INTRODUCTION
Mushrooms are used as an excellent source of food with great nutritional value,
as they contain minerals, vitamins and nutritive compounds such as proteins
and polysaccharides and have a low fat content (Manzi et
al., 1999; Mattila et al., 2000). Mushroom
fruiting bodies are also appreciated as a delicacy as they are palatable and
tasty. Mushrooms have huge medicinal importance as well.
In the present scenario of economy, it has opened up new vistas of export earnings.
Present world production is around 16 million tonnes. Among commercially cultivated
mushrooms, Agaricus bisporus (Lange). Imbach popularly known as White
button mushroom or European mushroom is extensively cultivated throughout the
world. Its large scale production is centered in Europe (mainly western part),
North America (USA, Canada) and Southeast Asia (China, Korea, Indonesia, Taiwan
and India) (Tewari, 2003).
The production of white button mushroom accounts for 35 to 45% of total world
production. In India, the annual production of mushrooms is estimated to be
around 1,20,000 metric tonnes with 85% of this production being of button mushrooms
(Anonymous, 2010). India in 90’s, gained an increase
in commercial production of white button mushroom and several high-tech export
oriented farms were setup with foreign technology collaborations. But still
the small farms contribute to the major share of mushroom production. Of late,
much emphasis is being laid in production of mushrooms in the state of Jammu
and Kashmir, where 79,277 spawn bottles for laying about 150,000 trays/poly
bags were distributed in 2009-2010 and about 5051.61 quintals mushroom harvested
under Rashtriya Krishi Vikas Yojna (RKVY) alone (Anonymous,
2011).
The main constraints in the speedy development of this crop in the valley to
the cottage level industry are mushroom diseases. The crop is infested by a
number of fungal, bacterial and viral pathogens which result either in the partial
or total failure of the crop or to the least deteriorates the quality of the
produce. Mushroom growers in the Jammu and Kashmir State, usually carry out
the practice of mushroom growing in the rooms of their residential houses. In
certain cases, specially built mushroom houses without any environmental control
system and without the provision of compost pasteurization, have also been used
for the cultivation. The increase in the number of mushroom production units
without the facilities of pasteurization coupled with the year round cultivation
lead to the growth in the populations of a few fungal and bacterial pathogens,
thus posing a serious threat in the profitable production of this crop. Major
fungal diseases viz., dry bubble, wet bubble and cobweb are responsible for
inflicting varying degree of crop losses in mushroom farms (Bhatt
and Singh, 2002; Singh et al., 2010). Among
these wet bubble disease (M. perniciosa) causes extensive damage by bringing
soft rot or decay of whole fruiting body. If not controlled well in time, the
pathogen causes havoc damaging the entire crop. The disease is most prevalent
in India in temperate areas although few reports are available from subtropics
as well (Sharma and Kumar, 2000; Bhatt
and Singh, 2000). The disease is characterized by the development of whitish
mouldy growth of mycelium on portions of fruit bodies. It spreads covering the
entire cap eventually reducing the sporophore to a foul smelling white mass
(Garcha, 1978). If the pathogen infects mushroom before
the differentiation of stipe and pileus, the sclerodermoid masses are formed,
whereas infection after differentiation results in the production of thickened
stipe with deformation of gills (Smith, 1924). Wet
bubble infected fruit bodies were often found to be infected by various types
of bacteria around day 6 of infection and this bacterial infection was the actual
cause of death of mushrooms which occurred around day 10 of infection (Fletcher
et al., 1995; Umar et al., 2000).
Keeping in view the destructive nature of the disease on growing mushrooms
crop, especially in temperate climatic conditions of the valley, the studies
were taken to ascertain status for the Wet bubble disease of Agaricus bisporus
and its yield losses in important mushroom growing areas of Kashmir.
MATERIALS AND METHODS
Survey of the mushroom units located in three districts viz., Srinagar, Budgam
and Pulwama, of Kashmir Division was conducted in both spring and autumn crop
seasons of 2008 and 2009, to ascertain the status of wet bubble disease (Mycogone
perniciosa) of white button mushroom, Agaricus bisporus (Lange)
Imbach. Nine representative locations/mushroom farms were randomly selected
in each district for assessing the disease incidence, disease intensity and
yield losses. The frequency of prevalence of wet bubble disease was recorded
on the basis of the number of mushroom units infected out of the total units
surveyed, as per the method adopted by Singh and Sharma
(2000).
Disease incidence: For working out the disease incidence for each mushroom
farm, the number of infected bags/trays out of the total number of bags/trays
observed was recorded and the % disease incidence was calculated by the formula,
given by Fletcher et al. (1983):
Disease intensity: For working out the disease intensity, the number
of healthy and infected sporophores in each randomly selected tray/bag in a
farm was counted and categorized on the following 0-5 scale (Table
1).
The percentage of the disease intensity was calculated using the formula:
Yield Loss: From each infected mushroom farm surveyed, yield obtained
was recorded and the percent yield loss due to disease was calculated using
the following formula given by Van Zaayen and van Adrichem
(1982):
Where:
Expected yield = Total No. Fruit bodies
formed×Average weight of healthy fruit body |
Yield obtained = No. of healthy fruit bodies×Average
weight of healthy fruit body |
During the survey, diseased material (sporophores along-with infected casing
soil) was collected in paper bags/containers and kept in a refrigerator at (2-5°C)
for further studies.
| Table 1: |
The scale for calculating the disease intensity of infected
sporophores |
 |
Diseased samples were also preserved in Formalin Acetic Acid alcohol (FAA)
solution for microscopic examinations.
RESULTS
Status of wet bubble disease: Survey for ascertaining the status of
wet bubble disease of white button mushroom was conducted in three districts-Srinagar,
Budgam and Pulwama-of Kashmir Division in both spring and autumn crop seasons
of the year 2008 and 2009. In each district, nine mushroom farms were randomly
selected for assessing the disease incidence, disease intensity and yield losses.
Disease incidence: Data presented in Table 2, reveals
that wet bubble disease on white button mushroom was prevalent during both the
years (2008 and 2009) and its prevalence ranged from 33 to 67% in mushroom farms
in the three districts.
| Table 2: |
Incidence of wet bubble disease of white button mushroom at
different mushroom units of district Srinagar, Budgam and Pulwama during
2008 and 2009 |
 |
The disease was most prevalent (67%) in district Budgam followed by that (56%)
in district Pulwama, whereas district Srinagar exhibited the least disease prevalence
(33%). On an overall basis, the disease incidence was more in spring (12.75%)
than in autumn (5.22%) season. It was highest (11.07%) in district Pulwama and
the lowest (7.27%) in district Budgam. The overall mean disease incidence over
the years in all the three districts was 9.09%. The disease incidence observed
in spring seasons of the year 2008 and 2009 revealed maximum incidence of 14.10-14.25%
in district Srinagar and Pulwama, while as minimum incidence of 10.55% was recorded
in district Budgam. In spring 2008, wet bubble incidence was maximum (66.67%)
in Bandzoo Pulwama and Saidpora Srinagar (60%) followed by that in Batapora
Pulwama (34%) and Mehjoornagar Srinagar (28.75%). Whereas, in 2009 spring the
disease was more in Batamaloo (60%) and Mehjoornagar (56%) in Srinagar followed
by Bandzoo (36.67%) in Pulwama district.
The disease incidence observed in Autumn seasons of the year 2008 and 2009
revealed maximum incidence of 8.05% in district Pulwama followed by minimum
3.99 and 3.61% recorded in district Budgam and Srinagar. In Autumn 2008, wet
bubble was maximum (44%) in Batapora Pulwama followed by 43.5 and 25.71% in
Parigam and Batpora, respectively, of the same district, whereas in Autumn 09
the disease incidence was maximum (17.5%) in Batamaloo Srinagar followed by
that in Mehjoornagar Srinagar (13.75%) and Saidpora, Harwan (12.0%). The minimum
disease incidence of 6 to 8% was recorded in Parigam and Batapora village of
Pulwama district.
Disease intensity: The data presented in the Table 3,
reveals that the intensity of wet bubble disease ranged from 0.0 to 83.0% in
2008 and 2009 at different mushroom farms in the three districts. On an overall
basis, the disease intensity was more (22.58%) in spring than in autumn (12.18%)
season. It was the highest (21.86%) in district Budgam and the lowest (13.33%)
in district Srinagar. The overall mean disease intensity in all the three districts
was 17.82%.
The average disease intensity observed in spring seasons of the year 2008 and
2009 was maximum in district Budgam (28.31%) and Pulwama (22.59%) and minimum
in district Srinagar (16.86%). In 2008 spring, wet bubble intensity was maximum
(56.67-66.67 %) in Parigam and Bandzoo areas of Pulwama district. It was followed
by Batpora Pulwama, Saidpora Srinagar and Zaloowa and Sonarkalipora villages
of district Budgam with the intensity recorded as (46.67-50.00%). In 2009 spring,
the maximum disease intensity was recorded (80.00-83.33%) in Mehjoornagar Srinagar
and Parnewa Budgam.
| Table 3: |
Intensity of wet bubble disease of white button mushroom at
different mushroom units of district Srinagar, Budgam and Pulwama during
2008 and 2009 |
 |
It was followed by Saidpora and Batmaloo Srinagar and Zaloowa Budgam, where
disease intensity of (60.00-60.33%) was recorded. The disease intensity observed
in autumn seasons of the year 2008 and 2009 revealed maximum intensity of 11.29
to 15.46% in district Pulwama and district Budgam and minimum intensity of 9.81%
in district Srinagar. In autumn 2008, wet bubble intensity was maximum (50%)
in Parigam Pulwama followed by that in Saidpora Srinagar, Zaloowa and Sonarkalipora
Budgam and Batapora Pulwama (33.33%). In autumn 2009, the disease intensity
was maximum (50%) in Mehjoornagar Srinagar followed by that in (36.67%) Sonarkalipora
of district Budgam. The minimum disease intensity (20.00 %) was recorded in
Parigam village of Pulwama district.
Yield loss: Data presented in the Table 4, reveals
that the extent of yield loss due to wet bubble disease ranged from 11.33 to
65.00% in different mushroom growing units in the three districts of the valley.
On an overall basis, the yield loss was the highest (21.08%) in spring than
in autumn season (11.58%).
| Table 4: |
Yield loss of white button mushroom inflicted by wet bubble
disease at various mushroom units of district Srinagar, Budgam and Pulwama
during 2008-2009 |
 |
It was the highest (22.41%) in district Pulwama followed by that (14.99%) in
district Budgam and the lowest (13.53%) in district Srinagar. The overall mean
yield loss over the years in all the three districts was 16.97%. The yield loss
observed in spring seasons of the year 2008 and 2009 revealed maximum yield
loss of 21.35 to 26.01% in district Budgam and Pulwama and minimum yield loss
of 15.88% in district Srinagar. In 2008 spring, the yield loss due to wet bubble
disease was maximum (65%) in Parigam Pulwama followed by that (50.00-53.33%)
in Batpora Pulwama and Saidpora Srinagar, whereas in spring 2009 the yield loss
was maximum (60.67%) in Saidpora Srinagar followed by that (52.00-54.67%) in
Mehjoornagar Srinagar and Parigam Pulwama. The% yield loss observed in Autumn
seasons of the year 2008 and 2009 revealed maximum yield loss of 11.19 to 14.92
in districts Srinagar and Pulwama and a minimum of 8.63% in district Budgam.
In autumn 2008, the% yield loss due to wet bubble was maximum (55.00%) in Saidpora
Srinagar which was followed by (43.67%) recorded in Parigam Pulwama. The minimum
yield loss of (11.33%) was recorded in Pakherpora Budgam. In autumn 2009, the%
yield loss was maximum (49.00%) again in Saidpora Srinagar, which was followed
by (40.67%) in Batapora Pulwama. The minimum (9.00%)% yield loss was recorded
in Pakherpora location of district Pulwama.
DISCUSSION
Wet bubble disease is a severe impediment in the profitable cultivation of
white button mushroom (Agaricus bisporus L.). It is incited by an important
and cosmopolitan fungal pathogen, Mycogone perniciosa Magn which is responsible
for frequent crop failures in Kashmir valley. It was The disease was found prevalent
in varying proportions in all the districts and locations across seasons indicating
thereby the presence of the mycoparasite inoculum in abundance in the valley
throughout the year. This confirms the observation made by Kaul
et al. (1978), who reported this disease for the first time in the
Jammu and Kashmir state in 1978 from Pinglin area of Pulwama. It was also observed
during the present surveys that the wet bubble disease incidence was more in
spring season compared to that in autumn season. These observations are in partial
agreement with the results of Sinden (1971), Hsu
and Han (1981) and Singh and Sharma (2000). Sinden
(1971) reported that the onset of pathogen-favourable environmental conditions
relating to temperature and high relative humidity outside mushroom production
houses seem to promote M. perniciosa growth and proliferation in contaminated
spent compost, casing materials and wild A. bisporus. Hsu
and Han (1981) and Singh and Sharma (2000) reported
that optimum temperature for mycelial growth, sporulation and conidial germination
of M. perniciosa was 25°C.
Like other diseases, the wet bubble of button mushrooms is also identified
by the manifestations of certain characteristic symptoms. Two main types of
symptoms were observed during the present studies-infected sporophores and brown
tumerous undifferentiated sclerodermoid masses, which resulted due to infection
at different stages in the development of sporophores. These results are in
agreement with the results of with the results of the earlier workers, Smith
(1924) and Hsu and Han (1981) recognized two main
symptom types, infected sporophores and sclerodermoid masses, Hsu
and Han (1981) also reported that the infected sporophores are recognized
by two types of symptoms, one is a tumerous form arising as a result of infections
of pin heads and the other is a malformation arising as a result of infection
at a later stage of sporophore development.
CONCLUSION
Survey of the mushroom farms in Srinagar, Budgam and Pulwama districts of Kashmir
valley during 2008 and 2009, indicated that maximum wet bubble prevalence of
67.0% was recorded in district Budgam. It was followed by 56.0% in district
Pulwama, whereas the least disease prevalence of 33.0% was exhibited in the
district Srinagar. The overall mean disease incidence ranged from 7.29 to 11.07%
in three districts with maximum incidence in district Pulwama and minimum in
district Budgam with the overall mean disease incidence of 9.09% over years
in three districts, the incidence was more (10.55-14.25%) in spring than (3.61-8.05%)
in Autumn season. Similarly, the overall mean disease intensity ranged from
13.33 to 21.86% in the three districts with maximum intensity in districts Budgam
and minimum in district Srinagar. With an overall mean disease intensity of
17.82% over years in these districts, the disease intensity was more 16.86 to
28.31% in spring than in autumn (9.81-15.46%) season. The% yield loss due to
the wet bubble disease ranged from 13.53 to 22.41% with maximum loss reported
in district Pulwama and minimum in district Srinagar. With an overall yield
loss of 16.97% over years, the loss was highest 15.88 to 26.01% in spring than
in autumn (8.63-14.92 %) season.
It is believed that the frequent incidence of mould disease including that
of wet bubble disease in Kashmir valley and the resultant crop failure of maximum
frequency, owing to lack of knowledge to effectively and efficiently manage
the disease led to abandoning of its cultivation in early eighties. The mycoparasite
parasitizes the fruit bodies/sporophores and/or growing mycelium and causes
variable yield losses depending upon the stage of infection, amount of inoculum
and the prevailing ecological factors inside the production rooms. Therefore,
the present study was carried out to establish the status of the disease and
the resultant yield losses due to it, which include the pre-requisites for deciding
at the adoption of disease management practices and form the basic components
of decision making in integrated disease management. The objective was achieved
by undertaking surveys of three predominant mushroom growing districts viz.,
Srinagar, Budgam and Pulwama of Kashmir valley during the present study.
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