Armillaria survey

RHS project team
Dr Liz Beal & Jenny Denton
Start date
23/01/2004 11:11:17
End date
23/12/2013 11:11:28

Armillaria, honey fungus, survey

The problem

For many years it was thought that Armillaria existed as just one very variable species. However, the range of species has now been confirmed and there are seven species recorded in the UK. These are A. mellea, A. gallica, A. ostoyae, A. cepistipes, A. borealis, A. tabescens and A. ectypa.

Much of the experimental work is carried out in woodland environments, which limits the amount of information that can be provided about this fungus as an unwanted pathogen in gardens. With the unique access to samples from gardens through our Members’ advisory service it has been possible to gain information about Armillaria in gardens which hopefully will help to broaden our understanding of this issue.


In 2004 a survey was begun using the samples sent for advisory queries with Armillaria. From each sample the fungus was isolated and a pure culture derived. Data from each of these samples was kept so that information such as the geographical region and the host plant could be linked to each culture.

The cultures were kept and stored, and each one was species identified using mainly molecular methods. This information was entered into a database so that a range of information can be extrapolated from it.

The most common species found so far in gardens in are A. mellea and A. gallica. There is a rarer occurrence of A. ostoyae and A. cepistipes. The remaining species A. tabescens, A. borealis and A. ectypa have not been found.

As well as helping us understand some of the issues laid out in the aims of this project, the wealth of cultures has also helped other projects on Armillaria. The survey has enabled us to have various different isolates of the same species, so in an experimental situation variation within a species can be identified, as well as variation between species, and this is extremely useful when trying to understand the behaviour of pathogens such as Armillaria.

Benefits to gardeners

This survey will collect information about species composition and host range and therefore help in giving more informed advice about infection risks from different Armillaria species to gardeners.

Further information

Effect of allicin on the growth of Armillaria mellea and A. gallica
Studies on the pathogenicity of Armillaria spp.
Survival of Armillaria in mulches (843kB pdf)

Advisory information

Read our advice on honey fungus

Read the studies on the pathogenicity of Armillaria spp

Read about the behaviour of severed rhizomorphs of Armillaria mellea and A. gallica in growing media


Henricot, B. 2011; Honey fungus. The Garden November 2011, 58-59

Pérez-Sierra A, Whitehead, D S & Whitehead, M P (1999). Investigation of a PCR-based method for the routine identification of British Armillaria species. Mycological Research 103 (12), 1631-1636.

Pérez-Sierra A (2003). Systematics, diagnostics and epidemiology of the fungal genus Armillaria. PhD. thesis, University of London.

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