full paper - THE BIOSCAN

ISSN: 0973 - 7049
NSave Nature to Survive
: Special issue, Vol. 2; 547-552; 2010
AEROMYCOLOGICAL STUDY OF STORE HOUSES OF ONION
AND GINGER IN GUWAHATI
Juri Devi et al.
Onion
Ginger
Aeromycoflora
Paper presented in International Conference on
Environment, Energy and Development (from
Stockholm to Copenhagen and beyond)
December 10 - 12, 2010, Sambalpur University
547

NSave Nature to Survive
JURI DEVI, SADHANA MEDHI AND T. C. SARMA*
Department of Botany, Gauhati University, Guwahati - 781 014
E mail: tarunchandrasarma@yahoo.com
ABSTRACT
A survey of indoor aeromycoflora of store houses of onion and ginger was carried out in
Guwahati, Assam, during the period of March, 2009 to August, 2010, employing gravity slides
and gravity petridish methods, with a view to correlating the decay of onion and ginger by the
fungi in their stored conditions. This was being carried out in pursuance with some informal
reports of the wholesellers regarding the spoilage of these two commercially important plant
produce. Some microfungi were isolated belonging to the genera- Alternaria, Aspergillus, Botrytis,
Cercospora, Colletotrichum, Curvularia, Cladosporim, Fusarium, Helminthosporium
,Lasiodiplodia, Mucor, Penicillium, Rhizopus, Trichoderma, Trichothecium, Verticillium.
*Corresponding author
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STUDY OF ONION AND GINGER
INTRODUCTION
Air is a natural medium for certain very very minute particles including many mycoflora. Investigations on
the aeromycoflora were carried out in order to correlate with the different types of crop diseases in India
viz.,diseases of banana, bajra, citrus, cotton, jowar, rice, sugarcane, wheat and other crops (Padmanabhan
et al., 1953; Sreeramulu and Seshavataram, 1962; Sreeramulu, 1959; Sreeramulu and Ramalingam, 1963,
1964, 1965; Tilak and Kulkarni, 1970, 1972, 1980; Tiwari and Sahu, 1995). Occurrence of aeromycoflora in
the fruit markets were also studied (Sarma and Bhattacharjee, 2001). Airborne mycoflora are largely
determined by topography, meteorological parameters, vegetation and biotic factors including human activities
(Lacey, 1981; Lyon et al., 1984). The mycoflora concentration in the atmosphere are influenced by the
processes involved in their production, release and deposition (Lyon et al.,1984). The present study has been
carried out to screen the mycoflora of air over the store houses of onion and ginger of Guwahati and to find
correlation of occurrence and also the incidence of decay of both onion and ginger in the store houses. Onion
is one of the most important vegetable crops. This important crop is being imported to Assam from different
parts of India. Guwahati is the gateway of North-East India and it is also the commercial capital of N.E
India. The imported onions are mostly stored in different storehouses of Guwahati and the varieties are-
White onion. Red onion and Yellow onion. The fungal deterioration of all these varieties have been observed.
Similarly rhizome of ginger which is also one of the most important spice crop of Assam are also stored in
the different store houses of Guwahati. The important varieties of ginger in N.E India are- Bola, Moran and
Jatia. There were some informal reports of the owners of the store houses that the decay of the rhizome of
ginger in the stored conditions were severe. Keeping in view of this the investigations on the aeromycoflora
and correlation with the decay of onion and ginger were carried out.
MATERIALS AND METHODS
Air samplings were carried out in different store houses of onion and ginger of Guwahati using gravity slides
and gravity petridish methods. In the Czapek’s medium aliquiet of streptomycin was added to inhibit the
bacterial growth. These petridishes were exposed to the air of different store houses at different duration
such as 0, 1, 2 and 3 minutes; and at different heights -0- level(ground level) and 500 cms, 1000 cms and
2000cms above ground level. The experiments were done monthly for one year and 4 replicates were used
for each sampling. The petridishes were incubated for 7 days. The isolates were examined and identified.
For pathogenecity test a loopful of fungal mat was inoculated aseptically to healthy onion and ginger by
making small incision in bulb and rhizome respectivily. The inoculated bulb and rhizome were kept wrapping
in cellophane bags. The progress of spoilage were observed periodically. The data were correlated with
meteorological parameters.
RESULTS AND DISSCUSSION
The mycoflora trapped from the air inside the store houses of onion and ginger were- Alternaria alternata,
A. solani, Aspergillus flavus, A. niger, A. terreus, Cercospora sp., Cladosporium sp., Colletotrichum capsici,
Curvularia lunata, Fusarium oxysporum, F. moniliforme, F. solani, F. zingiberi, Helminthosporium sp.,
Lasiodiplodia theobromae, Mucor mucedo, Penicillium citrinum, Rhizopus stolonifer, Trichoderma sp.,
Trichothecium sp. and Verticillium theobromae.
Species of Alternaria, Colletotrichum ,Lasiodiplodia, Trichoderma and Trichothecium were not available at
1000cms and 2000cms. Petridishes containing media were exposed for 1 minute, 2 minutes and 3 minutes at
different levels and accordingly microfungi were trapped. The fungal spores trapped at different levels and
at different times have been shown in Table 1 and 2.
The most predominant species found in air in store houses of onion were- Aspergillusniger, A. flavus,
Botrytis sp., Fusarium oxysporum, Helminthosporium sp., Trichoderma sp. and Mucor mucedo. On the other
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JURI DEVI et al.,
Table 1: Showing frequency of occurrence of fungal species at different heights (cms) in the store houses of onion and
ginger
Height (cm)
Fungi 0-level (ground) 500cms 1000cms 2000cms
1. Alternaria alternata + + + + + - - - - - -
2. A. solani + + + + + - - - - - -
3. Aspergillus flavus + + + + + + + +
4. A. niger + + + + + + + +
5. A. terreus + + + + + + + +
6. Botrytis cinerea + + + + + + +
7. Cercospora sp. + + + + + + + - - -
8. Cladosporium sp. + + + + + +
9. Colletotrichum capsici + + + + + - - - - - -
10. Curvularia lunata + + + + + + + + + +
11. F. oxysporum + + + + + + + + + +
12. F.moniliforme + + + + + + + + + +
13. F. solani + + + + + + +
14. F. zingiberi + + + + + + + + + +
15. Helminthosporium sp. + + + + + + +
16. Lasiodiplodia + + + + + + + - - - -
theobromae
17. Mucor mucedo + ++ + + + +
18. Penicillium citrinum + + + + + + +
19. Rhizopus stolonifer + + + + + + +
20. Trichoderma sp. + + + + - - - - - -
21. Trichothecium sp. + + + - - - - - -
22. Verticillium theobromae ++++ ++ + + + +
Exposure time: 1 minute
Table 2: Showing frequency of occurrence of fungal species at different period of exposure - inside the store houses of
onion and ginger
Different period of exposure
Fungi 0 minute 1 minute 2 minute 3 minute
Alternaria alternata — + + + + + +
A. solani — + + + +
Aspergillus flavus — + + + + + + + + +
A. niger — + + + + + + + +
A. terreus — ++ + + + + + + +
Botrytis cineria — + + + + + + + + +
Cercospora sp. — + + + +
Cladosporium sp. — + + + + + +
Colletotrichum capsici — + + + + + +
Curvularia lunata — + + + +
Fusarium oxysporum — + + + + + + + + +
F. moniliforme — + + + + + + + + +
F. solani — + + + + + + + + +
F. zingiberi — + + + + + + + + +
Helminthosporium sp. — + + +
Lasiodiplodia theobromae — — + + +
Mucor mucedo — + + + +
Penicillium citrinum — + + + + + +
Rhizopus stolonifer — + + + + + + + +
Trichoderma sp. — — + + +
Trichothecium sp. — — + + +
Verticillium theobromae — + + + + + +
hand predominant species in the store houses of ginger were- Aspergillus niger, Fusarium oxysporum, F.
solani, F. zingiberi, Lasiodiplodia sp. and Verticillium thebromae.
The concentration of mycoflora was recorded highest from the month of March to October and gradually
decline towards January. Certain genera like Cladosporium and Helminthosporium were predominant even
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STUDY OF ONION AND GINGER
90
80
70
60
50
40
30
20
10
0
35
30
25.5
70
60.5
55
RED ONION WHITE ONION YELLOW ONION
75
71.4
67
80
78
75
65
62
59
60.559.2
55.5
58
54
46
AA ASF ASN BC FO FS RS
AA- Alternaria alternate; ASF- Aspergillus flavus; ASN- A. niger; BC- Botrytis
cinerea; FO- F. xysporum; FS- F. solani; RS- Rhizopus stolonifer
80
70
60
50
40
30
20
10
0
35
31.5
30
50.4
46.7
40.4
Jatia Bola Moran
60.259.2
53.4
68.4 69
66.3 65.1
60.6
50.5
40.2
36.9
32.8
ASN BC FO FS FZ H
ASN- Aspergillus niger; BC- Botrytis cinerea; FO- Fusarium oxysporum; FS- F. solani; FZ-
F.zingiberi; H- Helminthosporium sp.
in the month of November. It coincides
with the report of Padmanavan et al.
(1953). Curvularia lunata was seen to
occur in gradual seasonal change and it
has also been coinciding with those of
Sreeramulu and Ramalingam (1966).
The present investigation also recorded
the presence of Botrytis sp. responsible
for neck rot of onion bulb which confirms
findings of Maude and Prestly (1977).
Similarly prevalence of Aspergillus sp.
in air of the store houses of onion can be
correlated with the findings of Lee et al.
(2000).The results of the pathogenecity
test have been shown in the Table 3 and
Table 4 and Fig. 1and Fig. 2.
Pathogenecity tests show that all the
trapped fungi from air were not equally
efficient in causing rot of onion and
ginger. Aspergillus sp., Fusarium
oxysporum and Botrytis cinerea were
found efficient in quicker rotting of onion.
Likewise Fusarium oxysporum and F.
solani and F. zingiberi were found to be
associated with rot of ginger. The months
of July, August, September and October
were most favourable for rotting which
coincides with the highest spore load in
the air. Among the varieties of onion,
red onion and white onion are more prone
to rotting. Similarly among the varieties
Table 3: Pathogenecity test in 3 varieties of onion with
trapped aeromycoflora
Isolated fungal pathogen
% of rot after 7 days of incubation
Red White Yellow
Onion Onion Onion
Alternaria alternata 35 30 25.5
Aspergillus flavus 70 60.5 55
A. niger 75 71.4 67
Botrytis cinerea 80 78 75
F. oxysporum 65 62 59
F. solani 60.5 59.2 55.5
Rhizopus stolonifer 58 54 46
Table 4: Pathogenecity test in 3 varieties of ginger with
trapped aeromycoflora
Isolated fungal pathogen % of rot after 7 days of incubation
Jatia Bola Moran
Aspergillus niger 35 31.5 30
Botrytis cinerea 50.4 46.7 40.4
Fusarium oxysporum 60.2 59.2 53.4
F. solani 68.4 66.3 50.5
F.zingiberi 69 65.1 60.6
Helminthosporium sp. 40.2 36.9 32.8
of ginger, jatia and bola are more prone to rotting. Meteorological parameters like temperature and humidity
seem to play vital role for the occurrence of mycoflora in the air of store houses and also the rotting of onion
and ginger.
ACKNOWLEDGEMENT
The authors are very much thankful to Prof. S.P.Bora, Head, Department of Botany, Gauhati University for
551

JURI DEVI et al.,
providing laboratory facilities and Prof S.K.Borthakur,Professor of Botany for inspiring us to undertake this
piece of research work.
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