Fungal Diseases Of Mushroom
WHITE BUTTON MUSHROOM (Agaricus bisporus, A.bitorquis)
[Referance : NCERT]
1. DRY BUBBLE
Pathogen : Verticillium fungicola
Common Name : Verticillium disease, brown spot, fungus spot, dry bubble, La mole.
This is the most common and serious fungal disease of mushroom crop. If it is left uncontrolled, disease can totally destroy a crop in 2-3 weeks
Symptoms
Whitish mycelial growth is initially noticed
on the casing soil which has a tendency to turn greyish yellow. If infection takes place in an early stage, typical onion shaped mushrooms are produced.
If the infection occurs at later stage,
grey mouldy fuzz can be seen on the
mushrooms.
Management
Use of sterilized casing soil, proper disposal of spent compost and proper hygiene and sanitation are essential to avoid primary infection.
Heat treatment of infected casing layer at 63°C for one hour completely prevented spore germination (Poppe, 1967).
Spraying casing soil with 100x106T richoderma propagules/litre/m2 controlled V.malthousei.
V.malthousei was controlled by Zineb on a large scale, Bercema - Zineb 80 used at 0.1 - 1.2% controlled the disease.
2. WET BUBBLE
Pathogen : Mycogone perniciosa
Common Name : Wet bubble, La mole, white mould, bubble, Mycogone disease.
One of the serious diseases from almost all the major mushroom growing countries of the world.
In India, this disease was reported for the first time in 1978 from some mushroom farms in Jammu and Kashmir
Symptoms
the symptoms in the form of white mouldy growth on the mushrooms, leading to their
putrifaction (giving foul odour) with a golden brown liquid exudate.
Hsu and Han (1981) reported that the infected sporophores may be recognised by two symptoms, one is tumorous form, infected from pinheads, and other is malformation, infected at later stage. Both types of infections may exude water drops on the surface of infected sporophores. These water drops later change into amber colour.
Managements
Use of clean compost, pasteurization or
sterilization of casing soil, good peak heating and fumigation of mushroom house and use of benomyl or Mertect 40 per cent
were effective in managing M. perniciosa.
Benomyl spray at 0.5-4g/m2 immediately after casing has been reported very effective for protecting the crop.
Wuest and Moore (1972) suggested that aerated steam at 54.4°C for 15 minutes
can eliminate M. perniciosa from casing soil.
3. COBWEB
Pathogen : Cladobotryum
dendroides
Common Name : Mildew, Soft decay, Hypomyces mildew disease,
Dactylium disease.
Symptoms
Cobweb appears first as small white patches on the casing soil which then spreads to the nearest mushroom by a fine
grey white mycelium.
As the infection develops, mycelium becomes pigmented eventually turning a delicate pink cover.
In severe attacks, a dense white mould develops over casing and mushrooms change from a fluffy cobweb to a dense mat of mycelium. The white colour can
turn pink or even red with age.
Managements
sterilization of casing mixture at 50C for 4 hours effectively eliminates the pathogen. Regular cleaning, removal of cut mushroom stems and young half dead mushrooms after each break and controlling temperature and humidity helps in controlling the disease.
4. GREEN MOULD
Pathogen : Trichoderma viride, T.
hamatum, T. harzianum, T. koningii,
Penicillium cyclopium, Aspergillus
spp.
Common names : Trichoderma spot, Trichoderma blotch,
Trichoderma mildew, Green mould
One of the most common and destructive diseases in mushroom cultivation.
Symptoms
A dense, pure white growth of mycelium may appear on casing surface or in compost which resembles to mushroom mycelium. Later on mycelial mat turns to green colour because of heavy sporulation of
causal agent which is a characteristic
symptom of the disease.
Managements
Green moulds can be prevented by
a) Very good hygiene
b) Proper pasteurization and conditioning of compost.
c) Sterilizing the supplements before use and mixing them throughly preferably after
spawning.
d) Using the correct concentration of formalin (maximum 2%).
e) Weekly sprays of mancozeb(0.2%) or bavistin (0.1%) TBZ(0.2%) or treatment with zineb dust or Calcium hypochlorite (15%) have given effective control of the disease.
5. FALSE TRUFFLE
Pathogen : Diehliomyces microsporus
Common name : Truffle disease
Symptoms
The coulour of the fluffy mycelium is white to start with and turns a creamy yellow at a later stage. It appears as small wefts of white cream coloured mycelium in compost and casing soil, usually more conspicuous in the layer where compost and casing mixture meet and also on casing.
At maturity they become pink, dry and reddish and finally disintegrating into a
powdery mass emitting a chlorine like odour. The fungus does not allow the mushroom mycelium to grow and compost turns dull brown.
Managements
Compost should be prepared on a concrete floor and never on uncovered soil. Because during composting there is rise in temperature which activates the ascospores present in the soil.
Temperature above 26-27°C during spawn run and after casing should be avoided.
During cropping, temperatures should
be kept below 18°C . Under such conditions, it is practically impossible to grow A. bitorquis but disease can be managed
effectively in A. bisporus.
4. Casing soils known to harbour traces of spores should not be used.
Young truffles must be picked and buried before the fruit bodies turn brown and spores are ripe.
