Young people are bringing nature-based solutions to farmers

How young people are bringing nature-based solutions to farmers

spray service provider

Young spray service providers are changing environmental protection and food safety by offering natural alternatives to chemical pesticides. They’re changing farmers’ minds about the types of pest control they use. In this blog, we look at PlantwisePlus training in pesticide application and how the programme supports young people – the future of safer and more environmentally-friendly food production.

Pests and invasive species severely threaten food security in Sub-Saharan Africa, but could young spray service providers be the frontline of action on invasives? In 2021, CABI scientists conducted the first comprehensive study on the economic impact of a range of invasive species on Africa’s agricultural sector. They estimated the cost to be $65.58 billion per year, equivalent to 2.5% of the gross domestic product of all African countries combined.

The pests affect crops essential to farmers’ livelihoods and food security, such as cassava, citrus fruits, tomato, maise and banana. Protecting these crops from pests and diseases is critical. Farmers tend to use pest control products that they know and trust. This includes chemical pesticides that can be toxic or unsafe. They harm not only the environment but also farm labourers and consumer health.

But training young spray service providers in natural, safer bioprotection products is bringing about a change for the better. As the young providers travel from farm to farm, offering their pest control spray services, they bring messages about safer food production and the natural products that are more effective and less harmful.

PlantwisePlus – supporting young spray service providers with training

Last year, PlantwisePlus delivered training to 363 spray service providers in bioprotection products (biopesticides and biocontrol) focusing on food safety and integrated pest management (IPM). This type of training helps to reduce the use of high-risk chemical pesticides. At the same time, it provides farmers with the critically required advisory services for increased quality yields.

These safer alternatives to synthetic pesticides are made from natural substances. They’re better for the environment and consumer health. The PlantwisePlus training can help young people learn new skills, generate a living, and help to protect the environment and food safety. Youth unemployment is high in Kenya. Young people (15 to 34-year-olds) form 35% of Kenya’s population but 67% are unemployed. Pest management training can help give young people income generating opportunities.

The young people trained are seasonal workers. They travel from one farm to another, offering spray services to farmers for a fee. PlantwisePlus sees the training as an opportunity to support young people and work with them to advocate the use of natural, safer pest control products. The young people learn crop bioprotection skills and pass their knowledge to farmers as they move around the region.

How are the spray service providers benefitting from the training?

So far, the programme has trained 130 young men and women under 35 in biopesticides, IPM and natural pest control products. These products are sold through a CABI collaboration with biopesticide producer Koppert. The farmer decides which crops must be sprayed and what products to use. But the spray service providers can offer non-chemical alternatives – products that farmers might not even know exist.

Through the training, PlantwisePlus is changing the range of the products on offer. Young sprayers are becoming advocates of low-risk products. The training also helps the young service providers understand the broader food safety chain and how pesticides are introduced into the chain.

Through PlantwisePlus, the spray service providers are creating business plans. They identify target crops and the products and services they would like to offer. The products the service providers chose to market include a biofertilizer applied mainly during planting, a Phthorimaea absoluta (tomato leafminer, also known as Tuta absoluta) trap and sticky yellow and blue pads. They also offer a false codling moth pheromone trap, which has become one of the most essential products.

Avocado is a lucrative crop in Kenya, and more farmers are growing it. In fact, Kenya is the only African nation in the top 10 producers of avocados with an annual output of over 170,000 tons. But the false codling moth has a devastating effect on avocados, causing much damage. The trainees understand the nature of the problem and recognise the need to introduce a trap to control the pest. The traps are selling well.

Tailoring existing training to help young spray service providers

There are many benefits to biocontrol, and young spray service providers are excited to learn about new products. Like farmers, some didn’t realise that natural pest control products existed. Aware of the benefits of organic produce, the discovery of biocontrol was exciting to them. One explained how the training opened his eyes to what’s possible.

The training uses Plantwise plant doctor materials as a basis. Then tailors them to the young spray service providers’ needs. They are also guided through the CABI BioProtection Portal to look for products they can offer. But this learning experience aims to be much more than just training. It’s about getting the messages of low-risk products out to farmers and boosting young people’s incomes.

By understanding and marketing these natural products, young people have an economic advantage and can grow their businesses. There are outlets in Nairobi that only buy organic produce. As the demand for organic fruits and vegetables increases, the need for biopesticide training will increase. These young people are the forerunners, helping to grow this part of the food value chain. They create a ripple effect, which spreads the word about the benefits of biocontrol.

One spray service provider said, “Through this training, I know there are low-risk products I can access from the agrodealer shops and recommend the same to my farmers.” He explained how the trained service providers could be invited to Kenya’s county government forums, where they meet to discuss agriculture and farming. Here, the providers could market themselves and their businesses.

Looking ahead …

Work still needs to be done in helping to share the messages, but it’s a step in the right direction, addressing several challenges – youth employment, environmental protection, and food safety – with one solution. It is hoped that the service providers become agents of change. After receiving biopesticide training, they’ll recommend new, safer products to farmers. As climate change worsens and pests spread to new regions, young Africans can be part of a movement to change attitudes and practices to crop health.

Learn more about PlantwisePlus at

Read more

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Enabling smallholder farmers’ easy access to agro-inputs: A CABI success story in Luweero District, Uganda

Kenyabiopesticidesspray service providersyouth

Gender and youth

How Do Bacteria and Fungi Live in Harmony?


Published: July 5, 2023

Original story from the Leibniz Institute for Natural Product Research and Infection Biology

The fluorescence image shows M. rhizoxinica bacteria (green) enclosed in parts of a fungal hyphal (blue). Credit: Ingrid Richter/Leibniz-HKI.Download Article



A study on the coexistence of bacteria and fungi reveals that a fragile symbiotic relationship exists between Mycetohabitans rhizoxinica bacterium and Rhizopus microsporus fungus. The presence of a specific bacterial protein maintains the symbiosis, while its absence leads to a potentially parasitic interaction.

Key Takeaways

The bacterium Mycetohabitans rhizoxinica and the fungus Rhizopus microsporus form a symbiotic relationship, with the bacterium producing a plant toxin essential for the fungus to spread efficiently and the fungus providing nutrients to the bacterium.A specific bacterial protein called TAL effector 1 (MTAL1) is crucial for maintaining the symbiosis between the bacterium and the fungus.When the TAL effector protein is deactivated, the bacteria multiply uncontrollably, and the fungus responds by trapping and killing the bacteria, indicating a shift from a symbiotic relationship to a potentially parasitic one.

A new study on the coexistence of bacteria and fungi shows that a mutually beneficial, functioning symbiosis can be very fragile. Researchers at the Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) in Jena found out that the bacterial species Mycetohabitans rhizoxinica lives happily in the hyphae of the fungus Rhizopus microsporus only when the bacteria produce a certain protein.

In a symbiosis, two organisms join together and benefit from each other; in endosymbiosis, one of the organisms takes this strategy further to live within the other. In some cases, they can’t do without each other, like the fungus Rhizopus microsporus and the bacterium Mycetohabitans rhizoxinica (previously known as (Para)burkholderia rhizoxinica). The fungus can cause rice seedling blight, which leads to enormous crop losses in Asia every year. However, R. microsporus can only do this with M. rhizoxinica: the bacterium produces a plant toxin that is processed and released by the fungus. Without the bacterium, the fungus can no longer form spores and spread efficiently. In return, it supplies its endosymbiont with nutrients.

“In the wild, the two always live in symbiosis,” explains Ingrid Richter, a postdoctoral researcher in the Department of Biomolecular Chemistry at Leibniz-HKI. In the laboratory, however, the researchers have succeeded in cultivating them separately. “As a result, we know that the bacteria are still able to infect the fungus,” Richter said.

From parasitism to symbiosis?

The research team now found that a specific bacterial protein, or more precisely an effector protein, maintains the symbiosis. If the researchers deactivate the so-called TAL effector 1 (MTAL1), the bacteria multiply uncontrollably, and the fungus, as a result, closes off parts of its hyphae with new cell walls. The now-trapped bacteria subsequently die. “These TAL effectors are known from various plant-infecting bacteria,” Richter said, where they allow the bacteria to invade plant cells.

The research results provide new insights into endosymbiotic partnerships that play a major role in evolution. For example, today’s mitochondria, the energy providers in plant, animal, and fungal cells, were probably originally endosymbionts. They have their own DNA, but have long been unable to survive independently – unlike M. rhizoxinica. “In addition, through close microscopic observation, we have learned quite a bit about what tasks different types of hyphae have in the fungal mycelium, for example, the transport of nutrients,” Richter explains.

Reference: Richter I, Wein P, Uzum Z, et al. Transcription activator-like effector protects bacterial endosymbionts from entrapment within fungal hyphae. Current Biology. 2023:S0960982223006231. doi: 10.1016/j.cub.2023.05.028

This article has been republished from the following materials. Article summaries may be generated using fact-checked AI models. Note: material may have been edited for length and content. For further information, please contact the cited source. Technology Networks



Biocontrol agent of root-knot nematode Meloidogyne javanica and root-rot fungi, Fusarium solani in okra.

Biocontrol agent of root-knot nematode Meloidogyne javanica and root-rot fungi, Fusarium solani in okra.

Monday, 10 July 2023 17:22:22

Grahame Jackson posted a new submission ‘Biocontrol agent of root-knot nematode Meloidogyne javanica and root-rot fungi, Fusarium solani in okra morphological, anatomical characteristics and productivity under greenhouse conditions ‘


Biocontrol agent of root-knot nematode Meloidogyne javanica and root-rot fungi, Fusarium solani in okra morphological, anatomical characteristics and productivity under greenhouse conditions

Nature Scientific Reports

Waleed M. Ali, M. A. Abdel-Mageed, M. G. A. Hegazy, M. K. Abou-Shlell, Sadoun M. E. Sultan, Ehab A. A. Salama & Ahmed Fathy Yousef

This study was conducted to evaluate the ability of some fungal culture filtrate, as biocontrol agents against okra wilt caused by Fusarium solani. and Meloidogyne javanica. In the present study, fungal culture filtrates (FCFs) of Aspergillus terreus (1), Aspergillus terreus (2), Penicillium chrysogenum, and Trichoderma spp. were tested against M. javanica in vitro. The effects of P. chrysogenum and Trichoderma spp. (FCFs) in controlling root-rot fungi and root-knot nematode disease complex on okra plants were studied under greenhouse conditions (In vivo). In vitro experiment, the results revealed cumulative rate of J2s mortality of M. javanica reached to 97.67 and 95% by P. chrysogenum and Trichoderma spp., respectively, after 72 h. incubation. Additionally, Trichoderma spp exhibited the most effective inhibitory activity against the pathogen’s radial growth, with a percentage of 68%. P. chrysogenum ranked second with 53.88%, while A. terreus (2) demonstrated the weakest inhibitory effect of 24.11%. T6 [Nematode infection (M. javanica) + Fungus infection (F. solani) + Overflowed with fungal culture filtrate (P. chrysogenum)] and T8 [Nematode infection (M. javanica) + Fungus infection (F. solani) + spray with fungal culture filtrate (P. chrysogenum)] had the greatest effects on nematode galling indices on okra roots and substantially reduced the reproductive factors in the greenhouse (In vivo experiment). T6 was the best treatment to decrease disease severity, as reached (28%) relatively. On the other hand, T12 [(Fungus infection (F. solani) + (Dovex 50% fungicide with irrigation water)] recorded the lowest disease severity reaching (8%) relatively. The results showed that nematode infection or fungus infection or both decreased all studied anatomical characteristics of okra root, stem, and leaves. We concluded from this study that root-knot nematode and root-rot fungi were reduced by using fungal culture filtrates and could improve plant growth

Read on:

International Conference on Plant Health Management ICPHM 2023 – Innovation and Sustainability

International Conference on Plant Health Management ICPHM 2023 – Innovation and Sustainability

International Conference on Plant Health Management
ICPHM 2023 – Innovation and Sustainability

15th -18th November 2023 | Professor Jayashankar Telangana State Agricultural University (PJTSAU)

Call for Awards by Plant Protection Association of India

Aim and Scope

Plant health management (PHM) is the science and practice of comprehending the interplay of biotic and abiotic stresses that limit plants from achieving their full genetic potential as crops, ornamentals, forest trees, or other uses. PHM embodies bulwarking and building upon the concept of Integrated Pest Management (IPM) of these stresses to ensure ecological, economic, and social benefits for all the stakeholders including general public.

Research is traditionally defined as a systematic investigation into an area of study in order to reveal new inferences, re-examine existing knowledge, or establish new acts. Entrepreneurship is the process of designing a new product/service and converting it to become a successful business.

The main objective of this international conference is to pursue for global opportunities in research and entrepreneurship related to the field of PHM. Agriculture continues to be the backbone for the economy of many countries as majority of the human population is dependent on it for food, feed, and fibre. The deliberations in this conference are expected to focus on preparing a roadmap for the identification, delineation and exploitation of the core research areas of PHM for business prospects in the field of Agriculture.

Chief Patron

Shri Narendra Singh Tomar

Hon’ble Union Minister of Agriculture and Farmers Welfare

Government of India

President of the ICAR Society


Shri Singireddy Niranjan Reddy

Hon’ble Minister of Agriculture, Co-Operation, and Marketing

Government of Telangana


Dr Himanshu Pathak

Secretary, DARE & DG, ICAR


Dr R S Paroda

Founder Chairman, TAAS, New Delhi

Conference Chair

Dr B Sarath Babu


Plant Protection Association of India

Former Principal Scientist & Head ICAR-NBPGR – Regional Station

Conference Co-Chair

Dr Rajan Sharma

Cluster Leader – Crop Protection and Seed Health, ICRISAT

Conference Co-Chair

Dr R Jagadeeswar

Director of Research

Professor Jayashankar Telangana State Agricultural University

Conference Co-Chair

Dr Celia ChalamVasimalla

Head & Principal Scientist, Division of Plant Quarantine,


Conference Co-Chair

Prof T V K Singh

Dean of Agriculture PJTSAU (Retd.),

Ex. Emeritus Scientist-ICAR

Conference Co-Chair

Dr Gururaj Katti

Former Principal Scientist (Entomology) & Head (Crop Protection)

ICAR – Indian Institute of Rice Research,Hyderabad

Conference Co-Chair

Dr S J Rahman

Senior Professor & Univ. Head of Entomology, Department of Entomology

College of Agriculture, Prof. Jayashankar Telangana State Agri. University, Hyderabad

Conference Co-Chair

Dr M Srinivasa Prasad

Principal Scientist,

ICAR-IIRR, Hyderabad

Plant Protection Association of India (PPAI)

Plant Protection Association of India has been in the forefront of the scientific community of Plant Protection both at National and International level during the past close to four decades. The society demonstrated its strengths in the past to bring the fruits of scientific research to the stakeholders by documentation and organization of several conferences and seminars and provided right science platform to deliberate, exchange and spread the emerging knowledge on plant protection.

India: International Conference on Plant Health Management November 15-18, 2023, in Hyderabad

India: International Conference on Plant Health Management November 15-18, 2023, in Hyderabad

 International Conference on Plant Health Management
ICPHM 2023 – Innovation and Sustainability

On behalf of the Local Organizing Committee (LOC), we would like to invite you to participate
in the forthcoming “International Conference on Plant Health Management, ICPHM 2023 – Innovation and Sustainability” that will take place from November 15-18, 2023, in Hyderabad, India.

Plant Protection Association of India (PPAI) Executive Committee together with the LOC are currently
establishing a Scientific Program Committee, to offer an up-to-date scientific program including
oral presentations and posters covering the most important challenges in the field of plant health management today. Plant health management (PHM) is the science and practice of comprehending the interplay of biotic and abiotic stresses that limit plants from achieving their full genetic potential as crops, ornamentals, forest trees, or other uses. PHM embodies bulwarking and building upon the concept of Integrated Pest Management (IPM) of these stresses to ensure ecological, economic, and social benefits for all the stakeholders including general public.

The main objective of this international conference is to pursue global opportunities in innovation and sustainability of research and entrepreneurship related to the field of Plant Health Management. Agriculture continues to be the backbone for the economy of many countries as majority of the human population is dependent on it for food, feed, and fibre. The deliberations in this conference are expected to focus on preparing a roadmap for the identification, delineation, and exploitation of the core research areas of PHM for innovation, sustainability, and business prospects in the field of Agriculture.

Well renowned world scientists to lead a wide range of topics and sessions will be invited. There will also be optional workshops, and you are welcome to propose topics. In addition, professional excursions encompassing the Indian agriculture combined with touristic attractions are planned, which will accommodate both scientists and accompanying persons to join and enjoy the conference. We would like to emphasize that the ICPHM 2023 is open to plant protection scientists from all over the world.

Hyderabad is the capital of the Indian state of Telangana and de jure capital of Andhra Pradesh. Occupying 650 square kilometres along the banks of the Musi River, it has a population of about 6.7 million and a metropolitan population of about 7.75 million, making it the fourth most populous city and sixth most populous urban agglomeration in India. Hyderabad was established in 1591 AD by Muhammad Quli Qutb Shah. The city has the famous Hussain Sagar lake, which was built in 1562 AD near the center of the city. It is historically known as a city of pearls and is one of the most popular pearl and diamond trading centers. It is a world-famous city for the ancient structures such as Charminar and Golconda Fort, and the modern Hitech City and Ramoji Film City. It is highly popular for the delicious Hyderabadi biriyani.

The LOC with its experienced and renowned crop protection scientists are working hard to offer you a memorable conference ICPHM 2023 in Hyderabad.

For more information, please visit the conference website: 

We look forward to your participation.
Dr Sarath Babu
President, PPAI & Conference Chair, ICPHM 2023
Dr Rajan Sharma
Conference Co-chair, ICPHM 2023
IAPPS Coordinator Region VII: South Asia
Cluster Leader – Crop Protection and Seed Health, ICRISAT, Hyderabad, India        

Rice plants target gut microbes to reduce brown planthopper damage

Hannah M. McMillan hannah.mcmillan@duke.eduAuthors Info & Affiliations

June 28, 2023

120 (28) e2308568120 RELATED CONTENT



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Plants must constantly identify and respond to a variety of abiotic and biotic stress, and they must do so in ways that balance defense and stress responses with growth and reproduction. In agricultural settings, understanding the mechanisms behind plant growth and stress trade-offs could facilitate identification and design of safe, effective treatments to improve plant performance, crop yield, and plant health. With respect to biotic threats such as bacteria, fungi, and insect herbivores, plants often produce specialized metabolites that act either directly to neutralize the attack or indirectly by activating various local and systemic responses (1). Many defensive plant metabolites have been identified; however, their mechanism of action is often unknown or poorly understood, especially for insect herbivores (2). Intriguingly, microbial endosymbionts can play important roles in plant–insect interactions (35), suggesting that previous research may have overlooked important multi-level interaction networks that determine the outcome of herbivore attack. In PNAS, Liu et al. explore one such network of interactions and show that a rice defense flavonoid, sakuranetin, targets and reduces the abundance of yeast-like beneficial endosymbionts in brown planthoppers (BPHs), thereby reducing BPH performance and improving plant health (Fig. 1) (6).

Fig. 1.

Proposed model for sakuranetin defense mechanism. BPH attack elicits sakuranetin production in rice. Sakuranetin is ingested during BPH feeding and subsequently reduces the number of YLS in the BPH gut. Decreased YLS abundance reduces BPH performance by limiting cholesterol production, resulting in improved plant health.


In PNAS, Liu et al. explore one such network of interactions and show that a rice defense flavonoid, sakuranetin, targets and reduces the abundance of yeast-like beneficial endosymbionts in brown planthoppers (BPHs), thereby reducing BPH performance and improving plant health (6).

The brown planthopper Nilaparvata lugens is a destructive phloem-feeding herbivore that causes hundreds of millions of US dollars in rice crop losses annually (78). Indeed, BPH damage leads to 20 to 80% yield loss, and in areas with heavy infestations, BPH damage can result in near-total crop failure (9). While chemical insecticides effectively control BPHs, application poses significant risks for human health and eliminates natural BPH predators. Without predators, BPH populations increase unchecked, which can lead to greater plant damage during outbreaks and in subsequent years (79). Further, BPHs display high levels of resistance to many insecticides (7). Safer, more effective BPH treatments are clearly needed to address these issues.

The main driver of plant immune responses to insect herbivores is the phytohormone jasmonate, which is induced upon insect attack and regulates the biosynthesis of many downstream defense proteins and metabolites (10). Some of these metabolites, such as the alkaloid nicotine and volatile terpenes, have broad impacts on insect pests including neuromuscular impairment and repellent effects (1112). In response to BPH attack, jasmonate signaling in rice plants regulates genes in the phenylpropanoid pathway, strongly increasing expression of flavonoid biosynthetic genes (13). This signaling network increases levels of the defense metabolite sakuranetin and subsequently reduces BPH performance; however, the precise mechanism of action for sakuranetin is unknown (13).

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One unexplored target for plant defense metabolites like sakuranetin is the insect microbiome (14). Microbial endosymbionts play many beneficial roles for their insect hosts, including essential roles in growth, development, reproduction, stress resilience, and insect–plant interactions (5). In BPHs, yeast-like symbionts (YLSs) are the most abundant endosymbionts, are transmitted via eggs, and are found in every developmental stage of BPHs (1516). Critically, YLSs provide essential amino acids and sterol precursors for BPHs and aid in nitrogen recycling (1719). These microbes play such an important role that depleting YLSs by heat treatment reduces growth of BPHs, resulting in lower body weight and delayed emergence (18). In light of previous data showing that sakuranetin has broad antifungal activity (20), Liu et al. hypothesized that this defense metabolite may reduce BPH performance by targeting YLSs.

As expected, Liu et al. show that BPH nymph survival decreased when fed an artificial diet with sakuranetin (6). Further, when allowed to feed on sakuranetin-deficient rice plants, BPH developmental rates were shorter, more eggs were produced, and hatching rates increased, confirming that sakuranetin decreased BPH performance (6). To probe whether sakuranetin decreased BPH performance via an effect on YLSs, Liu et al. used fungal ITS sequencing to characterize the BPH microbiome (6). Indeed, the two most abundant fungal taxa, Cordyceps and Candida, were enriched in BPHs that were fed on sakuranetin-deficient rice (6). Of note, the Cordyceps genus contains Ascomycetes YLSs, which are the dominant fungal endosymbionts in BPHs (15). Microscopy and qPCR experiments confirmed that in addition to altering the relative abundance of fungal endosymbionts, sakuranetin reduced the overall number of YLSs in BPHs (6).

These results provide compelling evidence that sakuranetin impacts the BPH microbiome and specifically reduces the abundance of YLSs; however, reduced YLS abundance could be an indirect result of a direct interaction between BPH and sakuranetin. Unfortunately, YLSs cannot be cultured outside of BPHs, which prohibits studying the direct impact of sakuranetin on YLSs in vitro (15). To circumvent this challenge and limit the influence of BPH responses, Liu et al. cleverly tested direct anti-YLS activity of sakuranetin using fresh BPH egg homogenate and showed that sakuranetin significantly reduced YLSs in egg homogenate and in fresh, intact BPH eggs (6). These results suggest that sakuranetin acts directly on the YLSs rather than on BPHs (6).

As shown previously, depleting YLSs has a significant negative impact on BPH performance and results in lower body weight and delayed emergence (18). In part, these effects are seen because YLSs provide BPHs with a basic sterol precursor that is required for cholesterol biosynthesis (1719). Indeed, Liu et al. show that when YLSs are depleted by sakuranetin, BPHs have significantly lower cholesterol levels than BPHs fed on sakuranetin-deficient rice that retain their YLSs (6). Increased cholesterol in BPHs with YLSs likely contributes to improved BPH performance and suggests a possible mechanism for plant defense in which the plant metabolite indirectly targets the insect herbivore by disrupting the insect microbiome (Fig. 1). Further, this finding highlights the importance of multilevel, interspecies interactions in determining outcomes for plant health.

These results reveal a new area for study when considering how plants defend against herbivore attack and raise a variety of questions to be considered in future mechanistic studies. It is curious that a plant could develop a defense response against a microbe it never physically encounters. One may consider whether insect gut microbes secrete signals that travel through the insect mouthparts during feeding and, in turn, elicit plant defense responses. Conversely, it has been shown that microbes present in herbivore saliva can suppress jasmonate signaling, dampening plant defense responses and benefiting the insect host (521). Perhaps it is also possible that herbivores recruit specific gut microbes that secrete signals to suppress plant responses. This new line of questioning may also reveal novel approaches to control plant pathogens that are spread by insect vectors, such as Candidatus Liberibacter asiaticus that causes the devastating citrus greening disease. In this scenario, crops could be engineered to express metabolites similar to sakuranetin for delivery as the insect feeds to its gut microbes or those present in herbivore mouthparts. As a result, this approach may eliminate microbial pathogens before they are transmitted to the plant host and cause disease. With this study, Liu et al. have opened the door to explore many exciting new directions in plant–insect interactions with the potential to unveil effective new agricultural control measures for both herbivore pests and insect-vectored microbial plant pathogens.


My research is supported by the NSF Postdoctoral Research Fellowships in Biology Program under Grant No. 2208939 and Howard Hughes Medical Institute.

Author contributions

H.M.M. wrote the paper.

Competing interests

The author declares no competing interest.



M. Erb, P. Reymond, Molecular interactions between plants and insect herbivores. Annu. Rev. Plant Biol. 70, 527–557 (2019).

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A. Mithöfer, W. Boland, Plant defense against herbivores: chemical aspects. Annu. Rev. Plant Biol. 63, 431–450 (2012).

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C. J. Mason, A. G. Jones, G. W. Felton, Co-option of microbi

Host genetics shown to play a significant role in the composition of switchgrass root microbiomes

by US Department of Energy

Confocal microscope image of a switchgrass root (colored in blue) colonized by fluorescently labeled bacteria (in yellow and orange). Credit: Joseph Edwards, University of Texas at Austin

Plants provide a home for a wide diversity of microbes, especially in their roots. In turn, these communities can provide important benefits for the host. A study published in Current Biology investigated how the genetics of host plants determine the composition of the bacterial communities associated with the plants’ roots. The study identified a core set of bacterial strains that colonize switchgrass roots.

Many of these bacteria differ in abundance across plants’ genotypes. The study then mapped genes in the host genome that appear to affect the abundance of these microbes. This mapping revealed that genes involved in host immunity, plant development, and hormone signaling have roles in how plants acquire their microbiome.

Plants rely on their microbiomes to perform vital functions. Researchers seek to breed plant varieties to increase the beneficial associations with bacteria. However, scientists have limited knowledge of the extent to which host genetics affect the composition of the microbiome.

This study found that the genotype of a host switchgrass plant affects a large portion of the plant’s microbiome. The study also identified the switchgrass genes that appear to influence the abundance of these microbes. These results may help to engineer or breed plant varieties that form stronger beneficial associations with their microbiomes.

Plant-associated microbiota can contribute significantly to plant growth and yield. How host genetic variation affects the root-microbiome assembly is an open question. In this study, researchers used a common garden approach with field sites in Texas, Missouri, and Michigan to uncover the composition of the switchgrass root microbiome, characterize the effect of environment vs. host genetics on the composition of the root microbiome, and identify putative loci in the host genome implicated the differential microbiome composition. The team included scientists from the University of Texas at Austin, the HudsonAlpha Institute for Biotechnology, the Joint Genome Institute at Lawrence Berkeley National Laboratory, the University of Missouri, and Michigan State University.

Through sequencing efforts at the Joint Genome Institute, the researchers found that switchgrass root microbiota composition is largely site dependent. Nevertheless, there is a conserved set of core bacteria found in high abundance on roots across sites. Most of these core microbes differ in abundance between host genotypes in an environmentally dependent manner.

Finally, the researchers used a genome wide association study (GWAS) framework to identify loci in the host genome associated with the differing abundance of these microbes. Variation in genes implicated in plant immunity, development, and signaling were associated with microbiome compositional differences. These results provide a deeper understanding of the mechanisms plants use to modify their microbiota and give an avenue for breeding host plants to tailor their microbiome.

More information: Joseph A. Edwards et al, Genetic determinants of switchgrass-root-associated microbiota in field sites spanning its natural range, Current Biology (2023). DOI: 10.1016/j.cub.2023.03.078

Journal information: Current Biology 

Provided by US Department of Energy 

Explore further

Aerial root mucilage fixes atmospheric nitrogen to support plant growth

Samurai wasps: Biocontrol agents for destructive brown marmorated stink bugs

by Ian Dewar, CSIRO

Samurai wasps one of the best pre-emptive biocontrol agents to tackle the destructive brown marmorated stink bug
The samurai wasp Trissolcus mitsukurii. Credit: Dr Elijah Talamas

Ever get that feeling you’ve lost something really important? Is it in your other pocket? Or down the back of the couch? We can’t find the samurai wasp, which we know was here before. It’s important as a potential future biocontrol superhero against a serious agricultural insect pest threatening Australia.

Samurai were ancient Japanese warriors, often serving in private armies. We’re hoping the namesake wasp could go into battle against one of world’s worst biosecurity pests, if it ever establishes here: brown marmorated stink bug (BMSB).

BMSB is in the top 10 National Priority Plant Pests for Australia. If introduced here, it would cause serious damage to fruit and vegetable crops and ornamental plants. It’s a voracious pest, which feeds on more than 300 plant species including key agricultural crops. And it can grow large populations and become a household nuisance as it seeks shelter indoors over winter.

The tiny samurai wasp, Trissolcus mitsukurii, is about the size of a sesame seed. It is one of the main egg parasitoids of BMSB in its native range in Japan. It can’t sting humans. And it’s so small it’s easy to miss.

The samurai wasp was first recorded in Australia in 1914, but it was given a different name. It was also introduced in a biocontrol program in 1962 to help control the Green Vegetable Bug (GVB), Nezara viridula.

Subsequently, it was found in the ACT, NSW, Queensland, Victoria, Western Australia (WA) and South Australia. But it hasn’t been recorded since 1998, when the last specimens were found in ACT and WA.

If the samurai wasp is still here, and can be found, then it could be a pre-emptive biocontrol agent ready to attack BMSB if it spreads here. A biological control program would involve breeding the wasp up in large numbers and releasing it to target BMSB wherever it is found in any future incursion.

But first we need to find out more about which hosts T. mitsukurii uses here. Australia has a high number of endemic stink bug species (94 genera and 330 species) so it probably uses some of these as hosts. This large number of native stink bug species would also make it tricky to import new host specific exotic biological control agents.

Our Australian National Insect Collection (ANIC) recently used our expertly identified stink bugs species from Australia and overseas to train artificial intelligence to distinguish BMSB from similar looking native species. The result is a smart phone app now being trialed at ports and airports by biosecurity officers.

Samurai wasps one of the best pre-emptive biocontrol agents to tackle the destructive brown marmorated stink bug
The green vegetable bug, Nezara viridula, in green and brown forms. Credit: CSIRO

Egg-cellent sentinel survey techniques

Our entomologist Dr. Valerie Caron and her team used egg sentinel surveys to hunt for the tiny samurai wasp at organic farms and gardens.

“Egg sentinel surveys are the most targeted technique to survey egg parasitoids such as this wasp,” Valerie said.

“We established a laboratory colony of GVB to produce eggs to use in the survey. We placed these eggs at organic farms across Queensland, NSW, ACT, Victoria and South Australia during 2021 and 2022.”

At each field site, the team deployed 10 egg rafts, either glued on a wooden stick or on a bandage and fastened to a marker. After a week, the team brought these back to the laboratory to monitor for parasitoid emergence.

Taxonomy tick off

The project team double-checked existing specimens previously found here to make sure they really were the samurai wasp Trissolcus mitsukurii.

World leading Trissolcus taxonomist Dr. Elijah Talamas reviewed previous taxonomic work and confirmed a match between previous specimens and T. mitsukurii from Asia.

The team also built Australia’s first molecular library of all Trissolcus specimens from Australia and New Zealand.

Specialist staff from ANIC used next generation sequencing to extract degraded DNA from old specimens. This new library will allow easy identification of these species.

Samurai wasps one of the best pre-emptive biocontrol agents to tackle the destructive brown marmorated stink bug
Egg sentinel sampling for the samurai wasp in the field. Credit: CSIRO

Tiny wasp, big future

Sadly we didn’t find any T. mitsukurii samurai wasps using the egg sentinel survey. But we have improved our knowledge of the species in Australia using taxonomic methods and molecular sampling of old specimens.

The door remains open for future survey work, which could use broader techniques such as insect traps. These require less input at the field work stage, but more sorting of the samples, because they catch a broader range of insects.

One option would be insect traps with chemical lures (pheromone traps). These could be easily manufactured with 3D printers and used across a wider range.

Parasitoid distribution can be patchy and we’re not exactly sure where the wasp is so a larger area survey could offer a greater chance of finding this elusive wasp.

On the plus side, the taxonomic and molecular genetic work has confirmed that this samurai wasp has been found previously in Australia, and overseas research shows its potential as a biological control agent for BMSB.

Provided by CSIRO 

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Samurai wasp has minimal impact on native stink bugs, new study confirms

Researchers study beech leaf disease in Pennsylvania forests

by Katie Bohn, Pennsylvania State University Beech trees affected by beech leaf disease produce leaves with a distinctive banded pattern, according to Penn State researchers. Credit: Mihail Kantor

In the woods of the northeastern U.S., a strange disease is creeping through the canopies. Spreading quickly, it causes leaves and branches to wither and, in many cases, the tree to eventually die.

The arboreal ailment—beech leaf disease—currently has no known treatment or cure, putting large swaths of trees or even entire forests in jeopardy. But researchers in Penn State’s College of Agricultural Sciences are on the case, spearheading ongoing efforts to learn more about the disease and how to combat it.

“This is a big problem for our forests, as well as the trees in our own backyards,” said Cristina Rosa, associate professor of plant virology. “Many species of wildlife depend on beech trees for food and shelter, in addition to the Pennsylvania citizens who value the forests for recreation. It’s vital that we learn more about this disease and how, eventually, to overcome it.”

While beech leaf disease first was observed in Ohio in 2012, it is now particularly widespread in Pennsylvania, with all 67 counties currently affected, said Mihail Kantor, assistant research professor of nematology. Early symptoms of the disease include a dark green banding pattern between the veins of leaves before more severe symptoms spread to the rest of the tree.

While the exact cause and mechanism of the disease is under investigation, Kantor said researchers now know that infection with beech leaf disease is associated with a particular species of nematode—tiny worms that feed on plant cells, bacteria, fungi and other microscopic creatures.

This nematode species, Litylenchus crenatae mccannii, was previously found to be associated with trees suffering from the disease.

“Based on data from a research collaboration with scientists from the U.S. Department of Agriculture’s Agricultural Research Service, we know the nematodes enter the buds and feed on the leaves while they’re still developing within the bud, which can cause morphological changes in the leaf,” Kantor said. “And then, when the buds open, the nematodes can spread among the leaves. But we’re not sure if the nematodes are the only ones causing the disease, or if, for example, they somehow facilitate other pathogens to enter the plant cells and cause the infections.”

Pakistan: Biocontrol agent released to control noxious parthenium weed

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23 June 2023, Pakistan: A “major step forward in the fight against noxious parthenium weed” in Pakistan has been taken with the release of a biological control agent at the National Agricultural Research Centre (NARC) in Islamabad.

The move is seen as a significant measure to help combat the risks parthenium poses to human and animal health, biodiversity and food security in Pakistan.

One of Pakistan’s most troublesome invasive species

According to the CABI Evidence Note ‘Parthenium: Impacts and coping strategies in Central West Asia’, parthenium can cause severe allergic reactions in humans and livestock, may harbour malaria-carrying mosquitoes and displace native plant species.

The plant – which is considered one of Pakistan’s most troublesome invasive species – can also reduce pasture carrying capacities by as much as 80% to 90% where in India, for example, the cost of restoring grazing land is around USD $6.7 billion per annum.

Stem boring weevils released

Five hundred stem boring weevils (Listronotus steosipennis) were released to serve as a more sustainable approach to managing parthenium which is also known as ‘famine weed’ due to its impacts on food security.

In attendance at a special release ceremony at the NARC premises were Dr Ghulam Muhammad Ali, Chairman of the Pakistan Agricultural Research Council (PARC), Dr Babar Bajwa, CABI’s Senior Regional Director, Asia, and a delegation of journalists from various media outlets.

The stem boring weevil was approved for release in 2021 after host range testing took place in Pakistan to determine its safe usage as a biological control agent to literally ‘nip parthenium in the bud.’

Busy implementing biocontrol measures

CABI’s centre in Pakistan, through the PlantwisePlus programme, is busy implementing biocontrol measures which are safer-to-use and more environmentally friendly. It carried out further tests that agreed with the earlier findings that the stem boring weevil is safe to use.

Dr Ghulam Muhammad Ali, said, “The release of the stem boring weevil is a major step forward in the fight against noxious parthenium weed in Pakistan which poses a major risk to human and animal health, biodiversity and food security.

“This breakthrough has been made possible through collaboration between CABI, PARC, NARC, universities in Faisalabad, Swabi and Mardan as well as integration with the PlantwisePlus programme.”

Parthenium is native to tropical America and was accidentally introduced into several countries. In Pakistan it now covers thousands of hectares of productive and rangeland, posing a huge economic burden.

CABI conducted host range testing

Dr Bajwa said, “Parthenium’s success as an invasive species can be attributed to its wide adaptability, drought tolerance, high seed production, longevity of seeds in soil seed banks and lack of natural enemies in non-native regions.

“At CABI’s quarantine facility in Rawalpindi it was important, prior to release, to conduct host range testing on several species and varieties of important native and crop plants to ensure the weevil did not pose a risk to indigenous fauna.”

The stem boring weevil controls parthenium by laying its eggs primarily in the flowers 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.

More sustainable way to manage parthenium spread

Several larvae feeding in the stem can kill parthenium rosettes and mature plants. In Australia, the weevils were found to provide additional control of parthenium particularly in drought areas, where other biocontrol agents struggled to survive.

It is hoped that the introduction of this weevil will help manage the spread of parthenium in a more sustainable way without the need of chemicals or machinery that can have a negative impact on the environment.

Also Read: Corteva Agriscience launches new herbicide Novlect™ to control weeds in rice fields

(For Latest Agriculture News & Updates, follow Krishak Jagat on Google News)

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