Grafting onto resistant rootstocks, biological/anaerobic soil disinfestation and biofumigation, and soilless (substrate and hydroponic) culture instead of methyl bromide and chemical soil fumigants

Replaces: methyl bromide and chemical soil fumigants · Scope: greenhouse and field vegetables, strawberries, flowers · Evidence: high

The chemical problem#

• Intensive greenhouse soils accumulate soilborne pathogens (Fusarium, Verticillium, Phytophthora), root-knot nematodes and weeds.
• Methyl bromide was the standard soil fumigant until its phase-out under the Montreal Protocol (developed countries 2005, developing countries 2015) because it depletes the ozone layer.
• Many growers switched to other chemical fumigants (metam, 1,3-D, chloropicrin), which are toxic and increasingly restricted.

Product overview#

1. Grafting onto resistant rootstocks — tomato, eggplant, pepper, cucumber, melon and watermelon scions grafted onto vigorous, disease- and nematode-resistant rootstocks.
2. Soilless culture — growing in coir, rock wool or other substrates, or hydroponics, removes the soil and its pathogens altogether (substrates: see CE01).
3. Biological / anaerobic soil disinfestation (BSD/ASD) — incorporating fresh organic matter, irrigating and covering with plastic film → anaerobic microbial activity kills pathogens.
4. Biofumigation — incorporating Brassica green manures (mustard) that release isothiocyanates.
5. Solarization (physical) and biological control agents (Trichoderma, Bacillus) as complements.

Active ingredient / Composition#

• Rootstocks: interspecific tomato hybrids, Solanum torvum (eggplant), Cucurbita (cucurbits), Lagenaria.
• ASD: fresh organic amendment (grass, rice bran, molasses) + water + gas-tight film for 3–6 weeks.
• Biofumigation: high-glucosinolate mustard incorporated at flowering.

Key facts#

Advantages#

• No fumigant exposure for workers and neighbours; no ozone or groundwater risk.
• Grafted plants are often more vigorous and yield more.
• Soilless culture enables water and nutrient recirculation.
• ASD and biofumigation add organic matter.

Mode of action#

• Resistant rootstocks carry resistance genes (e.g. Mi for root-knot nematodes, Fusarium resistance) and greater vigour.
• ASD: anaerobic decomposition produces organic acids, low redox and toxic volatiles that kill pathogens.
• Soilless culture breaks the soilborne disease cycle; disinfection of recirculating solution (slow sand filters, UV) prevents spread.

Application#

Limitations#

• Grafted plants cost more; rootstock–scion compatibility must be tested.
• Soilless culture needs capital, plastic substrates or slabs and technical skill.
• ASD needs heat, organic material and 3–6 weeks of field time.
• Some open-field crops still lack a full alternative.

Evidence of displacement — D2: measurable displacement (minority share)#

Assessment (hand-reviewed): Old process eliminated (>99.8% of non-QPS methyl bromide phased out), but alternatives include chemical fumigants — the bio share is not shown.

Figures found (verified as quoted, but the assessment above explains why they do not count as displacement evidence for this substitution):

• displacement — Parties have phased out greater than 99.8% of the baseline consumption of 66,428 tonnes of methyl bromide for controlled non-QPS uses by 1 January 2023. (global, 2023; government or intergovernmental: ozone.unep.org)
• displacement — By the end of 2012, non-A5 countries had phased out more than 98% of methyl bromide consumption for controlled uses. (multi-country or global, 2012; government or intergovernmental: ozone.unep.org)
• displacement — In 2006-2007, 95% of the protected tomato production area in Morocco was planted with grafted plants. (Morocco, 2006-2007; weak: sambuz.com)
• performance — A meta-analysis indicates that anaerobic soil disinfestation (ASD) can suppress pathogen inoculum by 50% to 94% across various environmental conditions. (—, 2016; peer-reviewed: frontiersin.org)

Suppliers — real products and services (from the vendor index)#

Active vendors whose own card shows grafting/rootstocks or soilless/hydroponic culture systems.

Government funding signals#

Scanned 2026-10-01 (OpenAIRE + NSF); candidates reviewed by hand.

Signal: Weak. NSF and OpenAIRE returned nothing relevant, but the USDA source (added 2026-10-01) shows applied grafting work: NIFA 20213882134598 (vegetable grafting, $0.59 M, 2021) and NRCS NR236740XXXXG003 (living-mulch cucumber and tomato systems using vegetable grafting, $99 k, 2023). The methyl-bromide transition itself was financed through the Montreal Protocol’s Multilateral Fund and national programmes.

Scientific evidence#

• Gullino ML, Camponogara A, Gasparrini G, et al. (2003). Replacing methyl bromide for soil disinfestation: the Italian experience and implications for other countries. Plant Disease 87: 1012–1021.
• Louws FJ, Rivard CL, Kubota C (2010). Grafting fruiting vegetables to manage soilborne pathogens, foliar pathogens, arthropods and weeds. Scientia Horticulturae 127: 127–146.
• Lee JM, Kubota C, Tsao SJ, et al. (2010). Current status of vegetable grafting: diffusion, grafting techniques, automation. Scientia Horticulturae 127: 93–105.
• Blok WJ, Lamers JG, Termorshuizen AJ, Bollen GJ (2000). Control of soilborne plant pathogens by incorporating fresh organic amendments followed by tarping. Phytopathology 90: 253–259.

Bioeconomy value#

Methyl bromide is gone, but chemical fumigation is not. Grafting nurseries, greenhouse builders and substrate suppliers are the bioeconomy route out, and Middle East and Latin American greenhouse firms in this index already sell it.

Cross-links: CE01 peat-free media; SG01 resistant varieties; A04 Trichoderma/Bacillus; NU03 compost.