EFFICACY OF SELECTED FUNGICIDES ON THE LINEAR COLONY GROWTH OF THE HELMINTHOSPORIUM ORYZAE CAUSED BY BROWN SPOT DISEASE OF RICE.

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1 Pak. J. Biotechnol. Vol. 13 (1) (16) ISSN Print: ISSN Online: EFFICACY OF SELECTED FUNGICIDES ON THE LINEAR COLONY GROWTH OF THE HELMINTHOSPORIUM ORYZAE CAUSED BY BROWN SPOT DISEASE OF RICE. Ghulam Hussain Jatoi 1*, Manzoor Ali Abro 1**, Javad Asghar Tariq 4**, Shabana Memon 2**, Naimatullah Mangi 2, sultan Ahmed Maitlo 1, Azhar-ul-Din Kerio 3, Shahid Hussain 1 and Abdul Salam Mengal 1, 1 Department of Plant Pathology, Faculty of Crop Protection, Sindh Agriculture University Tandojam. 2 Department of Plant Breeding & Genitics, Faculty of Crop Production, Sindh Agriculture University Tandojam, 3 Department of Emtomology, Faculty of Crop Protection, Sindh Agriculture University Tandojam, 4 Neuclear institute of Agriculture (NIA) Tandojam, Pakistan *: jatoighulamhussain@hotmail.com Article received ; Revised ; Accepted ABSTRACT Brown spot of rice caused by Helminthosporium oryzae, attacks the plant at any growth stage and it appears on the foliage as scattered brown spot that coalesces and result in withering and yellowing of the leaves. This fungal disease lowers the seed germination, causing rotting of seeds and roots that ultimately reduce yield by 16% to 43%. The method followed was based on survey and sampling of diseased seed samples from Larkana. Isolation and purification of fungi from these samples were conducted and performed pathogenicity test of the most predominant isolated fungus (H. Oryzae). So, this study was aimed to evaluate different fungicides. In vitro study of four fungicides efficacy revealed that Mencozeb and Thiomal completely inhibited growth of the test fungus. H. oryzae failed to grow at 150 and 0 ppm, (00. mm) as compared to control (36.62 mm) respectively. Whereas, Bavistin was moderately effective (.50 mm) and Melody duo was less effective (12.87 mm) as compared to control (36.62 mm). So, one can conclude that Mencozeb and Thiomal was the most effective fungicides. These studies could be helpful for researchers and farming community in future for better management of this disease. Key worlds: Brown spot of rice, Fungicides INTRODUCTION Rice (Oryza sativa. L) is one of the most important crops in the world and a staple food for more than half of the world s people. World s annual rice production during economic year 14 was million tonnes (FAO STAT, 14). Around 90% of total rice is produced by Asia continent alone (Hafiz et al., 08). Major rice producer countries are China, India, Indonesia, Bangladesh, Philippines and Pakistan. As a cash crop, it contributes 4.49% to the foreign exchange earnings and accounts for 1.3% GDP (Anonymous, 14). Rice crop is attacked by 50 diseases, i.e., fungal, bacterial, parasitic (nematodes) and viral diseases (Mew and Gonzales, 02). The three most important pathogens of rice are Pyricularia oryzae, Helminthosporium oryzae and Xanthomonas oryzae, which causes blast, brown spot and bacterial blight correspondingly (Singh et al., 13). Among them, H. oryze caused by brown spot of rice is the most devastating disease in the world. The first documented case of was reported in Bengal, India. In where 50-90% of the rice crops were destroyed that causes a major famine in which two million people died of starvation (Padmanabhan, 1973). Hau (1980) reported that causes both quantity and quality loses in the crop that may range 7-45% yield loss. While, heavily infected seeds may lead to 55% seedling transience. Although, Kamal and Mia (09) investigated and studied post-emergence nursery killing at 15 and 45 days after transplanting and 17-23% yield loss. While, Barnwal et al., (13) reported crop losses, due to, that may vary commonly from 4-54%. However, accurate organized estimates are absent. Shamima et al., (13) conducted a study to estimate the efficacy of the five selected fungicides Vizipordione (rovral), Tebuconazole (folicur) and Hexaconazole (Hayconazole, Orazole and Titan) beside in rice and reported a large variation from 4.3 to 13.99% in control of. Whereas, Percich et al., (1989) suggested that inoculated plant receiving one application of Propiconazole plus two of

2 14 Jatoi, G.H., et al., Pak. J. Biotechnol. Mancozeb resulted in average 24% higher yield than inoculated plants receiving one application of Propiconazole. Similarly Gupta et al., (13) reported that the application of Propiconazole extensively reduced the disease severity (70%) and increased the grain yield (21%) of all the cultivars as compared to their particular controls. Although, Samira et al., (02) reported that when applied to seeds, Tricyclazole, Mancozeb and the Carboxin+Thiram combination were the only fungicides that reduced all the symptoms induced by both pathogens without injurious the growth of young plants. Azher et al., (13) reported that the, X. oryzae and P.. oryzae could be controlled by new chemistry Gem Star Super, Nativo and Score as they were most effective in controlling pathogen incidence and superior yield as compared to control and other fungicides used in the field. MATERIALS AND METHODS Isolation and purification of fungi: Isolation of different fungi was carried out from infected grains and panicles (Mew and Gonzales, 02) Discolored grains were collected from the experimental field of RRI, Dokri and NIA, Tandojam. The diseased grains were separated from panicles and kept in petri plates. Seeds were surface sterilized with 5% Sodium Hypochlorite solution for two minutes and placed on fresh Potato Dextrose Agar (PDA) medium. Fifteen sterilized seeds were kept in three PDA plates ( seeds/plate) and these plates were incubated at 28 0 C for 5-7 days. Fungus was purified by taking small bit of fungus and transferring them in next PDA plate. Identification of the fungus was done by studying colony characteristics, spore shape and size following the method described in the Technical Bulletin of the Seed Borne Diseases and Seed Health Testing of Rice (Ellis, 1980 and Agarwal, 1989). The pure cultures of the isolated fungus were preserved at 5 0 C on PDA slants for further studies Colonization (%) = Effect of different fungicides on the linear colony growth of : Five different fungicides were tested under in-vitro condition such as (Thiomill, Signal, Melody Duo and Bavistin) for their efficacy against. The standard solution was prepared according to the active ingredients of the fungicides (Table 1). The experiment was conducted in complete randomized block design (CRD) with four treatments and three replications for each treatment. Petridishes containing amended PDA medium were inoculated with five mm disk removed with sterilized cork borer from the growing margin of a 7-8 days old mycelial culture of H.oryzae Petridishes containing PDA medium without fungicides were used as control. All the plates were incubated at 28 ± 1 o C for about 7 days. Mycelial growth of the fungus was recorded in mm after 48 hours of inoculation till 7 days of growth. Number of seeds colonized by pathogen Total number of seed studied x 0 T able -1: The fungicides and their doses used in the study Results and discussion Serial No. Tested fungicides 01 Thiomil 02 Mencozeb 03 Melody duo 04 Bavistin Treatment Dose in ppm No. /0 ml medium II 0 IV 0 II 0 IV 0 II 0 IV 0 II 0 IV 0

3 Vol. 13 No. 1 (16) Efficacy of Selected Fungi.. 15 RESULTS AND DISCUSION Total six fungi,,,, Fusarium, Penicillium and Tilletia spp., were isolated from the seeds of 12 rice varieties namely Dokri-Basmati, Winner, Hyb, Supper karnal, IR-06, IR-08, DR-59, DR-82, DR- 83, DR-92, Karal-Basmati, Denglo Hyb and Gard- 53 Hyb. Tillatia spp. was isolated only from Dokri-Basmati and IRRI-8 was the most predominant fungus was isolated from seeds of all rice varieties. Which showed maximum frequency, i.e., 61%, (Table 2) all other fungi such as,,, Fusarium, Penicillium, Tillatia spp. were isolated in comparatively with low frequency. Minimum frequency % was found by spp. (Table 2). Four different fungicides, i.e., Mancozeb, Melody duo, Thiomil and Bavistin at different doses 50 ppm, 0 ppm, 150 ppm and 0 ppm (Fig.- 1) were tested for their efficacy against H. oryzea causal agent of Brown spot of rice. The results of the the present studies shows that there was a highly significant effect of all the fungicides tested on the mycelia colony growth of the test fungus in vitro conditions (p<0.05). In all four fungicides tested Mancozeb was found highly effective (0.00) followed by Thiomil (0.00) Whereas, Bevisten was found mildly effective (3.75) as compared to control (36 mm). Moreover, the effect of Melody duo was found less effective (5.25) as compared to other three fungicides and control plates (Fig.-1). The mycelial colony growth was reduced gradually with increase in each fungicides concentration. Comparison of overall mean reduction in growth of by all tested fungicide revealed that Thiomill and Mancozeb were more effective to control the growth of fungus. The colony growth of was reduced with increasing concentration of all the fungicides. Among the fungicides used, Mencozeb and Thiomal completely inhibited growth of the test fungus. Mancozeb and Thiomal appeared to be highly effective fungicide as H. oryzae failed to grow at 150 and 0 ppm concentrations, respectively. Different works studied wide range of fungicides and found many of them effective for brown spot of rice disease fungus (Gupta et al., 13; Shamima et al., 13). Our findings are also in confirmation to those reported by Azher et al., (13) who is observed Mancozeb is the exhibited excellent control of brown spot of rice caused by. Samira et al., (02) evaluated fungicides against Tricyclazole and the tricyclazole + mancozeb carboxin+thiram combination, thiabendazole and mancozeb were highly effective against the test fungus. mancozeb, tricyclazole, chlorothalonil, edifenphos, carbendazim, pyroquilon and bitertanol (Saifulla et al., 1996), Tolylmercury acetate, Benomyl, Mancozeb, thiram and Quinolate (Esuruoso and Joaquim, 1980), Hadron (Krishnamurthy et al., 01) Captan, Mancozeb, Thiram and Emisan (Rao and Ranganathaiah, 1988) proved quite effective against B. oryzae. However, Vidhyasekaran, (1980) observed that seed treatment with seven fungicides including systemic ones did not eradicate the pathogen from endosperm tissues. The fungus was eradicated from all parts of the seed by dipping in a mixture of guazatine and dichloromethane for 1 h. The mixture of thiabendazole and maneb (Islam et al., 1992) iprodione and thiram (Coutinho et al., 00) fungicides Benomy-l50WP, Mancozeb, Fenapanil 50 WP and Iprodione 50 flowable resulted in significantly better control of brown leaf spot of wild rice Zizania aquaticat caused by Dreschlera (Bipolaris oryzae) and D. sorokiniana (B. sorokinianat) (Percich and Nickelson, 1982). Fig. -1: Effect of selected fungicides on the linear colony growth of

4 16 Jatoi, G.H., et al., Pak. J. Biotechnol. Table-2: Frequency of fungi isolated from rice seeds taken from different rice cultivar No. Variety name Isolated seed Frequency born pathogen % 01, 50 Winner, 30 Hyb 02 Supper karnal 03 IR IR DR DR DR DR Karnal- Basmati Fusarium Fusarium Penisillium, Tilletia ssp Curvulari, Tilletia ssp Denglo, Hyb Gard- 53 Hyb 12 Dokri-Basmati,,, Tilletia spp CONCLUSION: was found to be most predominant fungus among rice associated fungi. Mancozeb and Thiomil were found best effective. While, Bavistin and Melody duo less effective respectively all fungicides reduced linear colony growth as compeer to control among tested. REFERENCES Agarwal, P.C, C.N. Mortensen and B. Mathur, Seed-born diseases and seed health testing of rice. Tech. bull.no.3, Phytopathol. Paper No 30. CAB Int.Mycol. Inst. (CMI) Kew.Surrey, UK. Pp (1989). Anonymous, Agriculture Statistics of Pakistan. Govt. of Pak. Ministry of food, Agriculture and Livestock Division (Economic Wing), Islamabad. Pp. 29 (13). Azher, M., S.I. Yasin S. Mahmood, A. Hannan and M. Akhtar, Field evaluation of new fungicides against rice (Oryza sativa) diseases. Pak. J. Phytopathol. 25 (02): (13). Barnwal, M. K., A. Kotasthane, N. Magculia, P. K. Mukherjee, S. Savary, A. K. Sharma, H. B. Singh, U. S. Singh, A. H. Sparks, M. Variar and N. Zaidi, A review on crop losses, epidemiology and disease management of rice brown spot to identify research priorities and knowledge gaps. Eur J Plant Pathol 136: (13). Coutinho, W.M., L.A.A Pereira, J. Machado, C.Magalhaes, R.Pena, C.M. Das, M Vieira and G.G.C. Das, Physiological quality of rice seeds in relation to differential occurrence of Drechslera oryzae. Ciencia e Agrotecnologia 24: (00). Ellis, M.B., More Diatomaceous Hyphomycetes. Common Wealth Mycological Institute, Kew, Surrey, England. Pp. 608 (1980) Esuruoso, O.F. and Joaquim, M.A. Control of some important seed borne fungi of rice (Oryza sativa L.) in Nigeria. African J. Pl. Prot. 2: (1980). FAO. FAO Statistical Year Book. 13. Country Profiles-WEB Edition, Statistics Division FAO Food and Agriculture Surfed on NOV 12, at 22 (2): 6 (14). Gupta, V., N. Shamas, V. K. Razdan, B. C. Sharma, R. Sharma, K. Kaur, I. Singh, D. John and A.Kumar. Foliar application fungicides for the management of brown spot disease in rice (Oryza sativa L) caused by Bipolaris oryzae. African Journal of Agricultural Research 8(25): (13). Hafiz, M., I. Arshad, N. Hussain, S Ali, J A. Khan, K.Saleem and M.M.Babar. Behavior of bipolaris oryzae at different temperatures, culture media, fungicides and rice germplasm for resistance. Pak. J. Phytopathology 25 (01):84-90 (13). Hau, F.C. and M.C.Rush, A system for inducing sporulation of Bipolaris oryzae. Pl. Dis. 64: (1980). Islam, M.R., M.A.T Mia and M.A.Haque, Chemical control of seed borne diseases of rice. Bangladesh. J. Plant Pathol. 8: (1992). Kamal and M.A.T. Mia, Diversity and pathogenicity of the rice brown spot pathogen, Bipolaris oryzae (Breda de haan) shoem. In

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