Plasma-Produced Gas Helps Protect Plants from Pathogens

Add Cultivation AG as a preferred Google News source to see more of our trusted agriculture, farming, and crop coverage.

One promising innovation is plasma-produced gas, a technology that uses ionized gases to generate reactive compounds capable of killing harmful microbes and strengthening plant defenses. Unlike traditional chemical treatments, plasma-generated gases can reduce fungal, bacterial, and viral infections without leaving toxic residues on crops or damaging the environment.

Plant Diseases Are Costing Farmers More Than Ever

Plant pathogens and pests cause yield losses estimated at 21.5% in wheat, 30.3% in rice, and 22.6% in maize globally, with annual economic damage reaching US$220 billion across all major food crops (Nature Ecology and Evolution, 2019; Phytopathology, 2024). These are not abstract projections.

Every season, farmers across every growing region watch portions of their harvest disappear to fungi, bacteria, viruses, and soil-borne pathogens before the crop ever reaches a market. Post-harvest losses add further pressure, particularly in regions where cold-chain infrastructure is limited.

With global food demand projected to require a 60% increase in production by 2050 (PNAS, 2021), the margin for loss simply does not exist. For decades, chemical fungicides and bactericides formed the backbone of plant disease management. They were effective and scalable, but they came with compounding costs:

• residues on food,
• contamination of groundwater,
• documented resistance in target pathogens, and
• documented harm to soil microbial communities that crops depend upon.

The agricultural sector has been searching for treatments that are both potent and clean. Plasma-produced gas has emerged as one of the most scientifically credible answers to that search. The concept of using plasma in agriculture is no longer experimental fiction.

A growing body of peer-reviewed research published between 2020 and 2025 confirms that non-thermal plasma can inactivate a wide range of plant pathogens on seeds, plant surfaces, irrigation water, and storage environments.

The core mechanism involves plasma-generated reactive chemical species that destroy or disable pathogens at the molecular level while simultaneously triggering defense responses within the plant itself. This article explains exactly how that process works, where it is being applied, and what growers and agronomists should realistically expect from it.

What Is Plasma? Understanding the Fourth State of Matter

Most people learn about three states of matter in school: solid, liquid, and gas. Plasma is the fourth state, and it is actually the most abundant form of visible matter in the universe. Stars, lightning bolts, and the aurora borealis all consist of plasma.

In physics, plasma refers to an ionized gas, meaning a gas in which enough energy has been applied to strip electrons from atoms, producing a mixture of free electrons, ions, neutral atoms, and molecules in an energetically excited state. Because these particles carry charge and react readily with surrounding molecules, plasma is chemically extraordinarily active.

1. Types of Plasma Used in Agriculture

Not all plasma is equally useful for agricultural applications. The plasma inside the sun reaches temperatures of millions of degrees and is obviously incompatible with treating seeds or plant tissues. Agricultural research relies on two specific categories of plasma that can be generated at manageable conditions.

i. Cold plasma, also called non-thermal plasma (NTP), is generated at or near room temperature. It is produced when electrical energy is applied to a gas at atmospheric or near-atmospheric pressure, exciting the gas molecules without raising the bulk temperature to levels that would damage biological material.

Cold plasma is the type most relevant to plant disease management because it can be applied directly to seeds, plant surfaces, and treatment water without causing heat stress.

ii. Atmospheric plasma, often called cold atmospheric plasma (CAP), is a specific subset of cold plasma that operates at standard atmospheric pressure without requiring a controlled vacuum chamber. This distinction matters enormously for scalability. Vacuum-based plasma systems are expensive and impractical outside a laboratory. Atmospheric plasma systems can, in principle, be integrated into farm equipment, greenhouse sprayers, or seed treatment lines.

2. How Plasma Generates Reactive Gases

When an electric discharge is applied to air or another feed gas inside a plasma reactor, the energy excites and breaks apart the molecules present in the gas. Nitrogen (N2) and oxygen (O2), the two dominant components of air, dissociate and recombine to form a wide array of reactive compounds.

The type and concentration of these compounds depend on the reactor design, the input gas composition, the applied voltage, and the exposure duration. This tunability is one of plasma technology’s key advantages: a practitioner can, within limits, dial the chemistry of the output gas toward specific compounds suited to a target application.

Understanding Plasma-Produced Gas and Its Reactive Chemistry

The biological effects of plasma-produced gas are driven primarily by a class of compounds called Reactive Oxygen and Nitrogen Species, abbreviated as RONS. These are unstable molecules or molecular fragments that carry unpaired electrons, making them highly reactive with nearby biological structures.

Plants themselves produce RONS naturally as part of their immune signaling, so at controlled concentrations these species are recognized by plant biology as signals rather than poisons. At higher concentrations, the same species become directly toxic to microbial cells.

1. Key Gases and Compounds Produced by Plasma

Ozone (O3) is one of the most abundant antimicrobial agents generated by plasma. It is a molecule consisting of three oxygen atoms bonded together, and it is a powerful oxidizing agent that penetrates and disrupts the cell walls of bacteria and fungi efficiently.

i. Ozone has been used in food safety and water treatment for decades, and its production via plasma avoids the need for chemical ozone generators.

ii. Nitric oxide (NO) is a reactive nitrogen species that serves dual roles in biology. At low concentrations it acts as a signaling molecule that activates downstream immune responses in both animals and plants. Plasma can generate nitric oxide from atmospheric nitrogen and oxygen, making it accessible without any chemical precursors.

iii. Dinitrogen pentoxide (N2O5) is a reactive nitrogen species that Tohoku University researchers identified as the key active compound in their plant immunity activation experiments. N2O5 is formed in plasma from the further oxidation of nitrogen dioxide (NO2), and its physiological action in plant immunity had been poorly characterized before their 2022 research.

The Tohoku team showed that N2O5 specifically activated the jasmonic acid (JA) and ethylene (ET) immune signaling pathways, two of the most important defense-regulating hormones in plant biology.

iv. Hydrogen peroxide (H2O2), superoxide radicals (O2-), and hydroxyl radicals (OH-) are additional reactive oxygen species produced by plasma. Together with the nitrogen species described above, they form the reactive chemical cocktail that gives plasma-produced gas its antimicrobial and immunostimulatory effects.

How Plasma-Produced Gas Protects Plants

Plasma-produced gas protects plants through two parallel mechanisms: direct suppression of pathogens through chemical attack, and indirect protection through activation of the plant’s own immune system. Understanding both mechanisms is important because they operate at different stages of infection and require different application strategies.

1. Direct Suppression of Pathogens

Fungal and bacterial cells are structurally vulnerable to oxidative attack. Their outer cell walls and membranes, composed of lipids, proteins, and polysaccharides, are disrupted when high-energy reactive species make contact with them. The RONS produced by plasma oxidize these membrane components, creating pores through which cellular contents leak.

The consequence is loss of osmotic integrity and cell death. Frontiers in Plant Science (2020) documented that non-thermal plasma RONS oxidize proteins, lipids, and nucleic acids in pathogen cells, leading to structural destruction of the organism.

At the genetic level, reactive species cause strand breaks in microbial DNA and interfere with the function of ribosomes, the cellular machinery responsible for producing proteins. A pathogen whose DNA is damaged and whose protein synthesis is impaired cannot replicate, infect new tissue, or mount the enzymatic attacks on host cell walls that allow it to penetrate a plant.

Research on mung bean seeds artificially inoculated with Dickeya and Pectobacterium bacteria showed successful elimination following plasma treatment through exactly this DNA and protein damage pathway (MDPI Agronomy, 2022).

Fungal spores present a particular challenge in plant disease management because of their resilience to many conventional treatments. Plasma-mediated eradication of fungal spores prevents disease development after germination, limits inoculum spread through the growing environment, and reduces post-harvest pathogen pressure on stored crops.

2. Activation of Plant Immune Responses

The second and perhaps more strategically important mechanism is the activation of systemic plant immunity. When plants perceive RONS in their environment, they interpret these signals as evidence of a pathogen threat and initiate a cascade of defense responses. This process is broadly described as induced systemic resistance (ISR), or in the context of plasma, “plant vaccination.”

The Tohoku University research team led by Sugihiro Ando demonstrated this mechanism with precision using Arabidopsis thaliana (thale cress), a model plant species. Plants were exposed to plasma-generated N2O5 gas for just 20 seconds per day for three consecutive days.

RNA-Seq genetic analysis performed 24 hours after the final exposure showed upregulation of genes associated with the jasmonic acid and ethylene signaling pathways, along with apparent synthesis of antimicrobial molecules. When those plants were subsequently infected with Botrytis cinerea (a destructive fungal pathogen) and cucumber mosaic virus, they showed measurably suppressed disease progression compared to untreated controls.

Tsukidate et al., Tohoku University (PLOS ONE, 2022) found that plants exposed to plasma-generated N2O5 gas for 20 seconds per day over three days showed significantly reduced (P < 0.05) lesion size from Botrytis cinerea fungal infection and suppressed propagation of cucumber mosaic virus compared to untreated control plants.

Even brief, low-dose plasma gas exposure can activate durable immune priming in crops before pathogen challenge, offering a prophylactic rather than reactive disease management option.

This concept of immune priming before infection is analogous to vaccination in medicine. The plant is exposed to a sub-harmful dose of reactive species, its immune machinery is switched on, and when a real pathogen arrives, the defensive response is already prepared. This shifts the protective role of plasma from a contact-kill treatment to a systems-level agricultural tool.

Types of Plant Pathogens Targeted by Plasma-Produced Gas

Plasma-produced gas does not act identically against all classes of pathogens. Its effectiveness varies depending on the pathogen type, the mode of plasma application, and the concentration and mix of RONS generated. Understanding these distinctions helps practitioners choose the right application protocol for their specific disease pressure.

1. Fungal Pathogens

Fungi represent the largest category of economically significant plant pathogens. Diseases caused by Botrytis cinerea (grey mould), Fusarium species (root rot and wilt), Phytophthora infestans (late blight), and Colletotrichum species (anthracnose) collectively destroy hundreds of millions of tonnes of crops annually.

Plasma RONS are particularly effective against fungal spores and mycelium, with multiple studies confirming inhibition of spore germination and hyphal growth at plasma doses that do not damage plant tissue.

2. Bacterial Diseases

Bacterial pathogens such as Xanthomonas campestris (black rot in brassicas) and Pseudomonas syringae (bacterial speck in tomatoes) are surface-dwelling pathogens that infect plants through wounds and natural openings. Plasma treatment has shown strong efficacy against these organisms on seed surfaces and plant tissues.

Nishioka et al. eradicated Xanthomonas campestris from cruciferous seeds using cold plasma under an argon atmosphere, demonstrating near-complete pathogen elimination. However, the Tohoku University study found that internally proliferating bacterial pathogens like Pseudomonas syringae pv. tomato were not significantly affected by N2O5 gas exposure alone, indicating that pathogen location and accessibility influence treatment outcomes.

3. Viral Threats

Plant viruses present unique challenges because they replicate inside host cells and cannot be reached by surface-level chemical treatments once systemic infection is established. Plasma’s ability to prime plant immunity offers a meaningful response here.

The Tohoku University experiments showed that N2O5 gas exposure suppressed the propagation of cucumber mosaic virus, a widespread and economically damaging pathogen affecting cucumbers, peppers, tomatoes, and hundreds of other species, by activating internal immune signaling before the virus could establish itself.

4. Soil-Borne and Post-Harvest Pathogens

Soil-borne pathogens like Fusarium oxysporum and Pythium species are difficult to manage because they persist in the growing medium across seasons and are protected from foliar spray treatments. Plasma-activated water (PAW), in which plasma-generated RONS are dissolved into irrigation water, offers a delivery mechanism that can reach the root zone.

Post-harvest pathogens affecting storage crops are another high-impact target, since plasma treatments of harvested produce can reduce surface microbial loads without the chemical residues associated with conventional post-harvest fungicides.

Applications of Plasma Technology Across the Agricultural System

Plasma-produced gas and plasma-activated water are being explored and deployed across multiple stages of the agricultural production chain. Each application context has distinct technical requirements and evidence bases.

1. Seed Treatment

Seed treatment is currently the most commercially advanced application for agricultural plasma. Seeds are compact, easy to expose uniformly in a controlled environment, and surface decontamination at this stage prevents pathogens from accompanying the crop into the field.

Cold plasma exposure of seeds decontaminates surface-borne pathogens, functionalizes the seed coat surface to improve water uptake and germination, and can break dormancy in certain species.

Puac et al. (Plasma Processes and Polymers, 2024) confirmed that plasma treatment of seeds increases germination percentage and decontaminates pathogens from seed surfaces with results comparable to conventional seed treatments but without chemical residues.

2. Greenhouse Crop Protection

Greenhouses represent an ideal initial deployment environment for plasma technology because conditions are controlled, the space is enclosed, and the economics of high-value crops justify investment in advanced treatment systems. Plasma devices can be integrated into existing ventilation or irrigation systems to deliver continuous low-level RONS to the growing environment.

The enclosed space also means that ozone and other reactive gases produced by plasma treatments do not dissipate rapidly, extending their effective contact time with plant surfaces and potential airborne pathogen spores.

3. Field Crop Disease Management

Field deployment of plasma technology is more challenging because of the difficulty in delivering reactive gases uniformly over large areas and the rapid degradation of short-lived species like ozone in open air. Current field applications focus on plasma-activated water for irrigation and plasma seed treatment as prophylactic measures rather than direct in-field gas application.

Research on tomato plants showed that PAW irrigation upregulated defense hormones including salicylic acid and jasmonic acid while also stimulating pathogenesis-related gene expression, achieving both growth promotion and immune priming through a single irrigation treatment.

4. Post-Harvest Preservation and Hydroponic Systems

In post-harvest facilities, plasma treatment of harvested produce reduces surface microbial loads without the heat damage or chemical residues of alternative methods. For hydroponic and vertical farming systems, PAW can be prepared in batch quantities and added to recirculating nutrient solutions, providing ongoing antimicrobial activity that limits disease spread through the water circuit.

These closed-system applications benefit from the fact that reactive species do not need to travel far from their point of generation, making treatment concentrations easier to control and verify.

Jiang et al. (2014), cited in Frontiers in Plant Science (2020), found that tomato plants treated with plasma showed increased resistance to bacterial wilt disease, with H2O2 levels and resistant enzyme activities measurably higher in plasma-treated plants than in untreated controls after pathogen inoculation.

Plasma seed treatment in tomato production can provide systemic immune priming that persists into the growing plant, offering protection against bacterial wilt without any applied bactericide.

Benefits of Plasma-Produced Gas Over Traditional Chemicals

The value proposition of plasma-based plant protection becomes clearest when set against the limitations of the chemical treatments it can replace or reduce. These are not minor incremental improvements but structural advantages that address long-standing problems in conventional disease management.

1. Plasma treatments leave no chemical residues on crops or in soil. The reactive species generated by plasma are inherently unstable and degrade rapidly to harmless compounds like water, nitrogen gas, and oxygen, leaving no accumulation of synthetic molecules in the food or growing environment.

2. Plasma does not select for resistant pathogen strains in the way that synthetic fungicides and bactericides do. The multi-target oxidative mechanism of RONS attacks many biological structures simultaneously, making it extremely difficult for a pathogen population to evolve resistance to all of them at once.

Plasma-produced gas represents a genuine shift in how agriculture relates to plant immunity: instead of only killing pathogens externally, it works with the plant’s own biology to build defenses from within.

3. Reduced pesticide usage directly improves safety for farm workers who mix, apply, and re-enter treated fields, as well as for consumers who eat the harvested produce.

4. The environmental impact of plasma technology is significantly lower than that of conventional agrochemical application. Plasma devices require electricity as their main input and can be powered by renewable sources, whereas chemical pesticides require

• • energy-intensive synthesis,
  • packaging,
  • transportation, and
  • disposal chains.

5. Plasma treatment can actively improve crop quality metrics beyond disease control, including germination rates, seedling vigor, and shelf life of harvested produce, making the cost-benefit calculation more favorable than a pure disease-prevention comparison would suggest.

It is important to be precise about what plasma does not yet fully replace. For certain soil-borne and systemic bacterial diseases, plasma’s efficacy at commercially scalable doses has not matched that of targeted chemical interventions.

The technology works best as part of an integrated disease management system, replacing the most environmentally problematic treatments while chemical backup is maintained for cases where plasma alone is insufficient.

Recent Developments in Plasma Agriculture

The evidence base for plasma-based plant protection has expanded substantially since 2020. Research has moved from proof-of-concept laboratory studies toward mechanistic characterization, field trials, and integration with digital farming systems.

1. Laboratory and Field Trial Results

Laboratory studies have established the mechanisms described in this article with increasing precision. RNA-Seq analyses at Tohoku University mapped the specific gene expression changes triggered by N2O5 gas, identifying the jasmonic acid and ethylene pathways as the primary response channels.

Studies at Kwangwoon University in Seoul confirmed that PAW prepared from 30 minutes of cold atmospheric plasma exposure contained RONS at concentrations sufficient to induce non-toxic immune signaling in tomato seedlings, upregulating both defense hormones and pathogenesis-related gene expression.

The key variable across these studies is that the dose matters enormously: too little produces no protective effect, while too much induces oxidative damage in the plant. Research from 2024 confirmed that excessive RONS inhibit enzyme function and impair DNA and protein integrity in plant cells as well as microbial cells, making calibration critical for practical application.

2. Innovations in Plasma Delivery Systems

Dielectric barrier discharge (DBD) reactors represent the most commercially developed plasma generation technology for agricultural applications. A DBD reactor places two electrodes separated by a dielectric material (an electrical insulator) and applies a high-voltage alternating current between them.

The gas between the electrodes undergoes plasma formation, and the output can be directed at seeds, plant surfaces, or water. DBD systems are valued for operating at atmospheric pressure, producing a relatively uniform discharge, and being scalable to different treatment volumes.

Plasma jet systems, in which plasma is generated in a tube and blown through a nozzle onto a target surface, offer precision application for plant surface treatments and post-harvest decontamination.

3. Integration with Smart Farming Technologies

The most forward-looking research in this area concerns the integration of plasma treatment systems with sensor-driven precision agriculture platforms. In concept, disease pressure sensors or imaging systems detecting early-stage fungal or bacterial infection markers on crops would trigger targeted plasma treatments in affected zones before lesions spread.

This would concentrate treatment intensity where it is needed, reduce overall energy consumption, and build a feedback loop between detection and response. Work on this integration remains largely at the research prototype stage but represents the logical convergence of plasma technology with existing precision agriculture infrastructure.

Challenges and Limitations That Must Be Addressed

A balanced assessment of plasma technology requires direct engagement with the real obstacles to its broader adoption. The research results are genuinely promising, but the path from laboratory to field scale involves unresolved technical, economic, and regulatory challenges.

1. Equipment cost is the most immediate barrier for most growers. Industrial plasma systems with the power output and consistency required for commercial seed treatment or greenhouse application carry capital costs that are prohibitive for smallholder and medium-scale operations without subsidy or financing support.

2. Energy requirements are not trivial. Generating plasma requires continuous electrical input, and while the energy per treated unit is manageable at small scales, the aggregate energy demand of large-scale deployment needs careful life-cycle accounting, particularly in regions where the electrical grid is carbon-intensive.

3. Standardization is a significant challenge across the entire field. Plasma systems vary enormously in design, output chemistry, power levels, and application modes. Without standardized protocols and regulatory frameworks defining what constitutes an effective and safe treatment dose for specific crops and pathogens, commercial products and claims are difficult to compare, verify, or approve.

4. The effects of plasma RONS on beneficial soil and root microbiomes are not fully characterized. Soil microbial communities, including mycorrhizal fungi and nitrogen-fixing bacteria that support plant health, could be affected by RONS in ways that offset disease control benefits. Research specifically examining these interactions is still limited.

5. Regulatory and commercial adoption barriers vary significantly by region. In many jurisdictions, plasma-treated seeds or produce do not fit neatly into existing regulatory categories for food safety or pesticide registration, creating uncertainty that slows commercial investment.

Future Potential of Plasma Technology in Sustainable Agriculture

Despite these challenges, the structural fit between plasma technology and the direction that agriculture needs to move is compelling. Three developments in particular will shape how quickly plasma-based protection scales from niche to mainstream.

1. Role in Sustainable Farming and Precision Agriculture

As regulatory pressure on synthetic pesticide use intensifies across the European Union, the United Kingdom, and major export markets in Asia, growers face mandated reductions in chemical inputs without equivalent reductions in disease pressure.

Plasma technology, particularly seed treatment and PAW systems, is positioned as a direct substitute for a portion of this chemical load. Its compatibility with organic certification frameworks, where it does not involve synthetic chemical inputs, opens access to premium markets that carry price premiums sufficient to justify equipment investment.

Precision agriculture platforms offer the most transformative deployment pathway. If plasma treatment units can be made modular and compact enough for drone or autonomous robot integration, targeted gas or activated water application at the individual plant or field-zone level becomes technically feasible.

This would align plasma with the broader precision agriculture goal of applying inputs only where and when needed, maximizing efficacy and minimizing waste.

2. Reducing Global Crop Losses and Future Research Directions

The quantified scale of crop losses described at the start of this article represents the real-world target for plasma technology. If plasma seed treatment alone could reduce pathogen-induced field losses by even 5 to 10 percentage points in major cereals, the food security implications would be significant at a global level.

Research investment currently prioritizes several key areas: identifying the optimal RONS mix for specific pathogen-crop combinations, developing low-cost portable DBD reactors for smallholder use, characterizing long-term soil microbiome effects, and establishing regulatory dossiers that allow commercial market entry in major agricultural economies.

The jasmonic acid and ethylene immune activation pathways identified in the Tohoku University research also open a parallel line of investigation in plant biology. If plasma exposure can reliably prime these pathways at controlled doses, it becomes a research tool for understanding crop immunity that may lead to insights applicable beyond plasma treatment itself.

Conclusion

Plasma-produced gas helps protect plants from pathogens through two distinct and complementary mechanisms: the direct chemical destruction of fungal, bacterial, and viral pathogens through RONS-mediated oxidative attack, and the activation of the plant’s endogenous immune system through jasmonic acid and ethylene signaling pathways primed by sub-harmful doses of reactive species. These mechanisms have been characterized at the molecular level using RNA-Seq and biochemical assays, demonstrated across multiple crop and pathogen species, and validated in both controlled laboratory settings and applied research trials.