INTEGRATED MANAGEMENT OF ROOT ROT DISEASE OF MULBERRY CAUSED BY FUSARIUM SOLANI

Transcription

1 INTEGRATED MANAGEMENT OF ROOT ROT DISEASE OF MULBERRY CAUSED BY FUSARIUM SOLANI S.S. Choudhari1*, N.S. Solanke1 and B.M. Kareppa2 1Department of Botany, Adarsh College, Hingoli. 2Department of Botany, Dnyanopasak College, Parbhani. (Received : ; Revised : ; Accepted : ).ABSTRACT Mulberry is a commercially important crop, raised for its nutritious leaves required for production of most valued silkworm cocoons. Nowaday encountering a serious problem due to severe incidence of root rot disease caused mainly by species of Fusarium solani. Three antagonists T. viride, T. harzianum and Pseudomonas fluorescence and five fungicides carbendazim, captan, dithane M-45, thiophanate methyl and thiram were tested against Fusarium solani in vitro. T. viride was best in inhibiting the of pathogen by 73.6 per cent. Among the fungicides carbendazim, completely inhibited the of pathogen at all concentrations (100, 250, 500 ppm). The conventional control measures are unable to provide total control. Hence, antagonistic microorganisms along with fungicides were evaluated for their bio-control potential against Fusarium solani. Key words: Mulberry, biocontrol agents, fungicide, Fusarium solani. INTRODUCTION: Mulberry (Morus spp.) is a fast growing, deciduous, woody and perennial plant. It has a deep root system. The leaves are simple, alternate, stipulate, petiolate and lobed. The ideal range of temperature varies from 24-28ºC, humidity in the range of 65-80% and the optimum ph is 6.5 to 6.8 (Dandin, 2003). There are about 68 species of the genus Morus, the majority of them occurred in Asia, especially in China (24 species) and Japan (19 species). In India, there are many species of Morus of which Morus alba, M.Indica, M.serrata and M.caevigata are grown wildly in Himalayas and most of the states have taken up sericulture as an important agro industry with an excellent results. The total area of mulberry in India is around 2,82,244 hectare and in Tamilnadu is around 9,491 hectare (Vijayan,2009). Being a perennial crop soil borne diseases are widely prevalent and are a serious constraint for the production of quality leaf for feeding silkworm. The problem is observed both in nursery and established fields (Philip et al., 1995). Among the diseases, root rot caused by soil borne fungi like Fusarium solani and Rhizoctonia solani Kuhn is more alarming due to the ability to thrive well in soil and fast spread of disease once occurred besides absence of disease resistant varieties and inadequate control measures against this disease (Vineet et al., 1998). Many fungicides are known to be effective against soil borne diseases. The disease is soil borne in 135

2 nature and spreads fast primarily through contaminated soil, irrigation, diseased saplings farm implements etc. Due to its epidemic nature and potential to kill the plants completely, root rot is the deadliest disease of mulberry. Chemical control of disease is the most common and widely accepted method in the agricultural crops. Due to environmental pollution issues, imbalance in soil ecosystem as well as potential threat to silkworms the biological control method has been considered as a promising approach for the management of soil borne diseases. In this paper, we reviewed potential biocontrol agents against the fungal disease of mulberry. Also, we discussed the beneficial effect of application methods of the antagonistic microorganism on the suppression of Fusarium solani, based on the ecological characteristics of the disease and antagonistic mechanisms of the strain. In addition, integrated control techniques including chemical and biological control have recently been developed from an ecological and economic point of view. MATERIALS AND METHODS: Isolation and pathogenicity Wilted plants of mulberry were collected from cultivating field of sericulture garden of Adarsh college of Hingoli districts and fungus was isolated from infected root on PDA. The pathogenicity was proved by water culture technique (Nene and Kannaiyan, 1982) and the pathogen was identified as Fusarium solani based on morphological and cultural characteristics. In vitro evaluation of bioagents against Fusarium solani Efficient culture of Trichoderma viride (NCIM No. 1221), T. harzianum (NCIM No. 1185) and bacterial bioagent P. fluorescens (NCIM No. 5101) were obtained from National Collection of Industrial Microorganisms (NCIM), maintained in the Department of Botany, Adarsh College, Hingoli and were evaluated for their antagonism against Fusarium solani by dual culture technique (Dennis and Webster, 1971). Potato dextrose agar medium was used for the study as a culture media. Three replications for each bioagent along with control containing only one five mm disc of 5 days old culture of the pathogen in the center of the 90 mm plates were taken for the studies. All the plates were incubated at 28±1 C for 8 days and colony diameter of the pathogen was measured periodically and per cent inhibition over control was calculated by the following formula. Inhibition % = Growth of the pathogen in (control plate presence of antagonist) Growth of the pathogen in control plate In vitro efficacy of fungicides against Fusarium solani To select an effective fungicide among systemic (carbendazim, thiophanate methyl) and non-systemic fungicides (thiram, captan and dithane M-45) were tested at 100, 250 and 500 ppm concentrations by poisoned food technique (Nene and Thapliyal, 1993). PDA medium was prepared with double the recommended strength and sterilized in an 136

3 autoclave. For each fungicide, fungicidal solution was prepared double the test concentration. 10 ml of fungicidal solution was mixed thoroughly with 10 ml molten PDA medium in a sterilized Petri plate under aseptic conditions and allowed for 5 to 10 minutes to solidify. Appropriate control was maintained by using distilled water. From seven day old culture plates 5 mm disc were cut from outer margin of vigorously growing fungus with sterilized cork borer and transferred to the centre of the plates containing fungicidal medium. Three replications were maintained for each treatment. The whole procedure was carried out under aseptic conditions. The Petri plates were incubated at 28+1oC. The diameter of fungal colony was measured when the of the fungus in control plate was complete. Finally per cent inhibition was calculated by the formula. Inhibition % = Diameter of colony in the (control plate - treated plate) x 100 Diameter of the colony in control plate. RESULTS AND DISCUSSION: The results of dual culture technique revealed effectiveness of all the antagonists with varying degree of inhibition of the of the pathogen, (Table 1). Among the antagonists, Trichoderma viride was the best in inhibiting the of the pathogen by 73.6 per cent followed by T. harzianum (64.0%) and P. fluorescence (51.1%). Similar results were obtained by Suneel Anand and Harender Raj Gautam (2006), Goudar and Yadav et al. (2007) and Weindling (1932) reported that T. viride generally coil around the mycelium of the pathogen with or without penetration. Table 1. Effect of fungal and bacterial antagonists on radial of Fusarium solaniin vitro (dual culture technique) S.N. Fungal Isolate Radial (cm) Percent inhibition of 1 Trichoderma viride Trichoderma harzianum Pseudomonas fluroscens Control SEM CD at 5 % Table 2. Effect of systemic fungicides on inhibition of Fusarium solani by inhibition zone method S.N. Fungicide Concentration (ppm) Radial Percent (cm) inhibition 1. Carbendazim

4 Captan Dithane M Thiophanat methyle Thiram Control SEM CD at 5% The results of poisoned food technique revealed that all the fungicides reduced the of the fungus significantly at different concentrations (Table 2). Carbendazim inhibited the of the fungus completely (100%) at 100 ppm followed by thiophanate methyl (96.6%) and thiram (70.0%). However, captan and dithane M-45 were found to be least effective in inhibiting the of the fungus by 27.7 and 15.5 per cent, respectively. At 250 ppm and 500 ppm, carbendazim and thiophanate methyl completely inhibited the of the fungus (100%). These were followed by thiram (76.6%) at 250 ppm and 83.3% at 500 ppm. Captan and dithane M-45 were least effective both at 250 and 500 ppm concentration. These results are in agreement with Sumitha and Gaikwad (1995). Further, Sharma, 1984; Gaikwad and Sen, 1990, reported complete inhibition of of Fusarium solani by carbendazim even at 25 ppm concentration. It is therefore concluded that the antagonist Trichoderma viride and systemic fungicide carbendazim can be successfully utilized for the control of wilt pathogen Fusarium solani. REFERENCES: Bakshi B.K., M.A. Reddy Ram, Y.N. Puri and S. Singh. (1972). Survey of the disease of important FRIC, Dehradun, India. pp Dandin, S. B., Jayaswal, J. and Giridhar, K. (2003). Hand Book of Sericulture Technologies. Central Silk Board, Bangalore, pp: Gaikwad S. J. and B. Sen. (1990). Chemical control of cucurbit wilt caused by Fusarium oxysporum Schlecht. Rev. Plant Patho. 69 (6):

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