Commodity PRA for Agaricus bisporus - Defra

A UK commodity Pest Risk Analysis for the cultivated mushroom, 

Agaricus bisporus 

J.W. Woodhall 1 , J.E. Smith 2 , P.R Mills 2 & C.E. Sansford 1 

1 Plant Health Group, Central Science Laboratory, Defra. 

2 Warwick HRI, University of Warwick. 

February 24 th 2009 

(First version: December 18 th 2007)

Commodity PRA for Mushrooms 

CSL/Warwick HRI, December 18th 2007; revised 24 February 2009 

CSL Registered File No. PPP 12011A 

A UK commodity Pest Risk Analysis for the cultivated mushroom, 


Summary 

A commodity Pest Risk Analysis (PRA) was undertaken for the cultivated 

mushroom, Agaricus bisporus. The aim of the commodity PRA was to identify 

risks to UK mushroom crops from pathogens, weed moulds and invertebrate 

pests that are not present in the UK. The introduction of these organisms to 

UK mushroom crops has the potential to cause economic loss. 

The methodology for the development of the PRA was to construct lists of 

organisms that are potentially harmful to mushrooms, determining whether or 

not they are already present in the UK. 

The analysis determined that 19 species of fungi, 11 species of bacteria and 

five species of viruses were directly pathogenic to mushrooms. Weed mould 

fungi, whilst not directly affecting the mushroom crop, can colonise compost 

and cause losses through competition. This study determined that there are at 

least 59 species of weed mould of mushroom composts. Of the invertebrate 

pests associated with mushroom production, 21 insect species, 22 Acarina 

(mites), 28 mycophagous nematodes and at least 18 saprophytic nematodes 

were listed. 

The majority of mushroom pathogens, weed moulds and pests are present in 

the UK. However, one species of fungal pathogen, two species of bacterial 

pathogen and two species of weed mould competitor are not considered 

present in the UK. All known viral pathogens of mushroom are already known 

to occur in the UK. Of the invertebrate pests affecting mushrooms, one 

species of insect, seven mite species, 17 species of mycophagous 

nematodes and ten species of saprophytic nematodes are not present in the 

UK. 

One species that warrants further consideration with regards to the threat to 

UK mushroom crops is the weed mould Trichoderma aggressivum forma 

aggressivum, which is present in North America. It has the potential to cause 

severe outbreaks of green mould if introduced to the UK. An HDC-funded 

Project undertook a survey of Trichoderma species present in UK mushroom 

production on 15 farms, over a 6-month period, commencing in December 

2007. Of the 28 isolates tested, T. aggressivum f. aggressivum was not found. 

Trichoderma aggressivum forma europaeum is already present here (and was 

found in the survey). It is not known whether the North American species 

poses an additional risk to UK mushroom production. As Trichoderma species 

have the potential to spread with spawn it is feasible that this exotic species 

could be introduced in imported spawn. However, if sufficient inoculum was 

present in the spawn, then any species or form of Trichoderma is likely to be 

visible and consequently the spawn would not be used. Low levels of 

inoculum may not be symptomatic though and could therefore escape 

detection. Nevertheless, testing imported spawn for the presence of non-




indigenous pathogens, weed moulds and pests could be useful in preventing 

their introduction. Testing imported spawn for indigenous organisms would 

also help prevent their further introduction to commercial mushroom 

production. 

Mushroom growers are advised to remain vigilant against species that are 

already present in the UK and have the potential to affect mushroom 

production, but have not yet been officially recorded in mushroom production 

environments. These species include several species of weed mould and 

nematode, and one species of fungal pathogen, Verticillium fungicola var. 

aleophilum. This pathogen may present a risk to UK mushrooms. It has been 

recorded affecting mushrooms in North America, but despite being present in 

other habitats in the UK, has not yet been found in UK mushroom crops. 

3

Contents 




1 Introduction 

1.1 Mushroom production in the UK 

1.2 PRA initiation 

1.3 Aims of the PRA 

2. Methods 

3. Results 

4. Discussion 

4.1 Pathogen risks 

4.2 Weed mould risks 

4.3 Invertebrate risks 

4.4 Conclusions 

5. Acknowledgements 

6. References 

Annex: List of pathogens, weed mould competitors and invertebrate pests 

associated with mushroom, with notes on symptoms and distribution 

List of Tables 

Table 1. Values and quantities of mushrooms home produced, imported or 

exported/re-exported from 1996 to 2005 with regard to the UK 

Table 2. UK imports of mushroom spawn (tonnes) 1996 to 2005 8 

Table 3. UK imports of mushroom spawn (£’000s) 1996 to 2005 9 

Table 4. Micro-organisms associated with mushrooms not present in the UK 12 

Table 5. Invertebrate pests associated with mushroom not present in the UK 13 

7 

4

1. Introduction 

1. 1 Mushroom production in the UK 




Mushrooms have been cultivated in the UK for at least 300 years (Flegg et al., 

1985). The species of mushroom that is cultivated in the UK is predominantly 

Agaricus bisporus. Mushrooms are typically grown in purpose built houses or 

other protected environments where temperature and humidity can be 

controlled. However, it is reported that caves in Bradford-on-Avon are still 

used for mushroom growing (Spooner & Roberts, 2005). 

Mushroom production is essentially in two stages, composting and mushroom 

growth. Composting consists of the preparation of the growth media, which 

usually takes 10 to 14 days. Mushroom growth typically spans 9 to 11 weeks. 

Mushroom farms are usually organised so that the production of a mushroom 

crop commences every week. 

Material used for preparing compost varies but usually cheap sources of 

carbon and nitrogen are utilised, typically wheat straw and manure. These 

ingredients are mixed, made into stacks and then turned and watered at 

intervals. The temperature can reach up to 80°C dur ing this phase (Phase I). 

The compost is then transferred to a pasteurisation tunnel, where the 

temperature is raised to 55-60°C. This is maintaine d for 6 hours then the 

compost is cooled and aired to remove free ammonia (Phase II). Bacteria, 

particularly actinomycetes and some thermpophilic fungi develop in the 

compost. The thermophillic organisms out-compete and effectively remove 

any mesophillic organisms that could infect or compete with the mushroom 

crop. After cooling, the media, which is selective for A. bisporus, is inoculated 

with spawn. Compost can be supplied to mushroom producers directly usually 

as Phase II or Phase III compost (described below). 

Spawn is a mushroom starter culture, normally grown on a cereal grain 

substrate. Specialist spawn producing companies, who maintain strains of A. 

bisporus, supply growers with packages of mushroom spawn and some 

compost producers provide Phase III compost (Phase II compost that is 

spawned and fully colonised with mushroom mycelium). This is ready for 

casing (see below) immediately after dispatch. 

Spawn is mixed into the compost (0.5% by weight). The inoculated compost is 

then maintained at 25ºC, which is optimum for growth of mushroom mycelia. 

The compost is fully colonised by mycelium after 10 to 14 days and is then 

covered with an additional layer often including peat and chalk, to a depth of 3 

to 5 cm. This process is known as casing. The cased compost is then placed 

in the cropping room and fruiting bodies (the edible part) first appear after 

about two weeks. At about 7 day intervals, further flushes of fruiting bodies 

occur. Growers usually allow a crop to produce three flushes after which it, 

and the cropping house, is sterilised. The compost is then considered spent. 

At this stage, the cropping room is steam treated at 60ºC to kill invertebrate 

pests and micro-organisms and the treated spent mushroom compost is 

disposed of, typically for re-use by horticulturists and gardeners. 

5




Like diseases of plants, diseases of mushrooms can be caused by fungi, 

bacteria or viruses. A variety of insect, mite and nematode pests can also 

affect production, directly by consuming tissue of A. bisporus (mycophagous 

pests) or indirectly by damaging the substrate. The presence of these 

organisms can cause allergies and they can be a nuisance to mushroom farm 

workers. Weed moulds; fungi that are capable of colonising the mushroom 

compost and out competing A. bisporus for available nutrients, can also cause 

economic loss. A severe epidemic of green mould caused by Trichoderma 

aggressivum f. europaeum (then classified as Trichoderma harzinum strain 

Th2) was first observed in Scotland and Ireland in the 1980s (Seaby, 1996). 

Figures on UK production, imports and exports of mushrooms between 1996 

and 2005 are presented in Table 1. In 2005 (latest available figures at the 

time of writing), the value of marketed mushrooms produced in the UK was a 

little over £100 million representing 74,000 tonnes. In previous years this 

value has been higher, with a peak (in the period covered) of £174 million 

representing 110,000 tonnes in 1998. The outbreak of Mushroom virus X in 

1998 may have contributed to the subsequent decline. This virus affected the 

crops of 80% of commercial mushroom growers; losses amounted to £50 

million, this resulted in mushroom farm closures and the loss of nearly 800 

jobs (NAO, 2003). UK mushroom exports peaked at 4,400 tonnes in 1997 

declining significantly to 100 tonnes by 2000. Thereafter exports have 

remained at < 300 tonnes. Since 2003, the UK has imported more 

mushrooms for consumption than it produces. However, the risks posed by 

imports of harvested mushrooms is likely to be very low. This is because 

home-produced mushrooms are produced in protected environments where it 

is unlikely that imported mushrooms would be stored. 

In terms of growing material, the UK mushroom industry is not self-sufficient. 

A significant amount of spawn (please note that the data given are for all 

mushroom species, not just A. bisporus) from a wide variety of countries is 

imported, mainly from Europe but also from North America (USA) and Asia 

(Tables 2 and 3). It is unlikely that the spawn from Asia is imported for A. 

bisporus production though. It is also not known how much spawn is imported 

on cereal grain and how much as phase III compost. The weight of imported 

spawn given in Table 2 is approximately three times more than would be 

needed for the quantity of mushrooms produced in the UK. Therefore, phase 

III compost is likely to comprise a large proportion of the weight of imported 

spawn given in Table 2. 

6




Table 1. Values and quantities of mushrooms home produced, imported or exported/re-exported from 1996 to 2005 with regard to 

the UK (Defra, 2006) 

Category 

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 

Home production marketed ('000 tonnes) 106.6 107.4 110.0 104.7 89.9 92.6 84.7 81.0 74.0 74.0 

Average farm-gate price (£ per tonne) 1,607.58 1,571.75 1,565.02 1,653.59 1,664.15 1,622.64 1,622.92 1,465.34 1,448.17 1,494.72 

Value of home production marketed (£'000) 171,295 168,741 174,456 168,559 149,545 150,298 137,448 118,693 105,518 104,092 

Imports quantity from all countries* ('000 

tonnes) 

51.1 86.2 68.0 59.4 68.4 72.4 75.2 99.5 110.2 134.0 

Imports from all countries* (£000) 84,390 139,800 109,115 99,337 108,467 118,479 125,994 152,078 159,129 173,160 

Exports and re-exports - quantity for the 

calendar year ('000 tonnes) 

Exports and re-exports – value for the 

calendar year (£’000) 

*Excluding the Channel Islands 

3.2 4.4 3.4 2.2 0.1 0.1 0.2 0.3 0.2 0.2 

4,196 3,060 3,711 2,549 410 367 490 550 464 433 

7




Table 2. UK imports of mushroom spawn (tonnes) 1996 to 2005 from data prepared by Defra and originally sourced from HM 

Customs. 1 

Exporting country 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Totals 

France 2,431.6 1,609.2 1,939.5 1,710.4 1,269.4 1,914.6 2,265.6 2,053.9 2,812.4 2,922.3 20,928.9 

Netherlands 821.5 753.4 833.4 1,275.6 542.8 136.4 64.2 1,463.5 835.7 922.5 7,649.1 

Irish Republic 176.7 82.7 39.7 117.0 371.8 650.4 1,032.6 508.8 263.7 236.5 3,479.9 

Italy 0.3 0.1 0.5 45.3 271.8 520.7 528.6 333.0 1,700.2 

USA 140.5 348.7 137.4 2.9 0.5 29.3 23.4 0.0 0.5 683.4 

Singapore 231.8 316.6 80.4 628.9 

Indonesia 158.8 146.2 305.0 

Germany 0.5 1.7 27.9 30.1 

Hungary 42.4 42.4 

China 0.1 0.1 40.0 40.2 

Belgium 0.1 0.2 0.3 5.3 7.1 13.0 

Denmark 1.5 6.9 4.3 1.1 0.4 0.1 14.3 

Japan 0.1 0.4 0.8 2.0 3.3 

South Africa 0.0 

Portugal 0.2 2.4 2.6 

Greece 1.5 1.5 3.0 

Belgium-Luxembourg 0.3 0.4 0.3 1.1 

South Korea 0.0 0.0 

Totals 3,572.4 2,803.7 2,954.7 3,149.5 2,184.6 3,138.2 4,126.6 4,654.5 4,447.0 4,494.2 35,525.4 

1 These figures are likely to include both cereal grain spawn and phase III compost. However, the definition used in the original data 

is spawn. Note: these data include figures for all edible mushroom species. 

8




Table 3. UK imports of mushroom spawn (£’000s) 1996 to 2005 from data prepared by Defra and originally sourced from HM 

Customs 1 

Exporting country 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Totals 

France 2,781.9 1,825.1 2,223.9 2,364.8 1,839.7 1,794.4 1,851.6 1,738.2 1,802.1 1,800.8 20,022.5 

Netherlands 975.5 809.5 884.8 1,317.0 549.8 64.5 39.5 575.5 244.2 362.2 5,822.5 

Irish Republic 242.1 137.1 65.1 37.8 385.8 748.4 1,029.8 609.9 296.3 235.8 3,788.1 

Italy 0.8 0.2 4.7 42.0 435.5 615.7 524.2 333.6 1,956.6 

U.S.A. 135.8 282.9 94.7 4.7 0.8 32.4 29.5 0.7 2.7 584.2 

Singapore 47.0 155.6 35.2 237.8 

Indonesia 45.4 85.3 130.7 

Germany 1.7 1.5 12.6 15.8 

Hungary 34.3 34.3 

China 0.8 0.8 5.1 6.7 

Belgium 0.4 1.3 1.8 8.6 13.5 25.5 

Denmark 3.3 14.0 8.4 1.7 1.1 0.2 28.6 

Japan 0.8 3.5 5.6 13.0 22.9 

South Africa 0.0 

Portugal 0.3 2.7 3.0 

Greece 2.4 2.2 4.6 

Belgium-Luxembourg 0.4 0.8 0.6 1.8 

South Korea 0.9 0.9 

Totals 4,139.7 3,074.3 3,277.5 3,760.5 2,780.3 2,743.6 3,631.7 3,612.9 2,883.0 2,783.0 32,687.6 

1 These figures are likely to include both cereal grain spawn and phase III compost. However, the definition used in the original data 

is spawn. Note: these data include figures for all edible mushroom species. 

9

1.2 PRA initiation 




Mushrooms could be considered to come under the EC Plant Health Directive 

(2000/29/EC) and subject to the same legislation as plants. However, the 

directive does not stipulate or exclude mushrooms specifically. In the Plant 

Health (England) Order 2005, the Plant Health (Northern Ireland) Order 2006, 

the Plant Health (Wales) Order 2006, the Plant Health (Scotland) Order 2005 

(hereafter collectively referred to as the Order), the term ‘plant’ includes fungi 

and by implication therefore includes mushrooms. This is the reason for this 

commodity Pest Risk Analysis. 

EPPO do not have any recommendations on trade in mushrooms. However, 

an EPPO standard exists (PP2/20) giving guidelines on good protection 

practices for mushrooms (Anon., 2000). 

1.3 Aims of the PRA 

This PRA aims to identify the potential risks to mushroom crops from 

pathogens, weed moulds and pests not present in the UK. The methodology 

used to undertake this was to create a list of organisms associated with A. 

bisporus. We then went on to determine whether or not they are already 

present in the UK. 

The risks posed to the mushroom crop by organisms that are not present in 

the UK are discussed. 

11

2. Methods 




Searches of mushroom related literature (Fletcher et al., 1994; Flegg et al., 

1985; Geels et al., 1988), along with host-organism indexes (CABI 

Compendium, undated; Farr et al., undated; Moore, 1959; Bradbury, 1986) 

were used to construct a list of organisms that have an association with 

mushrooms. Diagnosis data from samples submitted for testing at CSL were 

also analysed to add any recent findings of organisms associated with 

mushrooms to the list as these would not necessarily be published in the 

literature. All parts of the mushroom lifecycle were considered (spawn, 

mycelium and fruiting body), as well as all media associated with mushroom 

production (spawn, compost, harvested mushrooms). 

Synonyms of organisms are given as the CSL preferred name (CSL records) 

or for the fungal species, the name given in the Index Fungorum Database 

(Anon., undated). The anamorph or teleomorph of fungi is given dependent 

upon which stage is usually associated with mushrooms. Once the pest list 

was created, worldwide distribution and presence or absence in the UK was 

determined for each species. This was done by consulting specific literature, 

the CABI Compendium (CABI Compendium, undated) and CSL internal 

diagnosis records as well as consulting the relevant CSL or Warwick HRI 

specialists. For fungal species, the British Mycological Database (BMS, 

undated) and Farr et al. (undated) were also used. Mushroom pathogens, 

weed moulds and pests that are not present in the UK and which could pose a 

risk to mushroom production were then identified and discussed. 

12

3. Results 




All organisms associated with mushroom found in the literature are listed in 

the tables in the Annex along with the supporting references. This analysis 

found that 19 species of fungal pathogens, 11 species of bacteria and five 

species of virus are associated with mushrooms worldwide. There are also at 

least 59 species of weed mould that could affect mushroom production. For 

the invertebrate pests, 21 insect species, 22 Acarina (mites), 28 

mycophagous nematodes and at least 18 saprophytic nematodes were found 

associated with mushroom production. 

Micro-organisms (pathogens and weed moulds) associated with mushroom 

production that are not present in the UK are shown in Table 4. Two species 

of weed mould competitors are not present in the UK. One fungal pathogen 

and two bacterial pathogens of mushroom are also exotic to the UK. All known 

mushroom viruses are already considered present in the UK. 

Table 4. Micro-organisms associated with mushrooms not present in the UK 

Species Type of 

organism 

Paecilomyces Fungal 

penicillatus pathogen 

Pseudomonas 

costantinii 

Pseudomonas 

‘reactans’ 

Trichoderma 

aggressivum f. 

aggressivum 

Trichoderma 

asperellum 

Bacterial 

pathogen 

Bacterial 

pathogen 

Weed mould 

competitor 

Weed mould 

competitor 

Worldwide distribution Means of movement 

Only one record of 

isolation from a 

decaying mushroom in 

Belgium. Has also been 

found on decaying 

plants and wood. 

Originally found in 

Finland but the present 

distribution is unknown. 

Originally considered a 

strain of Pseudomonas 

tolaasii. 

P. ‘reactans’ strains 

pathogenic to mushroom 

were originally reported 

in the USA 

Present in North 

America and relatively 

common as a cause of 

green mould in 

mushroom compost. 

Recorded in mushroom 

compost in Hungary. 

Appears to have a wide 

global distribution. Used 

as a biocontrol agent 

against plant pathogenic 

fungi. 

Airborne spores. 

Direct contact, 

contaminated compost or 

introduced to the growing 

environment via air 

currents. 

Direct contact, 

contaminated compost or 

introduced to the growing 

environment via air 

currents. 

Spores spread by pepper 

mites (Pygmephorus spp.) 

Some Trichoderma species 

can contaminate spawn. 

Spores spread by pepper 

mites (Pygmephorus spp.) 

Some Trichoderma species 

can contaminate spawn. 

13




Invertebrate pests of mushroom that are not present in the UK are listed in 

Table 5. These consist of one species of insect, seven mite species, 17 

species of mycophagous nematodes and ten species of saprophytic 

nematodes. 

Table 5. Invertebrate pests associated with mushroom not present in the UK 


Worldwide Means of movement 

organism distribution 

Bradysia 

matogrossensis 

Insect (sciarid) Brazil Compost and airborne 

Brennandania lambi 

Krczal 

(Australian 

mushroom pygmy 

mite) 

Digamasellus fallax 

Leitner 

Dolichocybe keiferi 

Krantz 

Pediculaster 

fletchmanni Wicht 

Pygmephorus 

athiasae Wicht 

(Red pepper mite) 

Pygmephorus 

kneeboni Wicht 


Pygmephorus 

murphyi Smiley 


Aphelenchoides 

agarici 


asterocaudatus 


bicaudatus 


coffeae 


cyrtus 


helophilus 


limberi 

Acarina (mite) Australia Primarily through infested 

spawn 

Acarina (mite) Worldwide (not 

UK) 

Acarina (mite) USA Not known 

In compost or phoretic (carried 

by other invertebrates) 

Acarina (mite) Brazil In compost or phoretic (carried 


Acarina (mite) France 



Acarina (mite) USA In compost or phoretic (carried 


Acarina (mite) USA In compost or phoretic (carried 


Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

India In compost or phoretic (carried 




Australia, 

Europe 



Australia In compost or phoretic (carried 


Germany In compost or phoretic (carried 


Europe In compost or phoretic (carried 


Europe, North 

America, Asia 



14


organism 

Aphelenchoides Mycophagous 

minor 

nematode 


myceliophagus 


neocomposticola 


sacchari 


spinosus 


swarupi 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Mycophagous 

nematode 

Ditylenchus filimus Mycophagous 

nematode 

Ditylenchus 

intermedius 

Mycophagous 

nematode 

Ditylenchus valveus Mycophagous 

nematode 

Filenchus misellus 

Acrobeloides 

apiculatus 

Acrobeloides 

buetschlii 

Pelodera 

(Cylindridera) 

icosiensis 

Pelodera 

lambdiensis 

Mycophagous 

nematode 

Saprophytic 

nematode 

Saprophytic 

nematode 

Saprophytic 

nematode 

Saprophytic 

nematode 

Prodontorhaditis sp. Saprophytic 

nematode 

Rhabditis 

(Cephaloboides) 

oxycera 

Saprophytic 

nematode 




Worldwide Means of movement 

distribution 







Europe, India In compost or phoretic (carried 


Germany, 

Australia 



India, Italy In compost or phoretic (carried 


Canada In compost or phoretic (carried 


Europe, North 

America 

North America, 

Asia 





Asia Not known – only observed to 

eat mushroom mycelia 

experimentally. But means of 

movement likely to be similar to 

Worldwide (not 

UK) 


UK) 

other nematodes. 

Passive dispersal, survival in 

compost or phoretic on flies. 

Possibly distributed by air 

currents when in a dried state. 





China Passive dispersal, survival in 




USA, 

Australia, Fiji 

and North 

Africa 





China Passive dispersal, survival in 




Not known Passive dispersal, survival in 




15


organism 

Rhabditis 

Saprophytic 

(Choriorhabditis) nematode 

longicaudatus 

Rhabditis (Pellioditis) 

pellio 

Saprophytic 

nematode 

Rhabditis terricola Saprophytic 

nematode 

Rhabditis cucumeris Saprophytic 

nematode 




Worldwide 

distribution 

Means of movement 






UK) 









Worldwide(not 

UK) 





16

4. Discussion 




This analysis has shown that the majority of the mushroom pathogens, weed 

moulds and pests recorded in the literature are present in the UK. 

Nevertheless, several species are not found in the UK that could potentially 

affect mushroom production if introduced. They are discussed in part below. 

There are also a number species that have been recorded in other habitats or 

on other hosts in the UK but have not recorded in UK mushroom crops. These 

species include several species of weed mould and nematode, and one 

species of fungal pathogen, Verticillium fungicola var. aleophilum. Of these 

species, the most significant threat is the fungal pathogen. This organism has 

been recorded affecting mushrooms in North America, where it is the main 

cause of dry bubble disease, causing a variety of symptoms on mushroom 

caps such as lesions, distortion and discolouration. However, in Europe, dry 

bubble is associated with Verticillium fungicola var. fungicola, therefore 

mushroom growers already deal with dry bubble caused by a related species. 

Nevertheless, mushroom growers are advised to remain vigilant against 

species that are already present in the UK and have the potential to affect 

mushroom production, but have not yet been officially recorded in mushroom 

production environments. 

4.1 Pathogen risks 

Paecilomyces penicillatus. This fungus has not been recorded in the UK. 

There is only one report of it affecting mushrooms (found on a decaying 

mushroom in Belgium). As this was an isolated report it may have been an 

opportunistic infection. If P. penicillatus were an aggressive pathogen of 

mushrooms then it is likely that the disease would have been more widely 

reported. Therefore the risk this pathogen presents to UK mushrooms is likely 

to be low. 

Pseudomonas species. Pseudomonas costantinii and Pseudomonas 

‘reactans’ have never been recorded in the UK. However, little is known about 

their current distribution. Pseudomonas costantinii was originally considered a 

strain of Pseudomonas tolaasi (Munsch et al., 2002). Both P. tolaasi and P. 

costantinii can cause brown blotches on mushroom caps. P. tolaasi is known 

to be common in the UK on mushrooms. Since many Pseudomonas strains 

already occur in UK mushrooms, many uncharacterised, it is possible that 

these species are also present but have not been formally reported. UK 

mushroom growers already manage diseases caused by several other 

Pseudomonas species. Therefore, it is likely that these Pseudomonas species 

present little additional risk to UK mushrooms. 

4.2 Weed mould competitor risks 

Trichoderma aggressivum forma aggressivum. This species is an 

aggressive coloniser of mushroom composts in North America but is not 

present in Europe. An HDC-funded Project undertook a survey of 

Trichoderma species present in UK mushroom production on 15 farms, over a 

17




6-month period, commencing in December 2007. Of the 28 isolates tested, T. 

aggressivum f. aggressivum was not found (Lane, 2008). Severe outbreaks of 

green mould in Europe are usually associated with Trichoderma aggressivum 

forma europaeum. In the UK and Ireland, T. aggressivum f. europaeum has 

caused severe outbreaks and economic losses (Seaby, 1996). Trichoderma 

aggressivum f. europaeum differs to T. aggressivum f. aggressivum by a 

subtly different growth rate at 25ºC and micromorphological differences 

(Samuels et al., 2002). Appropriate molecular tests can be used to distinguish 

between the two forms. 

The introduction of the North American strain would increase the genetic 

diversity of the T. aggressivum species complex in Europe, which could 

present new, unforeseen, problems to European mushroom growers. There is 

a pathway for this species to enter the UK, as Trichoderma species can be 

spread with spawn, which is imported from North America (Table 2). However, 

T. aggressivum has not been known to infect mushrooms through spawn but 

has the potential to do so. It is likely that either form of Trichoderma in spawn 

would be highly visible if a sufficient amount of inoculum was present and in 

these circumstances it would be rejected. 

Trichoderma asperellum. Although this species is recorded in mushroom 

composts in Hungary, it is not likely to present major problems to mushroom 

growers in the UK. This is because UK mushroom growers are used to 

managing more aggressive Trichoderma species, such as Trichoderma 

aggressivum f. europaeum. Trichoderma asperellum is present worldwide. It 

is used as a biocontrol agent against fungal plant pathogens in several 

countries. The relatively few reports for it indicate that it is likely to be one of 

the less aggressive Trichoderma species that can colonise mushroom 

composts. 

4.3 Invertebrate risks 

Bradysia matogrossensis. This species of sciarid is present in Brazil. Many 

Bradysia species are already present in the UK but they are rarely recorded 

as pests on mushroom crops. Should B. matogrossensis be introduced, it 

would seem unlikely to cause any additional problems for mushroom growers, 

who already deal with the native Bradysia species. At the present time the 

introduction of this species is unlikely, as there is no trade in spawn with 

South America (Table 2) and spawn is not a known source of infestation for 

this species. 

Acarina (Mites). Mites are almost ubiquitous in mushroom production, and 

since they are very small they are not usually noticed until large numbers are 

present (Flegg et al., 1988). Several of the mite species recorded in 

association with mushrooms as both pests and ‘incidentals’ are absent from 

the UK. Should they be introduced, it is unlikely that they will pose a 

significant additional risk to UK mushroom growers, who already deal with 

several species of mites. Two of the most important species, Brennandania 

18




lambi and Dolichocybe keiferi, are absent from the UK, and these directly 

affect mushroom mycelia. Brennandania lambi has only ever been reported in 

Australia but as there is no trade in spawn from this country, there is no 

obvious pathway for its introduction to the UK. Conversely, D. keiferi, a 

species present in the USA, may have a pathway for its introduction as spawn 

is imported to the UK from the USA. It is likely that these species will present 

no new risk to UK growers who already deal with several mycophagous mite 

species that are common in the UK. 

Pediculaster fletchmanni and several ‘red pepper mites’ (Pygmephorus 

species) are exotic to the UK and can occur in mushroom crops. Although 

harmless to the mushroom crop itself (feeding mainly on weed moulds such 

as Trichoderma), they can, when present in large numbers, lead to crop 

rejection due to contamination with their brightly coloured bodies. In addition, 

contact with these mites can induce allergic responses in mushroom pickers. 

Several Pygmephorus species are already present in the UK and similar 

problems already occur. Should these exotic species be introduced, they are 

unlikely to present a new risk to UK mushroom growers and are only likely to 

present a problem if high levels of weed mould such as Trichoderma are 

present. 

Nematode species. Thirteen Aphelenchoides and three Ditylenchus species 

affect mushroom crops and are considered absent from the UK. These are 

mycophagous and could therefore affect mushroom yield and quality. 

However, Aphelenchoides composticola and Ditylenchus myceliophagus are 

the most important species of each genus with regards to mushroom 

production. These are both present in the UK but are relatively rare in UK 

mushroom crops. It is unlikely that other members of each species would 

pose more of a risk to UK mushroom crops, since UK mushroom farmers 

already manage the most aggressive species of each genus. 

Filenchus misellus is also absent from the UK. It is present in Asia and it has 

been observed to consume mushroom mycelia under experimental conditions. 

The feeding habits of this species are not fully known but they have been 

observed to consume other species of fungi in experiments (Okada et al., 

2005). There are no further reports of the nematode in mushrooms. Therefore, 

it appears that this species is not established in mushroom production 

systems. Consequently, it is unlikely that there is a pathway for this species to 

be introduced to UK mushrooms at this time. 

Ten species of saprophytic nematodes associated with mushrooms are 

absent from the UK. These include species of Acrobeloides, Pelodera and 

Rhabditis and one species of Prodontorhaditis. Several saprophytic species 

are common in UK mushroom production. These do not directly affect the 

mushroom itself, so it is unlikely that these would present a new risk to UK 

mushroom producers. 

4.4 Conclusions 

19




Many of the major pathogen, weed mould and pest species of mushroom are 

already present in the UK. However, there is a considerable number of 

pathogen, weed mould and pest species of mushroom that are not present in 

the UK. This analysis considers that these species do not pose new risks for 

UK mushroom growers, as they already manage similar risks presented by 

existing related organisms. However, T. aggressivum f. aggressivum, the 

main cause of green mould in North America, may still pose a threat 

From this analysis, testing imported spawn may be useful in preventing the 

movement of harmful organisms be they indigenous or non-indigenous. There 

has been some movement of harmful organisms in mushroom production 

recently, such as the movement of Trichoderma species into central Europe 

(Hatvani et al., 2007) and the recent movement of V. fungicola var. fungicola 

from Europe into North America (Largeteau et al., 2004). Testing of spawn 

imports, at least those from non-Member States could be considered, in order 

to minimise the risk from new exotic pathogens, weed moulds and pests of 

mushroom. An EPPO protocol for testing spawn imported into the EPPO 

region could also be produced. 

This analysis has also highlighted that there are several species that are 

already present in the UK and have the potential to affect mushroom crops, 

but have not yet been observed affecting mushroom production to date. 

Verticillium fungicola var. aleophilum is one such species. Mushroom growers 

should remain vigilant against such organisms. 

5. Acknowledgments 

The authors would like to thank CSL specialists for their input into forming the 

pest lists: J. Ostojia-Starzewski (mites), D. Collins (insects), T. Prior and R. 

Lawson (nematodes). C. Lane is thanked for general help and advice. 

20

6. References 




Anon., undated. Index Fungorum Database. 

[http://www.speciesfungorum.org/Names/Names.asp]. 

Anon., 2000. EPPO Standards - Mushrooms PP 2/20(1). 

Anon., 2004. Diseases of Mushrooms. In Guidelines for the Control of Plant 

Diseases In Western Canada. Western Committee on Plant Diseases 

[http://www.westernforum.org/WCPD_main.htm]. 

Behnke JM, Lewis JW, Mohd Zain SN, Gilbert FS, 1999. Helminth infections 

in Apodemus sylvaticus in southern England: interactive effects of host age, 

sex and year on the prevalence and abundance of infections. Journal of 

Helminthology 73, 31-44. 

Betterley DA, Brown M F, 1989. A Mortierella species (Zygomycetes) 

associated with cultivation of Agaricus brunnescens. (Abstract) Mushroom 

science XII Part II Proceedings of the twelfth international congress on the 

science and cultivation of edible fungi, Braunschweig, Germany, September, 

1987, pp. 771-780. 

Beyer DM, 2002. Weed and Indicator Moulds. Chapter in Mushroom 

integrated pest management handbook. Pennsylvania State University. 

[http://paipm.cas.psu.edu/pdf/mushroomIPMhandbook.pdf], pp 61-74. 

BMS, undated. The British Mycological Society Fungal Records Database. 

[http://194.203.77.76/fieldmycology/GBCHKLST/gbchklst.htm]. 

Bradbury JF, 1986. Guide to Plant Pathogenic Bacteria. Farnham Royal, 

Slough, UK: CAB International. 

Brady BLK, Gibson IAS, 1976. Mycogone rosea. CMI Descriptions of Fungi 

500. 

CABI, undated. CABI Genetic Resource Collection catalogue. [www.cabibioscience.org/docs/pdf/GRCCatalogue.pdf]. 

CABI Compendium, undated. CABI Crop Protection Compendium. CAB 

International, Wallingford, UK. 

Chowdhury PR, Heinemann, JA. 2006. The general secretary pathway of 

Burkholderia gladioli pv. agaricicola BG164R is necessary for cavity disease 

in white button mushrooms. Applied and Environmental Microbiology 72, 

3558–3565. 

Coetzee JC, Eicker A, 1994. First report of Trichophaea abundans and the 

teleomorph of Peziza ostracoderma associated with mushroom cultivation in 

South Africa. South African Journal of Botany 60, 132-133. 

21




Coles PS, 2002. Nematodes Chapter in Mushroom Integrated Pest 

Management Handbook. Pennsylvania State University. 

[http://paipm.cas.psu.edu/pdf/mushroomIPMhandbook.pdf], pp. 78-84. 

Collopy PD, Largeteau-Mamoun ML, Romaine CP, Royse DJ, 2001. 

Molecular phylogenetic analyses of Verticillium fungicola and related species 

causing dry bubble disease of the cultivated button mushroom, Agaricus 

bisporus. Phytopathology 91, 905-912. 

Dmowska E, Dmoch J, Ilieva K, 1997. Early interaction of the bacterivourous 

nematode Rhabditis cucumeris and the edible fungus Agaricus bisporus in 

relation to time and quantity of nematode inoculation. International Journal of 

Mushroom Science 2, 15-23. 

Dodd SL, Lieckfeldt E, Samuels GJ, 2003. Hypocrea atroviridis, the 

teleomorph of Trichoderma atroviride. Mycologia 95, 27-40. 

Farr DF, Rossman AY, Palm ME, McCray EB, undated. Fungal Databases, 

Systematic Botany & Mycology Laboratory, ARS, USDA [http://nt.arsgrin.gov/fungaldatabases/]. 

Flegg PB, Spencer DM, Wood DA (eds), 1985. The Biology and Technology 

of the Cultivated Mushroom. John Wiley & Sons: Chichester. 

Fletcher JT, White PF, Gaze RH, 1994. Mushrooms: Pest & Disease Control, 

2nd edition. Intercept: Andover. 

Gao J, Zou P, 2001. Biology, life table and host specificity of the mushroom 

pest, Brennandania Lambi (Acari: Pygmephoroidea) Experimental and 

Applied Acarology 25, 187-202. 

Geels FP, van de Geijn J, Rutjens AJ, 1988. Pests and Disease. Chapter in 

van Griensven L.J.L.D (ed) The Cultivation of Mushrooms. Mushrooms 

Experimental Station, The Netherlands. 

Gill WM, Tsuneda A, 1997. The interaction of soft rot bacterium Pseudomonas 

gladioli pv. agaricicola with Japanese cultivated mushrooms. Canadian 

Journal of Microbiology 43, 639-648. 

Goodey JB, 1960. Observation on the effects of the parasitic nematodes 

Ditylenchus myceliophagus, Aphlenchoides composticola and 

Paraphelenchus myceliophthorus on the growth and cropping of mushrooms. 

Annals of Applied Biology 48, 655-664. 

Grewal PS, Richardson PN, 1990. Caenorhabditis elegans (Nematoda: 

Rhabditidae). A pest of mushrooms (Agaricus bisporus). Mededelingen Van 

De Faculteit 55, 729-738. 

Grewal PS, Siddiqi MR, Atkey PT, 1992. Aphelenchoides richardsoni sp. nov. 

and Seinura paynei sp. nov. from mushrooms in the British Isles, and Seinura 

22




obscura sp. nov. from India (Nematoda: Aphelenchina). Afro-Asian Journal of 

Nematology 1, 204–211. 

Grogan HM, Adie BAT, Gaze RH, Challen MP, Mills PR 2003. Doublestranded 

RNA elements associated with the MVX disease of Agaricus 

bisporus. Mycological Research 107, 147-154. 

Gurney B, Hussey NW, 1967 Pygmephorus species (Acarina; Pyemotidae) 

associated with cultivated mushrooms. Acarologia 9, 353-358. 

Hatvani L, Antal Z, Manczinger L, Szekeres A, Druzhinina IS, Kubicek CP, 

Nagy A, Nagy E, Vágvölgyi C, Kredics L, 2007. Green mould diseases of 

Agaricus and Pleurotus species are caused by related but phylogenetically 

different Trichoderma species. Phytopathology 97, 532-537. 

Hodda M, 2003. A Checklist of Aphelenchida. 

[http://www.ento.csiro.au/science/nematodes/checklist_dec2003.rtf]. 

Hooper D, 1962. Effects of a nematode on the growth of mushroom mycelium. 

Nature 193, 496-497. 

Hussey NW, 1963. A new species of Tarsonemus (Acarina: Tarsonemidae) 

from cultivated mushrooms. Acarologia 5, 540-544. 

Inglis PW, Peberdy JF, 1996. Isolation of Ewingella americana from the 

cultivated mushroom, Agaricus bisporus. Current Microbiology 33, 334-337. 

Jin Q, Cai W, Feng W, Shi L, Li F, 2006. Nematode species associated with 

the button mushroom in Zhejiang province. Acta Agriculturae Zhejiangensiss 

18, 195-197. 

Lane C, 2008. Trichoderma green mould – determining diversity and 

highlighting risks. HDC Project Report M46. 17pp. 

Largeteau ML, Mata G, Savoie J-M, 2004. Verticillium fungicola var. fungicola 

affects Agaricus bisporus cultivation in Mexico. FEMS Microbiology Letters 

236, 191-196. 

Liang T, Xiu O, Chongti T 1983. Studies on the plant nematodes in South 

Fujian III, Observation on Mushrooms-Nematodes. Acta Zoologia 29, 170- 

179. 

Lincoln SP, Fermor TR, 1999. Janthinobacterium agaricidamnosum sp. nov., 

a soft rot pathogen of Agaricus bisporus. International Journal of Systematic 

Bacteriology 49, 1577-1589. 

Luangsa-ard JJ, Hywel-Jones NL and Samson RA (2004) The polyphyletic 

nature of Paecilomyces sensu lato based on 18S-generated rDNA phylogeny. 

Mycologia 96, 773-780. 

23




Menzel F, Smith JE, Colauto NB, 2003. Bradysia difformis Frey and Bradysia 

ocellaris (Comstock): Two additional neotropical species of black fungus gnats 

(Diptera : Sciaridae) of economic importance: A redescription and review. 

Annals of the Entomological Society of America 96, 448-457. 

Miyairi K, Konno K, Harada Y, Okuno T, 1994. Fungus fruit body lytic enzyme 

from a myxomycete Badhamia utricularis. Mycoscience 35, 695-699. 

Moore WC, 1959. British Parasitic Fungi. Cambridge University Press. 

Munsch P, Alatossava T, Marttinen N, Meyer JM, Christen R, Gardan L, 2002. 

Pseudomonas costantinii sp. nov., another causal agent of brown blotch 

disease, isolated from cultivated mushroom sporophores in Finland. 

International Journal of Systematic and Evolutionary Microbiology 52, 1973- 

1983. 

NAO, 2003. Protecting England and Wales from plant pests and diseases. 

Report by the comptroller and auditor general. HC 1186 Session 2002-2003: 

29 October 2003. [http://www.nao.org.uk/publications/nao_reports/02- 

03/02031186.pdf] 

Okada H, Kadota I, 2002. Population growth rates of two fungal-feeding 

nematodes, Filenchus misellus (Tylenchidae) and Aphelenchus avenae 

(Aphelenchidae), on ten fungal isolates. Fourth International Congress of 

Nematology Programme and Abstracts. 8–13 June 2002, Tenbel, La Galletas, 

Arona, Tenerife, Canary Islands, Spain. 

Okada H, Harada H, Kadota I, 2005. Fungal-feeding habits of six nematode 

isolates in the genus Filenchus. Soil Biology and Biochemistry 37, 1113-1120. 

Pantou MP, Strunnikova OK, Shakhnazarova VY, Vishnevskaya NA, 

Papalouka VG, Typas MA, 2005. Molecular and immunochemical phylogeny 

of Verticillium species. Mycological Research 109, 889-902. 

Perkins DD, Davis RH, 2000. Evidence for safety of Neurospora species for 

academic and commercial uses. Applied and Environmental Microbiology 66, 

5107–5109. 

Perper T, Petriello R, 1977. Population growth patterns of four species of 

Aphelenchoides on fungi, Journal of Nematology 9, 301-307. 

Phillips R, 2006. Mushrooms. Macmillan: London. 

Reyes JE, Venturini ME, Oria R, Blanco D, 2004. Prevalence of Ewingella 

americana in retail fresh cultivated mushrooms (Agaricus bisporus, Lentinula 

edodes and Pleurotus ostreatus) in Zaragoza (Spain). FEMS Microbiology 

Ecology 47, 291–296. 

Richardson PN, Grewal PS, 1993. Nematode Pests of Glasshouse Crops and 

Mushrooms. Chapter in Plant parasitic Nematodes in Temperate Agriculture. 

24




Evans K, Trudgill DL, Webster JM (eds). CABI International: Wallingford. pp. 

501-544. 

Samuels GJ, 2006.Trichoderma: Systematics, the Sexual State, and Ecology. 

Phytopathology 96,195-200. 

Samuels, GJ, Dodd SL, Gams W, Castlebury LA, Petrini O, 2002. 

Trichoderma species associated with the green mould epidemic of 

commercially grown Agaricus bisporus. Mycologia 94, 146-170. 

Schroers HJ, Samuels GJ, Seifert KA, Gams W, 1999. Classification of the 

mycoparasite Gliocladium roseum in Clonostachys as C. rosea, its 

relationship to Bionectria ochroleuca, and notes on other Gliocladium-like 

fungi. Mycologia 91, 365-385. 

Seaby DA, 1996. Differentiation of Trichoderma taxa associated with 

mushroom production. Plant Pathology 45, 905-912. 

Sharma NK, Thapa CD, Nath A, 1981. Pathogenicity and identity of 

myceliophagus nematode infesting Agaricus bisporus in Himachal Pradesh 

(India). Indian Journal of Nematology 11, 230-231. 

Singh SK, Sharma VP, Sharma SR, Kumar S, Tiwari M, 2006. Molecular 

characterisation of Trichoderma taxa causing green mould disease in edible 

mushrooms. Current Science 90, 427-431. 

Spooner B, Roberts P, 2005. Fungi (Collins New Naturalist). London: Collins. 

Smilley RL, 1978. Taxonomic studies of Pygmephorus species from the 

western hemisphere, with a key to females and an overview of the current 

problems for classification (Acari: Pymotidae and Pygmephoridae) 

International Journal of Acarology 4, 125- 160. 

Steiner G, 1933. Rhabditis lambdiensis, a nematode possibly acting as a 

disease agent in mushroom beds. Journal of Agricultural Research 46, 427- 

438. 

Vakili NG,1989. Gonatobotrys simplex and its teleomorph Melanospora 

damnosa. Mycological Research 93, 67-74. 

van Greuning M, Eicker A, 1991. The identity of the lipstick mould of cultivated 

mushrooms Agaricus bisporus. Botanical Bulletin of Academia Sinica 32, 57- 

62. 

Wells JM, Saper GM, Fett WF, Butterfield JE, Jones JB, Bouzar H, Miller FC, 

1996. Post harvest discolouration of the cultivated mushroom Agaricus 

bisporus caused by Pseudomonas tolaasii, P. ‘reactans’, and P. ‘gingeri’. 

Phytopathology 86, 1098-1104. 

25




White PF Smith JE, 2000. Bradysia lutaria (Winn.) (Dipt., Sciaridae) - a recent 

addition to the British fauna and a pest of the cultivated mushroom (Agaricus 

bisporus). Entomologist’s Monthly Magazine. 136, 165-167. 

Wicht MC, 1970. Three new species of Pyemotid mites associated with 

commercial mushrooms. Acarologia 12, 262-268. 

Wood FC, 1957. Heleococcum aurantiacum; an uncommon weed fungus of 

mushroom compost. Nature 180, 283. 

Zamani AA, Talebi AA, Mohamedi E, 2005. Investigation on morphological 

and biological characteristics of Megaselia scalaris (Dipt. Phoridae) as an 

important pest of button mushrooms in Karaj, Iran. The Scientific Journal of 

Agriculture 27, 47-58. 

Zare R, Gams W, 2003. Lecanicillium psalliotae. IMI descriptions of Fungi 

1568. 

26




Annex. List of pathogens, weed mould competitors and invertebrate pests associated with mushroom, with notes on symptoms and distribution 

Table 1. Fungal pathogens associated with Agaricus bisporus 

Pathogen Synonyms Symptom Notes on worldwide 

distribution 

Notes on UK distribution Reference 

Acremonium Cephalosporium Moore (1959) reported Present on a wide Present on a wide range of Flegg et al. (1985); BMS 

strictum 

acremonium that one species of range of hosts and hosts and habitats in the UK but (undated); Moore (1959) 

Acremonium caused habitats worldwide. no records found after Moore 

chocolate brown Appears to be (1959). 

patches on mushroom. 

However, the species 

was not identified. Flegg 

et al. (1985) report that 

A. strictum has an 

association with 

mushroom but no other 

reports are available 

that describe the 

interaction. 

cosmopolitan. 

Aphanocladium Acremonium album, Circular brown spots on Cosmopolitan, Present and occasionally Fletcher et al. (1994); 

album 

Nectriopsis 

cap, white aerial recorded on a wide causes serious outbreaks in BMS (undated) 

sporangiicola hyphae. 

range of hosts and 

habitats. 

mushrooms. 

Badhamia 

This slime mould is Cosmopolitan, Present in the UK on a wide Moore (1959) 

utricularis 

capable of attacking the recorded on a wide range of hosts and habitats. Has BMS (undated); Miyairi 

fruiting bodies of range of hosts and been recorded attacking et al. (1994) 

several edible 

habitats. Probably mushrooms in the UK. 

mushroom species. It occurs wherever 

attacking stalks and mushrooms are 

eventually turns the grown and where 

fruiting body into a slimy hygiene measures 

mass. 

are insufficient. 

Cephalosporium 

White mycelium on Cephalosporium Rare in mushrooms in the UK. Fletcher et al. (1994) 

spp. 

fruiting body gills species can be found 

27





distribution 

all over the world. 

Likely to occur 

wherever 

mushrooms are 

grown. 


Fusarium 

Damping off Cosmopolitan, Reported causing damping off in Moore (1959) 

oxysporum 

recorded on a wide the UK. Also present on other 


habitats. Likely to 

occur wherever 

mushrooms are 

grown. 

hosts. 

Fusarium solani Damping off Cosmopolitan, Reported causing damping off in Moore (1959) 

recorded on a wide the UK. Also present on other 


habitats. Likely to 

occur wherever 

mushrooms are 

grown. 

hosts. 

Hormiactis alba Irregular brown spots Occurs wherever Present in UK mushrooms but Fletcher et al. (1994); 

mushrooms are uncommon, not a serious BMS (undated) 

grown. 

disease 

Hypomyces Sepedonium This species can cause Cosmopolitan, Relatively common in Britain on Flegg et al. (1985); 

chrysospermus chrysospermum, necrosis on mushroom recorded on a wide a wide range of hosts. Common Fletcher et al. (1994); 

Sepedonium tissue but it is more range of hosts and weed mould in UK mushroom Farr et al. (undated); 

mycophilum, common as a weed habitats. Reports of it composts. 

BMS (undated) 

Sporotrichum mould competitor (See infecting mushrooms 

mycophilum, 

Trichoderma 

mycophilum, 

Uredo mycophila 

Annex Table 2). are rare. 

Hypomyces Mycogone 

Massively distorted Occurs wherever Present and common on Fletcher et al. (1994); 

perniciosus (Wet perniciosa 

caps (cauliflower-like) mushrooms are mushroom and also present on BMS (undated) 

28





distribution 


bubble) 

with drops of amber 

liquid, also small 

‘bubbles’. 

grown. other hosts. 

Hypomyces Cladobotryum Rapid mycelial growth Occurs wherever Present and common on Fletcher et al. (1994); 

rosellues 

dendroides, 

over casing and mushrooms are mushroom and also present on BMS (undated) 

(Cobweb) 

Cladobotryum mushrooms; cap grown. 

other hosts. 

mycophilum, 

Dactylium 

dendroides 

spotting. 

Lecanicillium Cephalosporium Lesions on mushroom Cosmopolitan, Present but only observed Moore (1959); Zare & 

psalliotae 

curtipes var. 

cap. 

recorded on a wide occasionally in mushrooms. Gams (2003) 

uredinicola, 

range of hosts. 

Verticillium psalliotae 

Possibly occurs 

wherever 

mushrooms are 

grown. 

Melanospora Gonatobotrys Only detail is that it was Cosmopolitan, on a Recorded in mushrooms in the BMS (undated); Farr et 

damnosa 

simplex 

found infecting 

wide range of hosts. UK, also present on other hosts. al. (undated); Vakili 

mushroom in the UK. No reports infecting 

mushroom found for 

outside the UK. 

(1989) 

Mortierella bainieri 

Peeling stipe, dark Occurs wherever Present in the UK on a range of Fletcher et al. (1994); 

(Shaggy stipe) 

brown discolouration, mushrooms are hosts but rare in mushrooms. BMS (undated) 

coarse grey-white 

mycelium over casing. 

grown. 

Mycogone rosea White mould of 

Reported in Britain, Present in the UK. Has been Moore (1959); BMS 

mushroom. 

Germany, Uganda, recorded on mushrooms and (undated); Brady & 

Hungary and plant hosts. Rare because of Gibson (1976) 

Australasia, but current hygiene measures in 

probably more widely 

distributed in regions 

where edible fungi 

are cultivated 

mushroom growing. 

29





distribution 


Paecilomyces Spicaria penicillata Isolated from a 

Isolated from a No record for this species found CABI (undated); 

penicillatus 

decaying mushroom. decaying mushroom in the UK but it is likely to have a Luangsa-ard et al. 

in Belgium. Has been wider presence than that already (2004) 

found on decaying 

plants and wood. No 

other records for 

decaying 

mushrooms. 

reported. 

Penicillium 

Penicillium 

Isolated from decaying Has been isolated Present, has been observed CABI (undated); BMS 

brevicompactum brunneostoloniferum, mushrooms, probably from decaying on/with mushrooms in UK (undated) 

Penicillium 

also a cause of weed mushrooms in the amongst other hosts/habitats. 

brunneostoloniferum, mould (see Annex USA, likely to also 

Penicillium 

Table 2). 

occur with 

stoloniferum, 

mushrooms 

Penicillium 

wherever they are 

volgaense 

grown as the fungus 

is cosmopolitan and 

occurs on a wide 

range of 

hosts/habitats. 

Simplicillium Cephalosporium The mildew apparently Appears to have a Present in the UK but only Moore (1959); BMS 

lamellicola (Gill lamellicola, 

does little harm. wide distribution on a observed occasionally on (undated); Pantou et al. 

Mildew) 

Verticillium 

range of hosts and mushrooms. 

(2005) 

lamellicola 

habitats but few 

records for it on 

mushrooms. 

Verticillium 

Variety of symptoms on Predominant cause Recorded present in the UK but BMS (undated); Collopy 

fungicola var. 

the cap including of dry bubble in no record for mushrooms. et al. (2001); Largeteau 

aleophilum 

lesions, distortion and North America. Likely 

et al. (2004) 

discolouration. 

to have a wider 

distribution on other 

hosts. 

30


distribution 

Verticillium 

Verticillium 

Variety of symptoms Predominant cause 

fungicola var. malthousei 

including lesions from of dry bubble in 

fungicola 

the cap, cap distortion Europe. Likely to 

and discolouration. have a wider 

distribution on other 

hosts. Thought to 

have recently spread 

to North America 

from Europe through 

the import of material 

or machines used for 

mushroom 

cultivation. 





Recorded on mushrooms in the 

UK and common. 

Fletcher et al. (1994); 

BMS (undated); 

Collopy et al. (2001); 

Largeteau et al. (2004) 

31

Table 2. Weed moulds (fungi) associated with Agaricus bisporus 




Weed mould Synonym Notes on worldwide 

distribution 

Ascobolus leveillei Ascobolus boudieri, 

Likely to be cosmopolitan, in Present in a range of habitats, 

Ascozonus leveillei, Boudiera a wide range of countries recorded on mushroom compost 

boudieri, Comesia leveillei hosts and habitats. Possibly in the UK in 1935. Rarely occurs 

occurs wherever mushrooms now in mushroom composts, 

are grown should hygiene probably due to better hygiene. 

measures be insufficient. . 

Aspergillus spp. Aspergillus species are Aspergillus is a common weed 

cosmopolitan, and occur in a mould in the UK mushroom 

wide range of countries hosts composts, occurs if hygiene 

and habitats. Possibly occurs 

wherever mushrooms are 

grown should hygiene 

measures be insufficient. 

measures are insufficient. 

Botryotinia fuckeliana Botrytis cinerea, Botrytis Cosmopolitan, on a wide Has been reported on 

gemella, Sclerotinia 

range of hosts. Possibly mushroom beds in the UK, 

fuckeliana 

occurs wherever mushrooms probably due to insufficient 

are grown should hygiene 


hygiene. 

Botryotrichum piluliferum Sepedonium albogriseum, Cosmopolitan, on a wide Present in the UK in soil but no 

Chaetomium piluliferum range of hosts. Possibly records for UK mushroom 

occurs wherever mushrooms 



Reported to be a cause of 

plaster mould in the USA. 

composts. 


Moore (1959); BMS 

(undated) 


Beyer (2002) 

Moore (1959) 

Beyer (2002); BMS 

(undated) 

32


distribution 

Cephalotrichum microsporum Stysanus microsporus, Cosmopolitan, on a wide 

(Whisker mould) 

Doratomyces microsporus range of hosts and habitats. 

Whisker mould occurs 




Cephalotrichum 

purpureofuscum 


Cephalotrichum stemonitis 


Chaetomium globosum 

(Olive green mould) 

Chromelosporium fulvum 

(Cinnamon brown mould) 

Doratomyces 

purpureofuscus, 

Stysanus purpureofuscus 

Doratomyces stemonitis, 

Stysanus stemonitis 

Chaetomium olivaceum, 

Chaetomium subglobosum 

Alytosporium fulvum, 

Chromelosporium ollare, 

Ostracoderma dichotomum, 

Trichosporum fulvum, Peziza 

ostracoderma 



grown. This fungus appears 

to be cosmopolitan having a 

wide host/habitat range. 



grown. This fungus appears 

to be cosmopolitan having a 

wide host/habitat range. 

Occurs wherever mushrooms 

are grown. This fungus 

appears to be cosmopolitan 

having a wide host/habitat 

range. 


are grown. This fungus 

appears to be cosmopolitan 

having a wide host/habitat 

range. 





Present in the UK on a wide 

range of hosts/habitats although 

no records for mushrooms. 

Likely to occur as part of the 

species in the whisker mould 

complex which has been 

reported in UK mushroom 

composts. 







reported in UK mushroom 

composts. 







reported in UK mushrooms. 


range of hosts/habitats. 

Reported to occur in UK 

mushroom composts. 

Present on a wide range of 

hosts, reported in mushroom 

beds in the UK. 


(undated) 


(undated) 


(undated) 

Farr et al. (undated); 


(undated); Moore, 

(1959) 


(undated) 

33


distribution 

Chrysosporium merdarium Chrysosporium verruculatum, Reported to be present in 

(Yellow mould) 

Sporotrichum corii, 

mushroom beds wherever 

Sporotrichum merdarium, mushrooms are grown. This 

Sporotrichum scotophilum fungus appears to be 

cosmopolitan having a wide 

host/habitat range. 

Chrysosporium sulfureum Isaria sulfurea Reported to be present in 

(Yellow mould) 

mushroom beds wherever 

mushrooms are grown. 

Clitocybe dealbata 

Agaricus dealbatus The fungus appears to have 

a north temperate distribution 

and has a wide host/habitat 

range. Possibly occurs 




Clitopilus cretatus 

Agaricus cretatus, Clitopilus Likely to be cosmopolitan, 

scyphoides 

reported in soils in Europe, 

Asia and North America. 

Coprinopsis atramentaria 

Coprinopsis cinerea 

Coprinus atramentarius Coprinopsis or ink cap fungi 

are found all over the world. 

They have been observed as 

a weed mould wherever 


Coprinus fimetarius Coprinopsis or ink cap fungi 

are found all over the world. 








No records for this fungus in the 

UK specifically, but it is reported 

in several European countries 

indicating that it is likely be 

present. 

Reported as a weed mould in 

mushrooms in the UK, 

infrequent occurrence. 


range of hosts/habitats. 

Occasionally invades mushroom 

beds. 


range of hosts/habitats and has 

also been reported infesting UK 

mushroom beds. 









Geels et al. (1988) 


CSL records 

Moore (1959); Phillips 

(2006) 


(undated) 

CSL Records 

Beyer (2002); CSL 

Records 

34





distribution 


Coprinopsis radiata 

Coprinus radiatus Coprinopsis or ink cap fungi Present on a wide range of Beyer (2002); CSL 

are found all over the world. habitats in the UK, but no record Records 




of it in UK mushrooms beds. 

Coprinus comatus 

Agaricus comatus, Agaricus Coprinopsis or ink cap fungi Present in the UK on a wide CSL Records 

cylindricus, Agaricus 

are found all over the world. range of hosts/habitats and has 

fimetarius, Agaricus ovatus They have been observed as also been reported infesting UK 

Coprinus comatus var. a weed mould wherever mushroom beds. 

caprimammillatus, Coprinus 

comatus var. ovatus, 

Coprinus ovatus 


Corticium sp. (identity not 

Corticium species are Corticium species are present in Beyer (2002) 

known) 

present all over the world the UK but no published records 

and are common decay for its occurrence in UK 

agents. Likely to have been 

an opportunistic coloniser of 



Corynascus thermophilus Chaetomidium thermophilum, This has been reported on Present in the UK on straw and Beyer (2002); BMS 

(Flour mould) 

Thielavia thermophila mushroom compost in North straw compost but not reported (undated) 

America. 

in mushroom compost 

specifically. 

Diehliomyces microsporus Pseudobalsamia microspora Occurs wherever mushrooms Present, but outbreaks rare due Fletcher et al. (1994); 

(False truffle) 

are grown. 

to improved growing methods. Moore (1959) 

35





distribution 

Geosmithia emersonii 

Penicillium emersonii Isolated from mushroom Present in the UK, but no 

compost in the Netherlands, records for this species on 

likely to be one of many 

species classed as smokey 

mould. Species appears to 

be cosmopolitan, occurring 

on a wide range of habitats. 

mushroom compost in the UK. 

Heleococcum aurantiacum No records found elsewhere. Present in the UK. Has been 

recorded in mushroom compost 

but this appears to be a rare 

occurrence. 


CABI (undated) 

Moore (1959); Wood 

(1957) 

36


distribution 

Humicola insolens 

This fungus appears to be 

cosmopolitan having a wide 

host/habitat range. 

Hypomyces chrysospermus Sepedonium 

Cosmopolitan, on a range of 

(yellow mould) 

chrysospermum, 

hosts and habitats. Appears 

Sepedonium mycophilum, to cause yellow mould 

Sporotrichum mycophilum, wherever mushrooms are 

Trichoderma mycophilum, grown. Also known to be able 

Uredo mycophila 

to infect mushrooms (Annex 

Table 1) but reports of this 

are rare. 

Mortierella reticulata Reported to be present in 

mushroom compost in the 

USA. Probably occurs 


grown. 

Mucor mucedo 

Appears to be cosmopolitan, 

it is present on a range of 

hosts and habitats in several 

continents but there are few 

reports in mushroom 

compost. Possibly an 

opportunistic coloniser of 

composts. 

Myceliophthora lutea (mat and Chrysosporium luteum, Occurs wherever mushrooms 

confetti) 

Scopulariopsis lutea 

are grown. 

Nectria peziza Dialonectria peziza, 

Hydropisphaera peziza, 

Nectria aurea, Nectria 

epigaea, Sphaeria aurea, 

Sphaeria peziza 

Cosmopolitan, on a wide 

range of hosts. Possibly 








Present in the UK in mushroom 

compost amongst other habitats. 

Relatively common in the UK on 

a wide range of hosts. Common 

weed mould in UK mushroom 

composts. 

Recorded in mushroom compost 

in UK. Appears to be rare in the 

UK. 

Recorded in mushroom spawn. 

Unknown if it was causing a 

problem. 

Present in the UK, occurs 

infrequently in mushroom 

composts. 

Common in UK on a range of 

hosts. Has been reported in 


CABI (undated); BMS 

(undated) 

Flegg et al. (1985); 



BMS (undated) 

CABI (undated); BMS 

(undated); Betterley & 

Brown (1989) 

CABI (undated); Farr et 

al. (undated) 

Fletcher et al. (1994) 


(undated) 

37





distribution 


Neurospora sitophila Cosmopolitan, on a wide Present in the UK and likely to Perkins & Davis (2000); 

range of hosts. Possibly occur in mushroom compost – Farr et al. (undated); 


are grown. 

one unconfirmed CSL record. CSL Records 

Oedocephalum fimetarium Haplotrichum fimetarium Reported in North America Rare in the UK. Beyer (2002); HRI 

(Brown mould) 

and New Zealand but not 

common, likely to occur 


grown but major injury to 

mushrooms crops is 

improbable. 

records 

Oedocephalum glomerulosum Haplotrichum glomerulosum, Cosmopolitan, on a wide Present in the UK, recorded on BMS (undated); Farr et 

(Brown mould) 

Mucor glomerulosus, range of hosts. Possibly numerous hosts and habitats al. (undated) 

Pyronema omphalodes occurs wherever mushrooms 



including mushroom compost. 

Panaeolus subbalteatus Agaricus subbalteatus, Present in North America, Present and has been recorded Moore (1959); Phillips 

(weed panaeolus) 

Panaeolus cinctulus 

Europe in a wide range of 

habitats. Likely to occur 


grown if hygiene measures 

are insufficient. 

in mushroom compost. 

(2006) 

Papulaspora byssina 

Anamorphic Chaetomium Occurs wherever mushrooms Present and reported to be CABI (undated); Moore 

(Brown plaster mould) species 

are grown. 

common, but comparatively 

harmless unless compost is wet 

and tight. 

(1959); Anon. (2000) 

38


distribution 

Penicillium brevicompactum Penicillium 


brunneostoloniferum, range of hosts. Possibly 

Penicillium 


brunneostoloniferum, are grown if hygiene 

Penicillium stoloniferum, 

Penicillium volgaense 

measures are insufficient. 

Penicillium chermesinium 


are grown. 

Penicillium spp. 

(Smoky mould) 

Penicillium species are 

ubiquitous and smoky mould 


are grown. 





Present on many hosts and 

habitats in the UK. Observed in 

mushroom beds in the UK. 

Present in the UK but rare in 

mushroom composts. 

Smoky mould has been reported 

in the UK and is common. 

BMS (undated) 



(undated) 


Beyer (2002) 

39


distribution 

Peziza vesiculosa Helvella vesiculosa, Peziza Present in a range of habitats 

lycoperdioides, Scodellina in North America and 

vesiculosa, Rhopalomyces 

pallidus, Pustularia 

vesiculosa, Aleuria 

vesiculosa, Oedocephalum 

pallidum 

Europe. 

Podosordaria pedunculata Xylaria vaporaria 

There are few records for this 

species for outside the UK 

but it is likely to be present 

elsewhere. 

Pythium hydnosporum 

Artotrogus hydnosporus 

Pythium artotrogus 

Present in mushroom 

composts in North America 

and Europe. 

Pythium oligandrum Cosmopolitan, on a wide 




Roumegueriella rufula Chaetomium rufulum, 

Eurotium insigne, Lilliputia 

insignis, Lilliputia rufula, 

Mycogala macrospora 

Scopulariopsis coprophila 

(White plaster mould) 

Monilia fimicola, 

Monosporium coprophilum, 

Scopulariopsis fimicola 








are grown. 





Present in a range of habitats 

and has been recorded in 

mushroom beds in the UK. 

Present on a wide range of 

hosts and habitats in the UK. 

Due to improved hygiene 

measures now less likely to 

occur. 

Reported as present in the UK 

on other hosts. Likely to be a 

common occurrence in 


Reported as present in the UK 

on other hosts. Likely to be a 

common occurrence in 


Present in a wide variety of 

habitats. Has been reported on 

mushroom compost in past. 

Probably uncommon now due to 

better hygiene. 

Recorded on mushroom 

compost in the UK. Relatively 

common. 

Moore (1959); Phillips 

(2006) 


(undated) 


Beyer (2002); Farr et al. 

(undated) 



(undated) 


(undated); Schroers et 

al. (1999); CABI 

(undated) 

Anon (2000); BMS 

(undated) 

40


distribution 

Sporendonema purpurascens Coprotrichum purpurascens, Appears to be present 

(Lipstick mould) 

Geotrichum purpurascens, wherever mushrooms are 

Sporendonema 

purpurascens 

grown. 

Sporotrichum spp. (Plaster or Possibly the perfect stage of Species of Sporotrichum are 

Flour mould) 

Corticium sp. 

found in a variety of habitats 

throughout the world. 

Trichocladium pyriforme Recorded in mushroom 

compost in Ireland. Few 

records for elsewhere. Likely 

to be an opportunistic 

coloniser of mushroom 

Trichoderma aggressivum f. 

europaeum 


aggressivum 

compost. 

Trichoderma harzinum (Th2) Present in Europe and 

relatively common as a 

cause of green mould in 


Trichoderma harzinum (Th4) Present in North America 

and relatively common as a 



Trichoderma asperellum Recorded in mushroom 

compost in Hungary. 

Appears to have a wide 

global distribution. Used as a 

biocontrol agent. 





Present and an occasional 

contaminant but not usually 

damaging. 

Many species of Sporotrichum 

are present in the UK in a wide 

variety of habitats but no specific 

records found for mushrooms. 

No records for this fungus as 

present in the UK but present in 

soil in Ireland and therefore 

likely to be present in the UK. 

Present and common as a 



There are no records of this 

species in the UK. A 2008 

HDC-funded limited survey did 

not detect it. 

No record of this fungus in the 

UK. 

Moore (1959); van 

Greuning & Eicker 

(1991) 

BMS (undated); Beyer 

(2002) 

BMS (undated) 

Samuels et al. (2002) 

Samuels et al. (2002); 


Lane (2008). 

Hatvani et al. (2007) 

41


distribution 

Trichoderma atroviride Hypocrea atroviridis Occurs wherever mushrooms 

are grown. Also present on 

other hosts. 

Trichoderma harzianum Trichoderma lignorum var. Cosmopolitan on a range of 

narcissi, 

hosts and habitats Recorded 

Trichoderma narcissi in mushroom compost in 

Hungary. Probably occurs 


grown. Some strains of T. 

harzinum are known to not 

cause problems in 

mushroom production. 

Trichoderma koningii Acrostalagmus koningii North temperate on a range 

of hosts and habitats. Likely 

to occur in mushroom 

compost wherever 

mushrooms are produced. 

Green mould outbreaks 

originally attributed to be this 

species might have actually 

been caused by a species in 

the T. aggressivum complex. 

Trichoderma longibrachiatum Cosmopolitan on a range of 

hosts and habitats Recorded 

in mushroom compost in 

Hungary. Probably occurs 


grown. 





Present and relatively common 

in mushroom compost in the UK. 

Present, not known if the strains 

recorded on UK mushroom 

composts are strains of T. 

harzinum or isolates of 


europaeum. 

Present on numerous 

hosts/habitats in the UK. One 

record in BMS for its occurrence 

in mushroom compost. 

However, in the last decade this 

species is only considered to 

have caused very minor 

problems. 

Present in the UK in a wide 

variety of habitats. Possibly may 

occur in mushroom compost. 

Dodd et al. (2003); BMS 

(undated) 

Hatvani et al. (2007); 

BMS (undated) 

BMS (undated); Farr et 

al. (undated); CABI 

(undated) 

Seaby (1996); Samuels 

(2006). 

Hatvani et al. (2007) 

42





distribution 


Trichoderma pseudokoningii Appears to have a 

Present, several occurrences in BMS (undated); Farr et 

cosmopolitan distribution on mushroom compost. Present on al. (undated); Samuels 

a range of hosts and 

habitats. Likely to occur 


grown. 

other hosts. 

(2006); 

Trichoderma virens Gliocladium virens, 

Cosmopolitan on a range of Present in the UK on a range of CABI (undated); BMS 

Hypocrea virens 

hosts and habitats, few hosts/habitats. Recently (undated); C. Lane 

reports of it causing 

recorded as a weed mould in UK (CSL, 2007, Personal 

economic loss as a weed causing economic loss. 

Communication); Singh 

mould in mushroom 

production. Reported to be a 

weed mould in edible 

mushroom production in 

India. 

et al. (2006) 

Trichoderma viride 

Hypocrea rufa 

Cosmopolitan, on a wide Present on a wide range of Fletcher et al. (1994); 

(green mould) 

Hypocrea rufa f. sterilis range of hosts. Possibly hosts in the UK. Also relatively BMS (undated); Farr et 

Hypocrea rufa var. rufa occurs wherever mushrooms common in mushroom compost. al. (undated); Seaby 

Pyrenium lignorum 

are grown. Presence However, in the last decade this (1996) 

Sphaeria rufa 

indicates poor composting. species is considered to only 

Trichoderma lignorum Green mould outbreaks have caused very minor 

originally attributed to be this 

species might have actually 

been T. aggressivum. 

problems. 

Trichophaea abundans Anthracobia humillima, Appears to be cosmopolitan, Present in a range of hosts and Coetzee & Eicker 

Dichobotrys abundans, probably occurs on a wide habitats in the UK but no (1994); BMS (undated) 

Lachnea abundans, 

range of habitats and present records for mushroom compost. 

Patella abundans 

in mushroom compost 


grown. Reported to occur in 

mushrooms in South Africa. 

Trichothecium roseum Cephalothecium roseum, Appears to be cosmopolitan, Present in a range of hosts and Beyer (2002); Farr et al. 

(Plaster or Flour moulds) Hyphelia rosea, Hyphoderma probably occurs on a wide habitats in the UK but no (undated); BMS 

43


distribution 

roseum, Hypomyces roseus, range of habitats and 

Puccinia rosea, Sphaeria probably present in 

rosea, Trichoderma roseum mushroom compost 


grown. 

Trichurus spiralis 

Appears to be cosmopolitan, 


probably occurs on a wide 

range of habitats and 

probably present in 

mushroom compost 


grown. 

Volvaria sp. 

Numerous species of this 

genus distributed worldwide. 

Some are even cultivated for 

edible mushrooms. It is likely 

that this could be a weed 

mould should there be the 

opportunity. 





records for mushroom compost. (undated) 

Present in a wide variety of 

habitats but not recorded in UK 

mushrooms composts. 

Several Volvaria species are 

present in the UK. Moore (1959) 

reported one unidentified 

species invading mushroom 

beds in Norfolk in 1945. Likely to 

be rare with modern hygiene 

measures. 


(undated); BMS 

(undated) 

Moore (1959) 

44

Table 3. Bacterial pathogens associated with Agaricus bisporus 




Pathogen Symptom Notes on worldwide 

distribution 


Bacterial pit, agent not known Small dark slimy pits on Wherever mushrooms are Common in mushrooms. Fletcher et al. (1994) 

caps. 

grown. 

Burkholderia gladioli pv. 

Soft rot, mild lesions to Present in mushrooms in Common, with sporadic 

Gill & Tsuneda (1997); 

agaricicola 

deep pitting on caps. New Zealand, Europe. outbreaks occurring in 

Chowdhury & 

[syn. Pseudomonas cepacia] 

(Cavity disease) 

mushrooms crops. 

Heinemann (2006) 

Ewingella americana Browning in the centre of Reported to be associated First discovered on mushrooms Inglis & Peberdy (1996); 

the stipes and may be with mushrooms in Spain. in the UK but now considered Reyes et al. (2004) 

accompanied by the 

collapse of internal 

tissues. 

uncommon. 

Janthinobacterium 

Soft rot of cap. Reported originally in the UK Outbreaks in mushroom crops Lincoln et al. (1999) 

agaricidamnosum 

and France, now considered are rare. 

(Soft rot) 

present wherever 


Pseudomonas agarici 

Gills underdeveloped with Reported in the UK and New Rare, but when found in Fletcher et al. (1994), 

(Drippy gill) 

creamy-white ooze on Zealand, now considered mushrooms most severe in 

decayed areas. 

present wherever 


autumn and winter. 

Pseudomonas costantinii Brown blotches on cap. Originally found in Finland No record in UK mushroom Munsch et al. (2002) 

but the present distribution is 

unknown. Originally 

considered a strain of 

Pseudomonas tolaasii. 

crops. 

Pseudomonas fluorescens Possibly associated with Not known but reported in a Not known but no record of it in Anon. (2004) 

biotype G (Bacterial blotch) mummy disease. 

Canadian guidebook. UK mushroom crops. 

Pseudomonas fluorescens 

strains are present in the UK. 

Pseudomonas gingeri 

Ginger blotches on cap. Occurs wherever mushrooms Uncommon in mushrooms in the Fletcher et al. (1994) 

(Ginger blotch) 

are grown. 

UK. 

45

Pathogen Symptom Notes on worldwide 

distribution 

Pseudomonas ‘reactans’ Mild infection and P. ‘reactans’ strains 

superficial light brown pathogenic to mushroom 

discoloration. 

were originally reported in 

the USA. 

Pseudomonas sp./spp. 

Mushroom dries out and Mummy disease has been 

(Mummy and false mummy discolours; basal swelling observed worldwide but 

disease) 

of stipes. 

outbreaks are rare. 

Possibly includes Pseudomonas 

aeruginosa 

Pseudomonas tolaasii 

(Bacterial or Brown blotch) 

Brown blotches on cap; 

distortion and splitting. 

Wherever mushrooms are 

grown. 





Not known but no record in UK 

mushroom crops. 

Mummy disease has been 

observed in the UK but 

outbreaks are rare. 

Common on mushrooms in the 

UK. 

Wells et al. (1996) 



46

Table 4. Viral pathogens associated with Agaricus bisporus 

Pathogen Synonyms Symptoms Notes on worldwide 

distribution 


Part of the MVX Part of the MVX 

Endornavirus 1 

complex. 

complex found in 

Possibly no 

symptoms in 

isolation from 

other viruses. 

Europe. 

La France Isometric Virus AbV-4, 

Die back, yield Wherever mushrooms 

(LIV) 

Dieback, La loss, drumstick are grown. 

France disease, shaped 

MV4, Mushroom mushrooms, 

virus 4 

discolouration. 

Mushroom bacilliform Mushroom virus 3 None Probably wherever 

virus (MBV) 


Mushroom virus X 

(disease complex of 

several viruses) 

Bare patches on 

beds; brown 

caps; crop loss. 

Symptoms observed in 

Europe. 

Vesicle virus None Probably wherever 






Sporadic infections. P.R. Mills (2007, 

Warwick HRI, Personal 

Communication) 

Present but uncommon in the 

UK. 

Present but uncommon in the 

UK. Usually occurs with LIV. 

First found in the UK, sporadic 

infections occur. 


P.R. Mills (2007, 



Grogan et al. (2003) 

Likely to be present. P.R. Mills (2007, 



47

Table 5. Insect pests associated with Agaricus bisporus worldwide 




Pest Component attacked Notes on worldwide 

distribution 


Lycoriella castanescens 

(Sciarid) 

Compost, stipe Worldwide Common. Fletcher et al. (1994) 

Lycoriella ingenua 

(Sciarid) 

Compost, stipe Worldwide Common. Fletcher et al. (1994) 

Bradysia difformis Compost, stipe Worldwide Common in the UK but rare in Menzel et al. (2003) 

(Sciarid) 


Bradysia lutaria 

(Sciarid) 

Compost Worldwide Rare as a pest of mushrooms. White & Smith (2000) 

Bradysia matogrossensis 

(Sciarid) 

Compost Brazil Absent, not known in UK. Fletcher et al. (1994) 

Bradysia ocellaris Compost Worldwide Common but rare in mushroom Menzel et al. (2003) 

(Sciarid) 

crops. 

Megaselia bovista 

(Phorid) 

Mycelium Worldwide Rare in mushroom crops. Anon. (2000) 

Megaselia halterata 

(Phorid) 

Mycelium Worldwide Common. Fletcher et al. (1994) 

Megaselia nigra 

Mycelium, stipe, cap Worldwide Common in UK but rare in mushroom Fletcher et al. (1994) 

(Phorid) 

crops. 

Megaselia scalaris Mycelium Iran Common in UK but rare in mushroom Zamani et al. (2005) 

(Phorid) 

crops. 

Henria psalliotae 

Mycelium, stipe, cap Worldwide 

Common but uncommon as a pest in Fletcher et al. (1994) 

(Cecid) 

Heteropeza pygmaea 

(Cecid) 

Mycophila speyeri 

(Cecid) 

Mycophila barnesi 

(Cecid) 

Lestremia cinerea 

(Cecid) 


48





distribution 


Lestremia leucophaea 

(Cecid) 

Base of stipe Worldwide Now a rare pest in UK. Fletcher et al. (1994) 

Achorutes armatus Mycelium, stipe, cap, Worldwide Occasional pest. Fletcher et al. (1994) 

(Collembola) 

Drosophila funebris 

(Fruit fly) 

wet compost 

Compost, cap Worldwide Occasional pest. Fletcher et al. (1994) 

Pullimosina heteroneura 

(Sphaerocerid) 

Compost Worldwide Occasional pest. Fletcher et al. (1994) 

Colboldia fuscipes 

(Scatopsid) 

Compost Worldwide Occasional pest. Fletcher et al. (1994) 

Diplopoda spp. 

(Millipede) 

Stipe, compost Worldwide Rare. Fletcher et al. (1994) 

49

Table 6. Acarina (Mites) associated with Agaricus bisporus 

Pest 

Order: Prostigmata 

Component attacked Notes on worldwide 

distribution 

Dolichocybe keiferi 

Krantz 

Brennandania lambi 

Krczal 

(Australian mushroom 

pygmy mite) 

Linopodes antennaepes 

Banks 

Pediculaster 

fletchmanni (Wicht) 





Mycophagous. USA Absent Wicht (1970) 

Reported to attack mycelia. Australia Absent Gao & Zou (2001) 

Mycophagous. Europe Common on mushrooms Anon. (2000) 

Feed on weed moulds, and 

an indicator of Trichoderma. 

Can be a cause for crop 

rejection due to their bright 

colour. Can be a nuisance 

to pickers and is known to 

cause allergies in humans 

but is otherwise harmless to 

mushrooms. 

Brazil Absent Wicht (1970) 

50


distribution 

Pygmephorus spp. Feed on weed moulds, and Worldwide 

(Red Pepper Mites) are indicators of 

Trichoderma. Can cause 

Specifically: 

crop rejection Due to 

contamination with their 

P. mesembrinae bright red bodies and be Worldwide 

Canestrini 

can a nuisance to pickers. 

Pygmephorus sellnicki is 

P. sellnicki Krczal reported to cause allergies 

in humans but is otherwise 

Worldwide 

P. tarsalis Hirst 

harmless to mushrooms. Worldwide 

P. athiasae Wicht 

P. allmanni Krczal 

P. kneeboni Wicht 

P. quadratus Ewing 

P. murphyi Smiley 

France 

Australia, New 

Zealand 

USA 

USA, Germany 

USA 





Widespread on other hosts in 

the UK, rare in mushroom 

crops but potentially 

damaging. 

Present 

Present 

Present 

Absent 

Absent 

Absent 

Smiley (1978) reported this as 

present in England but the 

species is not reported in the 

UK checklist or Zoological 

Record. 

Absent 

Gurney & Hussey (1967);Fletcher et al. 

(1994); Anon. (2000); Geels et al. 

(1988); Flegg et al. (1985) 

Wicht (1970) 

Gurney & Hussey (1967) 

Wicht (1970) 

Smiley (1978) 

Smiley (1978) 

51


distribution 

Tarsonemus spp. Feed on the mycelial Species of 

threads at the base of the Tarsonemus can be 

Specifically: 

stem causing stems found all over the 

damage and discolouration. 

Virus vectors. 

world. 

T. floricolus (Canestrini 

& Fanzago) 

T. myceliophagus 

Hussey 

Order: Astigmata 

Caloglyphus 

mycophagus Megnin 

Caloglyphus 

mycophagus Megnin 

Tyrophagus 

putrescentiae 

(syn. Tyrophagus 

lintneri) 

Order: Mesostigmata 

Parasitus fimetorum 

Berlese 

Digamasellus fallax 

Leitner 

Seven species of 

Tarsonemid mite have been 

recorded in association with 

mushroom crops 

Mycophagous Worldwide. 

Mycophagous Worldwide. 

Mycophagous and feeds on 

mushroom mycelium and 

tissue as well as moulds 

and a variety of organic 

material. If present in large 

numbers, can results in 

both large and small pits on 

the mushrooms caps. 

Worldwide. 

Predatory mite Worldwide. 





Both T. floricolus and T. 

myceliophagus are present in 

the UK. 

Geels et al. (1988); Hussey (1963); 

Flegg et al. (1985) 

Common on mushrooms. Fletcher et al. (1994); Anon. (2000) 

Common on mushrooms. Fletcher et al. (1994); Anon. (2000) 

Common on mushrooms Fletcher et al. (1994); Anon. (2000) 

Common in Mushrooms. Fletcher et al. (1994) 

Predatory mite Worldwide. Not known to be present in the 

UK. 

J. Ostojia-Starzewski, (CSL, Personal 


52


distribution 

Arctoseius cetratus 

Sellnick 

Predatory mite Worldwide. 





Common in mushrooms where 

prey is present. Prey consists 

of other invertebrates. 

Dendrolaelaps spp. Predatory mite Worldwide. Common in mushrooms where 


Macrocheles spp. Predatory mite Worldwide. 


Common in mushrooms where 




Anon. (2000) 

Anon. (2000) 

53

Table 7. Mycophagous nematode pests associated with Agaricus bisporus 





distribution 


Aphelenchoides agarici Mycelium India No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides asterocaudatus Mycelium India No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides bicaudatus Mycelium Australia, Europe No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides coffeae Mycelium Australia No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides composticola Mycelium 

Worldwide. Considered with Present but rare in UK mushroom Fletcher et al. (1994) 

D. myceliophagus, to be one crops but potentially very 

of the two major species of 

mycophagous nematodes 

affecting mushroom 

production worldwide. 

damaging. 

Aphelenchoides cyrtus Mycelium Germany No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides dactylocercus Mycelium Europe, India Present in the UK on other hosts, Richardson & Grewal 

no records found for mushrooms (1993); Perper & 

Petriello (1977) 

Aphelenchoides helophilus Mycelium Europe No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides limberi Mycelium Europe, North America, Asia No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides minor Mycelium India No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides myceliophagus Mycelium India No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides neocomposticola Mycelium India No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides parientinus Mycelium Europe Present but no records associated Richardson & Grewal 

with mushrooms for UK 

(1993); Hodda (2003) 

54





distribution 


Aphelenchoides richardsoni Mycelium UK Present on mushrooms in UK. Grewal et al. (1992) 

Aphelenchoides sacchari Mycelium Europe, India No UK record for this species. Richardson & Grewal 

(1993); 

Sharma et al. (1981) 

Aphelenchoides saprophilus Mycelium Europe, Australia Present but no records associated Richardson & Grewal 

with mushrooms for UK. 

(1993); CSL Nematode 

Checklist (undated) 

Aphelenchoides spinosus Mycelium Germany, Australia No UK record for this species. Richardson & Grewal 

(1993) 

Aphelenchoides subtenuis Mycelium Europe, Israel, Australia, Present but no records associated Richardson & Grewal 

India 

with mushrooms for UK. 

(1993); Hodda (2003) 

Aphelenchoides swarupi Mycelium India, Italy No UK record for this species. Richardson & Grewal 

(1993); Hodda (2003) 

Aphelenchus avenae Mycelium Europe, Australia Present on mushrooms in the UK. Hooper (1962) 

Ditylenchus destructor Mycelium, but considered Worldwide Present but usually associated with Richardson & Grewal 

less capable of destroying 

other hosts. 

(1993); CABI 

mushroom mycelium than 

D. myceliophagus 

Compendium (undated) 

Ditylenchus dipsaci Mycelium Worldwide Present but usually associated with Richardson & Grewal 

other hosts in the UK. 

(1993); CABI 

Compendium (undated) 

Ditylenchus filimus Mycelium Canada No UK record for this species. Richardson & Grewal 

(1993) 

Ditylenchus intermedius Mycelium Europe, North America No UK record for this species. Richardson & Grewal 

(1993) 

Ditylenchus myceliophagus Mycelium 

Worldwide. Considered with Rare in UK mushroom crops but Fletcher et al. (1994) 

A. composticola, to be one of potentially very damaging – the 

the two major species of only Ditylenchus species 

mycophagous nematodes considered economically important 

affecting mushroom 

in commercial mushroom 

production worldwide. production according to 

Richardson & Grewal (1993). 

55





distribution 


Ditylenchus valveus Mycelium North America, Asia No UK record for this species. Richardson & Grewal 

(1993) 

Filenchus misellus 

Observed experimentally 

to eat mushroom mycelia. 

No natural records known. 

Asia No UK record for this species. Okada & Kadota (2002) 

Paraphelenchus myceliophthorus Mycelium England, India, Bulgaria Present on mushrooms in UK. Goodey (1958) 

Table 8. Saprophytic nematodes associated with Agaricus bisporus worldwide 


Notes on UK 

distribution 

Distribution 

Acrobeloides apiculatus Indirect effect on mushroom Worldwide. No UK record for this 

production – either through the 

release of toxins into the compost 

or facilitating the rapid and 

thorough bacterial colonisation of 

the compost. 

species. 

Acrobeloides buetschlii Indirect effect on mushroom Worldwide. No UK record for this 





the compost. 

species. 

Bursilla spp. Reported as saprophytic in Species of Bursilla can be No UK record known for 

mushrooms compost but affect on found worldwide. 

this genus on mushrooms 

yield uncertain. 

but species of this genus 

are likely to be present in 

the UK. 

Reference 

Coles (2002) 

Coles (2002) 

Richardson & Grewal 

(1990) 

56





Notes on UK 

Reference 

distribution 

Distribution 

Caenorhabditis elegans If the nematode establishes it can Worldwide. Most frequently found Richardson & Grewal 

rapidly inhibit mycelial growth. 

saprobe in the UK (1990) 

Complex relationship with 

bacterial species, which in some 

instances results in abnormal 

flushing patterns and mushroom 

distortion. 

mushroom industry. 

Mesorhabditis spp. Reported as saprophytic in Species of Mesorhabditis can No UK record known for Jin et al. (2006) 

mushrooms compost but affect on be found worldwide, reported this genus on mushrooms 


with mushrooms in China. but Mesorhabditis are 

found in the UK in other 

habitats. 

Panagrolaimus rigidus Indirect effect on mushroom Worldwide. Unconfirmed record for Coles (2002); CABI 





the compost. 

UK (no details of host). Compendium (undated) 

Pellioditis sp. Reported to have a harmful effect Species of Pellioditis can be No UK record known for Jin et al. (2006) 

– no further details. 

found worldwide; this 

this genus on 

unidentified species was 

reported with mushrooms in 

China. 

mushrooms. 

Pelodera (Cylindridera) icosiensis Reported with mushrooms but Reported with mushrooms in No UK record for this Liang et al. (1983) 

effects uncertain. 

China. 

species. 

Pelodera strongyloides Indirect effect on mushroom Worldwide distribution. Present but no record Coles (2002); Behnke et 





the compost. 

with mushrooms. 

al. (1999) 

57





Notes on UK 

Reference 

distribution 

Distribution 

Pelodera lambdiensis Vector of bacterial diseases of Reported on mushrooms beds No UK record for this 

mushrooms. 

in USA, but reported in other 

hosts in Australia, Fiji and 

North Africa. 

species. 

Prodontorhaditis sp. Reported to have a harmful effect Reported with mushrooms in No UK record for this Jin et al. (2006) 

– no further details. 

China. 

species. 

Rhabditella spp. Reported as saprophytic in Species of Rhabditella can be No UK record known for 

mushrooms compost but affect on found worldwide. 

this genus on 


mushrooms. 

Rhabditis (Cephaloboides) Indirect effect on mushroom Not known. No UK record known for Coles (2002) 

oxycera 





the compost. 

this species. 

Rhabditis (Choriorhabditis) Indirect effect on mushroom Not known. No UK record known for Coles (2002) 

longicaudatus 





the compost. 

this species. 

Rhabditis (Pellioditis) pellio Indirect effect on mushroom Worldwide. No UK record known for Coles (2002) 





the compost. 

this species. 

Rhabditis terricola Indirect effect on mushroom 





the compost. 

Not known. Not known. Coles (2002) 

Coles (2002); Steiner 

(1933) 

Richardson & Grewal 

(1993) 

58


distribution 

Rhabditis cucumeris Can suppress the development of Worldwide, but reported with 

mushroom mycelium, 

bacterivorous nematode possibly 

an indirect affect. 

mushrooms in Poland. 

Trilabiatus sp. Reported with mushrooms but Reported with mushrooms in 

effects uncertain. 

China. 




Notes on UK 

Distribution 

No UK record known for 

this species. 

No UK record known for 

this genus on 

mushrooms. 

Reference 

Dmowska et al. (1997) 

Liang et al. (1983) 

59

Commodity PRA for Agaricus bisporus - Defra

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?