Archive for the ‘Pesticides’ Category

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

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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.

Story Source:

Materials provided by Max Planck Institute of Molecular PhysiologyNote: Content may be edited for style and length.

Journal Reference:

  1. 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-EMNature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-27435-w


  • 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>.

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Using Integrated Pest Management to Reduce Pesticides and Increase Food Safety

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Integrated Pest Management Innovation Lab

Mar 06, 2018

Photo: A farmer sprays pesticides on cucurbit crops in Bangladesh.
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



Abating the Invasive Parthenium Weed to Improve Livestock Health


Cross-Border Technology Transfer: Biological Control of the Fall Armyworm in Asia and Africa


IPM Innovation Lab Helps Uganda and Kenya Secure Permits to Fight Invasive Weed


Enhancing the Private Sector: Two Teams 

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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

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Pesticides can harm bees twice—as larvae and adults

Impacts on pollinators may be worse than thought

Blue orchard bees
Blue orchard bees (Osmia lignaria) live a solitary life.JOE DLUGO/ALAMY STOCK PHOTO


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.

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How do we feed our growing population?

Jacqueline Rowarth05:00, Oct 27 2021

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.

Food prices rose 4 per cent in the year ending September 2021 (file photo).
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.

Dr 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.”
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.

The problem with the latter is that regulations are not always made with an understanding of the consequences.View the dashboard Tracking the speed of the economy

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.

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.
JAROMíR 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.

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Common insecticide linked to extreme decline in freshwater insects

by Leiden University

Common insecticide linked to extreme decline in freshwater insects
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.”

Explore furtherEffect of insecticides on damselflies greater than expected

More information: S. Henrik Barmentlo et al, Experimental evidence for neonicotinoid driven decline in aquatic emerging insects, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2105692118Journal information:Proceedings of the National Academy of SciencesProvided by Leiden University

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Destruction of nature and the rampant use of pesticides are the main drivers behind a rapid worldwide loss of bees and other pollinator species, an international panel of experts reported Monday. Shifts in land use to mono-crops, expanded grazing for livestock, and the widespread use of chemical fertilizers have also contributed significantly to their collapse, according to a global index of the causes and effects of pollinator decline.

For people everywhere, dwindling pollinator populations has potentially devastating consequences. Bees, butterflies, wasps, beetles, bats, flies and hummingbirds that distribute pollen are vital for the reproduction of more than three-quarters of food crops and flowering plants, including coffee, rapeseed and most fruits.

“What happens to pollinators could have huge knock-on effects for humanity,” said Lynn Dicks, a professor in Cambridge’s Department of Zoology and lead author of a study in Nature Ecology & Evolution. “These small creatures play central roles in the world’s ecosystems, including many that humans and other animals rely on for nutrition,” she added in a statement. 

“If they go, we may be in serious trouble.” 

The world has seen a three-fold increase in pollinator-dependent food production – valued at nearly $600 billion annually – over the last 50 years, according to a major UN report from 2016 to which Dicks contributed.

To get an up-to-date overview of pollinator status and the risks associated with their decline, Dicks worked with 20 scientists and indigenous representatives from around the world.

The causes and impacts of decline varied across regions.

Mass die-offs due to disease and so-called colony collapse disorder in industrial beehives and other “managed pollinators” ranked as a high risk in North America, where they play a key role in apple and almond production.

In Africa, Asia-Pacific and Latin America – regions where poorer rural populations rely on wild-growing foods – the impact of pollinator decline on wild plants and fruits poses a serious risk.

Latin America was viewed as the region with the most to lose. 

Insect-pollinated crops such as cashews, soybean, coffee and cocoa are essential to the region’s food supply and international trade. 

Indigenous populations also depend heavily on pollinated plants, with some pollinator species such as hummingbirds embedded in oral culture and history.

“This study highlights just how much we still don’t know about pollinator decline and the impacts on human societies, particularly in parts of the developing world,” said co-author Tom Breeze, Ecological Economics Research Fellow at the University of Reading. 

In China and India – increasingly reliant on fruit and vegetable crops that need pollinators – the loss of natural sources means it must sometimes be done by hand.

“We are in the midst of a species extinction crisis, but for many people that is intangible,” she added. “Perhaps pollinators are the bellwether of mass extinction.”

Another potential driver of pollinator decline that is likely to get worse is climate change, the study noted.

(Cover image via CFP)

(If you want to contribute and have specific expertise, please contact us at nature@cgtn.com.)Source(s): AFP

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Singapore: New accreditation scheme underway for pesticide-free vegetables

Work is being done on a new accreditation program to certify farms in Singapore that meet the national guidelines of producing pesticide-free and sustainably grown vegetables. This new program – to be drawn up by the Singapore Accreditation Council (SAC), which ESG oversees, together with the Singapore Food Agency – will ensure that independent certification bodies can competently assess and recognize clean and green farms.

In March of this year, guidelines to ensure produce from local vegetable farms are grown sustainably & free from pesticides were launched. They are known as the Singapore Standard (SS) 661: Specification for Clean and Green Urban Farms and contain criteria that urban farms have to meet in terms of minimizing contaminants in the food production process, as well as sustainable practices on resource and waste management.

ESG’s director-general of quality and excellence, Choy Sauw Kook: “You will also know that local farmers have implemented management systems to optimize the use of resources, such as water and electricity, in the farming process. With this information in hand, consumers know that locally-produced vegetables are grown without chemical pesticides and responsibly.”

This is where the accreditation program comes in to provide ‘an additional layer of checks’. “The accreditation program that the SAC is developing will ensure that conformity assessment bodies are qualified to assess farms’ compliance with the clean and green standard. This is how quality and standards build trust among consumers,” Ms. Choy told channelnewsasia.com.

Publication date: Wed 29 Sep 2021

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Why an integrated approach is best

By Bill KerrAugust 26, 2021 at 10:30 am

Farmers are finding more and more natural enemies to keep tomato leaf miners in check instead of resorting solely to chemicals, says Bill Kerr.

Why an integrated approach is best
These cherry tomatoes were planted long after the other plants in the tunnel, and so ripened much later. Despite this, no Tuta absoluta attacked them, proving the effectiveness of biological pest control. Photo: Bill Kerr

I once used a biological product to control Tuta absoluta (tomato leaf miner) in my own tomato crop. Unfortunately, the manufacturer ceased production of the product. But because I was using my crop solely for breeding purposes, I decided to stop spraying for the pest.

Last year, the plants suffered a fair amount of damage; this year, there was much less. I planted my first tunnel as soon as the frost was past and the final tunnel started maturing in March. There is very little damage to these tomatoes, despite the fact that I have never sprayed them or used traps.

I planted a quarter of the tunnel to a cherry tomato variety much later than the rest of the crop. This is just starting to set fruit, whereas the rest have been ripe for some time; yet there is no sign of the pest or larvae on this batch.

Taking a closer look at the plants, I recently found a number of Macrolophus spp in various stages of development, as well as the occasional Nesidiocoris tenuis. Both are mirid bugs that prey on T. absoluta and other pests. Macrolophus is now gaining control of T. absoluta in my tunnel.

Slight plant damage
More than 20 European countries are now using Macrolophus for pest control, and these are sold to tomato farmers.

When their prey is not available in sufficient numbers, Macrolophus spp can survive by feeding on the tomato plants themselves, and there are records of flower drop and other damage when their populations are very high. Nonetheless, they prefer insect eggs and first-instar larvae.

Generally, the small amount of potential damage is worth the protection provided by the bugs. They also feed on whitefly, aphids and thrips.

We still have much to learn about the local Macrolophus bugs. They may, for example, be better adapted to our conditions than those imported from the Netherlands. Whatever the case, they are apparently easy to rear.

Another group of beneficial insects is Trichogramma spp parasitoids. These are minute wasps that parasitise the eggs of the tomato leaf miner and other pests. There are many in the genus, with some being more specific in what they control and others having a wider range of prey.

In time, more natural enemies will make their presence felt. It is reported that some of the imported natural predators are not well adapted to high temperatures. As the inside of my tunnels can get particularly hot, this might indicate that our local bugs are better adapted.

Another approach is to set pheromone traps, which are available from suppliers of local biological products. These are an effective tool for lowering tomato leaf miner populations.

A combined approach
Control of this pest is not a matter of a one-size-fits-all approach and there is still a steep learning curve ahead. What is certain is that, eventually, we shall have to go over to integrated pest management with a combination of beneficial insects and insecticides that do not harm the natural enemies of T. absoluta.

This approach also means that tomato farmers have to carry out far more scouting and study to truly get the better of this highly destructive pest.

Bill Kerr is a vegetable specialist and breeder of a range of vegetables.

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New study shows decreasing effectiveness of fungicides to control the devastating Black Sigatoka disease of banana

Published onMay 19, 2021

The fungus Pseudocercospora fijiensis causes black leaf streak disease or Black Sigatoka of banana, which is the most damaging leaf disease of bananas worldwide. An analysis of 592 P. fijensis isolates from seven banana-producing countries on three continents shows how P. fijensis is evolving to insensitivity to azole fungicides due to the heavy use of pesticides.

The results of the study have been published in Pest Management Science and underscore the need to stop this vicious circle by developing alternative disease control methods and new banana varieties.

Black leaf streak disease is the most important banana disease worldwide. Cavendish bananas represent more than 50% of the global production – and dominate the export (95%) – but are very susceptible to this disease. In most countries, banana production relies on continual intensive disease control, usually at weekly intervals, throughout the year. It demonstrates the fragility of global banana production and its overall unsustainability. Azole fungicides are the cornerstone for fungal disease control in plants, animals and humans.

Nieuwe studie bevestigt dat verwoestende bananenziekte Black Sigatoka wereldwijd resistent raakt tegen pesticiden 2.jpg

First comprehensive analysis of reduced sensitivity

This study is the first comprehensive analysis of reduced sensitivity to these fungicides in banana production. In their study, researchers of Wageningen University & Research (WUR) and their collaborators, analyzed 592 P. fijensis isolates from seven countries in Latin America, the Caribbean, Africa and Southeast Asia for the sensitivity to three azole fungicides.

In addition, they sequenced the target gene – Pfcyp51 – in 266 isolates, to determine every mutation and analyzed the overall genomes of 155 isolates to study geographical clustering. All identified mutations could be associated with reduced sensitivity to the fungicides. This trend results in a vicious circle of even more fungicide applications in banana cultivation. Taken together, these alarming data call for a new view on sustainable banana production. For the benefit of the manifold producers and domestic and international consumers.

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