Feeds:
Posts
Comments

 Grahame Jackson

PestNet

 Sydney NSW, Australia

 For your information

 18 days ago

Insects struggle to adjust to extreme temperatures making them vulnerable to climate change

ScienceDailySource:University of BristolSummary:As more frequent and intense heat waves expose animals to temperatures outside of their normal limits, an international team has studied over 100 species of insect to better understand how these changes will likely affect them.Insects have weak ability to adjust their thermal limits to high temperatures and are thus more susceptible to global warming than previously thought.

As more frequent and intense heat waves expose animals to temperatures outside of their normal limits, an international team led by researchers at the University of Bristol studied over 100 species of insect to better understand how these changes will likely affect them.

Insects — which are as important as pollinators, crop pests and disease vectors — are particularly vulnerable to extreme temperatures. One way insects can deal with such extremes is through acclimation, where previous thermal exposure extends their critical thermal limits. Acclimation can trigger physiological changes such as the upregulation of heat shock proteins, and result in changes to phospholipid composition in the cell membrane.

Read on: https://www.sciencedaily.com/releases/2022/09/220913183113.htm

 Climate_change

Wednesday, 21 September 2022 01:02:45

Grahame Jackson posted a new submission ‘Playing the ‘wild card’: Is it possible that some wild potato relatives can help tame zebra chip disease?’

Submission

Playing the ‘wild card’: Is it possible that some wild potato relatives can help tame zebra chip disease?

Potato News Today

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

As Paul Schattenberg reports for AgriLife Today, 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,” recently appeared in the scientific 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

Funding for the study was provided through Texas A&M AgriLife’s Insect Vector Diseases Seed Grant Program.

“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%.

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.” 

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.

“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.

Source: Texas A&M AgriLife
Author: Paul Schattenberg is a communications and media relations specialist with Texas A&M AgriLife Communications. Based in San Antonio, Paul is responsible for writing advances, news releases and feature stories for Texas A&M AgriLife agencies, as well as providing any media relations support needed. He can be reached here: paschattenberg@ag.tamu.edu or Cell: 210-859-5752; MSTeams: 210-890-4548


Wednesday, 21 September 2022 00:51:45

Grahame Jackson posted a new submission ‘Decoding how bacteria talk with each other’

Submission

Decoding how bacteria talk with each other

University of Wisconsin Maddison
https://news.wisc.edu/decoding-how-bacteria-talk-with-each-other

Bacteria, the smallest living organisms in the world, form communities where unified bodies of individuals live together, contribute a share of the property and share common interests.

The soil around a plant’s roots contains millions of organisms interacting constantly — too many busy players to study at once, despite the importance of understanding how microbes mingle.

In a study published in the journal mBio, researchers at the University of Wisconsin–Madison learned that a drastically scaled-down model of a microbial community makes it possible to observe some of the complex interactions. In doing so, they discovered a key player in microbial communication: the presence or absence of an antibiotic compound produced by one of the community members affected the behavior of the other two members.

Little is understood about how individual microbes interact with each other in communities, but that knowledge holds incredible promise.

For example, the bacteria Bacillus cereus can protect plants by producing an antibiotic that deters the pathogen that causes “damping off,” a disease that kills seedlings and is costly to farmers. But biocontrol agents like B. cereus are not always effective. Sometimes plants treated with B. cereus flourish, sometimes they don’t — and researchers are trying to understand why.

Amanda Hurley

“Bacteria do not live in isolation,” says Amanda Hurley, lead author of the new study; AAAS Science and Technology Policy Fellow; and former postdoc in the lab of UW–Madison professor Jo Handelsman, director of the Wisconsin Institute for Discovery.

“If we could figure out how interactions between species change in the presence of multiple species, we can start to understand communication trends of whole microbial communities Using chemistry or genetics, we could interrupt certain conversations and amplify others, leading to microbiomes that interact with their environments more positively and predictably, whether it be humans, crops or the soil itself.”

Deciphering the interactions between microorganisms could help in engineering an environment more favorable to Bacillus cereus. Hurley and co-authors Marc Chevrette, former postdoc in the Handelsman lab and currently assistant professor at the University of Florida, and Natalia Rosario-Melendez, graduate student in the Handelsman lab, set out to decode and translate the chemical conversations. The group created a model system composed of three species — Flavobacterium johnsoniae and Pseudomonas koreensis were isolated with B. cereus from field-grown soybean roots — which they dubbed “The Hitchhikers of the Rhizosphere” or THOR.

Marc Chevrette

Bacteria often communicate through the language of chemistry. Manipulating that chemistry using genes and chemicals could change the conversation and make Bacillus cereus feel welcome on plant roots.

The researchers built profiles of the THOR organisms using their mRNA, molecules produced when a gene is expressed. In each combination of THOR bacteria, the researchers looked for differences in gene expression. The THOR organisms responded to each other differently in every combination, and when all three species were together, new things started to happen that did not happen in any of the pairs or single conditions.

In the THOR community, gene expression was dominated by interactions with one member, P. koreensis. The results were mediated by the presence of the antibiotic koreenceine — the metaphorical hammer of THOR. This single molecule appears to affect the expression and interaction of thousands of genes across community networks. Determining how koreenceine regulates the community’s genes will be a fruitful avenue for further investigation, according to the researchers.

The study validates Handelsman’s early idea that communities are worth investigating, because the activity within the community is not just the sum of the members but reflects community properties.

“Traditionally, people only look at a single organism. What makes our study different is that we looked at the community,” says Chevrette. “Communities are different. There is something inherently unique to a community that makes it different than the sum of its parts. Utilizing the simplicity of model microbiomes may help us with the challenge of understanding microbes in complex communities, and how they can be altered to improve human, environmental, and agricultural health.”

This research was supported by grants from the Department of Defense (W911NF1910269) and Department of Agriculture (2019-2018-08058 and 2020-67012-31772).


Scientific Reports volume 12, Article number: 15706 (2022) 

Abstract

Beauveria bassiana and Metarhizium anisopliae are two of the most important and widely used entomopathogenic fungi (EPFs) to control insect pests. Recent studies have revealed their function in promoting plant growth after artificial inoculation. To better assess fungal colonization and growth-promoting effects of B. bassiana and M. anisopliae on crops, maize Zea mays seedlings were treated separately with 13 B. bassiana and 73 M. anisopliae as rhizosphere fungi in a hydroponic cultural system. Plant growth indexes, including plant height, root length, fresh weight, etc., were traced recorded for 35 days to prove the growth promoting efficiency of the EPFs inoculation. Fungal recovery rate (FRR) verified that both B. bassiana and M. anisopliae could endophytically colonize in maize tissues. The recovery rates of B. bassiana in stems and leaves were 100% on the 7th day, but dropped to 11.1% in the stems and 22.2% in the leaves on the 28th day. Meanwhile, B. bassiana was not detected in the roots until the 28th day, reaching a recovery rate of 33.3%. M. anisopliae strains were isolated from the plant roots, stems and leaves throughout the tracing period with high recovery rates. The systematical colonization of B. bassiana and M. anisopliae in different tissues were further corroborated by PCR amplification of fungus-specified DNA band, which showed a higher detection sensitivity of 100% positive reaction. Fungal density comparing to the initial value in the hydroponic solution, dropped to be well below 1% on the 21st day. Thus, the two selected entomopathogenic fungal strains successfully established endophytic colonization rather than rhizospheric colonization in maize, and significantly promoted its growth in a hydroponic cultural system. Entomopathogenic fungi have great application potential in eco-agricultural fields including biopesticides and biofertilizers.

Read on: https://www.nature.com/articles/s41598-022-19899-7


Wednesday, 21 September 2022 00:51:45

ENTOMOLOGY TODAY  

The Mexican fruit fly (Anastrepha ludens) is one of the world’s most damaging insect pests. A key method for managing them is the sterile insect technique, in which sterile male flies are mass-reared and released into the wild, whereupon they mate with wild females, which then fail to produce offspring. Determining the precise age of mass-reared fruit flies is a critical step in the sterile insect technique, and researchers in Mexico have applied machine-learning algorithms that can accurately measure the age of fruit fly pupae to properly time irradiation. (Photo by Andrés Diaz Cervantes)

By Diana Pérez-Staples, Ph.D., and Horacio Tapia-McClung, Ph.D.

Horacio Tapia-McClung, Ph.D.

Diana Pérez-Staples, Ph.D.

Two of the world’s most damaging pests are the Mediterranean fruit fly (Ceratitis capitata) and the Mexican fruit fly (Anastrepha ludens), causing billions of dollars in damage to agriculture. Fortunately, the sterile insect technique is currently used as part of area-wide integrated management programs to control these flies is certain regions of the world.

The sterile insect technique (SIT) is a type of birth control, consisting in rearing millions of these flies in factories, irradiating them with X or gamma rays to make them sterile, and then releasing them in areas where the pests are present. When the sterile males mate with wild females, the females will not have fertile eggs to lay in the fruits. Thus, population levels are decreased. The SIT has good green credentials because it only targets the pest species, it does not introduce foreign genetic material into the population, and it reduces the use of insecticides.

The irradiation process in SIT is key to its success. For tephritid flies, irradiation is usually carried out a couple of days before the pupae emerge as adults. If pupae are irradiated too soon or too late in their development process, this can lead to problems in mobility and behavior as adults. However, even during controlled conditions, pupae can vary in their development time. Thus, one of the tests that are carried out pre-irradiation is to determine the physiological age of the pupae.

Currently, at these fruit fly factories throughout the world, technicians must determine the correct time to irradiate by taking a sample of pupae, removing the pupal case to expose the eyes, and then checking the eye color against a color chart. This can be laborious and prone to human error, as it depends on the skill, experience, and expertise of the technician, as well as natural biases in color interpretation. The technicians can get tired from this repetitive work, while sick days and vision problems could also cause variations in the correct determination.

Mexican fruit fly (Anastrepha ludens) pupae
fruit fly pupae eye colors

Artificial Intelligence to the Rescue

At the Universidad Veracruzana, in collaboration with the Secretary of Agriculture of Mexico (Programa Operativo de Moscas, DGSV-SENASICA), we teamed up with experts in artificial intelligence to develop methods based on algorithms that can accurately determine the age of a pupa from a digital image captured with a common mobile device. We share our results in a new article published this month in the Journal of Economic Entomology.

Iván González-López

For this, and as part of his Ph.D. at the Facultad de Ciencias Agrícolas of the Universidad Veracruzana, Iván González-López, currently based at the IAEA-FAO Entomology Laboratory in Austria, took photographs of the exposed eyes of pupae of both Mediterranean fruit flies and Mexican fruit flies. We chose pupae that still had a few days to emerge and deliberately took rough photographs that did not have perfect lighting conditions or focus. In fact, they were taken quickly and with a mobile phone.

Then, as a part of her master’s research at the Laboratorio Nacional de Informática Avanzada in Xalapa Veracruz, Georgina Carrasco processed the images with a program that was trained to detect the eye area in the photograph and crop it. Afterward, using the correct answers from a technician at the factory, another algorithm was trained through a supervised machine-learning method known as transfer learning, to accurately determine the age of the pupae.

We found that algorithms based on a neural network architecture known as Inception v1 correctly identified the physiological age of maturity at two days before emergence, with a 75 percent accuracy for the Mexican fruit fly and 83.16 percent for Mediterranean fruit fly, respectively. This method is not perfect for sure, and it still requires a technician to dissect the pupae and take photographs, but it is a promising approximation of how supervised machine learning and artificial intelligence can be used to help uncertainty in decisions about when to irradiate. The level of accuracy may also be improved as more pictures are taken and provided for the algorithm to learn from.

The next steps will be to develop software that could easily be used by technicians as well as to train these algorithms with other tephritid pest species currently controlled through SIT. Certainly, it highlights that there can be some exciting collaborations between entomologists and artificial intelligence researchers.

Read More

Determination of the Physiological Age in Two Tephritid Fruit Fly Species Using Artificial Intelligence

Journal of Economic Entomology

Diana Pérez-Staples, Ph.D., is a research professor at the Institute of Biotechnology and Applied Ecology at the Universidad Veracruzana, in Xalapa, Veracruz, Mexico. Email: diperez@uv.mxHoracio Tapia-McClung, Ph.D., is a research professor at the Artificial Intelligence Research Institute at the Universidad Veracruzana also in Xalapa. Email: htapia@uv.mx.

Wednesday, 28 September 2022 08:23:46

Grahame Jackson posted a new submission ‘Sugary poo could be used to lure destructive plant pests to their doom’

Submission

Sugary poo could be used to lure destructive plant pests to their doom

Newswise

Male spotted lanternflies are strongly attracted to smell of honeybee produced by male conspecifics
by Frontiers

Spotted lanternflies communicate through their smelly excretions  ̶  called honeydew, reports a new study in Frontiers in Insect Science. This invasive species has been impacting crops in the northeastern US, but little is known about how these insects locate each other for reproduction or feeding. According to this latest research, the insects’ honeydew emits several airborne chemicals that attract other lanternflies. Surprisingly, these effects are sex-specific, which may be the first known case of such signals in insects known as planthoppers.

“This research is important because the first step to managing any pest is to understand their biology and behavior,” said Dr Miriam Cooperband of the United States Department of Agriculture Animal and Plant Health Inspection Service, Plant Protection and Quarantine Division (USDA APHIS PPQ) in the US. “As we learn more about the behavior of the spotted lanternfly, we hope to find a vulnerability that we can use to develop pest management tools to reduce its population and spread.”

Attractive scents

Although these insects are known to leave their excretions throughout the understory, they have the peculiar habit of coming together in huge numbers on only select tree trunks. Other tree trunks are mysteriously left untouched. These multitudes of lanternflies can secrete so much honeydew that the surface of the tree becomes white and frothy, as well as emitting a smell of fermentation.

To study the signals sent by these excretions, Cooperband and her collaborators collected honeydew samples separately from male and female lanternflies in the field, to test in the lab. The researchers then gave lanternflies a choice between areas with or without the different types of honeydew to see what attracted them. 

Surprisingly, males were strongly attracted to male honeydew, while both males and females were only slightly attracted to female honeydew. Although it’s still unclear what would cause this behavior, this is consistent with observations of how these insects behave in the field.

The team went on to analyze the different components of the honeydew to determine which produced the strongest signals. Five molecules were tested for attraction and found to have specific sex-attractant profiles. Two molecules called benzyl acetate and 2-octanone attracted both sexes, one molecule called 2-heptanone attracted only males, one molecule 2-nonanone attracted only females and one molecule, 1-nonanol, repelled females, but not males.

Pest control

These findings are just the beginning for better understanding how to potentially control this invasive pest. There are many more questions, such as whether there are seasonal variations in this behavior, and whether there are interactions with microbes in the honeydew that produce the necessary chemicals.

“Spotted lanternfly behavior and communication is quite complex, and this is only the tip of the iceberg. In addition to our work studying chemical signals, such as those in honeydew, we are also interested in the role of substrate vibrations in their communication system,” said Cooperband. “Future research might focus on understanding how they locate each other when they gather and find mates using multiple types of signals.”

Original paper: https://www.frontiersin.org/articles/10.3389/finsc.2022.982965/full


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


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 

  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

  International Plant Health Conference  21 – 23 September 2022 | 09:00-18:00 Queen Elizabeth II Centre | London UK     Dear plant health colleagues and friends,   Plant health is a key factor in any strategy to achieve food security, protect the environment and biodiversity, and facilitate safe trade.   In the past months, the Secretariat of the International Plant Protection Convention has been working closely with the Department for Environment, Food & Rural Affairs (DEFRA) of the United Kingdom (UK) and the Food and Agriculture Organisation (FAO) of the United Nations, on organizing the first-ever International Plant Health Conference (IPHC), being held in London, the UK, from 21 – 23 September.     The IPHC aims to address new and emerging plant health challenges, including climate change impacts, the rapid loss of biological diversity, the significant increase in international trade, and new pest pathways such as e-commerce.   The IPHC is a unique opportunity to raise global awareness and promote the importance of protecting plant health. Take part in the crucial discussions on plant health by following the Live webcast on the IPHC webpage.   Information on the IPHC and a collection of plant health resources (key messages, social media assets, publications, videos, stories, podcasts, and more) are available on the IPHC Trello board. Please don’t forget to tag IPPC (Facebook, Twitter) when posting on social media and remember to use the official event hashtag #PlantHealthConference.    I would be pleased to hear your thoughts and ideas on the way forward to promote plant health globally. Sincerely, Osama El-Lissy 
Secretary 
International Plant Protection Convention
Join the conversation on the #PlantHealthConference!

https://769dbd10c437f0a5112c578daa7152cf.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

UAF VC Urges Scientists To Discover New Biological Control For Parthenium

 Sumaira FH  Published September 09, 2022 | 07:48 PM

UAF VC urges scientists to discover new biological control for Parthenium

University of Agriculture Faisalabad (UAF) Vice Chancellor Prof Dr Iqrar Ahmad Khan has urged agricultural scientists to discover new biological control for Parthenium as it is spreading at an alarming rate across the country

https://769dbd10c437f0a5112c578daa7152cf.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

FAISALABAD, (UrduPoint / Pakistan Point News – 9th Sep, 2022 ) :University of Agriculture Faisalabad (UAF) Vice Chancellor Prof Dr Iqrar Ahmad Khan has urged agricultural scientists to discover new biological control for Parthenium as it is spreading at an alarming rate across the country.

He was addressing an international seminar on “Biological Control of Parthenium hysterophorus in Pakistan using stem boring weevil (Listronotus setosipennis)”, organised by the university in collaboration with the CABI Regional Bioscience Centre Pakistan.

He said that Parthenium was spreading rapidly both in rural and urban landscapes in the country after crossing continents. It was highly-invasive due to its prolific seed production, flower production within four weeks of germination, tolerance to varying climatic conditions, and the production of allelochemicals that affect the growth of nearby plants.

He said that agri scientists were duty bound accelerate their efforts for control Parthenium in addition to creating awareness among the farming community about destructive effects of this weed so that it could be controlled at maximum extent.

Dr. Philip Weyl, Weed Biocontrol Specialist from CABI Switzerland during his address said that Listronotus was a natural enemy of Parthenium, from the weed’s native range of Central America. Listronotus was a nocturnal weevil that layed its eggs primarily in the flowers of Parthenium where newly hatched larvae tunnel into the stem and continue to feed, eventually exiting at the base of the stem to pupate in the soil. Several larvae feeding in the stem can kill Parthenium rosettes and mature plants.

Pro-Vice Chancellor UAF Prof Dr Anas Sarwar Qureshi also addressed the seminar and called for innovative approaches to address the issues of the agricultural sector.

He said that excessive usage of chemicals on crops was creating health and environmental hazards. He said that adoption of latest scientific trends was need of the hour to cope with agricultural challenges at national level because this sector was directly linked to poverty alleviation.

Chairman Entomology UAF Prof Dr Sohail Ahmad highlighted the importance of research needed around the biocontrol of parthenium and other invasive weeds.

He said that the country faced the catastrophe due to heavy floods in which we had lost vast range of agriculture. The university had also mapped out a comprehensive plan to rehabilitate this sector in flood hit areas, he added.

Abdul Rehman from CABI said that keeping in view the destructive impacts of Parthenium weed, CABI initiated a biological control programme in Pakistan in 2017. For this purpose, CABI’s established a new quarantine laboratory at its Rawalpindi centre in Pakistan to enhance its capabilities to manage Parthenium weed.

The new quarantine facility allowed scientists to investigate a range of biological control options including the stem boring weevil Listronotus setosipennis.

Dr. Ijaz Ashraf from UAF shared updates on an awareness campaign for control of Parthenium hysterophorus in Pakistan and said that university students were on front foot to sensitize stakeholders and communities on negative impacts of Parthenium.

He vowed that such awareness-raising interventions around invasive species management and other agricultural challenges would be continued in close collaboration with CABI.