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EPPO Datasheet: Aphelenchoides besseyi

Last updated: 2020-07-24

IDENTITY

Preferred name:Aphelenchoides besseyi
Authority: Christie
Taxonomic position: Animalia: Nematoda: Chromadorea: Rhabditida: Aphelenchoididae
Other scientific names: Aphelenchoides oryzae Yokoo, Asteroaphelenchoides besseyi (Christie) Drozdovski
Common names in English: rice leaf nematode, rice white-tip nematode, strawberry crimp disease nematode, white-tip nematode
view more common names online…
Notes on taxonomy and nomenclature

The taxonomy used in this datasheet reflects developments suggested by several recent publications, summarised in Decraemer & Hunt (2013), which place Aphelenchoides in the Order Rhabditida, Suborder Tylenchina. This contrasts with the taxonomy nomenclature occasionally used by some authors (such as the CABI Invasive Species Compendium CABI, 2019; Wheeler & Crow, 2020), which place Aphelenchoides in the Order Aphelenchida, Suborder Aphelenchina (Hunt, 1993). Whilst this makes no difference to classification from the level of Superfamily (Aphelenchoidea) to species level (Aphelenchoides besseyi), those studying the species might need to be aware of differences in the literature.EPPO Categorization: A2 list
EU Categorization: RNQP (Annex IV)
view more categorizations online…
EPPO Code: APLOBE HOSTS 2020-07-24 GEOGRAPHICAL DISTRIBUTION 2020-07-24 BIOLOGY 2020-07-24 DETECTION AND IDENTIFICATION 2020-07-24 PATHWAYS FOR MOVEMENT 2020-07-24 PEST SIGNIFICANCE 2020-07-24 PHYTOSANITARY MEASURES 2020-07-24 REFERENCES 2020-07-24 ACKNOWLEDGEMENTS 2020-07-24 How to cite this datasheet? Datasheet history 2020-07-24

New Atlas

SCIENCE

New Atlas

Genetically modified wheat boasts 11-percent higher yield

By Ben Coxworth

November 25, 2020https://newatlas.gystaudio.com/embedded/newatlas.com/science/genetically-modified-wheat-11-percent-higher-yield/

The best-performing line of the transgenic wheat produced grains that were an average of 12.3 percent heavier than those of regular wheat (pictured here), resulting in an 11.3-percent higher total yield

The best-performing line of the transgenic wheat produced grains that were an average of 12.3 percent heavier than those of regular wheat (pictured here), resulting in an 11.3-percent higher total yieldthreeart/DepositphotosVIEW 1 IMAGES

Wheat is one of the planet’s most widely grown crops, so any increases in its grain yield could go a long way towards reducing world hunger. That’s where a new variety of the plant comes in, as its yield is reportedly up to 11 percent higher than that of regular wheat.

One commonly used approach to boosting grain yield involves genetically modifying wheat plants, so that each one produces a greater number of grains. While this has worked in the past, the technology has somewhat plateaued in recent years – according to Britain’s University of York, the annual rate of yield increase currently sits at less than 1 percent.



Another approach involves causing the grains to grow larger and heavier. Unfortunately, though, plants that have been altered to produce bigger grains usually also grow fewer of them. As a result, the actual amount of food that can be obtained from each plant remains the same.

Led by Prof. Simon McQueen-Mason, York scientists set out to address the latter problem.

In their new genetically modified wheat, levels of a growth-rate-determining protein known as expansin are increased in the young plants. When those plants mature, they produce grains that are up to 12.3 percent heavier than those of their conventional counterparts, but which are also no fewer in number. The increased growth rate is limited to the grains, with the rest of each plant remaining normal.

Colleagues at the Universidad Austral de Chile successfully grew the new wheat in field trials conducted under regular agricultural conditions. Once the plants had been harvested, the final grain yield of the best-performing transgenic line was 11.3 percent higher than that of a control crop of traditional wheat.

The research is described in a paper that was recently published in the journal New Phytologist.

Source: University of York

Northern Farmer

22nd November

Dealing with slugs includes improving our biosecurity

By Wendy Short (4)    0 comment

Slugs are an increasing concern for arable farmers, especially in light of the impending ban on metaldehyde pellets. Wendy Short talks to Dr Jenna Ross, who has just completed a report for her Nuffield scholarship on ways of dealing with slugs and how the UK should be improving its biosecurity protocols.

SLUGS have always been one of the arable farmer’s main enemies and the impending spring 2022 ban on metaldehyde pellets is causing concern.

Scientist, Dr Jenna Ross, has studied the pests closely and produced a detailed report for her Nuffield scholarship. She suggests that a UK-wide survey is needed and that border biosecurity protocols should be ramped up, because more than 50 per cent of species are believed to be exotic.https://1871f234ec02f86900f171429d727f42.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

The slug population is constantly evolving and the pest is a prolific breeder, with up to 500 eggs per slug being laid. One of the most common among the exotic species is thought to be the Spanish slug, said Dr Ross.

Dr Ross says: “Little is known about the impact of the Spanish slug and the extent of its distribution, not to mention other species invasions.

“It is imperative that we try and stop slugs from being brought into the country. In the USA, scientists have given border control staff training in slug species identification. Import checks are conducted, including from one state to another.”

Ferric phosphate is a relatively new weapon in the battle against slugs, she pointed out.

She says: “Some manufacturers claim that a wet-processed, durum wheat-based product is superior to a dry version. However, it is widely accepted by all that pellet applicators must be specifically calibrated for individual products.

“There is little evidence of studies being carried out on the potential for ferric phosphate product resistance and if farmers switch from metaldehyde, we have no knowledge of any potential environmental impact.”

Currently, slug monitoring relies on farmers manually trapping and counting slugs, in order to review thresholds. In the future, growers will need to look more closely at integrated pest management strategies, including monitoring, advised Dr Ross. She has been involved in the development of SlugBot, an autonomous slug monitoring and treatment system. Supported by Innovate UK, it brings expertise from robotics, machine learning, phenotyping, malacology and biocontrol.https://1871f234ec02f86900f171429d727f42.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

During her Nuffield studies, Dr Ross looked at conclusions drawn by Dr Hayley Jones of the Royal Horticultural Society.

Dr Ross says: “Her work covered serrated copper tape, grit, pine bark mulch and eggshells, as well as wool pellets, but none of these methods appeared to offer superior control. “Nevertheless, Dr Jones was keen to further investigate copper tape, as it was unknown whether the varnish coating on the commercial product was hindering its efficacy. In California, copper barriers are widely used in plant nurseries.”

Dr Ross pulled together a number of other research findings from around the globe as part of her work.

She says: “Ploughing will control slugs through mechanical damage and by bringing slugs and eggs to the surface for exposure to UV radiation, desiccation and predators. The move towards min-till and no-till may increase numbers, so many advise cultivating the top 25-50mm of the soil. Whatever the cultivation method, clods and cavities should be minimised and any straw should be mixed in.

“A firm seedbed is preferable, and ideally crops should be sown as early as possible to ensure they pass the critical stages safely. When drilling winter cereals into a cloddy seedbed, slug damage could be reduced by drilling at a depth range of 4-5cm.https://1871f234ec02f86900f171429d727f42.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“Another investigation found that linseed may be less vulnerable and it also dries out the soil. In New Zealand, it was thought that grazing played a key role in crushing slugs. Meanwhile, trials by Natural England indicated that cover crops did not lead to higher slug numbers.”

Another area of worldwide research has focused on the concept that slugs and their by-products have useful properties, she added.

“Unlike snails, slugs have no exterior shell protection so they have evolved to possess exceptional healing abilities. Their mucus has been found to contain anti-viral agents, for example, while the material is already being utilised as an ingredient in beauty products such as face masks. There is thriving market for snails for the food industry and slugs could possibly be viewed as a viable alternative.

“The study of slugs in general appears to be in difficulty; no clear plan is in place and research funding is limited,” concluded Dr Ross. “We need to promote the subject to the next generation and encourage opportunities for knowledge sharing.

“It is possible that we are missing an opportunity. We should perhaps be investigating ways of farming slugs and targeting the animals and their by-products towards the food, pharmaceutical and cosmetic industries.”https://1871f234ec02f86900f171429d727f42.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

Dr Ross is an honorary research fellow at the University of Aberdeen and international business development manager for Crop Health and Protection.

Dr Ross makes the following recommendations for biosecurity protocol in the UK.

  • Identify slug specialists around the country;
  • Develop a central inspection system and a legal framework, to allow commodities to be held for analysis, action and control;
  • Set up a digital imaging system for relevant imported commodities;
  • Encourage collaboration between government departments and government-to-government.

All About Feed

Mycotoxins

Background 23 Nov 2020

Probiotics for tougher plants

Canadian researchers combine modern tech with ancient organisms to find solutions to mycotoxin-producing fungus.

Ancestral varieties of modern corn and wheat might be the key to non-chemical mycotoxin prevention. More specifically, some of the strains of bacteria which naturally developed alongside those varieties have been shown by Canadian researchers to be highly effective against Fusarium head blight and Gibberella ear rot. Now these researchers are working with the private sector to develop a practical product for grain growers to use.Photo: Mark PasveerPhoto: Mark Pasveer

Finding the right bacterial companion

Manish Raizada is a professor of plant agriculture at the University of Guelph in the province of Ontario. After elevated levels of mycotoxins had raised serious grain marketing issues in recent years (most notably in 2018), Manish was asked to head a team of researchers charged with developing a more effective biological control measure for grain growers. To do so, they turned to what appeared to be much older and more-resistant varieties of each crop. More specifically, that looked at microbial endophytes (bacteria that live between plant cells) isolated from ancient and landrace corn varieties, as well as finger millet (a very old African crop with natural Fusarium resistance). These microbes are very numerous in the natural world and, as Raizada explains, often have mutually beneficial relationship with the host plant (some strains can, for example, enhance root growth and nitrogen absorption).

Gilts are more sensitive to Beauvericin than sows
Beauvericin is a Fusarium mycotoxin known for its antiviral, antibacterial, anti-inflammatory, and anticancer properties, but it also causes oxidative stress and cell death.

He also states that the ability of fungi to rapidly develop resistance to commonly-used fungicides continues to be a growing concern – but, because probiotic microbes can evolve with the pathogen, the right endophyte could provide farmers with a longer-term mycotoxin management tool.

Startlingly positive results

Overall, Raizada and his colleagues screened approximately 200 microbial strains. 5 anti-Fusarium bacteria strains were isolated and used in greenhouse trials, with each one dramatically suppressing mycotoxin DON accumulation (up to 97% in corn and 85% in wheat). Applying the endophytes via seed coating was less effective than direct foliar applications, but the results overall were startlingly positive. “We had huge success here. It’s the best Fusarium control in a study ever reported in corn,” says Raizada. Indeed, he says some endophyte strains almost eliminated the ear rot pathogen. The results for wheat were less impressive, but 3 of the tested strains still managed to reduce pathogen levels by 60%.

Mobility

Why some of the endophytes were so successful in suppressing Fusarium and ear rot has to do with mobility. Raizada says they observed how one strain (known as M6, derived from finger millet) responded to infection by leaving the root system to coat the exterior of the plant. It also promoted root hair growth. Both factors combined, says Raizada, create an ideal habitat within which the endophyte can capture and kill the pathogen. “It’s actually mobile; Some of these microbes have little tails which they use to seek and destroy pathogens,” he says.Untreated corn infested with Fusarium (head blight) (left) and corn treated with the promising M6 endocyte (right). Photo: University of GuelphUntreated corn infested with Fusarium (head blight) (left) and corn treated with the promising M6 endocyte (right). Photo: University of Guelph

The overall goal of this research was to develop an in-season spray or a seed coating containing the microbes that could prevent and suppress the establishment and spread of mycotoxins. If commercialised, such a tool would also have greater longevity than standard fungicides. Grain growers could employ it in conjunction with chemical solutions for a multi-pronged attack strategy. Currently the university is working with the private sector to make this happen.

Barriers to commercialisation

There are some notable barriers to commercialisation, though. Delivering endophytes via seed coating – theoretically the ideal system – is inherently less effective than in-season applications made directly to corn ear silks and wheat heads. Indeed, bacteria delivered through seed coating did not appear to effectively colonise the plant in the field. The researchers are not entirely sure why this is the case, although they suspect it’s due to a combination of pressures – specifically fluctuating environmental conditions and the sheer volume of more competitive, already-naturalised microbes present in the soil. “If we spray directly onto the plant, we do see more success.”The M6 strain of endophyte, labelled with green florescent protein. It co-exists with maize and wheat plants. Photo: University of GuelphThe M6 strain of endophyte, labelled with green florescent protein. It co-exists with maize and wheat plants. Photo: University of Guelph

Raizada adds that inadequate storage during transportation and on the farm are an even greater barrier. As with some other biologicals, poor storage commonly means growers are applying dead or low-activity products. Raizada says the ideal solution to both issues would be improved seed formulations – that is, something that better protects the endophytes in storage and prevents them from being outcompeted in the soil. “If there’s some formulation that allows the microbes to be coated on the seed and can also tolerate poor storage conditions, that would be the best solution.” The cost of the endophytes should not be prohibitive for farmers. “Theoretically, the microbe itself is very inexpensive. We haven’t worked out the exact cost, but it’s certainly competitive with fungicides,” Raizada says.

Introducing SFR research on mycotoxins
Animal feed contamination with mycotoxins remains an important issue. Every new survey performed worldwide finds more mycotoxins in the analyses, including those commonly neglected, also called emerging mycotoxins.

Variability problems

Apart from the recent greenhouse tests at the University of Guelph, 3 additional field trials were conducted over 2 years. The results were not as positive – year-on-year variability in the corn crop itself was a problem, as was inherently low Fusarium pressure in the wheat plots – but professor Raizada reiterates that these and other variability problems are typical of in-field microbial studies. The most important revelation, he says, is how effective these microbes can be. Indeed, replicated field trials with corn showed 3 promising bacterial endophytes, with one strain in particular reducing (DON) mycotoxin accumulation by up to 65%.

Author: Matt McIntosh, correspondent for North America

Our Correspondents

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BBC

The tiny parasitic wasp that saved an industry Share using EmailShare on TwitterShare on FacebookShare on Linkedin(Image credit: Getty Images)

A parasitic wasp climbs onto a caterpillar (Credit: Getty Images)

By William Park25th November 2020

Before chemical pesticides were invented, farmers relied upon local predators to control crop-devastating pests for millennia, but now the practice is getting a modern revival.S

Scattered among the highly biodiverse forests of South East Asia, millions of farmers eke out their livelihoods by growing cassava. This cash crop – grown by both small-scale farmers who own just one or two hectares and industrial farms spread across thousands of hectares – is sold mainly to manufacturers who use its starch in plastics and glues.

When cassava was first imported to South East Asia from South America (as it was to Africa a few decades earlier), it was able to grow without the help of pesticides. Then in 2008, the cassava mealybug followed the root vegetable to the region and began devastating the crops. To compensate for the losses, farmers began encroaching into the forests around their plots to try to get a little bit more produce from their land.

“Some of those areas are under significant pressure from deforestation,” says Kris Wyckhuys, an expert in biological controls at China Academy of Agricultural Sciences’ Institute of Plant Protection in Beijing. “Cambodia has some of the highest rates of tropical deforestation.”

The arrival of the cassava mealybug not only had major impacts on the livelihoods of those who grow cassava, it affected the national economies of the countries in the region and might have had rippling effects elsewhere.

Substitute products in the starch market like corn and potato rose in price. There was a threefold increase in the price of cassava starch in Thailand – the world’s number one exporter of cassava starch.

“When an insect reduces crop yields by 60-80%, you have a major shock,” says Wyckhuys. The solution was to find the mealybug’s natural enemy, a 1mm-long parasitic wasp (Anagyrus lopezi), in its native South America. This wasp is extremely selective about using the cassava mealybug as a host for its larvae. By late 2009 it had been introduced to the cassava cropland in Thailand and had started working its way through the mealybugs.

There’s no detailed information on how quickly the wasp drove mealybug populations down in the country. But by mid-2010, “parasitic wasps were being reared by the millions and mass-released throughout Thailand, including by airplane, and we can assume that their impacts on mealybug populations could be felt fairly quickly,” says Wyckhuys.The cassava crop is incredibly important to the economies of South East Asia (Credit: Getty Images)

The cassava crop is incredibly important to the economies of South East Asia (Credit: Getty Images)

When the same wasp was used to control mealybugs in West Africa in the early 1980s, it promptly suppressed the pest population levels from more than 100 individuals on each cassava tip to fewer than 10-20. Less than three years later, the wasp had effectively dispersed over 200,000 sq km (77,220 sq miles) in southwestern Nigeria and could be found on the vast majority of cassava fields in the area.

This type of intervention is called classical biological control. You find a natural predator and introduce it to a crop to curb the spread of a pest. Wyckhuys calculated the economic benefit to the farmers across 26 countries in Asia-Pacific at $14.6bn to $19.5bn (£11.4bn to £15.2bn) per year. “The action of a 1mm wasp helped to resolve a major financial shock in the global starch market,” he says.

Biological control was the default for thousands of years, so it’s funny to think of it as new – Rose Buitenhuis

Our understanding of the benefits of the right predator in cropland stretches back millennia, though biocontrol has largely fallen out of fashion in modern farming practices. “Biological control was the default for thousands of years, so it’s funny to think of it as new,” says Rose Buitenhuis, a scientist at the independent horticulture science organisation, Vineland Research and Innovation Centre, in Ontario, Canada.

If biocontrol can be so successful, why is it now an uncommon method of fighting pests? What happens when it goes wrong? And why are researchers pushing to change that?

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To the people of pre-Columbian Mesoamerica, cane toads existed somewhere between life and death, and were revered as a mediator to the underworld. The amphibians produce a powerful toxin capable of inducing hallucinogenic experiences that priests used in rituals to communicate with their deceased ancestors. The Maya people are famous for worshipping snakes and birds of prey, which feature in exquisite examples of Mesoamerican art. But the Maya, and other indigenous peoples, also portrayed the humble toad in artworks, often grinning cheerily as if enjoying the effects of their own psychedelic toxin.

The Maya carved toads and frogs into pots and vessels. As semi-aquatic animals and harbingers of rain – essential to the health of crops – they are synonymous with water and therefore life. Their metamorphosis from eggs to tadpoles to toadlets indicated the beginning of the rainy season, emerging from the water as if they were emerging from the underworld.This ancient Maya vessel in the shape of a cane toad celebrates the amphibians water-bringing characteristics (Credit: Justin Kerr/K5935/Dumbarton Oaks)

This ancient Maya vessel in the shape of a cane toad celebrates the amphibians water-bringing characteristics (Credit: Justin Kerr/K5935/Dumbarton Oaks)

The toad was also seen a powerful ally in keeping crop-destroying pests at bay. They were welcomed in cornfields and storage bins, where they are a naturally-occurring predator of beetles and small rodents that might decimate a crop. But the same neurotoxin, bufotenin, that the priests used as a hallucinogen was also the cane toad’s primary defence against its own predators and it is poisonous enough to kill a human if they are careless.

The indigenous peoples of Mesoamerica understood the duality of the natural world. The cane toad represented both life and death. Painted on one Maya vessel is a cane toad presenting a platter with a human eye, bone and hand to a jaguar and serpent who dance joyously in the underworld. The Maya respected the toad’s potency and welcomed its presence. They also knew that messing with nature could have grave consequences.

In 2007, the cane toad was estimated to cover about 1.2 million sq km of Australian wilderness

The cane toad is hated in Australia. Imported from the Americas as a biocontrol in 1935, it thrived in its new environment on the sugarcane crops of the northeastern states. The abundance of its favourite prey, the cane beetle, along with other native Australian insects, and the absence of suitable predators meant that cane toad numbers exploded. In 2007, the cane toad was estimated to cover about 1.2 million sq km of Australian wilderness and number 1.5 billion individuals. Its range is likely to increase with climate change.

The result was devastating. Predator populations crashed – species that would normally prey on native toads, like quolls, a type of marsupial, and goannas, types of large monitor lizard, died from the cane toad’s toxin. The Australian government and local campaigners destroy millions of toads each year. The cane toad’s reputation is so poor in the country that the amphibian’s plight has been the subject of ironic children’s books.

“The toads were released contrary to scientific advice at the time,” says Wyckhuys. Releasing the toads “was something that should never have been done and is entirely impossible in modern biocontrol – you don’t release generalist, polyphagous, vertebrate predators. It is not a tiny red flag, it is a massive red banner”.

The cane toad is not alone. There are at least ten instances of biocontrols becoming invasive species throughout history. In World War Two, Japanese and Allied forces released mosquitofish to prey on mosquito larvae in an effort to reduce the spread of malaria among troops on Pacific islands. These small, innocuous-looking fish are now an invasive species in that area, where they dispersed quickly and outcompeted local species. The same applies to the Asian ladybug in Europe, introduced to control aphids.A cane toad secretes its dangerous bufotoxin from glands behind its head (Credit: Getty Images)

A cane toad secretes its dangerous bufotoxin from glands behind its head (Credit: Getty Images)

As a result of high-profile failures like this, the use of chemical controls – pesticides – instead of biocontrols gathered momentum in the first half of the 20th Century. But, with a handful of exceptions, the controversial image of biocontrols is largely unfounded. Successful introductions of biocontrols outnumber the failures at least twenty-five-fold.

Now, some researchers are trying to change biological controls’ perception. They say the days of pesticides are numbered.

The end of pesticides?

“Chemical controls solved a lot of problems in the 1930s, 1940s and 1950s,” says Buitenhuis. “Farmers didn’t have to work as hard. They could just go to their cabinet, find a spray and the pests would die.”

The issue with chemical controls is that pest species breed quickly, which means that an individual who is resistant to a pesticide can very quickly produce resistant offspring. Pesticide producers then have to constantly refine their products just to keep up with the pest – what Buitenhuis refers to as a pesticide resistance treadmill and is elsewhere called the “red queen effect”, after the Red Queen from Through the Looking Glass.

The number of pesticides available to farmers is running out. In 2018, three pesticides from a class of chemicals called neonicotinoids were banned outright by the EU having already had their use severely restricted in 2013. These chemicals, which are similar in structure to nicotine, coat seeds to protect them from pests in the soil. However, as the crop grows, the pesticide is absorbed and spreads throughout the plant’s tissue where it collects in the pollen and nectar. Both wild and domesticated pollinators feeding on those plants are then exposed to the pesticide.

Critics of the ban point out that limiting seed-treatment pesticides could end with them being replaced by spray-on pesticides, which can be equally damaging to pollinators and are more expensive to farmers.If pesticide use is to decrease, might more farmers turn to biological controls like this parasitic wasp? (Credit: Getty Images)

If pesticide use is to decrease, might more farmers turn to biological controls like this parasitic wasp? (Credit: Getty Images)

“There is a whole range of negative social and ecological factors tied to pesticides,” says Wyckhuys. “From the greenhouse gases used to produce and distribute chemicals – substantial greenhouse gas emissions – to human health implications for farmers and consumers. The impacts are not just restricted to the fields or to the farm but they are amplified across the landscape [by leaching], propagated through surface water or dust, taken up in the air by aerosols.”

Pesticide residues have been found in the cloud forest of Costa Rica and the Great Barrier Reef in Australia. And when pesticides appear in the wrong place, they become biocides – something that kills life. When they leach into the environment around farm land, they simplify biological communities and degrade ecosystems. What appeals to scientists like Wyckhuys about biocontrols is that their application can be much more targeted.

Caroline Reid, senior technical lead from Bioline Agrosciences, a biological control producer in the UK , agrees. Add to the specificity of biocontrols a reduction in the number of chemicals that are safe to use and a push across the EU towards sustainable farming and you can see why biocontrols are becoming increasingly mainstream. But how do they work?

Biological controls

There are broadly three types of biocontrols: predators, parasitoids and pathogens. Cane toads are an example of a predatory biocontrol. They prey on cane beetles, but unfortunately they are not overly choosy (they are “polyphagous”) and in Australia they began preying on other native insects which were not pests.

Parasitoids are a little more gruesome. Often these types of biocontrol are species of parasitic wasp or fly who lay their eggs inside caterpillars or beetles only for the resulting larvae to break out of their host’s abdomens, killing it in the process.

Successful biocontrols should have a high reproduction rate, so they can multiply quickly when they detect a pest

Pathogens can take the form of fungi, viruses or bacteria that kill or make their host infertile. These tend to target quite specific species of pest, making them a popular choice for modern biocontrol research because there is a lower risk of them attacking other harmless species with unintended consequences. Though, as we have all found out recently, viruses do from time to time jump species quite successfully.

Successful biocontrols should have a high reproduction rate, so they can multiply quickly when they detect a pest, be very specific in which species they target and able to seek their prey efficiently. In practice no biocontrol is perfect. Instead, researchers finely balance the risks associated with each of these.

There are also three ways that biological controls can be applied to a crop: classical, conservation and an augmented approach.

The cane toad is an example (if rather a bad one) of classical biocontrol – in which a new species is introduced into the environment.A parasitic wasp (Cotesia congregata) climbs onto the back of a tobacco hornworm caterpillar where it will lay eggs in the host, eventually nullifying it (Credit: Getty Images)

A parasitic wasp (Cotesia congregata) climbs onto the back of a tobacco hornworm caterpillar where it will lay eggs in the host, eventually nullifying it (Credit: Getty Images)

“The classical form of biocontrol is specifically geared to invasive species management,” says Wyckhuys.

Biocontrol offers the option to go back to the region of origin of that pest, study the co-evolved natural enemies and choose the organisms that are highly effective at controlling them. “We don’t want to introduce an organism that is going to attack other organisms. We select an effective biocontrol that is highly specific,” says Wyckhuys.

Alternatively, in conservation approaches, predators that already exist within the environment are promoted by protecting their habitat. This can be done by increasing the amount of hedgerow or meadow around a field.

In a study on cabbage farming, where there was a high proportion of meadows surrounding a cabbage plot, numbers of cabbage-eating caterpillars were lower. This was likely due to the greater presence of parasitic wasps in those environments, the researchers say. However, in other instances, meadows promoted the presence of pest species like aphids and flea beetles. It’s not as simple as introducing more meadow to cut down on pests – the dynamics between farmland and wild land need to be carefully managed.

Conservation biocontrols like this are also limited to controlling pests which are native to their local environment. Like classical biocontrols, many pest species were first introduced to their environment by humans – they weren’t necessarily already there. As countries import seeds and crops from across the world, it is easy to assume that the odd accidental pest tagged along. Now, finding themselves in a new environment without a natural predator, they flourish.

Finally, in augmented approaches a pathogen or parasite is introduced to a crop at a key time – perhaps when pests begin to breed or lay eggs, or even before the pest arrives – so that the control species quickly nullifies their threat before their own numbers dwindle and they too die out in that area. The advantage of this approach is that you can be very specific with how you tackle the pest species.

“Augmented control is very popular in the European greenhouse sector,” says Wyckhuys. “In some areas pesticide use is zero.”

Greenhouses have been the domain of biocontrols for decades, even while chemical pesticides had their boom years. They have a big advantage of being a more or less closed system, so a predatory biocontrol is not going to fly away. Then there is the fact that greenhouse crops tend to be higher value – tomatoes, peppers and cucumbers sell for more per unit area than cereals, for instance.

In more recent years the popularity for biocontrols has spread to other sectors such as floraculture, viticulture and outdoor fruits like strawberries.

“In Canada we did a survey in 2017/ 2018, 92% of flower growers use biocontrol as the main pest control strategy,” says Buitenhuis. “It is an amazing success story and came about because of pesticide resistance, especially in Canada.”

Buitenhuis and Reid know that when large surface area crop farmers switch to biocontrols for their cereals and grains, the momentum will have swung back in their favour. “If an arable farmer decided that a biocontrol is usable on wheat or barley that is us cracked it,” says Reid. Likewise, Buitenhuis says that persuading countries like Colombia, Ecuador and Kenya to adopt such approaches would be “big wins”.

“It is coming,” says Buitenhuis. “Using chemicals only is not a long-term sustainable strategy.”

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Coffee leaf rust

Last Updated on November 20, 2020 by monica chan

Coffee Leaf Rust (CLR) is confirmed to have spread across Hawaii islands. According to The Hawaii Department of Agriculture (HDOA), the disease has been tested and found on coffee plants at a farm in Holualoa.

This is shortly after we reported, CLR was discovered on October 21, where a coffee farm in the Haiku area of Maui, which is across the Maui Channel from Holualoa.

CLR is a parasitic fungus that infects coffee plants. This is found in all major coffee-growing areas of the world, but had not previously been found in Hawaii prior to its earlier discovery in Maui.

Samples were collected by a grower on a farm in the Holualoa area on Oct. 31., where it is now confirmed.

Phyllis Shimabukuro-Geiser, Chairperson of the Hawaii Board of Agriculture says,

Coffee is one of Hawai‘i’s signature crops, of which production was estimated to be $54.3 million in 2019.

As surveys continue across the state, the Hawaii Department of Agriculture is preparing to establish interim rules that will hopefully prevent the spread of the fungus to uninfected islands.

The Hawaii Department of Agriculture (HDOA) Advisory Committee on Plant and Animals had a meeting on November 13 to discuss how they could prevent the disease spreading.

They included an interim rule to restrict the movement of coffee plants and coffee plant material from islands found to have CLR to islands on which the fungus has not been detected.

CLR is a highly infectious plant disease that can be devastating and reduce coffee yields by up to 80%.

HDOA’s Plant Pest Control Branch has prepared a field guide to aid in the detection and reporting of possible CLR infections.

The field guide can be found at: http://hdoa.hawaii.gov/pi/ppc/new-pest-advisories/.TweetShareShareSharePin

A new outbreak of Xylella is declared in the Valencian Community

By Sarah Keane -16 November 2020 @ 18:310

A new outbreak of Xylella is declared in the Valencian Community
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A new outbreak of Xylella is declared in the Valencian Community as thousands of plants have to be destroyed

The DOGV revealed on Monday, November 16 that the Department of Agriculture has declared the thirteenth outbreak of Xylella fastidosa in the Valencian Community, affecting nine plant species in the province of Alicante.–

Experts in the region must now systematically destroy all affected plants, completely disposing of their root systems to avoid re-growth.

The diseased plants are found in public and private gardens, sidewalks, medians and other landscaped areas of the roads, highways and motorways.

How cover crops influence soil microbial populations

TAGS: COVER CROPS Tyler HarrisCereal rye FOOD AND HABITAT: Cover crops such as cereal rye provide a food source and a habitat for soil microbes. Their root exudates provide simple sugars and amino acids. Decomposing cover crop residue also provides carbon and nitrogen for microbes.A researcher looks at the effect of cereal rye cover crops on soil microbial communities.

Tyler Harris | Nov 30, 2020

These days, you don’t have to look hard to read or hear about the benefits of cover crops. Many of these benefits have been measured anecdotally. However, more recently, research by growers and universities has aimed to put some numbers behind these touted benefits.

Over the past two years, Katja Koehler-Cole, research assistant professor in the Department of Agronomy and Horticulture at the University of Nebraska-Lincoln, has researched the effect of cereal rye cover crops on soil microbial communities and soil nutrients after corn and before soybeans.

“The period where we actually lose the most soil nitrate in a corn-soybean rotation is the period before planting soybeans,” Koehler-Cole says. “Because the soil warms up, microbes decompose organic matter, and there are no plants there to take up the nitrogen that’s released. So, there is potentially quite a bit of nitrogen lost.”

Of course, there’s also the risk of loss of soil structure and organic matter because of erosion when there’s nothing growing in the field, and cover crops are one of the most obvious ways to mitigate this.

However, cover crops also are a food source and a habitat for soil microbes.

“Their root exudates are simple sugars, amino acids, and they’re preferred food for microbes,” Koehler-Cole says. “The decomposing cover crop residue also provides carbon and nitrogen to microbes.

“Roots are the favored habitat for microbes. Most microbes live in the root zone — either near or on roots, so having living roots in the ground increases habitat for microbes. Cover crops can help influence soil surface microclimates, for example, by lowering the temperature, preventing temperature extremes, preventing wind erosion or slowing evaporation.”

Search for microbial life

Koehler-Cole explains that soil microbes are responsible for nutrient retention, exchange and cycling. The biggest group of decomposers in ag fields is bacteria, which preferentially decompose simple organic compounds that are easy to break down, such as freshly terminated cover crops. Fungi decompose organic compounds that are tougher, like cornstalks or roots.

Koehler-Cole notes that while fungi are less numerous than bacteria, they bring big benefits to the soil.

“[Fungi] have threadlike growth, called hyphae, and they also release a gluelike substance called glomalin,” she says. “Those two together help combine little soil particles and make those nice aggregates. Fungi improve aggregate size, they improve aggregate stability, and that makes the soil much more resilient to erosion.”

The two fungi groups of interest are saprophytic fungi, which decompose cellulose and lignin, and arbuscular mycorrhizal fungi, which colonize roots and increase crop nutrient uptake.

“They can increase nutrient uptake because they can reach nutrient sources that are otherwise not accessible to plant roots,” Koehler-Cole says. “When you have a cover crop growing over the winter, it can be a host to AMF. It can live on the cover crop roots, and when the cover crop is terminated, and your soybean or corn is planted, AMF can actually spread from the cover crop roots to the crop roots, colonize the crop roots, and have benefits for the crops there as well.”

Putting rye to the test

Koehler-Cole compared cereal rye and a control treatment at two sites in Arlington and Shelby, Neb. Rye was planted in mid-November 2019, and terminated at soybean planting in early- to mid-May. Soil was tested for nitrogen, phosphorus, potassium and organic carbon. Koehler-Cole also conducted a phospholipid fatty acid analysis to determine which microbial groups are in the soil.

This year, Koehler-Cole explains, the total biomass produced was relatively low — with 1,082 pounds per acre at the Arlington site, and 1,310 pounds per acre at the Shelby site.

“These cover crops took up between 25 and 40 pounds of nitrogen per acre, and had a carbon-to-nitrogen ratio between 19 and 14,” she says. “Anytime the ratio is below 25-to-1, we expect it to decompose pretty quickly. With the ratios we have here, we think that cover crop will decompose relatively fast, which means it also releases the nitrogen it took up back to the crop.”

Overall, the cereal rye treatment saw a significant reduction in soil nitrate at both sites. However, there was no influence on phosphorus, potassium or organic carbon.

“With organic carbon, we expected that a cereal rye cover crop would not influence it within the short amount of time that we’ve grown it,” Koehler-Cole says. “You really need four, five years or more to really see differences in organic carbon.”

They also tested for microbial biomass and diversity with the phospholipid fatty acid analysis. While there were no differences between treatments this year, Koehler-Cole says in 2019, the cereal rye treatment did result in an increase in microbial population.

“I looked at my test results again, and actually realized that the microbial biomass at our sites, even in the controlled treatment, was already pretty high, or at least average,” she says. “Organic carbon in these sites was already relatively high already. These sites had relatively good soil health, and that’s probably one reason why we didn’t see more treatment differences.”

In 2019, Koehler-Cole tested rye’s effect on soil microbial communities at three sites in May, just before cover crops were terminated, and again in July. In May, soil microbial abundance was greater under cover crops, likely because of the food source provided by cover crop root exudates.

Soil bacterial biomass was significantly increased; however, fungi biomass did not increase. Bacteria reproduce quickly, so when living conditions improve — like with a cover crop — their numbers go up, while fungi are slower to respond.

Room for growth

How can growers increase soil microbial populations? Koehler-Cole notes that her research has, so far, focused on cereal rye, and using diverse cover crop mixes may be one way to increase microbial diversity. In addition, increasing cover crop biomass by planting earlier or terminating later provides microbial populations a food source and a habitat for a longer period of time.

“We think we could use the right cover crop to really reduce soil nitrate levels, which could help reduce soil nitrate contamination, and may reduce leaching,” she says. “At least this year, we did not see any improvements in soil microbial abundance. We have seen it in the past, but this year, we did not have very high cover crop biomass. Increasing cover crop biomass, and increasing the amount of plant species we’re growing, may lead to greater benefits for soil microbes.”

RELATEDNebraska grower harvests 148-bushel soybeansNovember 10, 2020How much nitrogen does a cover crop take up?September 1, 20205 principles of building soilMarch 27, 202

Phys.Org

New research maps potential global spread of devastating papaya mealybug pest

by CABI

New research maps potential global spread of devastating papaya mealybug pest
Credit: CABI

CABI scientists have mapped the potential global spread of the devastating papaya mealybug (Paracoccus marginatus), highlighting new areas in Africa, Asia and the Americas into which this pest could potentially invade.https://acc5e9c37d7b810ac61700bc528d240c.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

The papaya mealybug, which is native to Mexico and Central America, can have severe impacts upon livelihoods and food security. In Ghana, for example, infestations led to a 65% yield loss which reduced export earnings and resulted in the loss of 1,700 jobs.

Using location data received through collaborations with Kerala Agricultural University, India; the National Rice Research Institute, India; the Bangladesh Agricultural University; University of Queensland, Australia; the International Institute of Tropical Agriculture (IITA); Fujan Agriculture and Forestry University in China and CSIRO, researchers were able to model the potential distribution of this pest, taking into account environmental conditions, and the distribution of suitable host crops and irrigation patterns.

The researchers, led by CABI’s Dr. Elizabeth Finch, believe the polyphagous insect pest, which affects over 200 plants including economically important crops such as papaya, cassava and avocado, could spread to areas such as the south of the Democratic Republic of Congo, northern Cameroon, Zambia, Madagascar and western Ethiopia which are environmentally suitable and have suitable crop hosts.

In the Americas, the research, published in the journal Pest Management Science, suggests papaya mealybug could extend into El Salvador, Honduras, Nicaragua, and Panama—although the scientists believe it could already be in these locations but its presence is yet to be confirmed.

Whilst papaya mealybug is already present in Florida, where it is under successful control as a result of the release of endoparasitoid wasp species—Acerophagus papayae, Anagyrus loecki, Anagyrus californicus—suitable conditions for this pest are also present in the southern tip of Texas.

Conditions are likely to be too cold in the rest of the USA for permanent papaya mealybug populations, however the research showed that seasonal populations could survive in California, along the Pacific coastline and in the central and eastern states of the USA during the warmer summer months.

In Asia, the areas with suitable conditions were more expansive than the areas with known populations of papaya mealybug, suggesting the potential for further expansion of papaya mealybug specifically in India, Southeast Asia and the southern regions of the Guangxi and Guangdong provinces of southern China.

However, in Australasia the risk is low as only a small amount of fragmented land along the north-eastern side of Queensland, from the very northern tip of Queensland to Bundaberg, is climatically suitable. This is due to heat stress from the high temperatures on the continent.

Similarly, in Europe—though due to cold rather than heat stress—widespread distribution of papaya mealybug is not expected, with only a very small area of land surrounding Seville in Spain and around Sicily in Italy having suitable conditions for resident populations.

Dr. Finch said, “This pest has been so successful due to its quick development and prolific reproductive capacity. It has the potential to spread to new areas and rapidly reach high numbers unless suitable phytosanitary or control methods are implemented.

“Information about the papaya mealybug’s potential distribution is important as it can highlight key areas susceptible to invasion, giving an early warning to decision makers, allowing them to put into place phytosanitary measures to prevent or slow the invasion of the pest into their jurisdiction.”

Dr. Finch added, “In areas where the papaya mealybug has become established and reached a high enough population density, the use of parasitoids—such as Acerophagus papayae and Anagyrus loecki—remains an effective potential control method.

“Further ecological niche modeling of these parasitoid species is recommended to anticipate their survival, fitness and ultimate biological control impact in areas into which papaya mealybug could potentially expand and become established.”


Explore further Virginia Tech-led pest-control plan saves up to $309 million for Indian farmers, consumers

Potato News Today

ALL LATEST NEWSEUROPE, UK, IRELANDNEWS NOVEMBER 2020PESTS AND DISEASESPRESSRELEASESRESEARCH

Researchers found biopesticide to be effective in controlling potato cyst nematode

on November 15, 2020

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According to information published by the Extension Toxicology Network, “Abamectin is a mixture of avermectins containing about 80% avermectin B1a and 20% avermectin B1b. These two components, B1a and B1b, have very similar biological and toxicological properties. The avermectins are insecticidal/miticidal compounds derived from the soil bacterium Streptomyces avermitilis. Abamectin is a natural fermentation product of this bacterium. It acts as an insecticide by affecting the nervous system of and paralyzing insects.”

A team of researchers from Italy and Moldova took part in a research project to test the efficacy of Abamectin in the control of potato cyst nematode Globodera pallida. The research results were published in the scientific journal Plants.

The research team says in their paper that the potato cyst nematode Globodera pallida is a major pest of the potato crop. They write that “Abamectin is a biological pesticide showing high nematicide activity, but its efficacy to control G. pallida has not been investigated to date.”

In their study, a combination of different abamectin concentrations ranging from 1.125 to 36 µg/mL x and exposure times from 24 to 384 h were tested on the nematode in a hatching test. Abamectin induced mortality with LD50 value in the range of 13.23 (after 24 h) to 2.90 µg/mL (after 384 h). A glasshouse experiment was also performed in pots filled with soil infected with G. pallida in the presence of sprouted potato tubers cultivar “Spunta”. Abamectin at 4.5, 9.0, 18.0 and 36.0 µg/mL was used in comparison with nematicide fosthiazate.

The researchers found that the doses of 18 and 36 µg/mL significantly reduced number of eggs, juveniles, cyst/g soil and reproduction rate in comparison to both untreated control and fosthiazate treatment.

Soil applications of abamectin provided significant G. pallida control with LD50 and LD99.9 of 14.4 and 131.3 µg/mL, respectively.

The research team concluded: “These results indicate the efficacy of abamectin to control G. pallida on potato crops and its potential use in organic agriculture or in an integrated pest management program.”

Source: Plants. The abstract and full paper can be found here
Photo: Bayer Crop Science

Potato News Today

Crop.Zone: A revolutionary, sustainable new solution for weed control and crop desiccation

on November 12, 2020

More in All latest News:

Crop.Zone develops alternative solutions for weed control and crop desiccation. The German-based company creates chemical-free alternative concepts and products, helping farmers to prepare their fields and get their crops ready for harvest in a sustainable, environmentally sound way. In Europe, this is traditionally done with the aid of chemicals. But the individuals who are the driving force behind Crop.Zone want to change all of that.

“We are developing alternative methods for this, following the green deal regulations,” says Dirk Vandenhirtz, CEO of Crop.Zone. “We use a concept that has been around for a long time: If electricity is applied to plants, it destroys the chlorophyll and the water system of a plant. The problem is the high amount of energy required for this process. We have discovered that plants can be made more sensitive to such treatments with electricity, by spraying a very light saline solution on them beforehand. The environmental impact is extremely low. These are formulations that are already in use in organic farming.”

Dirk Vandenhirtz,
CEO of Crop.Zone

Vandenhirtz goes on to say: “Our so called ‘volt fuel’ increase the plants’ conductivity, and as a result we are able to apply ten times less energy to dessicate crops for example. This means that the crop.zone method uses less energy, and the application width for desiccation can be increased beyond 24 meters. Our 2021 generation products will already apply at 12 meters. From 2022 onwards we will be ready for 24 meter applications.”

Vandenhittz says Crop.Zone therefore has an even lower impact on the living organisms and other beneficiaries in the soil. He believes they have discovered a method that can economically and ecologically improve the existing model of crop desiccation.

When it comes to technical realities, Vandenhirtz explains that crop.zone uses two attachments. A standard sprayer is fitted at the front of the tractor, whilst the crop.zone electrical application unit is installed at the rear. The configuration is as follows: The tractor’s PTO shaft drives a generator. This converts the mechanical energy into electrical energy.

The energy is distributed to converters in a “switch cabinet”. Converters are electronic units that transform low voltage into high voltage. This power is then transferred to the application frame, which is located at the very back. These electrodes then channel the energy into the plants. The plant completes the circuit and is thereby destroyed.

Home - crop.zone

“This season we have been out in the field,” Vandenhirtz says. “We have driven, measured, examined the measured values, made adjustments, re-measured, and in doing so we have optimized the applicator step by step. We now know the optimum setting of the applicator. It will now go into series production with a design that is sufficiently robust to withstand continuous operation in real-field situations”.

Vandenhirtz says Crop.Zone has established a so-called “Groundbreaker Programme” for 2021. Working in cooperation with interested farmers and industrial partners, they will test their final design on the harsh conditions typical of a farmer’s field.

“For this purpose, we will construct 30 systems next year and operate them together with farmers, whilst also providing scientific support from our end. We are in contact with the chamber of agriculture, the Julius Kühn Institute, and in Switzerland with the FiBL Institute. The system will be made available to all farmers in 2022. We want to get started on a commercial level at that time.”

The Crop.Zone team

Vandenhirtz says they are now a team of 14. “I myself am a biologist with extensive knowledge of plants. Crop.Zone employs computer scientists, mechanical engineers, electrical engineers, agronomists, mechanics and electricians. Development of the Crop.Zone concept no doubt requires a wide range of expertise.”

Food production currently means high energy consumption and the extensive use of chemicals. Crop.Zone wants to ultimately change all of that.

Dirk Vandenhirtz: “I believe that everyone at Crop.Zone shares the idea and vision of breaking new ground and developing farming systems and solutions that are sustainable. After all, food production is a necessity. But perhaps it can be done in a different way.”

Anyone with an interest to join the Crop.Zone team is welcome to get in touch with Dirk Vandenhirtz at dirk.vandenhirtz@crop-zone.com.

Visit Crop.Zone’s website for further information: www.crop.zone

The Crop.Zone video below can also be found and watched on YouTube here.https://www.youtube-nocookie.com/embed/Xx16z-c_6rY?iv_load_policy=3&modestbranding=1&rel=0&autohide=1&playsinline=1&feature=youtu.be&autoplay=0

Source: Crop.Zone