Conifer root and butt rot (Heterobasidion) prevention by stump treatment with the competitive fungus Phlebiopsis gigantea (Rotstop) — instead of chemical stump treatments
Urea and borate (disodium octaborate) stump treatments; historically other chemical stump treatments
Spruce and pine forests during thinning and final felling (Nordic countries, Baltic, European Russia, Siberia)
Suppliers 0
Route into Russia / EAEU PEST
- Regulator
- Ministry of Agriculture (Minselkhoz)
- Typical time
- 2-3 years (registration trials over seasons)
- Legal basis
- Federal Law 109-FZ (19.07.1997); registration trials, expert assessment, entry in the State Catalogue of pesticides and agrochemicals permitted in the RF; microbial and viral biopesticides are pesticides (EEC)
Information, not legal advice — confirm the procedure for your product.
Proof 4 claims
Urea stump treatment
Phlebiopsis gigantea (e.g., Rotstop) stump treatment
- Displaced at scale?
- yes
- Caveats
- The adoption of biological control is not universal; some forest managers do not trust the efficacy of Phlebiopsis gigantea, and practical application often fails to meet the manufacturer's stipulated coverage requirements, leading to inconsistent results in the field.
- Hand review
- D3 Regional: Rotstop (Phlebiopsis) applied on 47,000 ha vs urea on 2,000 ha a year in Fennoscandia.
- checked
- 2026-10-06
| In Fennoscandia, Phlebiopsis gigantea (Rotstop) was applied to over 47,000 hectares and urea to over 2,000 hectares of forestland annually. “In Fennoscandia, Rotstop and urea are applied, respectively, on 47,000ha and on 2000ha of forestland each year.” Fennoscandia · 2003 (data reported in 2004) · majority share of a major market | peer-reviewed ✓ www.sciencedirect.com |
| Metsä Group has largely completed the transition from urea to Phlebiopsis gigantea for stump treatment, with urea remaining in use only for specific harvester models where technical deficiencies exist. “The move to Phlebiopsis gigantea has now been largely completed. In some harvester models (around one fifth of all the machines in use), technical deficiencies related to the use of Phlebiopsis gigantea have been detected. We have asked the machinery manufacturers to fix these. These harvester models will continue to …” Finland · 2024 · | weak (company, news, market research, other) www.metsagroup.com |
| In precommercial thinnings, urea performed better (92-94% efficacy) than P. gigantea (59-72%), while in final fellings both treatments showed high efficacy (urea 95.5-99.8% vs P. gigantea 90-98%). “In precommercial thinnings, urea performed better and had higher mean efficacy values (92-94%) compared to P. gigantea (59%-72%). In final fellings there were no significant differences between the treatments, both had high efficacy values (urea 95.5-99.8% vs P. gigantea 90-98%).” Sweden · 2020 · | weak (company, news, market research, other) ✓ research.slu.se |
| The switch from urea to Phlebiopsis gigantea is driven by regenerative forestry principles and the goal to reduce fossil carbon dioxide emissions associated with urea production. “The replacement of urea with Phlebiopsis gigantea in stump treatment implements Metsä Group’s principles of regenerative forestry and reduces fossil carbon dioxide emissions from harvesting.” Finland · 2024 · | weak (company, news, market research, other) www.metsagroup.com |
References 2
- Garbelotto M, Gonthier P (2013). Biology, epidemiology, and control of *Heterobasidion* species worldwide. *Annual Review of Phytopathology* 51: 39–59. VERIFIED DOI · cited by 274
- Berglund M, Rönnberg J (2004). Effectiveness of treatment of Norway spruce stumps with *Phlebiopsis gigantea* at different rates of coverage for the control of VERIFIED DOI · cited by 50
Details
Replaces: urea and borate stump treatments · Scope: forest thinning and harvesting · Evidence: high
The chemical problem#
Heterobasidion annosum s.l. (root and butt rot) is one of the most economically damaging forest diseases in the Northern Hemisphere, causing large losses of spruce timber in Europe. Spores infect fresh stumps after thinning, and the fungus spreads through roots to neighbouring trees. Chemical stump protection uses urea or borates, and borates are classified as reproductive toxicants in the EU.
Product overview#
Phlebiopsis gigantea is a native wood-decay fungus that rapidly colonizes fresh stump surfaces and occupies the wood before Heterobasidion. It is sold as Rotstop (Finland/Verdera) and PG Suspension (UK), and has been used on hundreds of thousands of hectares in Finland, Sweden, the Baltic states and the UK. It is applied automatically by harvester heads during felling.
Active ingredient / Composition#
Oidia (spores) of P. gigantea (selected strains), formulated as a powder mixed with water (with dye for coverage control).
Key facts#
| Parameter | Value |
|---|---|
| Class | Microbial biocontrol (competitive fungus), FRAC BM02 |
| Efficacy | Typically 80–100 % reduction of stump infection when stump coverage is complete |
| Application | Harvester-mounted spraying during cutting (summer felling) |
| Safety | Native fungus; no toxic residues |
Advantages#
- Replaces reproductively toxic borates.
- Built into modern harvesting (no extra pass).
- Protects future stand value; the fungus is a native decomposer.
Mode of action#
Competitive exclusion: P. gigantea colonizes the stump surface and sapwood, taking the space and nutrients Heterobasidion needs; it also shows hyphal interference.
Application#
| Stand | Measure | Specifics |
|---|---|---|
| Norway spruce thinning and felling (above about 5 °C) | Rotstop via harvester, full stump coverage | Coloured dye to check coverage |
| Pine stands | P. gigantea (strains adapted to pine) | – |
| Winter felling (below 0 °C) | Usually no treatment (no spore infection) | Silvicultural timing is itself a tool |
| Infected sites | Species change (birch, pine), stump removal | – |
Limitations#
- Only preventive (no cure for infected trees).
- Coverage must be complete; efficacy on spruce can vary with strain.
- Harvester equipment is needed for large-scale use.
Evidence of displacement — D3: proven displacement at scale#
Assessment (hand-reviewed): Regional: Rotstop (Phlebiopsis) applied on 47,000 ha vs urea on 2,000 ha a year in Fennoscandia.
Verified figures (the number is in the quoted sentence and the sentence is on the source page):
- displacement — In Fennoscandia, Phlebiopsis gigantea (Rotstop) was applied to over 47,000 hectares and urea to over 2,000 hectares of forestland annually. (Fennoscandia, 2003 (data reported in 2004); peer-reviewed: sciencedirect.com)
- performance — In precommercial thinnings, urea performed better (92-94% efficacy) than P. gigantea (59-72%), while in final fellings both treatments showed high efficacy (urea 95.5-99.8% vs P. gigantea 90-98%). (Sweden, 2020; weak: research.slu.se)
Suppliers — real products and services (from the vendor index)#
Honest finding: the vendor index has no Phlebiopsis stump-treatment supplier. This is recorded as a supplier gap.
Government funding signals#
Public grants for a specific technology are a leading indicator: governments fund what regulators want to replace and what is close to practical adoption. Searched on 2026-09-27 in: EU CORDIS (FP7, Horizon 2020, Horizon Europe), US federal awards (USAspending: USDA NIFA/ARS/APHIS/Forest Service, EPA, DOE, NOAA, USAID; plus NSF and NIH), UK UKRI Gateway to Research, Australian Research Council. Each grant below was reviewed by hand for relevance. China, Brazil and India are covered in the subsection below (publication-acknowledged grants). Not covered: Russia (RSF, FASIE — not reachable from the research environment) and national agencies outside these databases. Amounts are the funder’s contribution as recorded (US NIH/UKRI: per award or fiscal year).
Signal: Weak. 2 relevant grant(s) · about €0.1M in total · jurisdictions: USA.
| Funder / programme | Project | Lead organisation | Start | Amount | Link |
|---|---|---|---|---|---|
| US federal — Forest Service | A fifra-exempt stump protectant to prevent heterobasidion root disease | University Of Wisconsin System (US) | 2016 | 107,200 USD | link |
| US federal — Forest Service | Testing western us strains of phlebiopsis gigantea as biocontrol for heterobasidion root rot | Regents Of The University Of California, The (US) | 2022 | 18,427 USD | link |
China, Brazil, India — national research grants acknowledged in publications#
Chinese, Brazilian and Indian funders have no open grant databases reachable here, so this measures scientific papers published since 2015 that acknowledge national government grants, taken from the grant numbers publishers deposit with Crossref. Only papers whose title contains this article’s key terms are counted (a conservative lower bound; “100+” = search window full). It shows research-funding intensity, not budgets. Funders: China — NSFC, National Key R&D Program, China Agriculture Research System; Brazil — CNPq, CAPES, FAPESP, Embrapa, FAPEMIG; India — DBT, DST, ICAR, SERB, CSIR, BIRAC. Rating per country: Strong ≥50 papers · Moderate 10–49 · Weak 1–9.
| Country | Papers funded (2015–2026) | Signal | Main funders (grant acknowledgements) | Example grant → funded paper |
|---|---|---|---|---|
| China | 2 | Weak | NSFC (2) | NSFC 2023YFD1401304 → Biocontrol Potential of Streptomyces Strain FY4 Against Heterobasidion Root Rot Pathogen In Vitro (2024) doi |
| Brazil | 1 | Weak | CNPq (4), CAPES (1) | CNPq 563342/2010-2 → Additions to neotropical stereoid fungi (Polyporales, Basidiomycota): one new species of Lopharia and one… (2020) doi |
| India | 0 | None | – | – |
Scientific evidence#
- Garbelotto M, Gonthier P (2013). Biology, epidemiology, and control of Heterobasidion species worldwide. Annual Review of Phytopathology 51: 39–59.
- Berglund M, Rönnberg J (2004). Effectiveness of treatment of Norway spruce stumps with Phlebiopsis gigantea at different rates of coverage for the control of Heterobasidion. Forest Pathology 34: 233–243.
Bioeconomy value#
A native fungus protects the timber value chain (spruce sawlogs), replacing toxic boron chemistry.