Asian Journal of Plant Pathology1819-1541xxxx-xxxxScience International10.3923/ajppaj.2017.95.101Sclerotium rolfsii and Effect of Fungicides on in vitro Inhibition of Mycelial Growth]]>AkarapisanAngsana KumvinitAthidtaya RuamrungsriSoraya 22017112Background and Objective: Amaryllis production has dropped due to bulb rot in the cropping areas of Chiang Mai, Thailand. It has become a recurrent problem of amaryllis bulb production. It is very difficult to develop effective management strategies for soil-borne pathogens that produce sclerotia because of their long-term survival in the soil. Fungicides are among the most effective options for the control of diseases caused by soil-borne pathogens. The objectives of this study were to identify the pathogen of amaryllis bulb rot and to evaluate fungicides for their efficacy against the pathogen. Methodology: The experiments identified the pathogen based on morphological characteristics and PCR analysis using specific primers. The pathogenicity of fungal isolates was tested in the greenhouse and compared with the non-treated control. Five fungicides including captan, copper oxychloride, mancozeb, carbendazim and etridiazole+quintozene were tested by the poison agar method, this analysis was arranged in a completely randomized design with 5 replicates of each treatment. Results: The initial disease symptom was water-soaked lesions in bulbs followed by total rotting of bulbs and leaf sheath blight. White cottony mycelia formed on the blubs of diseased plants. Clamp connections were common at every septum. The isolate was identified as Sclerotium rolfsii. A pathogenicity test was conducted in the greenhouse, where the symptoms of leaf sheath blight were observed. Also, bulb fresh weight, circumference and number of bulblets were decreased after pathogen inoculation. Effective and efficient integrated management of crop diseases often includes the use of fungicides. At recommended doses, etridiazole+quintozene, captan and mancozeb significantly reduced the growth of the fungus by 100, 68.85 and 64.56%, respectively. Conclusion: The results revealed that S. rolfsii was the causal agent of bulb rot of amaryllis in Northern Thailand. The most effective fungicide treatment against S. rolfsii from rotted amaryllis bulbs was etridiazole+quintozene.]]>Stirling, A.M. and G.R. Stirling,2002Hippeastrum sp. caused by lesion nematode (Pratylenchus jordanensis).]]>31427427Raj, S.K., S.K. Snehi, S. Kumar and M.S. Khan,2009Hippeastrum hybridum Hort.) in India.]]>45053Tombolato, A.F.C., S.G.F. Castro, L.N. Coutinho, M.A.V. Alexandre and A.L. Lourencao,2004Hippeastrum×hybridium Hort.).]]>2004Mahato, A., B. Mondal, D.S. Dhakre and D.C. Khatua,2014In vitro sensitivity of Sclerotium rolfsii towards some fungicides and botanicals.]]>2467471Nareawuttikun, N. and A. Akarapisan,2010Sclerotium rolfsii and Fusarium oxysporum f. sp. lycopersici causing tomato soil-borne diseases.]]>26147154Rani, V.D. and H. Sudini,20133156164Thiessen, L.D. and J.E. Woodward,20122012Han, K.S., S.C. Lee, J.S. Lee, J.W. Soh and S. Kim,2012Cymbidium orchids caused by Sclerotium rolfsii in Korea.]]>40263264Kwon, J.H., D.W. Kang, S.D. Lee and J. Kim,2014Sclerotium rolfsii on Yacon in South Korea.]]>9811431143Paret, M., N. Dufault, T. Monol, J. Marois and S. Olson,20152015Sacchi, S., S. Maurya and A.K. Choudhary,2016Sclerotium rolfsii.]]>6419424Kwon, J.H.,2010Allium sativum) caused by Sclerotium rolfsii.]]>38156158Stewart, Jr. C.N. and L.E. Via,199314748750Jeeva, M.L., A.K. Mishra, P. Vidyadharan, R.S. Misra and V. Hegde,2010Sclerotium rolfsii.]]>39517523FRAC.,20162016Keyser, H.A. and J. Ferreira,1988Sclerotium rolfsii in grapevine nurseries.]]>94344Yaqub, F. and S. Shahzad,2006in vitro growth of Sclerotium rolfsii.]]>38881883Ohazurike, N.C.,1996Sclerotium rolfsii sacc.]]>40150153Punja, Z.K., R.G. Grogan and T. Unruh,1982Sclerorium roljirii on golf greens in northern California.]]>66108111Bhuiyan, M.A.H.B., M.T. Rahman and K.A. Bhuiyan,2012In vitro screening of fungicides and antagonists against Sclerotium rolfsii.]]>111482214827Khan, I.H. and A. Javaid,2015276168Skylakakis, G.,19817111191121Bhagat, I. and B. Chakraborty,201311208210Das, N.C., B.K. Dutta and D.C. Ray,2014Sclerotium rolfsii Sacc. in vitro.]]>415Manu, T.G., A. Nagaraja, S.J. Chetan and V. Hosamani,2012Sclerotium rolfsii causing foot rot disease of finger millet, under in vitro conditions.]]>14650Rakholiya, K.B.,2015Sclerotium rolfsii causing stem rot of groundnut.]]>10691694