservation Science Group, found that several species of indigenous bats are taking advantage of habitat modification to hunt insects swarming above the country’s rice fields. They include the Malagasy mouse-eared bat, Major’s long-fingered bat, the Malagasy white-bellied free-tailed bat, and Peters’ wrinkle-lipped bat.
“These winner species are providing a valuable free service to Madagascar as biological pest suppressors,” Rocha said. “We found that six species of bat are preying on rice pests such as the paddy swarming caterpillar and grass webworm. The damage that these insects cause puts the island’s farmers under huge financial pressure and that encourages deforestation.”
The study, published in the journal Agriculture, Ecosystems and Environment, used state-of-the-art ultrasonic recorders and molecular analysis to investigate the feeding activity of insectivorous bats in the farmland bordering the Ranomafana National Park in the southeast of the country.
The researchers recorded over a thousand bat ‘feeding buzzes’ (echolocation sequences used by bats to target their prey) at 54 sites, to identify their favourite feeding spots. This revealed that bat activity over rice fields was much higher than it was in continuous forest — seven times higher over irrigated rice fields, and sixteen times higher over hillside fields — which clearly shows that the animals are preferentially foraging in these human-made ecosystems. The researchers suggest that the bats favour hillside fields most because lack of water and nutrient run-off make these crops more susceptible to insect pest infestations.
The team next used DNA barcoding techniques to analyse droppings collected from bats captured within the rice plantations and nearby forest. All six species of bats were found to have fed on economically important insect pests. While the findings indicated that rice farming benefits most from the bats, the scientists also found pests of other crops, including the black twig borer (a pest of coffee), the sugarcane cicada, the macadamia nut-borer, and the sober tabby (a pest of citrus fruits).
“The effectiveness of bats as pest controllers has already been proven in the USA and Catalonia,” said co-author James Kemp, from the University of Lisbon. “But our study is the first to show this happening in Madagascar, where the stakes for both farmers and conservationists are very high.”
The researchers argue that maximising bat populations has the potential to boost crop yields and promote sustainable livelihoods. They are now calling for further research to quantify this contribution because Madagascar’s bats currently fall under game species legislation and are not actively protected in the country.
Bats comprise roughly one-fifth of all Malagasy mammal species and thirty-six recorded bat species are endemic to the island, making Madagascar one of the most important regions for conservation of this animal group anywhere in the world.
“Bats have a bad reputation in Madagascar because they are seen as a nuisance when they roost in buildings,” Rocha said. “The problem is that while these bats are benefiting from farming, deforestation is also denying them places to roost. With the right help, we hope that farmers can promote this mutually beneficial relationship by installing bat houses.”
Local people may have a further reason to be grateful to the animals. While bats are often associated with spreading disease, Rocha and his team found evidence that Malagasy bats feed not just on crop pests but also on mosquitos — vectors of malaria, Rift Valley fever virus and elephantiasis — as well as blackflies, which spread river blindness.
An international team led by researchers at The University of Manchester have discovered why some plants “live fast and die young” whilst others have long and healthy lives.
The study, published in Science Advances, also helps us understand how plant diversity is maintained. This, in turn, could help improve nature conservation, natural habitat restoration and growing healthier crops.
It seems the answer is hidden beneath our feet in the complex relationships between soil microbes and plant roots. Scientists have long suspected that the key to explaining plant diversity lay with their enemies, including harmful fungi found in the soil. However, studying microbial life in soil has been notoriously difficult, earning itself the name of “black box” among scientists.
By using new molecular techniques and existing knowledge on what different fungi do in soil, the researchers found that some plants harboured dozens of different harmful fungi in their roots, while others kept harmful microbes at bay and attracted many beneficial fungi that boost plant health.
Lead author, Dr. Marina Semchenko, from the University’s School of Earth and Environmental Sciences (SEES) said: “When walking through a flower-rich meadow, you might wonder why so many different plants grow together and no single plant dominates. We found that plant growth is strongly controlled by how many different harmful and beneficial fungi are attracted to plant roots.”
The researchers also found that the balance between harmful and beneficial fungi depended on plant lifestyle, providing an insight into why some plants live fast but die young while others grow slowly but enjoy a long life.
Dr. Semchenko explains: “Like in the story of the Tortoise and the Hare, some plants are slow to grow but enjoy long life by cooperating with beneficial fungi. Others grow fast and are initially successful, but then they are brought down by diseases caused by harmful fungi.”
As with humans, diet is also important for plant health. The scientists found that soils with plentiful nutrients can support lush plant growth, but also shift the balance from many beneficial fungi to those causing disease.
Richard Bardgett, who is Professor of Ecology at The University of Manchester, said: “While these results come from grasslands in northern England, it is likely that the same mechanisms occur in other ecosystems around the world, but more tests are needed to confirm this.”
These results could pave way to new approaches in agriculture to set microbial balance right for the production of healthy crops through tipping the balance towards beneficial rather than harmful microbes in the root zone of plants.
Dr. Semchenko added: “Soil microbes are known to be very sensitive to human interference such as intensive agriculture and our findings suggest that negative impacts on soil microbes may have knock-on effects on the conservation of plant diversity.”
The study was coordinated by the University of Manchester and involved collaboration between nine institutions including Universities of Colorado, Tartu, Berlin, Edinburgh and Lancaster.
Researchers report that they can efficiently produce antifungal proteins in plants based on a modified tobacco mosaic virus. The results of this research, which could have a major impact in the agri-food industry, have been published in the Plant Biotechnology Journal.
The fungi that cause diseases in plants, animals and human beings represent a serious threat for health, food safety and ecosystems. Every year, more people die from fungal infections than from malaria. Furthermore, fungal infections can have fatal consequences for immunosuppressed patients from diseases such as HIV or chemotherapies used to treat cancer. Fungi also typically represent a challenge for food safety because they destroy the main crops on a worldwide level and also pollute human and animal foods with mycotoxins which are harmful for their consumers.
María Coca, researcher of the CSIC in the CRAG, says, “We currently only have limited numbers of antifungal agent classes, and even these are not totally effective due to the hosts developing resistances and the existence of potential undesirable secondary effects. This is why there is an urgent need to develop new antifungals that improve those that already exist and which may be applied in different fields, including crop protection, post-harvest, material and food preservation, and human and animal health.”
CSIC researcher José Antonio Darós, who works at the IBMCP, says, “In this project, we have focused on the antifungal proteins secreted by filamentous fungi, which are small but highly stable proteins with strong specific activity against fungal pathogens, which could be used to develop new antifungal therapies in medicine and agriculture. The problem is that their use requires efficient, sustainable and safe production systems.”
The researchers have used a modified virus based on the tobacco mosaic virus to produce these small antifungal proteins in Nicotiana benthamiana, a plant from the tobacco family which is often used in research. “With this method, we have been able to produce large amounts of antifungal proteins against the Aspergillus giganteus and Penicillium digitatum fungi. We have also verified that these antifungal proteins are totally active against these pathogens, and that a fluid which contains these proteins can protect the tomato plant from the Botrytis cinérea fungi, more commonly known as grey mould,” says Darós.
More information: Xiaoqing Shi et al. Efficient production of antifungal proteins in plants using a new transient expression vector derived from tobacco mosaic virus, Plant Biotechnology Journal (2018). DOI: 10.1111/PBI.13038
Weed control ranks among the top challenges for farmers and the biggest pest control issue. Among different classes of pesticides, herbicide use dwarfs all others including insecticide use. Nobody wants to spray herbicides, but nobody wants to see weeds sucking up all the water and nutrients intended for the crops either. While herbicides come with some environmental trade offs, there is nothing sustainable about pouring irrigation, fertilizer, fuel and other inputs into a field — only to have them eaten up and wasted by weeds.
There are a dizzying number of projects and companies seeking to apply robotics, computer vision and artificial intelligence (or machine learning) to the task of weed control. For some, the dream is to take herbicides completely out of the equation. For others, the goal is to dramatically reduce their use. Let’s take a look at some of the technical strategies being pursued, interrogating the pros, cons, trade-offs and likelihood of success.
There have been attempts at pure mechanical control through robotics. This has the virtue of requiring no herbicides, and the nice clean environmental narrative that comes with that. There is a lot of upside, from a marketing perspective in being able to make the claim of controlling weeds without herbicides, but the technical challenges are daunting.
Bosch’s Bonirob weed control robot got a lot of hype back in 2015, and seems to have faded a bit in garnering attention. It is the size of a small car and kills weeds by punching them into the ground with a rod.
The other robot of note doing weed control mechanically is the Tertill, a garden weeder developed by the inventor of the Roomba. But a Roomba for your backyard garden isn’t going revolutionize agriculture as we know it any time soon.
Despite early enthusiasm for herbicide-free weed control, most companies in this space have abandoned that as a goal, at least for now. The technical challenges of automating the last eighteen inches or so came to be seen as too daunting. The current focus is on using robotics, sensors and machine learning to do precision spraying, targeting unwanted plants rather than entire fields. Precision spraying allows the unit to move over the field more quickly than mechanical control and doesn’t require a bullseye every time in order to kill the weed. They may not eliminate herbicides but every company is claiming reductions in use of up to 90 percent. Herbicides would go from making up the majority of pesticide use to one among many and a smaller footprint for pesticides overall.
One strategy is to build dedicated, autonomous sprayers, leveraging what’s possible with robotics, GPS and AI. These are units that drive themselves through the field, hunting weeds. The great advantage here is that a single farmer can put their time to better use, being freed up from the cab. While automating a robotic interaction with each weed is difficult, these days programming a unit to self-navigate a field or low traffic country road crossings is a piece of cake.
Ecorobotics has a tiny, solar powered unit that seems appropriate for smaller, high value specialty crop farms around Watsonville and Salinas, CA. It’s not designed to cover the ground you’d need for Midwest row crops, but it has the advantages of being solar powered and its light weight will not cause compaction (pressing the topsoil into a tight, airless, brick-like condition that comes from having the tires of heavy machinery running repeatedly over the same ground. A serious issue for soil health on farms).
Australian-based SwarmFarms is building modular system of small self driving frame to which components can be added or subtracted. A precision sprayer is just one function that it can be assembled for. The company envisions farms owning small fleets of units that drive themselves and coordinate among themselves in the field. While not as lightweight as the Ecorobotics unit, the compaction is going to be considerably lower than a full tractor pulling a sprayer.
On the other hand, I think of owning four or five autonomous units and I think of owning four or five times as many moving parts and four or five times as many points of failure. This is mitigated by the fact that an equipment failure in one leaves three to four still operational. Depending on how easy they are to work on, how much firmware is walled off from user repair, these look like a cool system. Freeing up human labor for more valuable work than sitting in the cab is a big benefit.
Tractor pulled spray units
While they don’t leverage autonomous self-driving technology, tractor units appear to have the most sophisticated precision technology and have the virtue of leveraging a piece of capital investment most farms already own — a big expensive tractor that moves quickly through a field. And they can certainly be used with self driving tractors.
Blue River’s See & Spray system is an ink jet printer for field spraying, with the option to spray other products like fungicides or fertilizer. The system allows farmers to customize their strategy, tailoring how wide or narrow an area to spray or how aggressively they go after anything that looks like a weed. One key aspect of the technology is that it stores a record of the weeds it encounters and can give farmers data on weed density and variety, allowing them to fine tune their weed control regime.
Related article:9 misdirected arguments against GMOs that really reflect modern and organic ag issues
Robotic weed control is very popular in Australia, and one farmer decided to make video demonstrating the speed and precision of his unit from WeedIt another Australian ag robotics company. To make this hit home for the average Joe or average Joey in the street, they programmed their field with weeds to coax the sprayer into performing Michael Jackson’s Beat It.
(While that’s fun, those bare fields are painful to behold.)
Could this technology help with resistant weeds?
This new technology would seem to have the potential to aid with managing herbicide resistant weeds. One could either apply more herbicide per weed, while lowering the amount per field or you might be able to use broad spectrum herbicides in settings where you currently can’t. To kick the tires of this idea, I spoke with three experts. But before we get to their insights, it’s worth understanding the genetics of weed resistance a little better.
When I spoke with Andrew Kniss at the University of Wyoming, I first wanted to make sure I understood the basic genetics of how weed resistance develops. This is the model I ran by him: “OK, you have a field with a million weeds and ten of them have traits that allow them to withstand exposure to an herbicide, but there is variation in how much of a dose they can survive, let’s say a scale of 1 to 10. If you we apply the herbicide at a rate of 7 on that scale of 1 to 10, we’ll kill seven of those weeds, but three will survive. The result is that their offspring will have that trait of tolerance, but with the variation around a higher set point. Seven becomes the new five.” He told me that was correct, but it was a description of a new form of resistance called creeping resistance, a problem that exacerbates when herbicide prices are high and farmers are tempted to apply at the lowest rate they think they can get by with. If farmers were able to apply higher doses per weed, while applying less to the field, they might kill potentially resistant weeds up to a higher threshold.
This is the form of resistance that the new precision tech might help in addressing. It wouldn’t make any difference with the older form of resistance. The other way that resistance develops is with a mutation that simply sidesteps the herbicide’s mode of action. That is, it renders the plant invisible to the herbicide, in the same way that the Roundup Ready trait renders Roundup Ready crops invisible to Roundup. If an herbicide binds to a certain receptor, the mutation just deletes that receptor.
While it’s plausible that these precision applications could be used to slow down the development of resistance or work around it, either through higher applications per weed or by allowing for more broad spectrum and different chemistries to be used on crops where they previously couldn’t be – because they would damage the crop – all three experts I talked to were dubious that this tech would play a major role in managing for resistance.
Adam Davis, department chair of crop sciences at the University of Illinois, pointed out that the technology might be useful if you were starting with a clean slate, but in Midwest row crops most weed populations already carry resistance traits for five to six modes of action already. It might be of more use in high value specialty crops where you have more of blank slate to start from.
The logistics of novel tank mixes isn’t so simple either. If the tech makes it possible to use an herbicide on a crop where it previously hadn’t been used, that requires regulatory approval, from the EPA and the relevant states.
Lynn Synososkie at UC Davis wondered what ways weed species and communities might start shifting in response to this new technology. Kniss noted that the technology is another step in making farming more capital intensive, which becomes another incentive towards farm consolidation and a headwind for smaller farms. Adam Davis said in his parting thoughts, “We can’t look for the answer to resistance in a jug, this technology may help on the margins, but the main strategy must continue to be confronting weeds with heterogeneity,diversification of crop rotations, of modes of action. We can’t maintain environments where weeds get too comfortable. They need to be challenged spatially, functionally, and temporally with diversity and heterogeneity.
Kiwifruit growers can now access a new tool to help them combat the bacterial disease Psa – the biocontrol product AureoGold™.
AureoGold™, developed by Plant & Food Research in collaboration with Arysta LifeScience, is a natural yeast strain that reduces growth and spread of Psa bacteria. It can be used during flowering and post fruit set, a time in the calendar when use of other controls for Psa is limited. AureoGold™ is a yeast found naturally on many different species of plants and fruits in New Zealand and is safe for bees.
AureoGold™ has been approved for use by the Ministry for Primary Industries under ACVM (agricultural compounds and veterinary medicine) regulations, and has BioGro Organic Certification.
“New bio-bactericides allow growers options to manage disease on orchards,” says Dr Suvi Viljanen, General Manager Science Bioprotection at Plant & Food Research. “AureoGold™ will provide kiwifruit growers, including organic growers, with an important new tool in their armoury to ensure plant health and good fruit yields despite the presence of the potentially devastating bacterial disease, Psa. This is a real achievement for our team, and yet another example of how we can work with industry to build new solutions to address key problems.”
Pseudomonas syringae pv actinidiae (Psa) was discovered in New Zealand in November 2010. The bacteria is present in around 92% of the regions where kiwifruit is grown in New Zealand, with symptoms including leaf spotting, shoot die-back, cane and leader die-back, bud browning, red-brown exudate from leaders and trunks and, in severe cases, plant death.
After the discovery of Psa, Plant & Food Research scientists began screening their library of microbes to identify any with the potential as a bio-bactericide control agent. The New Zealand yeast that forms the basis of AureoGold™ was identified in 2012, and was fast-tracked through glasshouse and field testing through a partnership with Zespri/KVH and Arysta LifeScience.
The team behind AureoGold™ were recently recognised with the Kudos Science Trust – Agriculture Science Award. The Team Leader, Dr Philip Elmer, was also presented with this year’s Kudos Lifetime Achievement Award and was a finalist in the Baldwins Researcher Entrepreneur category of the KiwiNet Commercialisation Awards. Plant & Food Research received the 2017 Prime Minister’s Science Prize for their scientific contribution to saving the kiwifruit industry from the effects of Psa.
The Plant & Food Research biocontrol research programme is funded by MBIE, Zespri, Kiwifruit Vine Health and the wider kiwifruit industry, with support from scientists at AgResearch, the BioProtection Research Centre and the University of Utrecht (the Netherlands). AureoGold™ is marketed by Arysta LifeScience (previously Etec Crop Solutions) and will be available from Horticentre, Farmlands and Fruitfed Supplies.
We are pleased to invite scientists, technicians, teachers, students, tomato producers and others with an interest in tomato diseases to the ISHS VIth International Symposium on Tomato Diseases in Taichung, Taiwan from 6-9 May 2019. Held every three years, this symposium brings together about 150 to 200 international experts from different fields to disseminate their progress and facilitate the exchange of research and ideas.
Symposium presentations on the theme of Managing tomato diseases in the face of globalization and climate change will illuminate how higher temperatures, more intense heat waves and longer periods of drought, change in precipitation patterns, more frequent wildfires, and an increase in the number, duration and intensity of tropical storms are fostering the development and spread of tomato diseases and altering pest behavior and distribution.
Explore the latest advances in research on diseases of the world’s most popular fruit vegetable in one of Asia’s most well-developed and vibrant agricultural economies.
Expect plenary lectures, invited papers, and oral and poster presentations in the following categories:
GENETICS AND BREEDING FOR RESISTANCE
FOOD SAFETY AND POSTHARVEST DISEASES
HOST – PATHOGEN INTERACTION
ECOLOGY AND EPIDEMIOLOGY
Prof. David M. Francis | The Ohio State University
Dr. Moshe Lapidot | Institute of Plant Sciences, Israel
Prof. Shyi-Dong Yeh | National Chung Hsing University, Taiwan
Prof. William Earl Fry (Emeritus) | Cornell University
Dr. Kai-Shu Ling | USDA-ARS, U.S. Vegetable Laboratory
Registration includes access to all sessions; all lunches and coffee breaks; two dinners; field trip lunch, snacks, and transportation; gift bag; copy of the symposium proceedings published as a volume of Acta Horticulturae.
World Vegetable Center
Taiwan Agricultural Research Insitution
National Chung Hsing University
International Society for Horticultural Science (ISHS)