Fusarium-resistant lettuce varieties are coming


Fusarium-resistant lettuce varieties are coming

Fusarium is a fungus that’s been prone to infect lettuce – predominantly iceberg – in several parts of the world. In Arizona, the disease has been around since 2001. While it was first contained in one field, it has since then spread through lettuce production areas of the Southwestern US. The problem is that it spreads very easily through people and machinery. Even cleaning machinery hasn’t stopped the spread.

“Once a plant has been infected, Fusarium gets into the root system, preventing the plant from taking up nutrients or water and causing it to die,” says Davie Brooks with Greengo Seed in Yuma, Arizona. Since the plants are affected from underground, it is hard to discover infected plants at first. Droopy leaves are the first sign, followed by the plant drying out and turning brown. “Once a field is infected, the only way to turn things around is to fumigate by applying chemicals,” commented Brooks. “However, most chemicals are no longer allowed to be used, and this solution is only effective for about two years.” After that, the Fusarium will start popping up again.

In addition to Yuma, which supplies 90 percent of lettuce grown in the US in winter, the Salinas region in California also witnesses some problems with Fusarium. “Although it is more widespread in Yuma, it is becoming an issue in Salinas as well,” commented Brooks. Furthermore, the same strain of Fusarium, Fol:1, is affecting lettuce production in Spain, an important lettuce supplier for Europe in winter.

Fusarium-resistant variety Balboa in the back and regular field variety impacted by Fusarium in front.

Fusarium-resistant varieties aren’t perfect
In the past five years, Greengo Seed has worked on the development of Fusarium-resistant varieties, and it’s the second year they have been planted commercially. Since then, the impact of Fusarium has decreased. “We have developed four iceberg lettuce varieties that are Fusarium resistant, including Adrian, Balboa, Mickey, and Paulie,” said Brooks. While the performance of these varieties is okay, many growers are still trying to use the old varieties they are used to. “The main reason is that the new varieties aren’t as adaptable as the old ones,” he shared. “They aren’t as bolt tolerant or sure heading, and the shape isn’t as pretty.” In addition to the Yuma region, Greengo Seed will also be sending over Fusarium-resistant seeds to Spain this winter.


Fusarium-resistant iceberg lettuce varieties Adrian and Balboa.

Improved varieties
However, Greengo Seed is working on developing new varieties that better align with the varieties growers are used to. The company is working on 40 new lines that better resemble the old varieties and will have a better bolting tolerance and more sure-heading, as well as offer higher yields and grow a larger size. “Within a year, we should be able to have a few Fusarium-resistant varieties for iceberg lettuce and Romaine lettuce out there that have the characteristics of the old varieties,” said Brooks.

In their search for the best Fusarium-resistant varieties, Greengo Seed has screened more than 700 different lettuce types in recent years. It has taken the company about five years, turning two generations per year, to develop Fusarium-resistant lettuce varieties. “We went from not having anything to commercializing a variety in five years.” Usually, this process takes about seven to ten years, but Greengo Seed chose to speed up the process by selecting, digging up, and replanting a variety twice a year instead of waiting until the next season.

For more information:
Davie Brooks
Greengo Seed
Tel.: (+1) 928-580-4222
dlb@greengoseed.com
www.greengoseed.com

Publication date: Fri 27 Oct 2023
Author: Marieke Hemmes
© FreshPlaza.com

Trait donors for early blight resistance in tomatoes


Trait donors for early blight resistance in tomatoes

By conducting hierarchical clustering along a sliding window, we generated haplotypes across hundreds of re-sequenced genomes in a few hours. We leveraged our method to define cryptic introgressions underlying disease resistance in tomatoes (Solanum lycopersicum L.) and to discover resistant germplasm in the tomato seed bank. The genomes of 9 accessions with early blight (Alternaria linariae) disease resistance were newly sequenced and analyzed together with published sequences for 770 tomato and wild species accessions, most of which are available in germplasm collections.

Identification of common ancestral haplotypes among resistant germplasm enabled rapid fine mapping of recently discovered quantitative trait loci (QTL), conferring resistance and the identification of possible causal variants. The source of the early blight QTL EB-9 was traced to a vintage tomato named ‘Devon Surprise.’ Another QTL, EB-5, as well as resistance to bacterial spot disease (Xanthomonas spp.), was traced to Hawaii 7998.

A genomic survey of all accessions forecasted EB-9-derived resistance in several heirloom tomatoes, accessions of S. lycopersicum var. cerasiforme, and S. pimpinellifolium PI 37009. Our haplotype-based predictions were validated by screening the accessions against the causal pathogen. There was little evidence of EB-5 prevalence in surveyed contemporary germplasm, presenting an opportunity to bolster tomato disease resistance by adding this rare locus. Our work demonstrates practical insights that can be derived from the efficient processing of large genome-scale datasets, including rapid functional prediction of disease resistance QTL in diverse genetic backgrounds. Finally, our work finds more efficient ways to leverage public genetic resources for crop improvement.

Anderson, T.A., Sudermann, M.A., DeJong, D.M., Francis, D.M., Smart, C.D. and Mutschler, M.A. (2023), Detection of trait donors and QTL boundaries for early blight resistance using local ancestry inference in a library of genomic sequences for tomato. Plant J. https://doi.org/10.1111/tpj.16495

Read the complete paper here

Publication date: Mon 23 Oct 2023

How soil viruses behave and interact with bacteria


How soil viruses behave and interact with bacteria

by Emily Dooley, UC Davis

Seasonal rain on California grasslands kicks off a rapid expansion and turnover of viruses in the soil, according to a new study by UC Davis and Lawrence Livermore National Lab. These viruses may influence the population of soil bacteria. Credit: Christian Santos-Medellín

Viruses in soil may not be as destructive to bacteria as once thought and could instead act like lawnmowers, culling older cells and giving space for new growth, according to research out of the University of California, Davis, published Sept. 28 in the journal Nature Ecology and Evolution.

https://d7c2e51b2340a891781f0ec3ab227d0d.safeframe.googlesyndication.com/safeframe/1-0-40/html/container.html

How viruses affect ecosystems, including bacteria, is challenging to untangle because they are complex and change over time and space. But the first annual rain on Mediterranean ecosystems, such as those in California, offers a kind of reset, triggering activity that can be observed.

Scientists took soil from four California grasslands, brought it back to their lab and simulated precipitation by watering the dry samples, which grew microorganisms and viruses. They tracked changes over 10 days.

“Viruses are really abundant in soil, but we didn’t know whether they were doing much of anything,” said Joanne B. Emerson, associate professor of plant pathology at UC Davis and corresponding author on the paper. “This level of extreme dynamics hasn’t been observed.”

Viruses likely not as deadly

The researchers found that the viral composition was diverse and changed so much that only 15% of the virus types were the same at the end of the experiment compared to the beginning. There was far less turnover when it came to bacteria. And the viruses preyed on the dominant types of bacteria but did not kill them off.

“Viral communities change much, much more over short temporal scales than bacterial communities from the same samples,” Emerson said. “We see this massive change, what we call turnover, in viral community composition over time.”

Viruses affect the makeup of bacterial communities, which can lead to differences in how ecosystems function because bacteria influence carbon and nutrient cycles in soil.

“Bacteria can affect plant health, ecosystem dynamics, all sorts of things,” Emerson said.

The finding suggests that viruses behave differently than once thought and this knowledge could lead to a better understanding of soil dynamics when it comes to bacteria.

“Instead of the viruses totally obliterating everything, maybe they do this gentle culling,” Emerson said.

A pattern for all

The study also found that viruses behaved similarly across the four grasslands even though they had different compositions and came from different places. This suggests that viral patterns are similar, despite their specific characteristics.

“The much greater change in viral compared to bacteria types over time suggests that possibly we’ve been measuring bacteria wrong,” Emerson said.

The lead author on the paper is Christian Santos-Medellín, who was a postdoctoral researcher at UC Davis, and now works at Corteva Agriscience. Researchers from Lawrence Livermore National Laboratory, UC Berkeley and UC Merced contributed to the research.

More information: Christian Santos-Medellín et al, Viral but not bacterial community successional patterns reflect extreme turnover shortly after rewetting dry soils, Nature Ecology & Evolution (2023). DOI: 10.1038/s41559-023-02207-5

Journal information: Nature Ecology & Evolution 

Provided by UC Davis 


CABI: Update: New Pest & Disease Records (13 October 2023)


CABI: Update: New Pest & Disease Records (13 October 2023)

Update: New Pest & Disease Records (13 October 2023)

This month’s pest alerts include information on Fusarium species causing root rot of tobacco and field peas.

We’ve selected a few of the latest new geographic, host and species records for plant pests and diseases from CAB Abstracts. Records this month include the first report of Fusarium sacchari causing root rot of tobacco in China and the first report of Fusarium commune causing root rot of field peas in Canada.


To view all search results for new geographic, host and species records for plant pests and diseases, click here or to view results by your location, click here.

If there’s another new record you’d like to highlight, please post a comment.

View past pest alerts

Plant pests and diseasesnew geographic recordsnew host recordsnew speciespest alertsplant diseasesplant healthplant pests

Agriculture and International DevelopmentCrop healthPlant Sciences

Leave a Reply

data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==

Subscribe to blog

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Email Address

Subscribe

Contribute


If you are active in the field of plant health or development and would like to contribute to the Plantwise Blog, please contact Donna Hutchinson. We are happy to post any credible articles that we think would be of interest to our readership.

Views expressed in contributions do not necessarily reflect official CABI or Plantwise positions.

Archives

Archives  Select Month   October 2023    September 2023    August 2023    July 2023    June 2023    May 2023    April 2023    March 2023    February 2023    January 2023    December 2022    November 2022    October 2022    September 2022    August 2022    July 2022    June 2022    May 2022    April 2022    March 2022    February 2022    January 2022    December 2021    November 2021    October 2021    September 2021    August 2021    July 2021    June 2021    May 2021    April 2021    March 2021    February 2021    January 2021    December 2020    November 2020    October 2020    September 2020    August 2020    July 2020    June 2020    May 2020    April 2020    March 2020    February 2020    January 2020    December 2019    November 2019    October 2019    September 2019    August 2019    July 2019    June 2019    May 2019    April 2019    March 2019    February 2019    January 2019    December 2018    November 2018    October 2018    September 2018    August 2018    July 2018    June 2018    May 2018    April 2018    March 2018    February 2018    January 2018    December 2017    November 2017    October 2017    September 2017    August 2017    July 2017    June 2017    May 2017    April 2017    March 2017    February 2017    January 2017    December 2016    November 2016    October 2016    September 2016    August 2016    July 2016    June 2016    May 2016    April 2016    March 2016    February 2016    January 2016    December 2015    November 2015    October 2015    September 2015    August 2015    July 2015    June 2015    May 2015    April 2015    March 2015    February 2015    January 2015    December 2014    November 2014    October 2014    September 2014    August 2014    July 2014    June 2014    May 2014    April 2014    March 2014    February 2014    January 2014    December 2013    November 2013    October 2013    September 2013    August 2013    July 2013    June 2013    May 2013    April 2013    March 2013    February 2013    January 2013    December 2012    November 2012    October 2012    September 2012    August 2012    July 2012    June 2012    May 2012    April 2012    March 2012    February 2012    January 2012    December 2011    November 2011    October 2011    September 2011    August 2011    July 2011    June 2011    May 2011    April 2011    March 2011    February 2011    January 2011    December 2010    November 2010  

Categories


CABI News & Blogs


Related News & Blogs

How has a ‘writeshop’ helped to address invasive apple snail in Kenya?

Invasive apple snail laying eggs. Image: CABI Invasive species, like apple snail, are a threat to food security. It’s important that they’re quickly managed before they start to spread. One of the best ways to do this is to share plant health knowledge…

19 October 2023

CABI trains young service providers to help smallholder mango farmers in Kenya produce quality goods for export10 October 2023

Update: New Pest & Disease Records (07 September 2023)11 September 2023

What are bioprotection products, and how do they work?16 August 2023

New bioprotection course paves the way for a more sustainable agricultural landscape 8 August 2023

CABI is a member of:   The Association of International Research and Development Centers for Agriculture

Join our mailing list

Sign up to receive the latest news, information, updates and offers from CABI.

Sign up

CABI_Logo_White

Improving lives by solving problems in agriculture and the environment

What we do

About CABI

Products and services

Other

CABI Centres

© Copyright 2021 CABI is a registered EU trademark

Like most websites we use cookies. This is to ensure that we give you the best experience possible. Continuing to use Plantwise Blog means you agree to our use of cookies. If you would like to, you can 

Kenya: ‘writeshop’ helped to address invasive apple snail


October 19, 2023 

Rachel Winks 

No Comments

How has a ‘writeshop’ helped to address invasive apple snail in Kenya?

Invasive apple snail laying eggs. Image: CABI

Invasive species, like apple snail, are a threat to food security. It’s important that they’re quickly managed before they start to spread. One of the best ways to do this is to share plant health knowledge with smallholder farmers. And writeshops are an excellent tool for gathering evidence-based information to do this. In this blog, we look at how a recent writeshop in Kenya has helped to curate knowledge to identify and manage invasive apple snail impacting Kenya’s rice production.

What’s apple snail, and why is it such a threat to Kenya’s food security?

In 2020, CABI confirmed the discovery of invasive apple snail (Pomacea canaliculata) in rice fields in the Mwea Irrigation Scheme in Kirinyaga County, Kenya. The snail is native to South America. However, over the last 40 years, this freshwater mollusc has spread across North America and Asia, and has now had its first report in continental Africa. The Kenya Plant Health Inspectorate Service (KEPHIS) and the Ministry of Agriculture have taken immediate action. This is critical as the IUCN/GISD lists the invasive apple snail among its 100 most damaging invasive species globally.

The snail usually lives in waterways, like rice paddies, where it feeds on young rice seedlings. One adult snail can destroy one square metre of rice in a single night. And females can lay up to 3,000 eggs overnight. Moreover, the hatched snails have a 90% survival rate and can live for up to four years. As a result, they are highly damaging to rice paddies.

data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==Animation showing the life cycle of the invasive apple snail

Taking action on invasive apple snail

In recent years, CABI has been working with Kenya’s authorities to control the spread of the snail through the PlantwisePlus programme. CABI has also researched the potential impact of the snail on rice production in Kenya. In July 2023, the journal of Pest Management Science published a CABI-led study on the snail. The paper laid out how an invasion of apple snail could be “disastrous” for rice production and food security in Kenya. The pest could spread and affect other rice-growing regions across Africa.

Today, extension agents report that apple snail is now one of Kenyan rice farmers’ top five concerns. Agro-dealers report that 70% of complaints they hear are due to apple snails. Household surveys and focus group discussions with smallholder farmers reveal the scale of the devastation. The snail has reduced rice yields by up to 14%. However, it has reduced net income from rice by up to 60% in addition to increasing the production costs.

Using writeshops to help limit to threat of the apple snail

Against this background, Kenya’s Ministry of Agriculture and Livestock Development (MoALD) took further action. Through its Plant Protection and Food Safety Directorate (PP&FSD), it organized a writeshop. In this context, a writeshop is a collaborative writing workshop. Experts drawn from different institutions and disciplines come together to write content capturing best practices for managing an invasive pest. Multiple authors or contributors work on the same piece of content. In this case, the writeshop aimed to create technical resources to manage the spread of invasive apple snail.

Facilitated by CABI’s David Onyango, this collaborative workshop brought together delegates from across Kenya. This included the national government, academia, national and international research organizations, and the National Irrigation Authority.

The more detailed goals of the writeshop included:

  • Developing a technical brief for the invasive apple snail in Kenya
  • Review existing technical posters (on identification, life cycle and management)
  • Aligning the posters to the Kenyan situation

The workshop was well attended, and participants got busy finding solutions. They talked about how the event created an excellent atmosphere for knowledge exchange. As the workshop drew to a close, attendees reported on the strides made to craft a comprehensive technical document to steer the management of apple snail. They produced a technical brief that outlines strategies for an integrated approach to tackling the snail across Kenya.

The future of rice production in Kenya

The researchers stressed the importance of rapidly addressing apple snail in Kenya. This includes raising awareness, outreach and capacity building. In Kenya, around 300,000 small-scale farmers are involved in rice cultivation. The work is an important source of income for many. Furthermore, the Mwea Irrigation Scheme accounts for 80-88% of the country’s rice production.

Rice consumption is set to grow in the next seven years. As a result, it’s been identified as a priority food value chain. However, Kenya’s authorities have recognized considerable untapped potential to expand rice production. Estimates suggest a production potential of up to 1.3 million hectares of irrigated rice.

CABI scientist, Dr Kate Constantine, explained how rice production has seen consistent growth in demand over the last three decades. She described how it has the potential to improve rural livelihoods. In Kenya, rice is the third most important cereal grain after maize and wheat. Its consumption is increasing at a faster rate than production.

Action a priority to safeguard farmer livelihoods

Dr Constantine also explained that rice farmers in Mwea face many challenges of which apple snail is only one. This includes water shortages, rice blast attacks and high input costs. They also face machinery shortages, bird damage, poor infrastructure, and a lack of resilient and acceptable rice varieties. “The recent introduction of apple snail has added to these challenges, posing a serious threat to rice production in the region and potentially across Africa,” she said.

Farmers have been increasing their use of chemical pesticides in an attempt to stop the snail. They have also hired labour, which is costly, to physically remove egg masses and snails. CABI research officer, Fernadis Makale, explained how the negative impacts will only increase. Over time, the apple snail will continue to spread if unchecked. Action is urgently needed. The window of opportunity to contain or eradicate the snail is limited. If it becomes widespread across Kenya, the only feasible option will be management. And management has high economic, livelihood and environmental costs.

The writeshop was an important step towards managing the snail. With the information curated, this technical resource will help smallholders and the people who support them to take action. 

Learn more on the Invasive Apple Snail Portal.

data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==

Kenyainvasiveinvasive apple snailinvasive speciesplant pests

Crop healthInvasive species

How plants respond to environmental threats


How plants respond to environmental threats

SEPTEMBER 25, 2023

 Editors’ notes

by Kara Headley, Michigan State University

Credit: Michigan State University

In plants, the jasmonate, or JA, signaling pathway helps plants control their defense responses to environmental stresses. Like the human body, plants respond differently to individual threats. Just as people wouldn’t get a fever due to a sprained ankle, plants deal with harmful elements in particular ways.

A study from the MSU-DOE Plant Research Laboratory (PRL) Howe lab looks at how plants respond to environmental threats in the correct way. This study was published in New Phytologist.

“Plants encounter so many environmental stressors, including biotic stressors like pathogens or insects,” said Leah Johnson, co-first author on the study and former graduate student in the Howe lab. “It can be really energy intensive for them to produce all these defense responses.”

Researchers have known that the JA signaling pathway controls defense responses for some time, but they were still seeking to understand how appropriate plant responses to different threats can be turned on or off as needed. JAZ and MYC proteins were known to have opposing effects on this pathway: JAZs keep the pathway off and the MYCs can turn the pathway on. Most plants have several copies of the JAZs and the MYCs and one common idea is that those multiple copies help plants fine-tune their responses.

“The real breakthrough of the paper is showing that different JAZ subsets control different responses,” said Ian Major, co-first author on the study and former postdoctoral researcher in the Howe lab.

The researchers grew mutant Arabidopsis thaliana plants which were missing most of their JAZs. As JAZs keep the defense responses under control, their removal results in an uncontrolled defense response, somewhat analogous to autoimmunity. Because the mutant plant was spending so much energy on defending itself from all threats, even if those threats were not present, it had less energy to grow. The plants were smaller and produced fewer seeds than their counterpart found in the wild.

This mutant was cross bred with wild-type Arabidopsis plants to generate offspring with different sets of missing JAZs. Some of those offspring showed increased levels of defense involved in protection against necrotrophic pathogens, which feed on dead tissue. By examining which JAZs were missing in those plants, the researchers were able to identify what part of the JA pathway allows for this defense to be turned on and off.

“We were able to show that with JAZ regulators, a certain set controls insect defense, and a completely separate set seems to control resistance to necrotrophic pathogens,” Major said.

Johnson continued, “We found that subsets of these families [JAZ and MYC] differentially regulate responses to insects versus necrotrophic pathogens. This suggests that these families obtained distinct regulatory functions at some point in plant evolutionary history and suggests a mechanism for how plants can respond correctly to different stressors.”

In the future, this work has potential to be applied to crop plants, activating defenses to insects or pathogens, without expending too much energy, to help them fight off these threats.

“The identification of plant regulatory genes that specifically control the partitioning of photosynthetic products creates new opportunities to engineer plants for enhanced yield and stress resistance,” said Gregg Howe, the primary investigator on this paper and MSU Foundation Professor in the PRL and the Department of Biochemistry & Molecular Biology.

More information: Leah Y. D. Johnson et al, Diversification of JAZ‐MYC signaling function in immune metabolism, New Phytologist (2023). DOI: 10.1111/nph.19114

Journal information: New Phytologist 

Provided by Michigan State University 


Explore further

Iron signaling functions partly as a plant immune system against pathogen

This Predatory Mite is a Rising Star in Pest Management


ENTOMOLOGY TODAY  LEAVE A COMMENT

The mite Amblyseius swirskii (adult female shown here) feeds on various insect and mite species, including many notorious pests of vegetable crops. A new article in the Journal of Integrated Pest Management explores the biology and applications of this versatile mite that have propelled it to the forefront of many IPM programs. (Image originally published in Lopez 2023, Journal of Integrated Pest Management)

By Lorena Lopez, Ph.D.

Lorena Lopez, Ph.D.

In the world of agricultural entomology, the quest for sustainable pest management solutions has led us down a fascinating path. Among the multitude of biocontrol agents, the predatory mite Amblyseius swirskii has emerged as a game changer. Its remarkable capabilities and versatility make it a highly valued asset in our efforts against pests in vegetable crops. However, several challenges and considerations must be addressed to realize its full potential.

Amblyseius swirskii, originally described in 1962 from almond trees in Israel, has taken center stage as a potent biological control agent—an insect or arthropod that can be deployed to suppress pests. Geographical boundaries no longer confine this predatory mite to the Mediterranean region; it has made its mark across the globe. From Europe to Asia, Africa, and the Americas, this commercially available predatory mite has been released in more than 50 countries worldwide and has established populations in many countries’ crops. This global distribution speaks loudly about its effectiveness as a biological control agent in various agricultural settings, from greenhouses to open fields.

In an article published in September in the open-access Journal of Integrated Pest Management, I profile Amblyseius swirskii and its biology, distribution, and various applications for biological control in IPM programs.

The Secret to Its Popularity: Versatility

What sets A. swirskii apart is its remarkable versatility. This predatory mite doesn’t discriminate when it comes to its diet. It feeds on various insect and mite species, including those notorious for wreaking havoc on vegetable crops. Its adaptability and effectiveness have propelled it to the forefront of integrated pest management (IPM) strategies. Amblyseius swirskii is a generalist predator that preys on various pests, including whiteflies, russet or gall mites, broad mites, spider mites, false spider mites, and first-instar thrips. Moreover, it can survive and thrive on non-prey food sources such as pollen, nectar, plant secretions, honeydew, and even a fungal secretion called pycnial fluid. This adaptability enhances its reproductive capacity and establishment during the early stages of crop growth when pest numbers are low.

Companion Planting: A Strategic Alliance

One of the most commonly used tactics employed in maximizing A. swirskii‘s performance is companion planting or intercropping. Growing specific companion plants alongside or within cash crops creates an ecosystem that promotes the establishment and dispersal of beneficial arthropods, including A. swirskii. These companion plants, such as sweet alyssum (Lobularia maritima), buckwheat (Fagopyrum esculentum), or ornamental peppers (Capsicum annuum, ‘Explosive Ember’ cultivar), offer alternative shelter and food sources to these predatory mites, promoting their presence when and where they are needed most: the periods of pest scarcity usually at early stages of the crop.

Additionally, providing pollen from crop or non-crop plants or using pollen supplements can be advantageous to enhance A. swirskii‘s performance. Cattail pollen (Typha spp.) is the most used source of pollen supplements that are commercialized and used to enhance A. swirskii establishment, followed by pollen from pepper species. Implementing additional suppression practices, including cultural methods such as sanitation and isolation, can complement A. swirskii‘s suppression efforts.

The Challenges: Nature’s Hurdles

While A. swirskii offers tremendous promise, it’s not without its challenges. One significant factor is its preference for glabrous (i.e., smooth or glossy) leaves or those offering specialized shelters like domatia. Glandular trichomes, small hair-like outgrowths common on newly unfolded leaves of plants like squash and tomato, are usually not preferred by A. swirskii. This preference can limit its establishment on certain crops, challenging growers who rely on these plants.

Close-up of the center of a flower with light purple petals, and dark purple filaments capped with grayish-green anthers (the latter of which are blurry and out of focus in the foreground of the image. Visible at the base of the filaments are several small round mites, each slightly oval in shape and a semi-translucent light brown in color.

Pesticides: A Double-Edged Sword

Another challenge arises from the ever-present use of pesticides in agriculture. While A. swirskii can be a robust biocontrol agent, it is not immune to the effects of chemical insecticides and miticides. The impact of these chemicals varies depending on developmental stages, with immature stages of A. swirskii often more susceptible than adults. Some pesticides, like abamectin, were once considered selective but have since been shown to harm A. swirskii. Careful consideration and timing of pesticide applications are necessary to mitigate the risk to these beneficial predators.

Reduced-risk pesticides offer a glimmer of hope. Certain products, such as potassium salts of fatty acids (often called pesticide soaps), have minimal detrimental effects on A. swirskii when applied correctly. These products are known for their short environmental persistence, which can be advantageous when managing pest outbreaks. Moreover, conventional insecticides such as fenpyroximate have shown potential to be integrated into pest management programs if applications follow low levels indicated in the label and are scheduled properly when predatory mite populations in the field consist primarily of adults.

Timing Is Everything

Meanwhile, the timing of A. swirskii releases is crucial. Releasing them within three days after pesticide treatments should be avoided to prevent detrimental effects due to pesticide residues. Ideally, pesticide applications should be scheduled at least five days or one week after releasing A. swirskii, allowing the predators to acclimate and establish in the crop.

A Multi-Faceted Approach

The success of A. swirskii in vegetable crops centers on a multi-faceted approach. Growers or scouts must identify the pests requiring suppression and assess A. swirskii‘s efficiency in tackling them. Environmental conditions within the target crop—such as temperature, humidity, and water availability—must align with the predator’s optimal requirements. Choosing reputable providers for A. swirskii is equally vital. High-quality predatory mites from trusted sources are essential for the success of biocontrol programs. The provider’s reliability and adherence to best practices in rearing and distribution ensure that growers receive effective agents.

Amblyseius swirskii is the third-most researched predatory mite after Phytoseiulus persimilis and Neoseiulus californicus, ranking first and second, respectivelyIn the last two decades, A. swirskii has led a new era for biocontrol agents in vegetable crops by quickly becoming one of the most used and researched predatory mites. Its adaptability and global presence make it a compelling ally for growers seeking sustainable solutions. While challenges exist, careful planning, reduced-risk pesticides, and understanding A. swirskii’s unique characteristics can pave the way for its successful incorporation into IPM programs.

Read More

Meet Amblyseius swirskii (Acari: Phytoseiidae): a commonly used predatory mite in vegetable crops

Journal of Integrated Pest Management

Lorena Lopez, Ph.D., is postdoctoral associate in entomology at Virginia Tech’s Eastern Shore Agricultural Research and Extension Center in Painter, Virginia. Email: lorelopezq257@vt.edu.  

The effect of Trichoderma harzianum on physiological-biochemical characteristics of cucumber and the control effect against Fusarium wilt


The effect of Trichoderma harzianum on physiological-biochemical characteristics of cucumber and the control effect against Fusarium wilt

At the seedling and adult plant phases, pot experiments were carried out to enhance the physiological-biochemical characteristics of cucumber, guarantee its high yield, and ensure its cultivation of quality. Trichoderma harzianum conidia agents at 104, 105, 106, and 107 cfu g−1 were applied in accordance with the application of Fusarium oxysporum powder at concentrations of 104 cfu/g on the protective enzyme activity, physiological and biochemical indices, seedling quality, resilience to Fusarium wilt, quality, and yield traits. Fusarium oxysporum powder at 104 cfu g−1 was used to treat CK1, while Fusarium oxysporum powder and T. harzianum conidia agents were not used to treat CK2.

The results show that different T. harzianum agents improved the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD) in cucumber seedlings, improved chlorophyll content, root activity, root-shoot ratio, and seedling strength index, and decreased malondialdehyde (MAD) content (P < 0.05). T3, a combination of 104 cfu g−1 Fusarium oxysporum powder and 106 cfu g−1 T. harzianum conidia agents, had the greatest promoting effect. The effects of different T. harzianum conidia agents and their application amounts on the control of cucumber Fusarium wilt were explored. T3 had the best promotion impact, and the control effect of cucumber Fusarium wilt at the seedling stage and adult stage reached 83.98% and 70.08%, respectively.

The quality index and yield formation of cucumber were also increased by several T. harzianum agents, with T3 having the strongest promotion effects. In comparison to CK1, the soluble sugar, Vc, soluble protein, and soluble solid contents of T3 cucumber fruit were 120.75%, 39.14%, 42.26%, and 11.64% higher (P < 0.05), respectively. In comparison to CK2, the soluble sugar, Vc, soluble protein, and soluble solid contents of T3 cucumber fruit were 66.06%, 24.28%, 36.15%, and 7.95% higher (P < 0.05), respectively. In comparison to CK1 and CK2, the yields of T3 cucumber were 50.19% and 35.86% higher, respectively.

As a result, T. harzianum agents can enhance the physiological and biochemical traits of cucumber seedlings, raise the quality of cucumber seedlings, have a controlling impact on Fusarium wilt, and increase the yield and quality of cucumber fruit. The greatest effectiveness of T3 comes from its use. In this study, Trichoderma harzianum conidia agents demonstrated good impacts on cucumber yield formation and plant disease prevention, demonstrating their high potential as biocontrol agents.

Lian, H., Li, R., Ma, G. et al. The effect of Trichoderma harzianum agents on physiological-biochemical characteristics of cucumber and the control effect against Fusarium wilt. Sci Rep 13, 17606 (2023). https://doi.org/10.1038/s41598-023-44296-z

Read the complete paper here.

Publication date: Wed 18 Oct 2023 email this article   Print 

Receive the daily newsletter in your email for free | Click here

Novel plant pathogen discovered on world’s northernmost island


Novel plant pathogen discovered on world’s northernmost island

SEPTEMBER 25, 2023

 Editors’ notes

by University of Tsukuba

A novel pathogenic fungus causing leaf spot disease in Arctic plants was reported on Ellesmere Island. Although there are a few reports on plant pathogens in Arctic ecosystems, this study showed that even in the Arctic, the regional location and the host species-level differences drive pathogenic diversity. Credit: University of Tsukuba

Ellesmere Island (76°N–83°N) is one of the northernmost islands in the world, along with Greenland and Spitsbergen Island. More than 100 species of vascular plants are distributed across this island in the ice-free areas in summer. However, there has been little research on fungal diseases in these plants.

https://cd488277d7d9a6456d3ba0ab3b864983.safeframe.googlesyndication.com/safeframe/1-0-40/html/container.html

In this new study published in Forest Pathology, a researcher at the University of Tsukuba discovered a pathogenic fungus that forms a unique black stroma (reproductive organs of fungi, such as mushrooms) on the leaves of the Arctic willow, which is a dominant plant on the island.

The morphological characteristics of fungus were different from those of any related species discovered as yet in terms of the key points for species identification, namely, the size of the spores and shape of stroma. Molecular phylogenetic analysis also supports the uniqueness of this specimen, and it has been described as a novel species of fungus of the genus Rhytisma.

This study has shown that even in the Arctic, the regional location and the host species–level differences drive the diversity of the pathogens. Further data on Rhytisma spp. from other regions in the Arctic will help researchers understand how they spread across the Arctic region with their hosts and how they survived in the tundra ecosystem.

More information: Shota Masumoto, The northernmost plant pathogenic fungus, Rhytisma arcticum sp. nov.: Morphological and molecular characterization of a novel species from Ellesmere Island, Canada, Forest Pathology (2023). DOI: 10.1111/efp.12818

Provided by University of Tsukuba 


Explore further

Confirmed new fungus has mysterious origins

XX International Plant Protection Congress, Athens, Greece, July 1-5, 2024.


XX International Plant Protection Congress, Athens, Greece, July 1-5, 2024.

  Dear colleagues,   On behalf of the Hellenic Society of Phytiatry we would like to invite you to participate in the XX IPP Congress which is going to take place at the Megaron Conference center in Athens Greece, in July 1-5, 2024.The Congress is hosted by the Hellenic Society of Phytiatry in Athens, Greece and organized under the auspices of the International Association for the Plant Protection Sciences (IAPPS), and of the Agricultural University of Athens.   In an era of the undoubted phenomenon of climate change around the globe, in a period of the vast increase of earth population with immense problems in food security, in a period of enormous pressure on natural resources to meet α vast need for nutritious and safe food, conservation of biodiversity and creating opportunities for economic growth, Plant Protection will play an extremely important universal role in securing human welfare.   Management of Crop Loss caused by pathogens and pests is a complicated issue of paramount importance for global agriculture, involving hosts and environment, plus scopious and intense scientific research, political decisions and application of international rules and measures. There is an urgent need for developing ecofriendly and safe biologicals and agrochemicals, pesticides either with nano-formulations. Research is also required to study evolutionary dynamics in reference to climate change, measurements and analysis, modelling of crop loss and predictive modelling. So, there is an urgent need to identify new pests and efficiently cope with diseases or pests threatening global human welfare. Obviously, new pathogen resistant sources in germplasm for confronting destructive pests and diseases are an everyday request by farmers. In an era of the boom of artificial intelligence able in perceiving, synthesizing, and inferring information—demonstrated by machines, Plant Protection is on the center of international interest.   Therefore, the Congress will be consisted of plenary and concurrent sessions of updated information and research data with invited speakers along with oral and poster presentations to cover all plant protection disciplines including plant pathology, entomology, weed science, nematology, plant breeding, technology transfer and relative to plant protection disciplines. Satellite sessions will be also welcomed. Plenary lectures will be among others focused on:   Molecular diagnostics for evidence based rational use of pesticides, in the European Green Deal era Enabling sustainable agriculture through understanding and enhancement of microbiomes Applying chemical ecology for environmentally friendly strategies to control insect pests Impact and control of transboundary/invasive banana wilt pathogen, Fusarium oxysporum f. sp. cubense Microbial pesticides: Discovery, piloting and scaling up in Africa Sustainable weed management Coordinated approach for transboundary plant pest and disease management Food security in Africa needs policy support for sustainable plant health management   Concurrent Sessions will be generally focus on:
Current plant protection problems affecting major regional crops or crops of international significance such as grapevines, olives, citrus, tropical fruit trees, cereals, vegetables, forests etc. will be highlighted. Top scientists will be invited to present updated information on chemical plant protection problems contributing to current advances and alternatives offered by the private sector of agrochemical-pharmaceutical chemistry. Further objectives of the IPPCAthens2024, will be invited lectures and oral presentations on hot research topics and recent developments in Plant Protection sciences directly originating from research translation of molecular plant pest interactions. Scientific contact among young scientists and top research leaders, helping opening research cooperation and contacts with leading research groups around the globe will be promoted and facilitated.    
  International organizations dealing with food security, food safety and plant health will be welcomed to critically analyze crucial current problems related to world agriculture and propose measures and actions. FAO, EFSA, EPPO and other leading organizations will be invited to participate in this unique Global Plant Protection Congress.

We are confident that as congress organizers will make any effort needed to succeed in organizing a scientifically profitable event and assure you for a memorable stay in Athens Greece.
  More information regarding the Congress are available at www.ippcathens2024.gr   Sincerely yours, The Chairman of the XX IPPCATHENS2024
Eris Tjamos
  ​For any further information, do not hesitate to contact
Congress Secretariat
Panagiotis Georgakopoulos
Senior Project Manager
Tel: +30 2103250260 email: panagiotis@globalevents.gr