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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 550
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
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