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Contribute to CABI’s new Plant Health Cases

Real-life examples of plant health in practice. 

About Plant Health Cases

Fresh green soy plants on the field in spring. Rows of young soybean plants . High quality photo

CABI, together with Editors in Chief Lone Buchwaldt, David B. Collinge, and Boyd A. Mori is embarking on a new type of online publication called Plant Health Cases.

Plant Health Cases will be a curated, peer-reviewed collection of real-life examples of plant health in practice. This will be an invaluable resource for students, lecturers, researchers, and research-led practitioners. We will be developing cases in all areas relevant to plant health, including:

  • plant diseases
  • plants pests
  • weeds
  • environmental factors
  • agronomic practices
  • diagnosis, prevention, monitoring and control
  • international trade and travel

What is a Case Study?

A Plant Health Case is a relatively short publication with a well-defined example of research in plant health, e.g. a study which results in reduced impact from a disease or pest problem. Cases should be between 3000 and 5000 words long, and can include photos, figures and tables. They should be written in an engaging style that is both science-based and accessible using a limited number of references. Importantly, each case should suggest points for discussion to broaden the reader’s horizon, inspire critical thinking and lead to interactions in the classroom or field.

Interested in Contributing to Plant Health Cases?

We are currently looking for contributions of case studies, and we welcome your ideas! You may have existing case study material ready prepared for use in teaching, or a good example of research in plant health which could be easily adapted to our template. For further information and guidance on how to submit your idea for a case study please see here: https://www.cabi.org/products-and-services/plant-health-cases/

Your submission will be peer-reviewed, and a DOI assigned at the time of publication similar to your other scientific publications. The corresponding author will receive £100 upon acceptance of the final case study. 

Publication Plan

We’re aiming to launch Plant Health Cases in mid-2023. Our case studies will offer practical, real-life examples in one easily searchable platform. All users will be able to search, browse and read summaries of case studies. Full text access will be available via individual or institutional subscription, or by purchasing a single case study.

Further Information

Please get in touch with Rebecca Stubbs, Commissioning Editor, CABI

r.stubbs@cabi.org

About CABI

CABI is a not-for-profit, scientific research, international development and publishing organisation. Unlike other publishers, we use our surpluses to support scientific and rural development projects that help improve the lives of the world’s poorest people, which means that by publishing with us, you are helping to improve the lives of some of the world’s poorest people. Please visit our website at www.cabi.org

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SEPTEMBER 14, 2022

Can wild potato relatives help tame zebra chip disease?

by Paul Schattenberg, Texas A&M University

Can wild potato relatives help tame zebra chip disease?
Kranthi Mandadi, Ph.D, a Texas A&M AgriLife Research scientist at the Texas A&M AgriLife Research and Extension Center in Weslaco, was the primary investigator for the new zebra chip-related study. Credit: Texas A&M AgriLife photo

A new study led by Texas A&M AgriLife researchers has revealed some resistance to zebra chip disease among certain wild species of potato.

The study of 52 wild potato species—of which one accession was resistant and three were tolerant to the disease—took place as part of an effort to identify novel genetic resistance to the disease, which affects potato production worldwide.

The study, “Identification and Characterization of Potato Zebra Chip Resistance Among Wild Solanum Species,” appeared recently in the journal Frontiers in Microbiology.

The primary investigator for the study was Kranthi Mandadi, Ph.D., a Texas A&M AgriLife Research scientist at the Texas A&M AgriLife Research and Extension Center at Weslaco and associate professor in Texas A&M’s Department of Plant Pathology and Microbiology.

Study co-investigators include Isabel Vales, Ph.D., AgriLife Research associate professor and potato breeder, Bryan-College Station, and Carlos Avila, Ph.D., AgriLife Research associate professor and vegetable breeder, Weslaco, both in the Department of Horticultural Sciences; and Freddy Ibanez, Ph.D., an AgriLife Research scientist at the center and assistant professor in the Texas A&M Department of Entomology.

Others involved in the study were Texas A&M AgriLife Research scientists Victoria Mora, M.S., Manikandan Ramasamy, Ph.D., Mona Damaj, Ph.D., and Sonia Irigoyen, Ph.D., at the Weslaco center, as well as Veronica Ancona, Ph.D., a plant pathologist and associate professor at Texas A&M University-Kingsville.

“This type of outcome was precisely what AgriLife Research envisioned when we decided to fund Insect Vector Diseases Seed Grants,” said Henry Fadamiro, Ph.D., chief scientific officer and associate director, AgriLife Research, and associate dean, Texas A&M College of Agriculture and Life Sciences. “We would like to thank the Texas Legislature for funding AgriLife Research’s IVD Exceptional Item Request that has made these seed grants possible. Their continued support is invaluable.”

What is zebra chip disease?

Zebra chip is a complex disease due to its association with the unculturable bacteria Candidatus Liberibacter solanacearum and transmission by an insect vector, the potato psyllid. First reported in Saltillo, Mexico, and subsequently in South Texas, the disease was detected in many other states and commercial potato-growing regions of the world. Left unchecked, it can result in potato yield losses of up to 94%.

Can wild potato relatives help tame zebra chip disease?
Potato tubers affected by zebra chip disease are of poor quality, have a bitter taste and display dark brown zebra-like patterns when fried. Credit: Texas A&M AgriLife photo

Above-ground symptoms of zebra chip-affected plants include purplish discoloration of young leaves, upward rolling of top leaves, the presence of aerial tubers, wilting, stunted growth and plant death.

“Zebra chip-affected tubers are of poor quality, exhibiting vascular ring browning and brown flecks,” Mandadi said. “These chips also have a bitter taste and dark brown striped, zebra-like patterns when fried.”

He said the disease ultimately lowers yield and tuber quality becomes unmarketable.

“If left uncontrolled, the disease can become a significant detriment to potato production.”

Why the study?

The potato is cultivated in over 160 countries and is considered the fourth most important staple food crop after wheat, corn and rice. It is a rich source of carbohydrates and provides other essential nutrients, such as dietary fiber, vitamins, minerals, protein and antioxidants.

“The potato is an important food crop worldwide,” Mandadi said. “As the demand for fresh and processed potato products increases globally, there is a need to manage and control emerging diseases such as zebra chip.”

In Texas, potatoes are grown in all regions that have a significant amount of commercial vegetable production. Commercial acreage for potato production is found in the South Plains, Panhandle and Rolling Plains, as well as the Winter Garden and Rio Grande Valley areas.

“In Texas, we have been dealing with the zebra chip issues for more than 20 years,” Vales said. “Over that time, the disease has become pervasive and has expanded not only in this state but also in other potato-producing states.”

Can wild potato relatives help tame zebra chip disease?
The Texas A&M AgriLife-led study involved the assessment of plant material from 52 wild potato accessions. Credit: Texas A&M AgriLife photo by Kranthi Mandadi

The bacterium and the insect vector associated with zebra chip disease can also affect other vegetable crops and produce, including tomatoes, peppers and carrots.

Vales said current zebra chip management strategies revolve primarily around controlling the psyllid vector with insecticides or by altering cultural practices, such as timing planting dates to delay exposure to the psyllid population.

“But both of these have only marginal benefits, and while using chemical measures has helped control the psyllid population, this approach is associated with high costs and the potential for increased insecticide resistance,” she said. “That’s why identifying and breeding novel genetic resistance and tolerance to the zebra chip is another important avenue to achieve integrated pest management.”

Vales said previous studies have reported variations in the psyllid’s preference for wild potato species and their breeding clones.

The study results

“For the past four years, our team has been studying approaches to control zebra chip disease thanks to seed funding from projects associated with the Insect Vector Diseases Grant Program,” Mandadi said.

The plant material of 52 wild potato accessions belonging to a Solanum sect. Petota diversity panel, grown from true potato seeds obtained from the U.S. National Plant Germplasm System in Wisconsin, was used in the study.

“New sources of zebra chip resistance were identified among a wild collection of tuber-bearing Solanum species present in the Petota panel,” Mandadi said. “This panel of wild potato is a taxonomically well-characterized and diverse collection from which one can mine for valuable potato traits.”

Several of the 52 accessions were susceptible and moderately susceptible, showing some upward leaf rolling, chlorosis and plant stunting, Mandadi said.

Can wild potato relatives help tame zebra chip disease?
According to the study, the S. berthautii wild potato accession, shown here, demonstrated zebra chip psyllid resistance. Credit: Texas A&M AgriLife photo by Kranthi Mandadi

“But following the screening, phenotypic evaluations and quantification of the bacteria in the accessions infected with bacteria-carrying psyllids, we identified one zebra chip resistant accession, Solanum berthaultii, along with three other accessions that were moderately tolerant to zebra chip.”

The three accessions identified in the study as moderately tolerant to zebra chip were S. kurtzianum, S. okadae and S. raphanifolium.

Mandadi’s team also found S. berthaultii has dense glandular leaf trichomes, and this foliar structural modification could be one factor responsible for much of the observed zebra chip resistance.

“The foliar portion produces a sticky substance that seems to trap the psyllid to the plant when it comes in contact with it,” Mandadi explained. “As a result, many psyllids die before reproducing, thus reducing transmission of the bacterium into plants.”

He noted the S. berthautii wild potato accession originated in Bolivia, which is adjacent to Peru, historically identified as the ancestral “birthplace” of the cultivated potato.

He said S. berthaultii is a promising source for zebra chip psyllid resistance that can be further studied to understand insect resistance mechanisms and incorporated into the potato production system.

“It could possibly be used in breeding new potato cultivars or even as a ‘trap crop’ that can be planted next to more traditional potato cultivars as a way to help eliminate psyllids,” Mandadi said.

He also noted that similar approaches in identifying novel genetic resistance and tolerance in wild plant species could help control other devastating crop diseases, such as potato late blight, citrus greening, Pierce’s disease of grapes and banana wilt.


Explore further

New variety of zebra chip disease threatens potato production in southwestern Oregon


More information: Victoria Mora et al, Identification and Characterization of Potato Zebra Chip Resistance Among Wild Solanum Species, Frontiers in Microbiology (2022). DOI: 10.3389/fmicb.2022.857493

Provided by Texas A&M University 

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  Grahame Jackson

PestNet

 Sydney NSW, Australia

 For your information

 8 days ago

Soybean virus may give plant-munching bugs a boost in survival

PennState

UNIVERSITY PARK, Pa. — Most viral infections negatively affect an organism’s health, but one plant virus in particular — soybean vein necrosis orthotospovirus, often referred to as SVNV — may actually benefit a type of insect that commonly feeds on soybean plants and can transmit the virus to the plant, causing disease, according to Penn State research.

In a laboratory study, the Penn State College of Agricultural Sciences researchers found that when soybean thrips — small insects ranging from 0.03 to 0.20 inches long — were infected with SVNV, they tended to survive longer and reproduce better than thrips that were not infected.

Asifa Hameed, who led the study while completing her doctoral degree in entomology at Penn State and is now a senior scientist of entomology at Ayub Agricultural Research Institute in Multan, Pakistan, said the findings give key insight into how the virus spreads in plants and affects its insect hosts.

“In addition to prolonging the life of the insects, SVNV infection also shortened the doubling time of soybean thrip populations,” Hameed said. 

 Soybean_vein_necrosis_orthotospovirus

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Could biocontrol solve the papaya mealybug problem for Ugandan farmers?

Papaya mealybugParaccous margniatus, is native to Central America but has spread rapidly in invaded countries. It was detected in Uganda in 2021 where it has the potential to affect the production and quality of papaya and other host crops.

Papaya
Papaya fruit

Typically, mealybugs are not pest problems in the countries they are native to because naturally occurring parasitoids and predators keep their numbers in check. The most serious outbreaks occur when mealybugs are introduced accidentally to new countries without natural enemies.

Papaya mealybug spread

The trade in live plant material, such as papaya fruits and seedlings, has accidentally accelerated the spread of papaya mealybug outside its native range. This pest threatens food and nutrition security and adversely affects the safe trade and competitiveness of the agricultural sector for many countries.

Without natural enemies to manage outbreaks, farmers often turn to pesticides. The lack of registered pesticides results in farmers using highly hazardous chemicals that are not only ineffective but can negatively impact native insect biodiversity such as pollinators and natural enemies of pests. A more ecologically sound approach to management is the use of biological control.

Rapid Rural Appraisal of papaya mealybug

As part of the PlantwisePlus programme, CABI in collaboration with the National Agricultural Research Organisation (NARO, Uganda), conducted a Rapid Rural Appraisal (RRA) of papaya mealybug in Uganda. The appraisal sought to gain an understanding of the presence, distribution, and impact of papaya mealybug in Uganda as well as farmers’ management practices. The evaluation also assessed farmers’ willingness to adopt and use biocontrol and their information requirements around biocontrol products.

Information from the appraisal will be used to design an integrated management strategy for papaya mealybug as well as help target community-level communications.

Papaya mealybug on fruit
Papaya mealybug on a papaya fruit

A major cash crop

The seventeen focus group discussions brought together papaya growers from four districts: North District (Lira), Central District (Kayunga, Luwero and Mukono). The districts captured a diversity of farming systems, agro-ecological zones, and agricultural potential. Papaya is a major cash crop for farmers in these districts, in addition to pineapple and traditional cash crops such as coffee. The average farmer cultivates the crop on 0.75-2.5 acres.

The participants confirmed papaya mealybug is already widespread in all four districts where it causes damage to several crops, not just papaya. Farmers started observing the pest between 2017 and 2019 with most saying it is a serious pest that can cause up to 100% crop loss. The official pest reporting to IPPC took place in 2021.

Papaya mealybug management

Farmers mainly attributed the papaya mealybug outbreaks to low productivity and poor-quality fruits. They observed that trees take longer to bear fruit and when they do, they only last one season compared to an average of 4 before. It was estimated that before the pest invaded, farmers obtained UGX 6-8 million/acre each season (£1,800), but currently only obtain UGX 1 million/acre each season (£230).

Regarding management options, commercial farmers reported using pesticides to deal with outbreaks. However, managing papaya mealybugs with pesticides is not always successful due to the pest’s waxy covering. In addition, misuse and/or improper use of these pesticides exacerbate pest problems by reducing beneficial organisms and natural enemies and negatively impacting biodiversity, human health and environmental safety. Further, some farmers don’t observe pre-harvest intervals, thus toxic substances are likely to enter the human food chain posing long-term health risks to consumers and the environment.

Papaya on a farm infected with papaya mealybug
Papaya on a farm infected with papaya mealybug

Sustainable options

Biological control represents a sustainable and effective management option, however, the farmers interviewed had mixed views on the method and the efficacy of the parasitoid in Uganda’s agroecologies. This highlights the importance of proper testing and community-level communications before the introduction of exotic natural enemies. Farmer and community engagement, and mass awareness are key in pest identification and management, especially with the promotion of unfamiliar pest management options. Extension in particular plays a vital role in the research and advancement of low-risk options.

However, one of the main takeaways from the appraisal was farmers’ papaya problems extend beyond papaya mealybug. Farmers reported other associated viral and bacterial diseases causing challenges, including bunchy top disease and leaf necrosis. As such, it is important that researchers assess the economic damage, effect and losses due to papaya mealybug and the associated pests and diseases before releasing biological control parasitoids.

Implementing a biocontrol programme

The PlantwisePlus programme is now looking at the activities required for the implementation of the biocontrol programme in Uganda. In particular, they are developing extension and farmer training manuals to cover papaya crop integrated pest management. These will include papaya mealybug as well as other pests affecting papaya production in the country. In addition, continuous community engagement and mass awareness campaigns will help farmers and their communities manage this highly destructive pest in a more sustainable way. 

PlantwisePlus is working to reduce the reliance on high-risk farm inputs that have adverse effects on human health and biodiversity. By implementing biological control programmes, PlantwisePlus is responding to the challenge and working to improve livelihoods through sustainable approaches to crop production.

About PlantwisePlus

PlantwisePlus is supported by contributions from the UK Foreign, Commonwealth and Development Office, the Swiss Agency for Development and Cooperation, the Netherlands Ministry of Foreign Affairs and the European Commission (DG INTPA).

PapayaPapaya mealybugParaccous margniatusUgandaplant healthplant pestsplantwiseplus

Agriculture and International DevelopmentCrop healthInvasive species

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As a grower, you want to have an overview of what’s happening in your crop at all times. This is why many growers make sure that scouting takes place at regular times. Natutec Scout is a tool developed by Koppert to make sure every grower can utilize the benefits of having all your scout data in one central place.

To accommodate growers’ way of working, Natutec Scout offers four different ways to input your data:

  • Pen and paper scouting: write down your observations on paper like you’re used to, and enter your findings straight and simply. Record your findings directly into Natutec Scout using the manual input feature. Input is easier and quicker than using Excel with all the benefits and tools that Natutec Scout provides.
  • Enter your observations on the mobile Natutec Scout app – available for both Android and iOS – in which you make your observations, provide your location, and add notes and photos if you want to add additional findings to your scouting session. This data is then uploaded to the dashboard.
  • Automatic detection of whitefly using the Horiver Scanner: Using the power of Artificial Intelligence (AI) for automatic whitefly counts enables you to save a significant amount of time and labor when counting the whitefly on Horiver cards. Just take a picture of a Horiver card, and you are done.
  • Import historical scout data using the Excel import functionality. You can easily load multiple years of previous scout data (averages and specifics) into Natutec Scout. You immediately get the tools at your disposal to discover trends, hotspots, and other significant events in the IPM of your crop.

The scout data are transferable. Because of that, it’s nice to work with this knowledge between everyone in your company and for your external consultant(s).

For more information:
Koppert Biological Systems
koppert.com

Publication date: Wed 14 Sep 2022

Scouting pests and diseases

As a grower, you want to have an overview of what’s happening in your crop at all times. This is why many growers make sure that scouting takes place at regular times. Natutec Scout is a tool developed by Koppert to make sure every grower can utilize the benefits of having all your scout data in one central place.

To accommodate growers’ way of working, Natutec Scout offers four different ways to input your data:

  • Pen and paper scouting: write down your observations on paper like you’re used to, and enter your findings straight and simply. Record your findings directly into Natutec Scout using the manual input feature. Input is easier and quicker than using Excel with all the benefits and tools that Natutec Scout provides.
  • Enter your observations on the mobile Natutec Scout app – available for both Android and iOS – in which you make your observations, provide your location, and add notes and photos if you want to add additional findings to your scouting session. This data is then uploaded to the dashboard.
  • Automatic detection of whitefly using the Horiver Scanner: Using the power of Artificial Intelligence (AI) for automatic whitefly counts enables you to save a significant amount of time and labor when counting the whitefly on Horiver cards. Just take a picture of a Horiver card, and you are done.
  • Import historical scout data using the Excel import functionality. You can easily load multiple years of previous scout data (averages and specifics) into Natutec Scout. You immediately get the tools at your disposal to discover trends, hotspots, and other significant events in the IPM of your crop.

The scout data are transferable. Because of that, it’s nice to work with this knowledge between everyone in your company and for your external consultant(s).

For more information:
Koppert Biological Systems
koppert.com

Publication date: Wed 14 Sep 2022

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Bioengineered plants help produce moth pheromones for pest control

Pheromones are often used by farmers for controlling pest insects but the chemical process for producing them is expensive. A method for making them using bioengineered oil plants could be cheaper

ENVIRONMENT 1 September 2022

By James Dinneen

camelina oilseeds
The camelina oilseed plant can be used to make insect pheromones Kurt Miller

A bioengineered oilseed plant can produce a moth sex pheromone molecule used to control insect pests.

Pheromones are chemical signals that cause a behavioural response in members of the same or closely related species. For decades, farmers have used pheromones to keep pest insects away from high-value crops like apples and grapes, for instance by baiting traps with the chemicals or saturating fields with them to make it difficult for the insects to find mates. But the chemical process for making pheromones is too expensive to use for lower-value row crops like maize, soybeans and cotton.

Hong-Lei Wang at Lund University in Sweden and his colleagues bioengineered plants to produce a sex pheromone molecule secreted by two damaging pest species: female diamondback moths (Plutella xylostella) and cotton bollworms (Helicoverpa armigera).

The team used the bacterium Agrobacterium tumefaciens to introduce two genes into the oilseed plant Camelina sativa.

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Country Matters: Tiny but brilliant creatures are better than pesticides

Ants are incredible, hard-working creatures

Ants are incredible, hard-working creatures

Joe Kennedy

August 28 2022 02:30 AM


Patiently I have watched ants for lengthy periods at their agricultural practices, endlessly busy cutting and ferrying vegetation to maintain the farms producing their fungal livelihood. Leaning over cliff top fences on Portugal’s Atlantic coast, I have looked at endless processions of insects moving along rutted tracks to disappear underground and reappear to collect more leaf fragments from a far source. Such lives of endless toil appear to be never-ending.

This leaf-cutting species works continuously to keep its fungal farms in production. The ants live on fungi that grows in their formicaries, or colonies, nurtured by leaf fragments which are further reduced by a separate team of stalk cutters before being laid out in ‘gardens’ to be tended by yet another crew.

There is careful husbandry: if a leaf source is found to be toxic, the ants promptly move to another. Source sites may be up to 300m away but, like slugs, the insects follow a scent trail laid down by the original surveyors. Individual ‘soldiers’, separate from the constantly moving lines, are on the lookout for intruders who might steal the crops. Colonies can also be raided and resident insects enslaved. Within the formicaries, reigning queen ants — who can live for up to 15 years — preside over colonies of between 100,000 and 500,000. The largest was found in Switzerland in 1977 with 300 million living in 1,200 anthills crossed by 60km of paths in the Jura Mountains.

Most of us have had unpleasant encounters with ants, red and black, in this country.

In Africa there is a species called Matabele which have remarkable human-like traits in that they save wounded comrades on termite battlefields. If an ant can stand on just one leg after a fight, it is carried off to have its wounds tended to by triage ‘doctors and nurses’ to fight another day. Prone casualties, however, are left where they fall.

A scientific report recently suggested that ‘ant power’ in crop production can be more efficient than chemicals. The ants are better at disposing of pests, thereby reducing damage and increasing yields. An analysis published in Proceedings of the Royal Society looked at 17 crops in several countries and found some ant species with proper management had similar or higher efficacy than pesticides — and at lower cost.

However, ants can also be a problem where meal bugs, aphids and whiteflies are concerned. They produce a sugary substance called honeydew to which ants are attracted and which they ‘farm’ like livestock. But researchers say alternative sugar sources may be used to distract the ants so they continue to attack the other pests.

There are more ants than any other insects in the world, about 14,000 known species, making up about half of the earth’s biomass. They are incredible creatures.

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Using pheromones and mating disruption to fight Tuta absoluta

Tuta absoluta is a pest found in many greenhouses around the world. “Due to the climate change and the movement of goods, Tuta absoluta can now be found in many parts of the world,” says Irina Caraeva from Eco Center. “Generally speaking, if you see mining on the leaves  or the pests themselves – there might be a chance of an infestation.” And this can get quite nasty, not only because they inevitably weaken the plants but also because these get more susceptible to other pathogens.

The risk of using chemical products
Usually, a good practice to prevent that is to use insecticides, but they come with a downside. “The main issue has to do with the beneficial insects present in the greenhouse,” Irina points out. “Insecticides tend to affect those too, which is something growers definitely don’t want.” Another disadvantage of the use of insecticides to counter Tuta absoluta is the residue levels. “First of all, most of the insecticides are quite toxic, and residues can then be found on the produce. You can perhaps use them before the planting, but not during the entire growing season, it’s really not advisable. Additionally, Tuta absoluta develops resistance to most insecticides available on the market, even if there are products that can control the pest, they contain highly concentrated substances that cannot be used immediately before collection since the degradation period is too high.”

Pheromones
That is why Eco Center has devoted its efforts to developing solutions to control greenhouse pests in the most natural and environmentally friendly way. “Pheromones,” Irina points out. “These are species-specific, which means that they will affect only a given insect. In this way, a grower can be sure that beneficial insects don’t get harmed. At Eco Center, we have developed many pheromone products, with the most recent addition of the Tuta Protect – a mating disruption product.” The Eco Center also makes pheromone lures for monitoring tomato leaf miner to go together with their Delta Traps. “These are designed specifically to monitor the insect population in a cost-efficient and environmentally friendly way. They will help the growers to make decisions on further application of other pest management actions.”

Mating disruption
Irina continues to explain that before planting, a grower should start the monitoring process by installing a couple of Delta traps with pheromone lures. At the same time, if traps indicate the need for control of pests, Eco Center has come up with another solution. “Mating disruption,” she says. “These pheromone dispensers contain 170-180 milligrams of pheromone. Bluntly put, the mating disruption dispensers create “false pheromone trails” that affect Tuta absoluta males, which interferes with their mating finding behavior.”

Irina says that Eco Center is constantly working to include more insects in their pheromones catalog. “Right now, we are testing our products for the pink bollworm, which are mainly asked by our customers from the Middle East and Africa. At the same time, we are in the process of figuring out the best pheromone solution for the most common cannabis pests. Hopefully, we’ll get into that market soon,” she concludes.

For more information:
Eco Center
MD-2005, Moara Rosie 5E str.
Chisinau, Republic of Moldova
+373 68979696
info@ecocenter.md 
ecocenter.md

Publication date: Mon 29 Aug 2022
Author: Andrea Di Pastena
© HortiDaily.com

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AUGUST 19, 2022

Microbes protect a leaf beetle—but for a price

by Daniel Fleiter, Max Planck Institute for Biology Tübingen

Microbes protect a leaf beetle - but for a price
Leaf Beetle. Credit: Max Planck Institute for Biology Tübingen

Insects are known to rely on microbial protection during immobile developmental stages, such as eggs. But despite the susceptibility of pupae to antagonistic challenges, the role of microbes in ensuring defense during an insect’s metamorphosis remained an open question. Scientists from Germany and Panama have now discovered a novel defensive partnership between a fungus and a leaf beetle. The microbe provides a protective layer around the beetle’s pupae and thus prevents predation. In exchange, the beetle disperses the fungus to its host plant, expanding its range. Now published in Current Biology, the researchers present the results of their study.

Antagonistic interactions are widespread in nature, spurring the evolution of protective traits. In insects, as with other animals, symbioses with beneficial microbes can serve as a source of defensive adaptations.

In their study, biologists from the Max Planck Institute for Biology in Tübingen, the University of Tübingen, both Germany, and the Smithsonian Tropical Research Institute, Panama, discovered a mutualistic partnership between the ascomycete Fusarium oxysporum and Chelymorpha alternans, a leaf beetle: The fungus protects the pupae of the leaf beetle against predators. And in exchange, the beetle disperses the fungus to its host plants and thus contributes to its transmission.

“The fungus retained a metabolic profile that reflects its dual lifestyle,” explains Hassan Salem, Research Group Leader at the Max Planck Institute for Biology and senior author of the study. “Our findings show a mutualism ensuring pupal protection for an herbivorous beetle on the one hand, in exchange for symbiont dissemination and propagation on the other hand,” Salem adds.

A microbial dimension to pupal defense

Previous research across numerous study systems described such partnerships with microbes and insects by examining eggs and other juvenile phases. But for the critical pupal stage, the role of microbial protection remained unexplored. And despite birds and some rodents posing threats to pupae, it is rather the smallest predators and parasitoids such as ground beetles, ants and wasps that pursue them in the wild.

“Structural and chemical adaptations are known to protect pupae against predators and other threats. But microbes appear to also play an important role when we consider how a beetle defends itself during metamorphosis,” comments Aileen Berasategui, an Early Career Researcher at the Cluster of Excellence “Controlling Microbes to Fight Infections” (CMFI), University of Tübingen and the first author of the study.

A protective microbial coat

The research team was driven by the observation that a dense microbial growth appears to form at the onset of pupation. Sequence- and culture-based approaches revealed this growth to be Fusarium oxysporum. To understand and demonstrate their hypothesis of a mutual partnership, the researchers performed field studies in Panama while they explored the survival rates of pupae with and without the protective fungus.

Based on follow up investigation using sweet potato plants, the research team further determined that the leaf beetle carries and distributes the fungus to uninfected plants. As the beetles carry the fungus on legs during the adult stage, this resulted in widespread infection of the plants.

The leaf beetle Chelymorpha alternans belongs to the speciose Cassidinae subfamily of leaf beetles. Many members of this group appear to carry the morphological features of the symbiosis with Fusarium oxysporum, the most conspicuous being the microbial coat that covers pupae. When the symbiosis evolved and how it is maintained are central questions that members of this international team hope to uncover.


Explore further

Whether horseradish flea beetles deter predators depends on their food plant and their life stage


More information: Aileen Berasategui et al, The leaf beetle Chelymorpha alternans propagates a plant pathogen in exchange for pupal protection, Current Biology (2022). DOI: 10.1016/j.cub.2022.07.065

Journal information: Current Biology 

Provided by Max Planck Institute for Biology Tübingen

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Weed seed destructor

SEED DESTRUCTOR: One of the more innovative ways to control weed seeds is with a weed seed destructor. The Redekop seed destructor unit is attached to a John Deere S680 combine. The machine was recently tested in soybean fields with waterhemp infestations in central Iowa.

Learn about new ways researchers are working to help farmers control weeds at the ISU Extension display at the Farm Progress Show.

Prashant Jha | Aug 24, 2022

SUGGESTED EVENT

fps-generic.jpg

Farm Progress Show

Aug 30, 2022 to Sep 01, 2022

Controlling weeds in farm fields is an annual challenge — especially with more weeds becoming resistant to herbicides. Fortunately, producers have a wide range of options to counter weeds, including some creative ways that may not have been employed in the past.

At this year’s Farm Progress Show, Iowa State University Extension and Outreach will showcase one of the more innovative and practical methods of controlling weeds: a weed seed destructor.

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Fitted to a combine, the weed seed destructor does what its name implies. It pulverizes and destroys seeds so that they cannot germinate.

The weed seed destructor (Redekop) will be attached to the back of a John Deere S680 combine and will be available for viewing outside of the ISU Extension and Outreach tent.

While the machine will not be operating during the show, visitors can see it in operation on a computer screen, and they can ask questions of weed science experts.

“We want to give the public a chance to see and ask about this innovative form of weed control technology,” says Prashant Jha, ISU professor and Extension weed specialist. “Farmers in central Iowa and in Harrison County are already using this technology, and we expect more will do so in the coming years.”

Alternative methods

Other methods of weed control will also be featured, including videos of chaff lining, a method that guides the harvested chaff into narrow bands as it flows out the back of the combine at harvest, which reduces the spread of weed seeds by more than 95% across fields and contains weed seeds in smaller spaces.

The harvester or combine is modified with a baffle that separates the chaff (containing the majority of weed seeds) from the straw. The chaff is directed into narrow central bands using a chute at the rear of the combine. 

Weed seeds in the chaff are subjected to decay, and burial of small-seeded weed species such as waterhemp in the chaff will potentially result in reduced emergence in the subsequent growing season. High application rates of herbicides or shielded sprayers can be used to selectively control emerged weeds in those narrow bands in the field. 

The weed control display will also allow visitors the chance to test their knowledge of weed specimens found in the Midwest. Sixteen different species will be available for visitors to identify.

Visitors will also have the chance to learn more about waterhemp, and how it can be suppressed using cereal rye as a cover crop.

Photos and sample trays will show the results of using no rye, rye terminated at 4 to 6 inches tall, and rye terminated close to heading.

“We’re going to be showing the potential for biomass [cover crops] to suppress weeds like waterhemp, and how the results vary based on the height of the cover crop,” Jha says.

Rye helps suppress weeds

Cereal rye has the best potential to suppress weeds because it accumulates more biomass than other cover crop species. A study that was done for the Farm Progress Show shows an incremental decrease in waterhemp based on the density of rye.  

Field studies indicate cereal rye biomass of 4,500 to 5,000 pounds per acre at termination can significantly suppress waterhemp emergence in soybeans, and reduce the size and density of waterhemp at the time of exposure to postemergence herbicides.  

Additionally, producers can view a map of where herbicide resistance has been documented in Iowa based on the recent survey, and ask questions to Jha and other specialists about their own experience with herbicide-resistant weeds.

Jha will be joined at the show by ISU Extension and Outreach field agronomists Angie Rieck-Hintz, Meaghan Anderson, Gentry Sorenson and Mike Witt, and several weed science graduate students.

Jha is an ISO professor and ISU Extension weed specialist.

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A biopesticide manages to be as effective as sulfoxaflor in controlling aphids in melon

One of the agronomic challenges of Fruta Bollo, a company specializing in the production and marketing of fruits, especially citrus fruits and melons, is the sustainable management of pests, whose impact can generate losses of up to 80% of production when efficient management is not carried out.

To meet this important agronomic challenge, Kimitec carried out a successful investigation for Frutas Bollo, as part of the MAAVi Lab signed by both companies in April 2021.

The MAAVI IC selected three possible natural solutions for the field study and applied them from late June to early July, a time in which the crops are most prone to the development of aphids, to a very persistent aphid population (more than 100 individuals per leaf) in advanced melon crops with only 20 days to be harvested.

After 3 weeks of evaluations, using 2 applications at one-week intervals, Kimitec experts and the Bollo field team closely monitored the population concluding that one of its three developing biopesticides achieved the same efficacy as sulfoxaflor, the reference chemical.

“The finding represents a great advance for melon producers since they will be able to count on a substitute that has the same effectiveness as the chemical that cannot be used due to maximum residue limits (MRLs) restrictions, which translates into a more sustainable and safe agriculture,” stated Juan Puchades, managing director of Bollo for Brazil and responsible for Sustainability at Frutas Bollo.

In addition, fieldwork has shown that blending Kimitec’s new formulation with sulfoxaflor achieves almost 100% efficacy in just one application, halving the number of applications to control a persistent focus in times of increased need for efficient applications.

The biopesticide created by Kimitec, which is still under development, will be available in the USA, Mexico, and Brazil by 2023-2024 and on the European continent over a period of five years.

Source: kimitec.com 

Publication date: Mon 15 Aug 2022

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