Oyster Mushroom

Contents Introduction

Advantages of growing oyster mushroom

The biology of oyster mushroom

Varieties of oyster mushroom

Cultivation o Preparation or procurement of spawn. o Substrate preparation Steam pasteurization Hot water treatment Chemical sterilization technique Sterile technique Fermentation or composting with steam pasteurization o Spawning of substrate o Crop management

Competitor Moulds and Diseases

Insect pests

Abiotic disorders

Spent mushroom substrates

Characteristics

Utilities

Medicinal and nutritional value of oyster mushroom

Introduction

‘Oyster mushroom’or ‘Dhingri’ as refered in India is a basidiomycetes and belongs to the

genus ‘Pleurotus’. It is lignocellulolytic fungus that grows naturally in the temperate and tropical

forest on dead, decaying wooden logs, sometimes on drying trunks of deciduous or coniferous

woods. It can also grow on decaying organic matter. The fruit bodies of this mushroom are

distinctly shell, fan or spatula shaped with different shades of white, cream, grey, yellow, pink or

light brown depending upon the species. However, the colour of the sporophores is extremely

variable character influenced by the temperature, light intensity and nutrients present in the

substrate. The name Pleurotus has its origin from Greek word, ‘Pleuro’ means formed laterally

or lateral position of the stalk or stem.

The oyster mushroom is one of the most suitable fungal organism for producing protein rich

food from various agrowastes without composting.

This mushroom is cultivated in about 25 countries of far-east Asia, Europe and America. It

is the 3rd largest cultivated mushroom in the world. China alone contributes 88% of the total

world production. The other major producing countries are South Korea, Japan, Italy, Taiwan,

Thailand and Philippines. At present India produces annually 10,000 tones of this mushroom. It

is popularly grown in the states of Orissa, Karnataka, Maharashtra, Andhra Pradesh, Madhya

Pradesh, West Bengal and in the North-Eastern States of Meghalaya, Tripura Manipur, Mizoram

and Assam.

A. Advantages of growing oyster mushroom

1. Variety of substrates

Pleurotus mushroom can degrade and grow on any kind of agricultural or forest wastes,

which contain lignin, cellulose and hemicellulose.

2. Choice of species

Among all the cultivated mushrooms Pleurotus has maximum number of commercially

cultivated species suitable for round the year cultivation. Moreover, variation in shape, colour,

texture, and aroma are also available as per consumer’s choice.

3. Simple Cultivation Technology

Pleurotus mycelium can grow on fresh and fermented straw and it does not require

composted substrate for growth. Substrate preparation for oyster mushroom is very simple.

Further this mushroom does not require controlled environmental conditions like A.bisporus as

most of the species have very wide temperature, relatively humidity and CO2 tolerance.

4. Longer shelf life

Unlike white button mushroom, the oyster mushroom fruit bodies can be easily dried and

stored. Dried oyster mushrooms can be instantly used after soaking in hot water for 5 to 10

minutes or it can be used in powdered form for several preparations. Fresh mushrooms have a

shelf life of 24-48 h even at room temperature.

5. High productivity

The productivity of oyster mushroom per unit time is very high as compared to all other

cultivated mushrooms. One can harvest minimum of about 500 to 700 kg of fresh oyster

mushroom from one ton of dry wheat or paddy straw in 45-60 days, while with the same quantity

of straw only about 400-500 kg of white button mushrooms are obtained in 80-100 days

(including period needed for compost preparation). Yield of this mushroom can further be

increased by supplementing the substrate with suitable nitrogen source viz., Soybean and

cottonseed meal or by introducing high yielding cultures/strains.

The present day cultivation technology of oyster mushroom is a result of various successive

steps evolved throughout the world during 20th century. A very primitive form of growing

Pleurotus spp. was adopted by Lumberman in Europe during 19th century that involved collection

of wood logs and stumps showing fructification in nature and keeping them in cool and moist

places. First successful experimental cultivation of Pleurotus ostreatus was achieved in Germany

by Falck in 1917. In India cultivation of P.flabellatus on paddy straw was reported by Bano &

Srivastava in 1962 at CFTRI, Mysore. Kaul and Janardhanan (1970) cultivated a white form of P.

ostreatus on dried Euphorbia royleana (Thor) stems. Jandaik and Kapoor in 1974 could grow P.

sajor-caju on various substrates including wheat and banana pseudostems.

B. The biology of oyster mushroom

Visually the basidiocarps or fruit bodies of an oyster mushroom have three distinct parts - a

fleshy shell or spatula shaped cap (pileus), a short or long lateral or central stalk called stipe and

long ridges and furrows underneath the pileus called gills or lamellae. The gills stretch from the

edge of the cap down to the stalk and bear the spores. If a fruit body is kept on a paper directly

(gills facing the paper) a dirty white or lilac deposition of powdery spores can be seen. The spore

print colour may be whitish, pinkish, lilac or grey. The spores are hyaline, smooth and cylindric.

The spores are heterothallic and germinate very easily on any kind of mycological media and

within 48-96 h whitish thread like colonies could be seen. The mycelium of most Pleurotus sp. is

pure white in colour. P. cystidiosus and P. columbinus forms coremia like stalked structures

(asexual spores). Basidiospores on germination forms primary mycelium. Fusion between two

compatible primary mycelia develops into secondary mycelium, which is having clamp

connections and it is fertile. Primary mycelium is clampless and non fertile.

C. Varieties of oyster mushroom

All the varieties or species of oyster mushroom are edible except P. olearius and

P.nidiformis which are reported to be poisonous. There are 38 species of the genus recorded

throughout the world (Singer). In recent years 25 species are commercially cultivated in

different parts of the world which are as follows: P. ostreatus, P. flabellatus, P. florida,

P.sajor-caju, P. sapidus, P. cystidiosus, P. eryngii, P. fossulatus, P. opuntiae, P. cornucopiae,

P.yuccae, P. platypus, P. djamor, P. tuber-regium, P. australis, P. purpureo-olivaceus, P.

populinus, P. levis, P. columbinus, P. membranaceus etc.(Fig. 1)

D. Cultivation

The procedure for oyster mushroom cultivation can be divided into following four steps

(Fig.2)

1. Preparation or procurement of spawn.

2. Substrate preparation.

3. Spawning of substrate

4. Crop management.

1. Preparation or procurement of spawn

The spawn preparation technique for oyster mushroom is similar to white button mushroom

(A.bisporus). One should have a pure culture of Pleurotus spp. for inoculation on sterilized

wheat grain. It takes 10-15 days for mycelial growth on grains. It has been reported that Jowar

and Bajra grains are superior over wheat grains. The mycelium of oyster mushroom grows very

fast on wheat grains and 25-30 days old spawn starts forming fruitbodies in the bottle itself. It is

therefore, suggested that the schedule for spawn preparation or spawn procurement should be

planned accordingly. Sometimes the mushroom farmers are using active mycelium growing on

substrate for spawning fresh new oyster mushroom bags. This method can be used on a small

scale. There are always chances of spread of contamination through infested straw by active

mycelium spawning method so it is not advisable on large scale commercial cultivation.

2. Substrate preparation

a. Substrates for oyster mushroom and their nutrition quality

A large number of agricultural, forest and agro-industrial by-products are useful for growing

oyster mushroom. These by-products or wastes are rich in cellulose, lignin and

hemicellulose. However, yield of oyster mushroom largely depends on the nutrition and nature of

the substrate. The substrate should be fresh, dry, free from mould infestation and properly

stored. The substrates exposed to rain and harvested immature with green chlorophyll patches

inhibit the growth of Pleurotus mycelium due to the presence of competitor moulds. Oyster

mushroom can utilize a number of agro wastes including straws of wheat, paddy and ragi, stalks

and leaves of maize, jowar, bajra and cotton, sugarcane bagasse, jute and cotton waste, dehulled

corncobs, pea nut shells, dried grasses, sunflower stalks, used tea leaf waste, discarded waste

paper and synthetic compost of button mushroom. It can also be cultivated using industrial

wastes like paper mill sludges, coffee byproducts, tobacco waste, apple pomace etc. The cellulose

and lignin contents are important components of any substrate as far as yield is concerned.

Cellulose rich substrates like cotton waste give better yields. Cellulose helps in more enzyme

production, which is correlated, with higher yield.

b. Methods of substrate preparation

The mycelium of Pleurotus is saprophytic in nature and it does not require selective

substrate for its growth. The mycelial growth can take place on a simple water treated straw but

there are number of other cellulolytic moulds already present on straw which compete with

Pleurotus mycelium during spawn run and also toxic metabolites secreted by these competitors

hampers its growth. There are various methods to kill undesirable microorganism present in the

straw to favour the growth of Pleurotus mycelium. The substrate can be prepared by adopting

different methods like steam pasteurization, hot water treatment, chemical sterilization

technique, sterile technique and fermentation or composting. The choice of method will depend

upon the scale of cultivation envisages and the facilities available. The growers may adopt any

one of these method depending upon their need. The details of different methods are given

below:

i. Steam pasteurization

In this method prewetted straw is packed in wooden trays or boxes and then kept in a

pasteurization room at 58-620C for four hours. Temperature of the pasteurization room is

manipulated with the help of steam through a boiler. Substrate after cooling at room

temperature is seeded with spawn. The entire process takes around 3-5 days. This method is

adopted on a commercial scale by Zadrazil and Schneidereit in Germany. There are various

minor variations of this methods adopted in Europe. The tunnel prepared for pasteurizing

compost/casing of button mushroom can be used for pasteurizing the straw for oyster. However,

adequate boiler facility will be must.

ii. Hot water treatment

The substrate after chopping (5-10 cm) as such in case of wheat straw is soaked in cold water

overnight. The substrate is taken out and excess water is drained. Thereafter the straw is soaked

in hot water for one hour where the temperature may be in the range of 65 to 70C. normally

soaking the substrate in boiling water helps in achieving this temperature and no further heating

may be necessary. It will be appropriate to check the temperature and standardize the conditions

as per your location. Over boiling or over heating may not lead to proper result. Hot water

treatment makes the hard substrate like maize cobs, stems etc. soft so the growth of mycelial

takes place very easily. This method is not suitable for large-scale commercial cultivation.

iii. Chemical sterilization technique

Various species of Trichoderma, Gliocladium Penicillium, Aspergillus and Doratomycs spp.

are the common competitor fungi on the straw during oyster mushroom cultivation. If present on

the straw during spawn run, they do not allow the growth of mushroom mycelium resulting in

yield loss or complete crop failure. When wheat straw or paddy straw is treated by steeping in a

chemical solution of carbendazim 50% WP (37.5 ppm) and formaldehyde (500 ppm) for a period

of 16-18 h, most of the competitor moulds are either killed or their growth is suppressed for 25-

40 days after spawning. The technique, which was standardized at DMR, Solan in 1987, is as

follows:

Ninety litres of water is taken in a rust proof drum (preferably of galvanized sheet) or G.I.

tub of 200 litres capacity. Ten to twelve kg of wheat straw is slowly steeped in water. In another

plastic bucket, Bavistin 7.5 g and 125 ml formaldehyde (37-40%) is dissolved and slowly poured

on the already soaked wheat straw. Straw is pressed and covered with a polythene sheet. After 15

to 18 hour the straw is taken out and excess water drained. One can use a larger container or

cemented tank of 1000-2000 liters for soaking more straw. The chemicals to be added can be

calculated accordingly. The remaining solution can be used at least once again for chemical

sterilization of straw without any further addition of chemicals. Some of the farmers fill the

prewetted substrate in nylon net bags and press these bags in to the cemented tank containing

chemical solution. This makes the process of taking out of substrate easier.

iv. Sterile technique

The chopped substrate after soaking in cold water is put in heat resistant polypropylene bags

and sterilize in an autoclave at 22 lb. pressure for 1-2 hours (depending upon the size of the bags)

followed by spawning under aseptic conditions. This method is more suitable for research work

rather then on large-scale commercial production. Some species of oyster like king oyster can be

cultivated only by following this method of substrate preparation. Most commonly used bag size

is 20 x 40 cm for 3 kg wet substrate.

v. Fermentation or composting without pasteurisation

This method is a modification of composting technique used for white button mushroom. It

is most suitable for hard substrates like cotton stalks, maize stalks and leguminous stubbles, etc.

Composting should be done on a covered area or shed. Chop the substrate into 5-6 cm long

pieces. Add ammonium sulphate or urea (0.5-1%) and lime (1%) on dry weight basis of the

ingredients. Horse manure or chicken manure (10% dry weight basis) can also be used instead of

nitrogenous fertilizers. Addition of lime improves the physical structure and pH of the compost.

After wetting of straw, other ingredients are mixed to make a pile. Prepare a heap 75-90 cm high,

about one meter wide. After 2 days of fermentation, turning of pile is done and 1%

superphosphate and 0.5% lime is added. The compost will be ready after 6 days with three

turnings.

vi Fermentation or composting with steam pasteurization

Straw is prewetted and made into pile as described above. One per cent lime is added to

adjust the pH at the time of stacking. After two turning at two days interval, the substrate is

filled in the tunnel and steam pasteurized as described in the steam pasteurization section above.

c. Substrate supplementation

The nitrogen content in most of the substrates ranges between 0.5 to 0.8% and hence

addition of organic nitrogen in the straw helps in getting higher yields. Some of the common

supplements are wheat bran, rice bran, cottonseed meal, soybean cake, etc. Wheat bran and rice

bran should be used at the rate of 10% while cottonseed meal, soybean cake and groundnut cake

should be used at the rate of 3-6% on dry weight basis of the substrate. The supplements should

be treated with 25 ppm carbendazim (250 mg in 10 litre water) + 500 ppm of formaldehyde for

48 hour. Supplements are thoroughly mixed with straw while spawning. Addition of supplements

increases substrate temperature by 2-3C or even more and hence supplementation during

summer season is not advisable. However, during winter months though increased temperature

is observed, which helps in quick spawn run. Excess nitrogen can attract mould infestation,

which should be taken care of. In many cases, addition of supplements is counter productive due

to the diseases. The better results of supplementation can be obtained in sterile techniques.

3 .Spawning of substrate

Freshly prepared (20-30 days old) grain spawn is best for spawning. The spawning should

be done in a pre-fumigated room (48 h with 2% formaldehyde). The spawn should be mixed @ 2

to 3% of the wet weight of the substrate. One bag spawn of 500 g is sufficient for 20 kg of wet

substrate or 5 kg dry substrate. Spawn can be mixed thoroughly or mixed in layers. Spawned

substrates can be filled in polythene bags (60 x 45 cm) of 125-150 gauze thickness. Ten to 15

small holes (0.5-1.0 cm dia) should be made on all sides especially two to four holes in the

bottom for draining excess water. Perforated bags give higher and early crop (4-6 days) than non-

perforated bags. One can also use empty fruit packing cartons or boxes for filling substrate. We

can also make a block of the substrate by using compression machine. Polythene sheets of 200-

300 gauze thickness of 1.25 x 1.25 m are spread in rectangular wooden or metal box. Spawned

substrate is filled and the polythene sheet is folded from all the four sides and compressed to

make a compact rectangular block. It is taken out of the box and tied with a nylon rope. The block

is incubated as such and after mycelium growth polythene sheet is removed.

4. Crop management

The spawned bags or blocks are kept in incubation room for mycelial growth at desirable

temperature. Some of the Pleurotus species fruit at low temperature around 150C whereas other

species fruit between 20-300C. The incubation temperature for mycelial spread, however, is

around 250C for most of the species.

a. Incubation

Spawn bags can be kept on a raised platform or shelves or can be hanged in cropping room

for mycelial colonization of the substrate. Although mycelium can grow between 10-30°C but the

optimum temperature lies between 22-26°C. Higher temperature (more than 30C) in the

cropping room will inhibit the growth and kill the mycelium. Daily maximum and minimum

temperature of cropping rooms and beds should be recorded. The bed temperature is generally 2-

4°C higher from the room temperature. Mycelium can tolerate very high CO2 concentration of

1.5-2.0%. During mycelial growth the bags are not opened and no ventilation is needed.

Moreover, there is no need for any high relative humidity, so no water should be sprayed.

However, some chemicals for control of flies can be sprayed on the walls. Similarly, water can be

sprayed in the room or on the wall in case the environmental temperature is more than required.

b. Fruit body induction

Once the mycelium has fully colonized the substrate, it forms a thick mycelial mat

and is ready for fruiting. Contaminated bags with mould infestation should be discarded while

bags with patchy mycelial growth may be left for few more days to complete the spawn run. In no

case bags should be opened before 16-18 days except in case of P. membranaceus and P. djamore

var.roseus which forms fruit bodies within 10 days even in closed bags from small holes. Casing

is not required in oyster mushroom cultivation. All the bundles, cubes or blocks are arranged on

wooden platforms or shelves with a minimum distance of 15-20 cm between each bag in the tier.

They can also be hanged. In case, small long bags are used these can be stacked horizontally or in

a inclined manner one above the other. This method helps to accommodate more substrate in

less space and therefore getting more production from the same area. Some workers have also

used long cylinder for mushroom production. The poly bags can be tied at the base to get a

circular base or alternatively bags with side in-folds can be used. Various cultural conditions

required for fruiting are as follows.

i. Temperature

Mycelial growth of all the Pleurotus spp. can take place between 20-30°C. However, for

fruiting different species have different temperature requirement. Depending upon the

temperature requirement of a species they can be categorized into two groups-winter or low

temperature requiring species (10-20°C) and summer or moderate temperature requiring species

(16-30°C). Summer varieties can fruit at low temperature but the winter varieties will not fruit at

higher temperature. They need a low temperature shock for inducing fruit body formation.

Commercial varieties which can be cultivated during summer are P. flabellatus, P. sapidus, P.

citrinopileatus, P. sajor-caju and P. eous. Low temperature requiring species are P. ostreatus,

P. florida, P. eryngii, P. fossulatus and P. cornucopiae. The growing temperature not only affects

the yield but also the quality of produce. The pileus or cap colour of P. florida is light brown when

cultivated at low temperature (10-15°C) but changes to white pale to yellowish at 20-25°C.

Similarly fruit body colour of P.sajor-caju when cultivated at 15-19°C is white to dull white with

high dry matter content while at 25-30°C it is grayish brown.

ii. Relative humidity

All the Pleurotus species require high relative humidity (70-80%) during fruiting. To

maintain relative humidity, water spraying is to be done in the cropping rooms. During hot and

dry weather conditions, daily 2-3 spray are recommended while in hot and humid conditions

(monsoon) one light spray will be sufficient. The requirement of water spray can be judged by

touching the surface of the substrate. Spraying should be done with a fine nozzle to create a mist

or fog in the cropping room. It is desirable that mushrooms are harvested before water spray.

Ventilators and exhausts fans should be operated for air circulation so that the excess moisture

from the cap surface evaporates. Sometimes fruit bodies give offensive smell due to the growth

of saprophytic bacteria on the wet cap surface; under such conditions 0.05% bleaching powder

spray at weekly interval is recommended.

iii. Oxygen and carbon dioxide requirements

The oyster mushroom mycelium can tolerate high carbon dioxide concentration during

spawn run (up to 20,000 ppm or 2%) while it should be less than 600 ppm or 0.06% during

cropping. Therefore sufficient ventilation should be provided during fructification. If the CO2

concentration is high the, mushrooms will have long stipe and small pileus. Mushrooms will

appear like a mouth of trumpet.

iv. Light

Unlike green plants mushrooms do not require light for the synthesis of food. They grow on

dead organic plant material. Light is, however, required to initiate fruit body formation. For

primordia formation light requirement is 200 lux intensity for 8-12 hour. Inadequate light

conditions can be judged by long stalk (stipe), small cap and poor yield. The colour of the pileus

is also influenced by the light intensity and its duration. Fruit bodies raised in bright light are

dark brown, grey or blackish coloured. If the light intensity is less than 100 lux the mushrooms

will be pale yellowish. Thus both light and fresh air is necessary for formation of normal fruit

body. It is not necessary to give the light and fresh air simultaneously but the required CO2

concentration and light requirement must be met for getting normal fruit body. It may be a good

idea to give the fresh air just after water spray as it helps in removal of excess water from the

surface of fruit bodies.

v. Hydrogen ion concentration (pH)

The optimum pH during mycelial colonization should be between 7.0 and 8.0. The pH of the

water for spraying should be neither too acidic nor alkaline. Water should not contain harmful

salts or heavy metals. The mushrooms tend to accumulate various metals if present in substrate

or water used. Rusted iron drums and tubs used for substrate treatment or storing water for

spraying delay fructification due to presence of excess iron in the water.

F. Post Harvest Practices

Mushrooms should always be harvested before water spray. The right stage for picking can

be judged by the shape and size of fruit body. In young mushrooms the edge of the cap is thick

and cap margin is enrolled while the cap of mature mushroom as flat and inward curling starts.

It is advisable to harvest all the mushrooms at one time from a bag so that the next crop of

mushrooms starts early. After harvesting lower portion of the stalk with adhering debris should

be cut using a knife. Stipe is kept short or almost non-existent, as it is hard and not liked by many

consumers. Fresh mushrooms should be packed in perforated polythene bags for marketing.

They can also be sun dried by spreading thinly on a cotton cloth in bright sunlight or diffused

light. The dried produce with 2-4% moisture can be stored for 3 to 4 months after sealing

properly.

Fig.1: Different types of cultivated Pleurotus spp.

Fig.2. Different steps for oyster mushroom cultivation

Wet straw piled on cement floor

(120 cm x 100 cm x 300-350 cm

Straw socked in 100 lit. water contain

5 g Bavistin = 125 ml formaldehydes

Turning after every alternate days

(6-8 days) Wet straw pasteurized in bulk chamber at 58-62C

for 4 hr followed by 40-45 C for 36-48 hr

Spawning

Select Fresh Straw of any Cereals/Legumes or Oil seed Crop

Chop Straw (3-4 cm size)

Substrate preparation

Hot water socking Composting Chemical Sterilization Pasteurization

Spawn (20-30 days old) @10% dry wt.or 2.5-3% of wet wt

Filling straw + spawn in polythene bags (35 x 45 x 30) or in shelves

Incubation in a dark cropping room for 20-30 days till mycelium colonized the straw

Remove polythene bags or paper sheet from bag

Spray water daily 2-3 times, fresh air, 6-8 hr light

6-8 days mushroom pinhead appears

Harvest by twisting stipe between thumb and fingers

Cut stipe base to remove adhering straw etc

Pack in PP bags for sale or Dry in Oven

Remove the bags from cropping rooms & put in a pit for composting to use after one year as farm manure

Fig. 3. Pictorial flow chart of oyster mushroom cultivation

Competitor Moulds and Diseases

Competitor moulds/weed moulds

Different fungi occurring in the substrate and competing with

mushroom mycelium for space and nutrition are: Arthrobotrys sp.,

Aspergillus niger, A.flavus, A.fumigatus, alternaria alternata,

Cephalosporium aspermum, C. acremonium, Chaetomium globosum,

Cladosporium cladosporoides, Coprinus retirugis, C.sterguilinus, Coprinus

spp., Cochliobolus specifer, Drechslera bicolor, Furarium nomiliforme,

f.moniliforme var. ferbolutinans, F.moniliforme var. subglutinans

F.graminearusn, Momniella echinata, Mucor sp., Penicillium sp., Rhizopus

oryzae, Rhizopus spp., R.stolonifer, Stachybotrys chartarum, Stilbum

nanum, Stysanus medius, Sclerotium rolfsii, Sordaria fimicola,

Oedocephalum globerulosum, O.lineatum, Trichoderma viride,

Trichothecium roseum, Trichurus terrophilus and Phialospora sp. Loss in

yield in different Pleurotus spp. by these competitor moulds has been

reported up to 70%. In addition to these moulds being competitive some

have been shown to produce metabolites which directly inhibit the growth of

mushroom mycelium. However, detailed information about these

competitor moulds especially on their relative importance, epidemiology

and management is not yet available. Most of the competitor moulds have

been reported to be completely inhibited under in vitro and/or in vivo

conditions by benomyl (50 ppm), carbendazim + blitox (100ppm each) and

Thiram (100ppm).

Diseases

There are four fungal diseases reported on oyster mushroom from India.

Their causal agents, symptoms and control measures are presented in Table

1.

Table 1: Fungal diseases of oyster mushrooms in India

Cobweb disease

Green mould

Disease Casual

organism

Sympto

ms

Control

Cobweb Cladobotrym

apiculatum

C.verticillatum

C.variospermum

White cottony growth on

the substrate (Fig. 14);

small brown irregular

sunken spots or fluffy

growth on fruit bodies;

soft rot and decay of

sporophores emitting

foul smell.

Spray carbendazim50 ppm

Green

blotch

Gliocladium virens

G.deliguescens

Fruit bodies covered by

mycelium and green

spots; yound pin-heads

become soft, brown, pale

yellow and decay.

Mature fruit bodies show

brown spots enclosed by

yellow halo.

Spray 100 ppm carbendazim

Brown

rot

Arthrobotrys pleuroti Fluffy growth on

substrate and fruit

bodies; infected tissues

turn yellow, water logged

and rot.

Spray 50

ppm

carbendazim

Sibirina

rot

Sibirina fungicola Powdery white growth on

stipe, gills and the

primordia; primordia

show brownish

discolouration and soft

rot and mature fruit

bodies turn fragile.

Proper aeration and RH is

essential; spray benomyl twice

Insect-Pests

Insect-pests damaging button mushrooms are also associated with the oyster mushrooms..

Sensitivity of the oyster mushroom to chemicals and residue problems limit the scope of liberal

pesticide application. Further, shape of the fruit body and physical conditions of the substrate

protect/provide shelter to the pests against applied pesticides. Therefore, efforts should be made to

prevent the entry of these pests into the cropping rooms, rather than relying upon the chemicals.

Different insect and mite pests commonly damaging oyster mushrooms are discussed below.

1. Sciarids (Diptera: Sciaridae)

Sciarid L. auripila on oyster mushrooms. The yield loss in oyster mushroom due to L.

auripila infestation varied from 30-34.5%. Heavy infestation by sciarid larvae, render the fruit

unfit for consumption. Different species of sciarids recorded on oyster mushroom are

Phorodonta flavipes, Lycoriella solani, L. auripla, L. pleuroti, L. yunpluroti, L. upleuroti, L.

jingpleuroti, L. jipleuroti and L. bispinalis.

Nature of damage

Larvae initially feed on the mycelium. They tunnel through the stalk and the fruit body and

subsequently feed on the gills and contaminate fruit bodies with feaces. Infected fruit body

withers and rots.

Biology

Single female of L. auripila lays 132-163 eggs singly or in the batches of 5-8 on the

mycelial mat or at the base of the stipe. The eggs are oval translucent, 0.7x0.3mm in size. Eggs

hatch in 2-4 days. Maggot pass through 5 larval instars. Full grown larva constructs cocoon

consisting of silken threads. Pupation takes place in the compost or inside the tunnel of

sporophore. Larval period varies from 14-19 days depending upon the temperature. Pupae are 2-3

mm long. Pupal period is of 3-6 days. Single female of Phorodonta flavipes lays 47-300 eggs. At

18-22oC developmental period of egg, larva, pupa and adults are 6-7, 12-13, 4-5 and 3-4 days,

respectively.

Epidemiology

As described under the button mushroom .

2. Phorids (Diptera : Phoridae): Megaselia halterata and M. nigra damage Pleurotus sajor-

caju. Phorids attacking oyster mushrooms are Megaselia tamilnarieusia , Megaselia halterata

and M. nigra.

Nature of damage

Phorids enter the oyster mushroom bags through the vent. Larvae feed on mycelium and

spawn forming a clear wet rotten zone around the vents. Subsequently bacterial decay of the grain

spawn and substrate set in and around the site of feeding. Maggots of Megaselia sp. feed on

mycelium of P. citrinopleatus and P. sajor-caju causing extensive damage in spawn running

stage. After the pinning, larvae tunnel through the stalk and form small hole on the stalk. In

longer fruit bodies, larvae feed on gills and render the gill linning full of fecal matter.

Biology: as described in case of button mushroom.

Epidemiology

Phorids are attracted towards the smell of growing mycelium. Adults lay eggs on the

substrate and subsequent larval development takes place during the spawn run period. Flies also

enter the mushroom houses after the opening of bags and lays eggs on substrate.

Management of Sciarid and Phorid flies

a) Prophylactic measures: as in case of button mushroom.

b) Chemical methods

1) Spray application of Decis (2.5%) as an adulticide gives effective control of the flies.

2) Chlorpyrifos and primiphos ethyl both at 50 ppm ,when mixed with substrate give

effective control of flies. Surface application of both the insecticides at 0.11g a.i/m2 gives the

effective control of flies.

3. Cecids (Diptera: Cecidomyiidae)

Cecid larvae damaging oyster mushroom, P. sajor-caju. Heavy infestation of identified

orange coloured cecid larvae on the spawn run bags of Pleurotus sajor-caju was observed at

Solan during the year 1998 .

Species: as given under button mushroom.

Nature of damage

Larvae feed on the growing mycelium, tear of the bundles of hyphae and feed on exuding

sap. Because of very high rate of reproduction cecids can cause extensive damage.

Biology : As described in button mushroom.

Management

No information on the management and chemical control of cecid flie is available under

Indian conditions. However, general cleanliness and disposal of spent compost and cookout will

help in checking infestation by cecids.

4 Springtails

Occurrence of Lepidocyrtus sp on oyster mushrooms in H. P. was reported by Thapa and

Seth (1983). Bhandari and Singh (1983) reported the serious damage to oyster mushroom by L.

cyaneus at Udaipur (Rajasthan). Seira iricolor was reported damaging oyster mushroom under

Punjab conditions.

Description of pest: As described in button mushroom.

Species: As given under button mushroom.

Nature of damage

Lepidocyrtus sp. feed on mycelium in the substrate resulting in disappearance of

mycelium in the spawned compost. Springtails feed on mycelium by scraping the spawn grains

and rendering them naked. Sporophore of oyster mushroom attacked by Lepidocyrtus sp. lose gill

linning and gives webby look. Springtails also cause small irregular pits on pileus and basal

portion of stipe. The pitted area turns brown.

Biology: As described in case of button mushroom.

Management: As described in case of button mushroom.

5. Beetles (Coleoptera)

Staphylinus sp. And Cyollodes whiteii damage oyster mushroom Two beetles belonging to

the families Histeridae and Languriidae have been found to cause total crop failure during the

months of July and August at Solan (HP). Severe infestation by beetles may cause 100% loss in

yield.

Description of the Pest

Adult beetles area brown or black in colour depending upon the species. Adults have two

pairs of wings. The first pair is veinless, hard and shell like and folds together over the back to

make a stout wing cover. Body is normally hard and compact. Grub has a distinct black head.

Grubs have three pair of legs.

Species

Beetles associated with the oyster mushroom are:

Cyollodes whiteii, Oxyporus stygicus, Hoplosoma unicolor, Phiolomycus bilineatus and

Alphitobius laevigatus. In India C. whiteii, Oxyporus stygicus, and A. laevigatus have been

recorded.

Nature of damage

Beetles cause damage to mushroom at both adult and grubs stages. They feed on the

mycelium, more succulent tissue of the stipe, gills and pileus. Eaten margin of gills, edge of the

fruit bodies give a fringed look. In severe cases adults bore windows in pileus. Phiolomycus

bilineatus consumes 0.20-0.35g of the fungus per gram pest weight in 24 hours at 12.5-15oC.

Biology

Developmental period of Oxyporus stygicus under laboratory conditions at 22-24oC, for

egg, first, second, third instar larvae, prepupae and pupae is 1, 1-2, 1-2, 1-2, 1-2 and 7-10 days

respectively. Life cycle is completed in three weeks. Adult beetles of Staphylinus sp. also predate

on mites and springtails. P. bilineatus completes one generation in 299-325 days.

Epidemiology

The adults are attracted by the smell of decayed mushroom and they lay eggs on the over

matured pileus and mushroom substrate.

Management

Beetles belonging to the families Histeridae and Nitidulidae are scavengers. Removal of

waste and debris of the mushroom from mushroom houses and surrounding areas prevents the

adults from egg laying and checks further build up of the population. Flat surface of the pileus,

and porous nature of the substrate provide ideal shelter to the pests which enables pest to avoid

the chemicals. Some of the preventive measures are:

1. Over mature mushrooms should not be left unharvested.

2. For preventing entry of beetles into mushroom houses doors and ventilators should be

screened with nylon net of 35-40 mesh.

3. Application of bleaching powder in and around the premises of mushroom houses repels

the beetles.

4. General cleanliness of mushroom houses and surroundings is also helpful in checking the

perpetuation of beetles around the mushroom houses.

6. Mites

Das (1986) reported mite complex of domesticated mushroom (P. sajor-caju and P.

ostreatus) which consists of Rhizoglyphus echinopus, Tyroglyphus dimidiatus, Histiostoma

heinemanni and H. miles. H. heinemanni was the most injurious, inflicting nearly 90% loss in

yield. The yield loss by T. dimidiatus H. miles and R. echinopus has been reported to vary

between 75-80%. Economic injury level of the four mites ranged between 50 and 100 mites/50g

of compost.

Description of pest: As described under the button mushroom.

Species

Fifty four species of mites have been reported on mushroom from various part of the

world of which sixteen have been identified to be economically important ones. Mites associated

with mushroom in India are Tyrophagus putrescentiae, Tyroglyphsu dimidiatus Rhizoglyphus

echinopus, Histiostoma heinemanni, H. miles and Hypoaspis miles.

Nature of damage

Symptoms produced due to the infestation of mites are characterized by the change in

shape, size and colour of mushroom. Due to the infestation of R. echinopus, basal area becomes

pointed and colour changes from white to yellow or brown. T. dimidiatus makes large hole at the

basal region mushroom. H. heinemanni disrupts vertical growth of the mushroom forcing it to

develop in a crawling manner and infested area shows sings of decomposition. H. miles detach

mushroom buds. These mites also feed on the growing mycelium.

Management

The following measures are helpful against mites control:

(i) Proper pasteurization of compost and casing material.

(ii) Proper hygiene and sanitation

(iii) Disinfection of the mushroom houses by spraying 0.1% dicofol (Sandhu, 1995)

(iv) Burning sulfur in the empty rooms @ 2-3 lb/1000 cu. ft.

(v) Cooking out at 71 C for 1-2 hours, after each crop

(vi) Sterilization of empty trays

(vii) Disposal of spent compost in pits at least one mile away from mushroom house

(viii) Applying Propargite (Omite 590 EC) at 0.88 and 0.66 g a.i/m2 at spawning and

casing gives effective control of C. berlesei.

Spraying diazinon 20 EC (1.5-2.0 ml/10 lit. of water) in the compost or Dicofol (0.1 %)

in mushroom beds, or drenching mushroom houses and all their premises with diazinon is

also effective.

Abiotic disorders

As compared to white button mushroom, there are few physiological disorders recorded

in oyster mushrooms. Reduced light in the cropping room results in longer and thicker stipes

and pileus is partly reduced. Insufficient ventilation (1-2% carbon dioxide) and low light

exposure induce bunched growth regeneration.

Spent mushroom substrate

Characteristics

The spent substrates of different species of oyster mushroom vary in their pH

from 5.60 to 8.21. The other parameters viz., conductivity, total dissolved solids,

dissolved oxygen and bulk density vary from 6.48 to 6.83 mmho/cm, 3.59 to 3.62 ppm,

0.64 to 0.71 ppm and 0.27 to 0.30 g/cm3, respectively. Particle density and porosity vary

from 0.66 to 1.25 g/cm3 and 44 to 58.40 %, respectively. The contents of major elements

like nitrogen, phosphorus and potassium vary from 1.30 to 1.70 %, 0.31 to 0.46 % and

183 to 217 ppm, respectively. The SMS also contains calcium in the range of 16.0 to 17.20

ppm, while sodium and lead do not exist.

Utilities

i) Livestock feed: Many substrates used for production of mushrooms are

generally considered unsuitable for animal feed mainly because of their constituents

(cellulose, lignin and little protein). However, after harvesting of mushrooms, the spent

mushroom substrate becomes more easily digestible by ruminants owing to the

enzymatic conversion processes during mushroom cultivation. The mushroom mycelia

degrade lignin and improve the in vivo dry matter digestibility (IVDMD) of the substrate

used for mushroom cultivation. It also leads to an enhancement in crude protein, fat

content and ash content of the spent substrates with time. The most notable change of

composition in the spent substrate is the reduction of hemicelluloses (17 %), cellulose (15

%), lignin (4 %) and gossypol (60 %). This means, the cell wall components are degraded

by enzymes secreted during mycelial growth and mushroom production. This actually

increases the in vivo dry matter digestibility of SMS as a ruminant food. The experiments

have been mostly done on Holstein steers and sheep. SMS also generates

polysaccharides, vitamins and some trace elements such as Fe, Ca, Zn and Mg, which

adds value to the ruminant feed.

According to Zhang et al. (1995), the solid-state fermentation increases the crude

protein contents in SMS and its digestibility nearly by 70 %, thus making SMS a potential

source of nitrogen for poultry and animals. However, not all the animals tested accepted

voluntarily the inclusion of SMS into the feeding diet. The higher level of ash content and

presence of phenolic compounds limit the voluntary intake of SMS by the ruminants. The

SMS could be used as a potential roughage source for ruminants. The formulation of the

diet of animal feed which includes SMS is not an easy task, as one must take into account

factors like species of animal, mushroom strains, nutrition level of the SMS, cell wall

component, digestibility and voluntary intake (Langar et al. 1982). The oyster mushroom

SMS can substitute about 30% of the total feed without affecting the growth of animals.

ii) Biogas: As indicated above, SMS obtained after oyster mushroom cultivation can

be utilized further as cattle feed and the waste of cattle, i.e., cow dung can be used for

producing biogas, and the sludge accumulated in biogas tank can be used as casing

material for button mushroom. Again the SMS thus generated can again be used as

manure for raising the crop. The use of SMS for biogas production has multiple benefits,

such as possibility to utilize feed stocks of high moisture content, ability to be scaled to

suit family as well as community needs, effluent (sludge) with properties of good manure

can replace chemical fertilizers, and can give indirect economic benefits to the users. The

increased susceptibility to microbes and nitrogen contents of spent substrate are

reported to be the reasons behind higher percentage of gas yield. Solids from biogas

digester act as good manure for nursery raising as well as for the vegetable crops.

iii) Vermicomposting: Recently, SMS has also found uses as the feeding

material for vermicompost. In case of vermicompost preparation, the SMS from oyster

mushroom has been found suitable. Fresh as well as 15-20 days old rotten SMS from

oyster mushroom is an acceptable material for the worms to multiply and convert it in to

manure for field crops. The SMS either alone or in different combinations with FYM,

agricultural and vegetable farming wastes (depending upon the availability) is a good

medium for effective vermicomposting by following the standard protocol. The time

period for vermicomposting using SMS varies between 2 to 2.5 months.

iv) Mulch

Fresh oyster SMS contains enough macro pores and void spaces. Hence application

of oyster SMS as mulch in soil reduces water evaporation and soil temperature by

restricting water translocation and sunlight. In addition, it helps to control the growth of

weeds naturally. The use of SMS as mulch will have additional advantages for increasing

soil carbon and providing nutrients.

v) Bioremediation: The uncontrolled release of industrial waste in open and the

poor availability of pretreatment facilities are the important factors contributing towards

environmental pollution. The degradation of various chemicals in environment depends

upon the prevailing physical and chemical conditions and the nature of microorganisms

thriving within the system. SMS has the ability to chemically adsorb the organic and

inorganic pollutants, and in addition it also contains diverse category of microbes having

capability of biologically breaking down of the organic xenobiotic compounds present in

soil and water. The SMS of Pleurotus spp. has been found effective against polycyclic

aromatic compounds, phenolic compounds, biocides and fungicides, petroleum,

synthetic & textile dyes, etc

vi) Substrate for other mushrooms: The composted sawdust based spent

substrate of Pleurotus spp. can be used for preparing the casing material for button

mushroom cultivation. It can be used for compost preparation in a certain proportion. It

can also be used for taking repeat crop of Pleurotus spp. and Stropharia sp.

vii) Diseases management: Pleurotus spp. spent substrate helps to check

the nematodes population.

Medicinal and nutritional value of oyster mushroom

Oyster mushrooms are 100% vegetarian and the nutritive value of oyster mushroom is as

good as other edible mushrooms like white button mushroom (A.bisporus), shiitake (Lentinula

edodes) or paddy straw mushroom (Volvariella spp.). They are rich in vitamin B complex.

Protein content varies between 1.6 to 2.5% on fresh weight basis. It has most of the mineral salts

required by the human body such as potassium, sodium, phosphorus, iron and calcium. The

niacin content is about ten times higher than any other vegetables. A polycyclic aromatic

compound pleurotin has been isolated from P .griseus which possess antibiotic properties.

Oyster mushroom contains compounds like lovastatin that helps in lowering cholesterol.