Pollinators: the ominous findings of first global risk index for species declines

Disappearing habitats and the use of pesticides are driving the loss of pollinator species around the world, posing a threat to “ecosystem services” that provide food and wellbeing to many millions — particularly in the Global South — as well as billions of dollars in crop productivity.

This is according to an international panel of experts, led by the University of Cambridge, who used available evidence to create the first planetary risk index of the causes and effects of dramatic pollinator declines in six global regions.

The bees, butterflies, wasps, beetles, bats, flies and hummingbirds that distribute pollen, vital for the reproduction of over 75% of food crops and flowering plants — including coffee, rapeseed and most fruits — are visibly diminishing the world over, yet little is known of the consequences for human populations. Continue reading

Ghosts of past pesticide use can haunt organic farms for decades

Although the use of pesticides in agriculture is increasing, some farms have transitioned to organic practices and avoid applying them.

But it’s uncertain whether chemicals applied to land decades ago can continue to influence the soil’s health after switching to organic management.

Now, researchers reporting in ACS’ Environmental Science & Technology have identified pesticide residues at 100 Swiss farms, including all the organic fields studied, with beneficial soil microbes’ abundance negatively impacted by their occurrence.

Fungicides, herbicides and insecticides protect crops by repelling or destroying organisms that harm the plants. In contrast, organic agriculture management strategies avoid adding synthetic substances, instead relying on a presumably healthy existing soil ecosystem.

However, some organic farms are operating on land treated with pesticides in the past. Yet, it’s unclear whether pesticides have a long-lasting presence in organically managed fields and what the reverberations are to soil life, specifically microbes and beneficial soil fungi, years after their application.

So, Judith Riedo, Thomas Bucheli, Florian Walder, Marcel van der Heijden and colleagues wanted to examine pesticide levels and their impact on soil health on farms managed with conventional versus organic practices, as well as on farms converted to organic methods.

The researchers measured surface soil characteristics and the concentrations of 46 regularly used pesticides and their breakdown products in samples taken from 100 fields that were managed with either conventional or organic practices.

Surprisingly, the researchers found pesticide residues at all of the sites, including organic farms converted more than 20 years prior.

Multiple herbicides and one fungicide remained in the surface soil after the conversion to organic practices; though the total number of synthetic chemicals and their concentrations decreased significantly the longer the fields were in organic management.

According to the researchers, some of the pesticides alternatively could have contaminated the organic fields by traveling through the air, water or soil from nearby conventional fields. In addition, the team observed lower microbial abundance and decreased levels of a beneficial microbe when fields had higher numbers of pesticides in the fields, suggesting that the presence of these substances can decrease soil health.

The researchers say future work should examine the synergistic effects of pesticide residues and other environmental stressors on soil health.

Journal Reference:
  1. Judith Riedo, Felix E. Wettstein, Andrea Rösch, Chantal Herzog, Samiran Banerjee, Lucie Büchi, Raphaël Charles, Daniel Wächter, Fabrice Martin-Laurent, Thomas D. Bucheli, Florian Walder, Marcel G. A. van der Heijden. Widespread Occurrence of Pesticides in Organically Managed Agricultural Soils—the Ghost of a Conventional Agricultural Past? Environmental Science & Technology, 2021; 55 (5): 2919 DOI: 10.1021/acs.est.0c06405

Source:  ScienceDaily

Pesticides and food scarcity dramatically reduce wild bee population

American researchers have found that the combined threats from a loss of flowering plants and the widespread use of pesticides have reduced blue orchard bee reproduction by 57 per cent and resulted in fewer female offspring.

Just like humans, bees don’t face one single stress or threat, said lead author Clara Stuligross, a Ph.D. candidate in ecology at University of California – Davis.

“Understanding how multiple stressors interplay is really important, especially for bee populations in agricultural systems, where wild bees are commonly exposed to pesticides and food can be scarce.” Continue reading

Understanding non-lethal effects of pesticides on honey bees

Scientists are developing a new way of studying bees in the laboratory to determine whether pesticides are having a negative effect on their health and behaviour.

Understanding the effects of pesticides on honey bee health is imperative in making informed choices about the risks associated with use of pesticides in crop production. Previously, tests have focused on whether the pesticide kills developing bees, but scientists are developing new lab-based methods for understanding the non-lethal effects of pesticides on bees.

Dr Ashley Mortensen, who recently joined Plant & Food Research’s Pollination & Apiculture Team, has been studying bee behaviour as part of her PhD studies at the University of Florida. Tests for pesticide responses involve rearing honey bees in a lab environment prior to exposure to the pesticide. Dr Mortensen’s research analysed changes in behaviour that occur as a result of rearing bees in an artificial environment so that these can be factored into standardised tests and not confused with other changes that may occur as a response to pesticide exposure.

Her research has been published in the journal Behavioural Ecology and Sociobiology.

“One obvious way that stressors, such as pesticides, pests or disease, prevent bees from pollinating plants is by killing the bees either during immature development or by reducing the lifespan of the adults,” says Dr Mortensen.

“However, even if the bees don’t die, changes in their behaviour after exposure to one or more stressor during development could reduce bees’ efficiency at hive tasks such as rearing brood, tending to the queen, or foraging for nectar or pollen.

“This work is expected to further our understanding of how pesticides or other developmental stressors, like pathogens, temperature change and more, could alter the behaviour of adult bees.”

Dr Mortensen’s research will inform the development of new standardised tests for use by regulatory agencies around the world to determine what pesticides are safe for use in the environment and how or when they can be used in crop production.

New Zealand has more than 7,800 registered beekeepers with close to 800,000 hives producing nearly 15,000 tonnes of honey each year (Fresh Facts 2017). Commercial hives are used in the pollination of many of New Zealand’s high value fruit crops, including kiwifruit, apples and berryfruit.

Public views sought on persistent organic pollutants

The Environmental Protection Authority is seeking public views on a proposal that New Zealand ratify international agreements on banning and controlling some of the world’s most toxic and persistent substances.

The Acting General Manager of the Hazardous Substances Group, Gayle Holmes, says parties to both the Stockholm and Rotterdam Conventions meet every two years and decide on the addition of any new chemicals to the list of those that should be banned or restricted.

“This is important work where key global players agree to eliminate or restrict the use and production of the worst of the worst chemicals in the world,” says Gayle.

“But in order for this to take place in New Zealand, amendments are required to the relevant New Zealand laws.”

The Stockholm Convention bans and restricts persistent organic pollutants while the Rotterdam Convention focuses on cooperation between member countries about these chemicals.

“Persistent organic pollutants are dangerous substances that remain in the environment and can accumulate in the bodies of people and other living things,” says Gayle.

The Stockholm Convention has called for the ban of decabromodiphenyl ether, which is a flame retardant that was commonly used in plastics in electronic equipment, and in textiles in furniture and carpets.

Additionally, short-chain chlorinated paraffins, which were used in rubber, paints, adhesives and sealants, and metal-working cutting fluids, have made the list.

The Rotterdam Convention has added the pesticides carbofuran and trichlorfon to their watch list, both of these chemicals have been reassessed under the HSNO Act, and were subsequently prohibited for use as pesticides in New Zealand in 2011.

It is proposed that Tributyl tin compounds, commonly used on an industrial scale as boat anti-fouling paint prior to 2000, will now be subject to more notification and control between member states.

The public can provide feedback on our website until 16 July 2018.

Online submissions can be made HERE. 

Source: Environmental Protection Authority

The past, present and future of integrated pest management in fruit crops

Pests and the use of pesticide to deal with them have long been a problem for the New Zealand Pip Fruit industry, especially when it sought to gain access into new, high-value export markets.

But work carried out by Dr Jim Walker and his team has contributed to a reduction of more than 90 per cent in insecticide use (kg/ha) by local apple growers since the mid 1990s.

Alternative strategies have included the introduction of new natural enemies through to the development of selective pest management and use of semio-chemicals (pheromones) to support greater use of biological control in apple orchards.

The development and implementation of these innovative pest control measures are now central to today’s pest management systems.

Dr Walker, entomologist and Principal Scientist with Plant and Food Research, will talk about this research as well as the future sustainability and biosecurity threats facing the apple industry in Havelock North at 5.30pm on Wednesday..

Readers can register here to guarantee a seat

WHERE: Havelock North Function Centre, 30 Te Mata Road, Havelock North, Hawke’s Bay.


Organic not the only ingredient in recipe for sustainable food production

A new UBC study published in Science Advances finds organic thinking alone is not necessarily better for humans and the planet.

Organic is often proposed a holy grail solution to current environmental and food scarcity problems, “but we found that the costs and benefits will vary heavily depending on the context,” said Verena Seufert, a researcher at the Institute for Resources, Environment and Sustainability (IRES).

Seufert and her co-author, Navin Ramankutty, Canada Research Chair in Global Environmental Change and Food Security at UBC, analysed organic crop farming across 17 criteria such as yield, impact on climate change, farmer livelihood and consumer health.

It is the first study to systematically review the scientific literature on the environmental and socioeconomic performance of organic farming, not only assessing where previous studies agree and disagree, but also identifying the conditions leading to good or bad performance of organic agriculture.

Two factors that are top of mind for many consumers are synthetic pesticide use and nutritional benefits of organic. Seufert and Ramankutty argue that in countries like Canada where pesticide regulations are stringent and diets are rich in micronutrients, the health benefits of choosing organic may be marginal.

“But in a developing country where pesticide use is not carefully regulated and people are micronutrient deficient, we think that the benefits for consumer and farm worker health may be much higher,” said Ramankutty, professor at IRES and the Liu Institute for Global Issues at UBC.

Another important measure of the sustainability of farming systems is the yield of a crop. To date, most studies have compared the costs and benefits of organic and conventional farms of the same size, which does not account for differences in yield.

Previous research has shown the yield of an organic crop on average is 19 to 25 per cent lower than under conventional management. Seufert and Ramankutty find that many of the environmental benefits of organic agriculture diminish once lower yields are accounted for.

“While an organic farm may be better for things like biodiversity, farmers will need more land to grow the same amount of food,” said Seufert. “And land conversion for agriculture is the leading contributor to habitat loss and climate change.”

The findings suggest that organic alone cannot create a sustainable food future. The authors nevertheless conclude it still has an important role to play. Buying organic is one way that consumers have control over and knowledge of how their food is produced since it is the only farming system regulated in law.

“We need to stop thinking of organic and conventional agriculture as two ends of the spectrum,” said Seufert.

Instead, consumers should demand better practices for both so the world’s food needs can be met in a sustainable way.

Chemicals that make plants defend themselves could replace pesticides

New research published in Bioorganic & Medicinal Chemistry Letters identifies five chemicals that trigger rice plants to fend off a common pest – the white-backed planthopper, Sogatella furcifera.

This paves the way for  pesticides being replaced by chemical triggers that make plants defend themselves against insects.

The widespread use of pesticides to control insects that destroy crops has raised environmental concerns because of the detrimental effect on ecosystems. One problem is that many pesticides kill indiscriminately.

Plants have natural self-defence mechanisms that kick in when they are infested with pests like the white-backed planthopper, Sogatella furcifera, that is a pest for rice crops. This mechanism can be switched on using chemicals that do not harm the environment and are not toxic to the insects or their natural enemies.

In the new study, researchers from Zhejiang University 
in China developed a new way of identifying these chemicals. Using a specially designed screening system, they determined to what extent different chemicals switched on the plants’ defence mechanism.

The team designed and synthesized 29 phenoxyalkanoic acid derivatives. Of these, they identified five that could be effective at triggering the rice plants to defend themselves.

The researchers used bioassays to show that these chemicals could trigger the plant defense mechanism and repel the white-backed planthopper. This suggests that these chemicals have the potential to be used in insect pest management.

“We demonstrate for the first time that some phenoxyalkanoic acid derivatives have the potential to become such plant protection agents against the rice white-backed planthopper,” said Dr. Yonggen Lou, one of the authors of the study and professor at Zhejiang University 
in China.

“This new approach to pest management could help protect the ecosystem while defending important crops against attack.”

The next step for the research will be to explore how effective the chemicals are at boosting the plants’ defenses and controlling planthoppers in the field.

EPA approves biopesticide Blossom Protect

An Environmental Protection Authority (EPA) Decision-making Committee has approved an application to import the biopesticide Blossom Protect, which contains two strains of Aureobasidium pullulans. This is the first application received by the EPA for a pesticide containing these strains.

Blossom Protect is intended to be used for the protection of pipfruit trees against the disease fire blight (Erwinia amylovora) and kiwifruit vines against Psa (Pseudomonas syringae pv. actinidiae).

The application, by Zelam Limited, was publicly notified as it contained two strains of Aureobasidium pullulans not previously assessed in New Zealand. No submissions were received.

The Decision-making Committee has approved the application with controls, in accordance with the Hazardous Substances and New Organisms (HSNO) Act 1996.

Otago study shows the legacy of pesticides is difficult to avoid

A University of Otago study shows that the tell-tale legacy in rural South Island areas of pesticides banned many years ago remains, regardless of the type of sheep and beef farming now taking place on the land.

The research, led by Department of Chemistry recent PhD graduate, Dr Pourya Shahpoury, and just published in the international journal Environmental Pollution, nevertheless shows that average pesticide levels found in sediments of streams running through the 15 South Island farms assessed as part of the study were still within recommended thresholds.

A media statement from the university says the most frequently detected pesticide (chlorpyrifos) found in the stream beds is one that is approved in New Zealand for current use against pests.

But the study also found the presence of chemicals (or their toxic degradation products) that had been widely used many years ago before they were banned.

Continue reading