Produced by the International Association for the Plant Protection Sciences (IAPPS). To join IAPPS and receive the Crop Protection journal online go to: www.plantprotection.org
Can amino acid also be developed as pesticide against plant viruses?
by Higher Education Press
Credit: Hongjian Song, Qingmin Wang
Plant viruses create a great variety of harm. Virus disease pandemics and epidemics are estimated to have a global economic impact in the tens of billions of dollars. At present, there are not many effective and satisfactory varieties of anti-plant virus agents in practical use, and especially few therapeutic agents.
In the face of the harm viruses cause to agricultural production, it is necessary to develop environmentally friendly anti-plant virus drugs. It is increasingly important, and a growing research focus, to find drug candidates from natural products. Natural products possess many of the properties that can make them useful drug candidates, including structural diversity, specificity and novel modes of action. However, natural products also have some disadvantages, such as limited compound availability, high structural complexity and poor drug-likeness. Therefore, pesticide creation based on natural products has become an important direction of green pesticide creation.
Tryptophan is one of the essential amino acids and the biosynthetic precursor of many alkaloids. Prof. Qingmin Wang and Dr. Hongjian Song from Nankai University previously found that tryptophan, the biosynthesis precursor of Peganum harmala alkaloids, and its derivatives have anti-TMV activity both in vitro and in vivo. Further exploration of this led to the identification of NK0238 as a highly effective agent for the prevention and control of diseases caused by plant viruses, but the existing routes are unsuitable for its large-scale synthesis.
They optimized a route for two-step synthesis of this virucide candidate. The optimized route provides a solid foundation for its large-scale synthesis and subsequent efficacy and toxicity studies. Field experiment results showed that it had good effect on multiple plant viruses. The oral toxicity in rats was mild, and it had no effect on the safety of birds, fish or bees. The study entitled “Route development, antiviral studies, field evaluation and toxicity of an antiviral plant protectant NK0238” is published on the Journal of Frontiers of Agricultural Science and Engineering in 2022.
In this study, a two-step synthetic route for the antiviral plant protectant, NK0238, was developed. By this route, NK0238 can be obtained in 94% yield and nearly 97% HPLC purity. Compared with the previously reported routes, this route has the advantages of high atom economy, high yield and operational simplicity. In addition, it can be used for the preparation of more than 40 g of NK0238 in a single batch. After completing the process optimization, an in-depth study of antiviral activity in greenhouse and field experiments and toxicity tests were conducted. NK0238 exhibited a broad antiviral spectrum, in field experiments, the activities of NK0238 against TMV, pepper virus, panax notoginseng virus Y, gladiolus mosaic virus, banana bunchy top virus were equal to or higher than amino-oligosaccharins and moroxydine hydrochloride-copper acetate. The results of ecotoxicological testing showed that the compound was not harmful to birds, fish, bees and silkworms, its excellent activity and safety make NK0238 a promising drug candidate for further development.
More information: Wentao Xu et al, Route Development, Antiviral Studies, Field Evaluation And Toxicity Of An Antiviral Plant Protectant Nk0238, Frontiers of Agricultural Science and Engineering (2021). DOI: 10.15302/J-FASE-2021390
A local carp living with rice plants in the co-culture experiment. Lufeng Zhao (CC BY 4.0)
While rice is an important staple in global diets, rice cultivation and production are not so eco-friendly. Most rice agriculture relies on pesticides and chemical fertilizers for higher yields and less issues with insects and weeds. Now, researchers have found a way to minimize pesticide use for rice fields, instead using aquatic animals to help stifle weeds and improve crop yields.
Conventional farming involves planting large monocultures, or fields of the same crop. That makes each crop vulnerable to pests and weeds, which could wipe out most of one field. As such, farmers use pesticides to prevent weeds, pests, and diseases from taking over the crops and to boost yields.
But some farmers are testing ways to grow their crops while using natural methods to keep away pests and weeds.
“One example includes farmers experimenting with growing aquatic animals in rice paddies,” said Liang Guo, study author and postdoctoral fellow at the College of Life Sciences at Zhejiang University in Hangzhou, China. “Learning more about how these animals contribute to rice paddy ecosystems could help with producing rice in a more sustainable way.”
The research, published in eLife, analyzes three experiments and four years of study. In each experiment, the study authors considered rice grown alone or alongside carp, mitten crabs, or softshell turtles. According to the study, growing rice alongside these aquatic animals helped prevent weed growth.
The animals also improved decomposition of organic matter and ultimately provided better yields compared to the rice that was grown alone. The researchers found yields that were 8.7% to 12.1% higher than the control crop grown without the aquatic animals.
Lufeng Zhao, author of the study and a Ph.D. student at the College of Life Sciences at Zhejiang University, added that the nitrogen levels in the soil remained stable with the aquatic animals present, so less chemical fertilizers were needed for the rice. The animals were given feed, but they scavenged for up to half of their diet. In turn, the rice plants absorbed 13% to 35% of nitrogen from leftover feed that the animals didn’t eat.
“These results enhance our understanding of the roles of animals in agricultural ecosystems, and support the view that growing crops alongside animals has a number of benefits,” said Xin Chen, co-senior author of the study and an ecology professor at Zhejiang University. “In terms of rice production, adding aquatic animals to paddies may increase farmers’ profits as they can sell both the animals and the rice, spend less on fertilizer and pesticides, and charge more for sustainably grown products.”
Planting season for corn and soybeans across the U.S. will begin as soon as March in Southern states and then move north. As farmers plant, they will deploy vast quantities of insecticides into the environment, without ever spraying a drop.
Almost every field corn seed planted this year in the United States will be coated with neonicotinoids, the most widely used class of insecticides in the world. So will seeds for about half of U.S. soybeans and nearly all cotton, along with other crops. By my estimate, based on acres planted in 2021, neonicotinoids will be deployed across at least 150 million acres of cropland – an area about the size of Texas.
Neonicotinoids, among the most effective insecticides ever developed, are able to kill insects at concentrations that often are just a few parts per billion. That’s equivalent to a pinch of salt in 10 tons of potato chips. Compared with older classes of insecticides, they appear to be relatively less toxic to vertebrates, especially mammals.
In response to these concerns, Connecticut, Maryland, Vermont, Massachusetts, Maine and New Jersey have enacted laws limiting use of neonicotinoid insecticides. Other states are considering similar measures. Consumer and environmental advocates are also suing to force the U.S. Environmental Protection Agency to regulate coated seeds more tightly.
Most neonicotinoids in the U.S. are used as coatings on seeds for field crops like corn and soybeans. They protect against a relatively small suite of secondary insect pests – that is, not the main pests that typically damage crops. National companies or seed suppliers apply these coatings so that when farmers buy seeds they just have to plant them. As a result, surveys of farmers indicate that about 40% are unaware that insecticides are on their seeds.
Unlike most insecticides, neonicotinoids are water soluble. This means that when a seedling grows from a treated seed, its roots can absorb some of the insecticide that coated the seed. This can protect the seedling for a limited time from certain insects.
But only a small fraction of the insecticide applied to seeds actually enters seedlings. For example, corn seedlings take up only about 2%, and the insecticide persists in the plant for only two to three weeks. The critical question: Where does the rest go?
Soybean seeds treated with neonicotinoids (dyed blue to alert users to the presence of pesticide) and treated corn seeds (dyed red) versus untreated seeds. Ian Grettenberger/PennState University, CC BY-ND
Pervading the environment
One answer is that leftover insecticide not taken up by plants can easily wash into nearby waterways. Neonicotinoids from seed coatings are now polluting streams and rivers across the U.S.
Neonicotinoids also can strongly influence pest and predator populations in crop fields. In a 2015 study, colleagues and I found that use of coated soybean seeds reduced crop yields by poisoning insect predators that usually kill slugs, which cause serious damage in mid-Atlantic corn and soybeans fields. Subsequently, we found that neonicotinoids can decrease populations of insect predators in crop fields by 15% to 20%.
Recently we found that these insecticides can contaminate honeydew, a sugary fluid that aphids and other common sucking insects excrete when they feed on plant sap. Many beneficial insects, such as predators and parasitic wasps, feed on honeydew and may be poisoned or killed by neonicotinoids.
Slugs, shown here on a soybean plant, are unaffected by neonicotinoids but can transmit the insecticides to beetles that are important slug predators. Nick Sloff/Penn State University, CC BY-ND
Are neonicotinoids essential?
Neonicotinoid advocates point to reports – often funded by industry – that argue that these products provide value to field crop agriculture and farmers. However, these sources typically assume that insecticides of some type are needed on every acre of corn and soybeans. Therefore, their value calculations rest on comparing neonicotinoid seed coatings with the cost of other available insecticides.
Recent field studies, however, demonstrate that neonicotinoid-coated seeds provide limited insect control because target pest populations tend to be scarce and treating fields for them yields little benefit.
Does this mean that the U.S. should follow the European Union’s lead and ban neonicotinoids or adopt strict limits like those enacted in New Jersey?
As I see it, neonicotinoids can provide good value in controlling critical pest species, particularly in vegetable and fruit production, and managing invasive species like the spotted lanternfly. However, I believe the time has come to rein in their use as seed coatings in field crops like corn and soybeans, where they are providing little benefit and where the scale of their use is causing the most critical environmental problems.
Instead, I believe agricultural companies should promote, and farmers should use, integrated pest management, a strategy for sustainable insect control that is based on using insecticides only when they are economically justified. Recent research at Penn State and elsewhere reaffirms that integrated pest management can control pests in corn and other crops without reducing harvests.
Concerns about neonicotinoid-coated seeds are mounting as research reveals more routes of exposure to beneficial animals and effects on creatures they are not designed to kill. Agricultural companies have done little to address these issues and seem more committed than ever to selling coated seeds. Farmers often have very limited choice if they want to plant uncoated seeds.
This was written by Esther Ngumbi, and appeared on Sci Dev Net.
USAID recently offered prize money for the best digital tools that can be used to help combat the fall armyworm (FAW), an invasive pest that has spread across Africa. The winners will be announced in the coming months.
Map of areas affected by Fall Armyworm (as of January 2018) Credit: FAO
But this is not the first invasive pest the African continent is dealing with. Just a few years ago, African smallholder farmers battled the invasive South American tomato moth, Tuta absoluta. According to recent research, five invasive insect pests including T. absoluta cost the African continent US$ 1.1 billion every year.
Around the world, invasive pests are causing US$ 540 billion in economic losses to agriculture each year despite the fact that many countries are doing their best to prevent insect invasions now and into the future.
Tackling invasive pests reactively
To deal with invasive insects, African countries assisted by other stakeholders, including aid agencies such as USAID, research institutions such as the International Center for Insect Physiology and Ecology, the Center for Agriculture and Bioscience International (CABI, the parent organization of SciDev.Net) and the United Nations Food and Agriculture Organization (UN FAO) have repeatedly taken a reactive rather than a proactive approach in tackling the invasive pests only after they have established a foothold and caused considerable damage.
Ghana, for example, established a National Taskforce to control and manage FAW after the worms had invaded local fields. This taskforce mandate includes sensitizing farmers and making them aware of the symptoms of armyworm attacks so they can report infestations to authorities and undertake research aimed at finding short and long term solutions to combat the spread of FAW.
“While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem.”
Esther Ngumbi, University of Illinois
Malawi’s government prioritized the use of pesticides as an immediate and short-term strategy to fight the FAW after many of their smallholder farmers lost crops to this invasive insect. Further, the government intensified training and awareness campaigns about this pest and installed pheromone traps to help monitor the spread only after the pest had established a foothold.
The FAO, a leader in the efforts to deal with invasive pests in Africa, has spearheaded many efforts including bringing together experts from the Americas, Africa and other regions to share and update each other on FAW. The FAO has launched a mobile phone app to be used as an early warning system tool. But again, many of these efforts happened after the first detection of the FAW.
While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem. How can aid agencies such as USAID, UN FAO and other development partners that are currently spending billions to fight the invasive FAW help Africa to take the necessary steps to ensure that it is better prepared to deal with invasive insects now and into the future?
Anticipate and prepare
Recent research predicts that threats from invasive insects will continue to increase with African countries expected to be the most vulnerable. African governments must anticipate and prepare for such invasions using already available resources.
Early this year, CABI launched invasive species Horizon Scanning Tool (beta), a tool that allows countries to identify potential invasive species. This online and open source tool supported by United States Department of Agriculture and the UK Department for International Development allows countries to generate a list of invasive species that are absent from their countries at the moment but present in “source areas,” which may be relevant because they are neighboring countries, linked by trade and transport routes, or share similar climates. Doing so could allow African countries to prepare action plans that can be quickly rolled out when potential invaders actually arrive.
Learn from other regions
Africa can learn from other regions that have comprehensive plans on dealing with invasive insects and countries that have gone through similar invasions. The United States and Australia are examples of countries that have comprehensive plans on preventing and dealing with insect invasions, while Brazil has gone through its own FAW invasion.
“African governments must learn to be proactive rather than reactive in dealing with invasive insects.”
Esther Ngumbi, University of Illinois
Through workshops and training programs that help bring experts together, African countries can learn how to prevent and deal with future insect invasions. Moreover, key actors should help organize more workshops and training programs to enable African experts to learn from their counterparts overseas. At the same time, the manuals, and all the information exchanged and learned during such workshops, could be stored in online repositories that can be accessed by all African countries.
Strengthen African pest surveillance
A recent Feed the Future funded technical brief, which I helped to write, looked at the strength of existing African plant protection regulatory frameworks by examining eight indicators including the existence of a specified government agency mandated with the task of carrying out pest surveillance.
It reveals that many African countries have weak plant protection regulatory systems and that many governments do not carry out routine pest surveillance which involves the collection, recording, analysis, interpretation and timely dissemination of information about the presence, prevalence and distribution of pests.
The International Plant Protection Convention offers a comprehensive document that can help African countries to design pest surveillance programs. Also, the convention offers other guiding documents that can be used by African countries to strengthen their plant protection frameworks. African countries can use these available documents to strengthen national and regional pest surveillance abilities.
Set up emergency funds
Invasive insects know no borders. Thus, African countries must work together. At the same time, given the rapid spread of invasive insect outbreaks, the African continent must set up an emergency fund that can easily be tapped when insects invade. In dealing with the recent FAW invasion, it was evident that individual African countries and the continent did not have an emergency financing plan. This must change.
By anticipating potential invasive insects and learning from countries that have comprehensive national plant protection frameworks, Africa can be prepared for the next insect invasion. African governments must learn to be proactive rather than reactive in dealing with invasive insects.
Doing so will help safeguard Africa’s agriculture and protect the meaningful gains made in agricultural development. Time is ripe.
Esther Ngumbi is a distinguished postdoctoral researcher with the Department of Entomology at the US-based University of Illinois at Urbana Champaign, a World Policy Institute Senior Fellow, Aspen Institute New Voices Food Security Fellow and a Clinton Global University Initiative Agriculture Commitments Mentor and Ambassador. She can be contacted at enn0002@tigermail.auburn.edu
This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.
Honeydew contaminated with systemic insecticides threatens beneficial insects
Neonicotinoids and other systemic insecticides can contaminate honeydew, which is an important food source for beneficial insects in the agroecosystems, according to an international team of researchers.
John Tooker, professor of entomology in Penn State’s College of Agricultural Sciences, was part of the multidisciplinary team that conducted a review of the scientific literature, concluding that systemic insecticides in honeydew are a serious concern, particularly in large-acreage crops that commonly are treated with these products.
Honeydew is the excretion product of sap-sucking insects such as aphids, mealybugs, whiteflies, and psyllids, Tooker explained.
“This rich carbohydrate source is a common food for many beneficial insects, including pollinators, such as bees and flies, and some natural enemies of pests, such as ants, wasps, and beetles,” he said. “Honeydew often is more abundant than nectar in agroecosystems.”
In their review, the researchers cited a 2019 study published in the Proceedings of the National Academy of Sciences by some of the co-authors, who found that honeydew represents a novel route of exposure to neonicotinoids, the most widely used group of systemic insecticides in the world. These insecticides often are applied in the form of seed coatings, and as a plant germinates and grows, the insecticide in its sap kills pest insects that feed on it.
As part of the 2019 study, the scientists conducted chemical analyses of honeydew excreted by insects feeding on sap from plants treated with neonicotinoids. They found clear evidence that this honeydew was contaminated and toxic to beneficial insects such as parasitic wasps and pollinating hoverflies, which died within a few days of consuming the contaminated honeydew.
The study was the subject of industry skepticism because it was conducted under laboratory conditions that may not exist in the field. Subsequently, members of the research team conducted a two-year field study — published recently in Environmental Pollution — which found that neonicotinoids from soybean plants grown from neonicotinoid-coated seeds reached honeydew excreted by soybean aphid 30-40 days after the seeds were sown.
“Continued work by our consortium, and studies published by other researchers, have revealed that the phenomenon is widespread, occurring in several species of plants and honeydew producers and with several systemic insecticides with various modes of action and modes of application,” said co-author Miguel Calvo-Agudo, of the Instituto Valenciano de Investigaciones Agrarias in Valencia, Spain. “As a result, many beneficial insect species are at risk of being exposed to neonicotinoids via contaminated honeydew.”
Resistant insect species The research team’s summary, published recently in Biological Reviews, analyzed relevant information from the fields of plant and insect physiology, toxicology, and ecology to identify the systemic insecticides that are more likely to reach honeydew and those insect species that are more likely to excrete contaminated honeydew.
For example, the authors raise serious concerns about invasive sap-sucking insect species that are resistant or tolerant to systemic insecticides and infest large-acreage crops — such as corn, wheat, rice and barley — that are commonly treated with systemic insecticides. These crops represent more than 50% of the worldwide harvest area, and honeydew is the main carbohydrate source in these crops for beneficial insects.
This review study can raise awareness among integrated pest management programs and environmental protection agencies that regulate the use of systemic insecticides, the researchers noted. Among their conclusions is a recommendation that agencies restrict the use of highly water-soluble systemic insecticides that are persistent in the environment and those that have a broad-spectrum activity to avoid nontarget impacts on beneficial insects through honeydew and other avenues of exposure.For more information: PennState University www.news.psu.edu
Finding new channels to selectively target pest insects
Date:December 14, 2021Source:Max Planck Institute of Molecular Physiology Summary: Ion channels in the nervous system are among the most important targets for insecticides. Understanding the structure of the channels is key for the identification of novel species-specific binding sites of agrochemicals. Researchers have revealed the structure and function of a potassium ion channel in fruit flies. Their newly obtained insights reveal the differences between human and insect channels, explain how known compounds affect the channel and propose new target sites for drugs. The research could help pesticide manufacturers design new drugs apt to specifically kill pest insects and parasites without affecting other animals like bees and mammals.Share:FULL STORY
Ion channels in the nervous system are among the most important targets for insecticides. Understanding the structure of the channels is key for the identification of novel species-specific binding sites of agrochemicals. Researchers have revealed the structure and function of a potassium ion channel in fruit flies. Their newly obtained insights reveal the differences between human and insect channels, explain how known compounds affect the channel and propose new target sites for drugs. The research could help pesticide manufacturers design new drugs apt to specifically kill pest insects and parasites without affecting other animals like bees and mammals.
The Slowpoke potassium channels in Drosophila, the common fruit fly, are huge and complex proteins that sit inside the cellular membrane and selectively and rapidly transport vital potassium ions through it. They are found in all animals and are responsible for completing various tasks, most importantly in the brain and in muscle cells. The essential roles of the potassium channels signify the importance of targeting Slowpoke with newly developed insecticides in order to help overcome the global problem concerning the decrease in efficiency due to the growing pesticide resistance. Yet, there is always the risk of not aiming properly: “Ideally, you want insecticides to be really specific to the pest insect, avoiding drugs that are toxic for humans, or other animals, such as birds, rodents and beneficial insects like bees,” says Stefan Raunser, Director at the Max Planck Institute of Molecular Physiology in Dortmund, and lead author of the study.
In order to design drugs that are specific for pest insects, scientists need high-resolution structures of the ion channels. Raunser and colleagues used cryo-electron microscopy (cryo-EM) to obtain the structures of the protein in the open and in the closed states and compared them with structures of the human proteins that are already known. “The difference between human and insect channels are really tiny, but we found protein regions that are specific to insects,” says Raunser.
Detailed map of the potassium channel for drug discovery
One specific site of the channel, named RCK2 pocket, has amino acids that differ between Drosophila and humans. It is located at the gating ring at the bottom of the channel. The gating ring sits inside the cell, picks up calcium ions when abundant and kicks off a cascade of rearrangements that open up the central cavity for potassium ions to pass through. The RCK2 pocket changes its shape as it shifts between closed and open states. Therefore, it is a potentially perfect target for small molecules to block the channel in either state. Scientists pinpointed also other less insect-specific drug target sites. Among them, the S6 pocket appears in the closed state and could be used to lock the channel. “We are providing pharmaceutical scientists with a detailed map of the potassium channel, which they can use to make better, highly selective insecticides,” concludes Raunser.
Additionally, the researchers also solved the cryo-EM structures of the channel with two known compounds, verruculogen and emodepside. The fungal neurotoxin verruculogen is a small molecule that fits perfectly in the S6 pocket, close to the central cavity. Verruculogen keeps the channel narrow, locking it in the closed state. Another compound, emodepside, a drug used against gastrointestinal worms in cats and dogs, also binds close to the S6 pocket. Yet, it acts differently, as an additional passing filter, making it difficult for potassium to go through the channel in an optimal way. “It’s important to understand how these ligands can manipulate the channel,” says Raunser.
Tobias Raisch, Andreas Brockmann, Ulrich Ebbinghaus-Kintscher, Jörg Freigang, Oliver Gutbrod, Jan Kubicek, Barbara Maertens, Oliver Hofnagel, Stefan Raunser. Small molecule modulation of the Drosophila Slo channel elucidated by cryo-EM. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-27435-w
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Max Planck Institute of Molecular Physiology. “Finding new channels to selectively target pest insects.” ScienceDaily. ScienceDaily, 14 December 2021. <www.sciencedaily.com/releases/2021/12/211214152144.htm>.
Photo: A farmer sprays pesticides on cucurbit crops in Bangladesh.
Written by Sara Hendery, Communications Coordinator of the Feed the Future Innovation Lab for Integrated Pest Management
In 2017, thousands of beetles and weevils moved into Ethiopia’s Amhara region. Like most living things, they were hungry, but their appetites desired a specific earthly delicacy: weeds.
Zygogramma, the leaf-feeding beetle, and Listronotus, the stem-boring weevil, were released in Ethiopia by Virginia State University, collaborators of the Feed the Future Innovation Lab for Integrated Pest Management, funded by USAID and housed at Virginia Tech. Zygogramma and Listronotus combat Parthenium, an invasive weed that threatens food security and biodiversity, causes respiratory issues and rashes on human skin, and taints meat and dairy products when consumed by animals. Biological control and other holistic agricultural methods are specialities of the Integrated Pest Management (IPM) Innovation Lab. Its team of scientists and collaborators generate IPM technologies to fight, reduce and manage crop-destroying pests in developing countries while reducing the use of pesticides.
The application of pesticides is a major threat to human health. In sub-Saharan Africa, more than 50,000 tons of obsolete pesticides blanket the already at-risk land. Pesticides can taint food, water, soil and air, causing headaches, drowsiness, fertility issues and life-threatening illness. Especially vulnerable populations are children, pregnant women and farmers themselves; hundreds of thousands of known deaths occur each year due to pesticide poisoning. Pesticides often increase crop yields, but an abundance of crops is anachronistic when the cost is human life.
In a small community in Bangladesh, farmers used to rely on pesticides to manage insects and agricultural diseases destroying crops, but community members began to develop symptoms from the excessive pesticide use, and, more than that, children were doing the spraying. The IPM Innovation Lab implemented a grafting program in the community that generated eggplant grafted varieties resistant to bacterial wilt. Eggplant yields increased dramatically and purchases of chemical pesticides dropped, which meant safer and healthier produce for families.
This story is one of many. The IPM Innovation Lab taps into a collection of inventive technologies in both its current phase of projects in East Africa and Asia, and since its inception in 1993, to enhance the livelihoods and standards of living for smallholder farmers and people across the globe:
In Vietnam, dragon fruit is covered in biodegradable plastic bags to protect the plants from fungal disease.
In Niger, the release of parasitoids eliminates the pearl millet headminer.
The spread of coconut dust inside seedling trays grows healthy plants in India.
Parasitic wasps destroy the papaya mealybug from India to Florida.
Trichoderma, a naturally occurring fungus in soil, fights against fungal diseases in India, the Philippines and elsewhere.
Cuelure bait traps save cucurbits from fruit flies in Bangladesh.
Eggplant fruit and shootborer baits protect eggplants from insect damage in Nepal, India and Bangladesh.
Pesticides do not necessarily eliminate pest invasion; they eliminate even the “good” insects on plants. Insects often develop resistance to popular chemicals when applied frequently, so not only is chemical spraying sometimes unnecessary, it is excessive.
Tuta absoluta, for example, is a tomato leafminer destroying tomato crops across the globe. In Spain, in the first year of the pest’s introduction, pesticides were applied 15 times per season, but the pest is resistant to pesticides and is so small (about the size of a stray pencil mark) that it often burrows inside the plant rather than around it. The IPM Innovation Lab and its collaborators generated one-of-a-kind modeling to track the movement of the species and introduced pheromone traps and neem-based bio-pesticides to help manage its spread, further ensuring the implementation of a series of technologies, rather than just relying on one, to reduce crop damage. The age-old saying “two heads are better than one” is accurate — just ask Zygogramma and Listronotus.
In developing countries, it is difficult to regulate the amount of chemical pesticides that make it onto crops, thus increasing the risk that chemicals will have a dramatic effect on the safety of food and the potential for exposure to foreign markets. One of the reasons pesticide over-application is common in developing countries is due to misinformation. In Cambodian rice production, pesticides are often misused because labels are printed in a foreign language; it is common that farmers mix two to five pesticides, resulting in pesticide poisoning. The IPM Innovation Lab’s project in Cambodia reduces the number of pesticides in rice production by introducing host-plant resistance and biological control.
Also, a fundamental practice of the IPM Innovation Lab is conducting trainings and symposia for farmers and IPM collaborators across the world to educate on the use and implementation of IPM technologies, further reducing the risk of possible harm to crops and human life. Additionally, IPM Innovation Lab partners with agriculture input suppliers and markets in project communities to ensure that bio-pesticides and IPM materials such as traps are readily available and that the purchase of pesticides are not the only option.
Ultimately, when you spray, you pay. The IPM Innovation Lab prioritizes both human and plant health by reducing the use of pesticides, and with the human population growing by the thousands every day, it is crucial that food is not only abundant but also safe and healthy to eat.FILED UNDER:AGRICULTURAL PRODUCTIVITYFOOD SAFETYNUTRITION
Chemical crop protection affects bee reproduction over several generations
A new study from researchers at the University of California, Davis, finds that chemical crop protection not only directly affects bee health, but effects from past exposure can carry over to future generations. The study, published in the journal Proceedings of the National Academy of Sciences, suggests that bees may require multiple generations to recover from even a single application.
Bees play a critical role in agricultural ecosystems, providing pollination for many important crops. In most agricultural areas, bees may be exposed to chemical crop protection multiple times, over multiple years. Studies to date have only looked at exposure to chemical crop protection in one life stage or over one year.
“It was important for us to understand how exposure persists from one generation to the next,” said lead author Clara Stuligross, a Ph.D. candidate in ecology at UC Davis. “Our findings suggest we need to be doing more to help mitigate risks or we limit critical pollination services.”
Reproduction drops In the study, the blue orchard bee was exposed to imidacloprid — the most commonly used neonicotinoid in California — according to amounts recommended on the label. Neonicotinoids are a class of insecticides chemically related to nicotine. Stuligross said the exposures were similar to what the bees would experience in the field. Female bees that were exposed to the insecticide as larvae had 20% fewer offspring than bees not exposed. Those bees that were exposed as larvae and as adults had 44% fewer offspring.
“We gave them one application in the first year and one in the second — that’s a pretty standard exposure. Even then, we saw strong results that added up, each exposure reducing fertility,” said Stuligross.
Populations affected Because the impacts of insecticides tend to be additive across life stages, repeated exposure has profound implications for population growth. The research showed that bees exposed to neonicotinoids in both the first and second years resulted in a 72% lower population growth rate compared to bees not exposed at all. Neonicotinoids also persist in the environment long after application.
The study reveals how past chemical crop protection exposure can have lasting impacts, said co-author Neal Williams, professor of entomology at UC Davis. “One could draw parallels to human health where impacts early in development show up much later in life,” he said. “We just didn’t know the same was true for bees. Now we do and we need to continue to manage risks appropriately.”
For more information: University of California Davis One Shields Avenue, Davis California 95616, US www.ucdavis.edu
Honey bees have a reputation for working hard, but carpenter bees and other bee species that don’t live in colonies might be even more industrious. For these so-called solitary bees, there is no dedicated worker class to help with rearing young and foraging. “Each female is kind of like a lone wolf,” says Clara Stuligross, a Ph.D. student at the University of California (UC), Davis.
Now, a study by Stuligross and colleagues tallying the detrimental impacts of a key pesticide on reproduction of a solitary bee species adds to growing evidence that such insects, which make up the vast majority of bees species, are vulnerable to the compounds just like their more social counterparts. Their finding suggest the harm of pesticides can accumulate over multiple generations, which could exacerbate the loss of species that provide valuable pollination for farms and ecosystems.
The work demonstrates that chronic pesticide poisoning can cause “meaningful and significant impacts” on bees, says Nigel Raine, a bee ecologist at the University of Guelph who was not involved with the study. “That’s really quite important.”
Of all the types of pesticides that harm bees, one is particularly insidious. Known as neonicotinoids, they are coated on seeds or sprayed on soil. Then they permeate the tissue of plants, eventually showing up in pollen and nectar. The pesticides disrupt learning and memory in honey bees and several studies have shown solitary bees suffer the same kind of damage. At higher levels, the chemicals impair reproduction, such as by reducing the viability of sperm, leading to fewer offspring. Yet little research has examined how neonicotinoids might harm pollinators throughout their life cycle.
So Stuligross and her UC Davis adviser, ecologist Neal Williams, designed a study to find out. They looked at the blue orchard bee (Osmia lignaria), a solitary species native to North America that farmers sometimes use to pollinate almond and other fruit trees.
Stuligross set up 16 cages, each about the size of two small cars, and planted three species of wildflower to feed the bees. In half of the cages, she drenched the soil with imidacloprid, as farmers do with this common neonicotinoid. The eight females bees in each cage had the company of 16 males, and they were provided with nesting space (holes drilled in wood) and a supply of mud that insects use to create cells for their brood inside the holes. Other solitary bee species do this as well, which is why they’re also called mason bees.
After the females mated, they laid eggs inside the holes, provided each egg with a ball of pollen and nectar, and sealed them up in individual cells made of mud. Meanwhile, the females were themselves consuming pesticide-contaminated pollen and nectar. They seemed sluggish and needed longer to find their holes, for example, and they laid fewer eggs than healthy bees. “They just seemed like they weren’t well,” Stuligross says.
Adult blue orchard bees typically only live for a few weeks. After they die, their larvae develop while feeding on the food left behind. This exposure to the pesticide had lasting harm. Bees that had consumed pesticides had 30% fewer offspring, compared with bees that had grown up without pesticides.
To figure out the effect of chronic exposure, Stuligross drenched the soil in some cages again the next year. Fertility suffered even more. Those insects with a double dose over the 2 years—they had consumed pesticides as larvae in the first year of the experiment and then again as adults, when they collected pesticide-laden pollen from flowers—laid about 20% fewer eggs than did bees that had only been exposed as larvae, Stuligross and Williams report today in the Proceedings of the National Academy of Sciences.
“Clearly, this paper shows that there are substantial impacts,” Raine says.
Over two generations, the damage to bee fertility adds up: The number of offspring would be about 75% less than for bees never exposed to imidacloprid, the team concludes. Such a reduction in fertility could tip populations into a long-term decline in the real world, where uncaged bees are not protected from predators or provided with easy access to unlimited food, Stuligross says.
“This is very important because it can explain at least partly the decline of bees worldwide,” says Fabio Sgolastra, a bee ecologist at the University of Bologna. “This is another piece of the puzzle showing that neonicotinoids are bad for solitary bees.” Government regulators should start to consider the risk to solitary bees, and not just honey bees, Sgolastra and others say. Although solitary bee species have not been commercialized as much as honey bees, they provide essential—and free—pollination for many farmers.
The Detail: The sky-high cost of living in New Zealand
The Detail explores what makes our food so pricey when we produce enough to feed 40 million people.
There are also more than 350 restaurants, cafés and fast-food outlets involved – and the restaurant and ready-to-eat-food prices increased 4.6 per cent. Further, 30 per cent of the food budget is now spent on convenience, despite lockdown and the perceived focus on home cooking.
For the farmer, this means that more of what consumers spend is on processing and preparation, rather than on the basic food they have produced.
ALDEN WILLIAMS/STUFFFood prices rose 4 per cent in the year ending September 2021 (file photo).
The New Zealand Institute of Economic Research analysed the farm share of retail prices in 2019. Approximately 31 per cent of every dollar spent on meat returned to the farm, 19 per cent of dairy dollars, 22 per cent of grain dollars, 10 per cent of fruit, 16 per cent of vegetables and 2 per cent of the egg dollar.
Not much, really.
And farmers are consumers – so they have been hit by inflation like every other business. In the last quarter, prices paid by farmers have increased 5.9 per cent. Prices received were certainly up 4 per cent, but that hasn’t covered the increase in costs of fertiliser, fuel, electricity and wages.
Even more of a shock might be that what is being experienced in New Zealand in terms of increased food prices is nothing in comparison with that being experienced in the world. The FAO food price index has increased 32.8 per cent from September 2020 – food prices globally have increased by a third in a year.
STUFFDr Jacqueline Rowarth: “Ever-cheaper food … is likely to be a thing of the past as farmers try to manage improved productivity (more food with reduced inputs) within the uncertainties of a changing environment.”
Uncertainty in harvest due to Covid-19, fire, drought and flood, as well as demand, have combined to stimulate inflation not seen since 2011. Food accessibility (available and affordable) is an issue globally.
Ever-cheaper food, though an expectation in developed countries, is likely to be a thing of the past as farmers try to manage improved productivity (more food with reduced inputs) within the uncertainties of a changing environment – due to both the climate and regulation.
On April 29, the Sri Lankan Cabinet approved a ban on importation of chemical fertilisers and other agrochemicals in a bid to become the first country to practise organic-only agriculture. Less than six months later and the government has backed down. Yields and quality of tea crashed.
Despite well-meaning belief, there was insufficient organic fertiliser available for the tea plantations. And with lower yields and quality, tea prices increased, meaning local tea drinkers were as unhappy as the growers.
JAROMÃR KAVAN/UNSPLASH Sri Lanka wanted to be the first country to practise organic-only agriculture. Less than six months later and the government backed down after yields and quality of tea crashed.
In the European Union, Farm Europe (a think tank) has calculated that the new farm to fork strategy will have significant impact on food supply, and hence food prices. The strategy recommends reducing the use of chemical pesticides by 50 per cent and fertilisers by 20 per cent, setting aside of at least 10 per cent of agricultural area under high-diversity landscape features and putting at least 25 per cent under organic farming.
The estimated result will be a reduction in food supply by 10 to 15 per cent in the key sectors of cereals, oilseeds, beef, dairy cows; over 15 per cent in pork and poultry; and over 5 per cent in vegetables and permanent crops. There will be an increase in prices by 17 per cent and little to no increase in biodiversity or ecological benefits.
Increasingly, research is showing that our best chance of preserving biodiversity and achieving ecological benefits is to ensure productivity gains on existing agricultural area. This will avoid needing more area to compensate – deforestation being the most obvious detrimental effect. The big differences in biodiversity are between natural and managed ecosystems, not within different types of management (organic versus conventional, for instance).Get the latest small business updates, straight to your inboxSubscribe for free
While the wealthy countries develop new technologies to assist the challenge of meeting the nutritional needs of an ever-increasing global population from current agricultural land, work is vital with the less developed countries to help them achieve higher yields – to overcome what is known as the yield gap.
Better soil management, improved genetics and matching inputs with plant and animal needs (including health and welfare) is key. So is harvesting, processing, storage and distribution to reduce waste.
New Zealand farmers already hold global records in yield (grain) and low GHG (meat and milk). They are also leaders in precision agriculture. Food here is produced without the subsidies common in other countries. Removal of technological tools will increase prices to the consumer as already calculated for the EU.
For good policy to be developed, all the different consequences need evaluation. Research is showing the way.
– Dr Jacqueline Rowarth, Adjunct Professor Lincoln University, is a farmer-elected director of DairyNZ and Ravensdown. The analysis and conclusions above are her own. Contact her at jsrowarth@gmail.com.
Henrik Barmentlo at work at the Living Lab, accompanied by Professor Martina Vijver. Credit: Edwin Giesbers
The widely used pesticide thiacloprid can cause a large-scale decline in freshwater insects. This was discovered by researchers from the Living Lab in Leiden. For three months they counted the flying insects in the 36 ditches of the lab. Their research appeared in PNAS.
In the ditches of the Living Lab, Henrik Barmentlo and his colleagues exposed freshwater insects to different concentrations of thiacloprid. This substance belongs to the neonicotinoids, the world’s most widely used group of insecticides. “We used realistic concentrations,” says Barmentlo. They correspond to concentrations we actually measure in the surface water.
Dramatic decline in all species
That neonicotinoids can be harmful to many insects had already been proven. But there was no conclusive evidence that these insecticides are at least partly responsible for the large-scale insect decline.
Therefore, in a unique experiment, the researchers caught no less than 55,574 insects that flew out of the lab’s 36 thiacloprid-contaminated ditches over a period of three months. Afterwards, they identified all specimens. They compared the results with nine control ditches, without added thiacloprid. Barmentlo: “We saw dramatic declines in all the species groups studied, such as dragonflies, beetles and sedges. Both in absolute numbers and in total biomass. In the most extreme scenario, the diversity of the most species-rich group, the dance flies, even dropped to a single species.”
Consequences for the whole ecosystem
And that while all these insects have an important role in their ecosystem. For example, they serve as food for many insect-eating bird species. Previously, other researchers had already discovered that these bird species occur in lower numbers when there are more neonicotinoids in the water. Barmentlo: “So it is quite possible that these bird species suffer from a lack of insects, or in other words: food.”
Barmentlo calls the results alarming. “Given the urgency of the large-scale decline in insects, we think the mass use of these insecticides should be reconsidered. In the EU, the use of thiacloprid was banned last year, but not yet in other parts of the world. In order to protect freshwater insects and all the life that depends on them, we must stop using these neonicotinoides as soon as possible.”
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