IN VITRO EVALUATION OF FUNGICIDES AND BOTANICALS AGAINST FUSARIUM OXYSPORUM AND MACROPHOMINA PHASEOLINA ISOLATED FROM SOYBEAN SEEDS
A. Chaity, A. A. Khan and I. H. Mian. 2012. In vitro evaluation of fungicides and botanicals against Fusarium oxysporum and Macrophomina phaseolina isolated from soybean seeds. Bangladesh J. Plant Pathol. 28 (1&2): 59-62.
Fusarium oxysporum and Macrophomina phaseolina are two seed-borne pathogens of soybean. An in-vitro test was conducted to evaluate the efficacy of six fungicides namely Bavistin 50 WP (Carbendazim), Provax-200 (Carboxin), Rovral 50 WP (Iprodione), Cupravit (Copper Oxy-chloride), Ridomil MZ 78 (Metalaxyl + Mancozeb) and Dithane M-45 (Mancozcb); and extracts of four plant species namely ginger rhizome (Zingiber officinale), garlic clove (Allium sativum), neem leaf (Azadiracta indica) and onion bulb (Allium cepa) against F. oxysporum and M. phaseolina following poison food technique using potato dextrose agar (PDA) as the basic medium. The fungicides were used @ 100, 200 and 400 ppm and the plant extracts were used @ 10, 20 and 40% concentrations. Complete (100%) inhibition in colony growth of both the pathogens was obtained with Bavistin 50 WP at all concentrations. Inhibition of colony growth was 85.74-89.26% in M. phaseolina and 50.55 – 67.03% in F. oxysporum at all concentrations of Provax-200. Rovral 50 WP gave 50.55 – 67.03% and 34.07 – 63.70% of F. oxysporum, and 85.74-89.26% and 82.96-88.70% inhibition of M. phaseolina, respectively. Provax-200 and Rovral 50 gave 50.55 – 67.03% and 34.07 – 63.70% growth inhibition of F. oxysporum, and 85.74-89.26% and 82.96-88.70% inhibition of M. phaseolina, respectively. Garlic was noted as the most effective botanical against F. oxysporum causing 64.64 to 89.45% growth inhibition followed by ginger (67.97 to 87.78%) at different concentrations. It was also effective against M. phaseolina showing 41.86, 20.56 and 14.82% inhibition in colony diameter, respectively at 40, 20 and 10%.
Macrophomina phaseolina and Fusarium oxysporum are two important seed-borne pathogens of many crops causing charcoal rot and wilt, respectively. They are important pathogens of cotton, jute, maize, pulses, cucurbits, okra, sesame, etc. A study was undertaken to evaluate the efficacy of six fungicides and four plant extracts to inhibit in-vitro colony growth of two fungal pathogens. The selected fungicides were Provax-200 (Carboxin), Rovral 50 WP (Iprodione), Dithane M-45 (Mancozeb), Bavistin 50 WP (Carbendazim), Ridomil-MZ 78 (Metalaxyl + Mancozeb) and Cupravit (Copper Oxy-chloride); and the botanicals were extract of garlic (Allium sativum), ginger (Zingiber officinale), onion (Allium cepa) and neem (Azadirachta indica). The tests were conducted following poison food technique using potato dextrose agar (PDA) as a basic medium (Dhingra and Sinclair 1985). The test fungi were isolated from soybean seeds infected with the pathogens following tissue planting methods.
Freshly prepared PDA was amended with each fungicide @ 100, 200 and 400 ppm; and water extract of each botanical @ 10, 20 and 40% (v/v) concentrations. Extracts of garlic cloves, ginger rhizomes, onion bulbs and Neem leaves were prepared by blending 100 g of each plant material in 100 ml of sterilized distilled water in a blender. The extracts were filtered through two-ply cheese cloth. Requisite quantity of individual plant extract or fungicide was added to freshly prepare warm PDA in 100 ml conical flask to have desired concentrations. The amended PDA was autoclaved at 121C under 1.05 kg/cm2 pressures for 20 minutes and dispensed into 90 mm glass Petri dishes at 20 ml/dish. The medium without fungicide served as control. After solidification of the medium, the plates were inoculated with 5 mm mycelial discs cut from the margin of 7 days old cultures of F. oxysporum or M. phaseolioa with a 5 mm cork borer. One mycelial disc of test fungus was placed reversely at the center of each Petri dish. The plates were incubated in an incubator at 28C.
Individual experiment was conducted for each material. The experiments were conducted following completely randomized design. Data were transformed following square root transformation method and analyzed for ANOVA using MSTAT-C computer program. The means were compared following Duncan’s New Multiple Range Test using the same computer program.
Radial colony diameter of M. phaseolina and F. oxysporum was 90.00 mm under control (fresh PDA without amendment) was 90 mm (diameter of plates was 90 mm). At all concentrations of Cupravit, Dithane M-45 and Ridomil MZ-78 did not show any inhibitory effect on colony growth of M. phaseolina. Amendment of PDA with Rovral 50 WP, Provax-200 and Bavistin 50 WP caused significant inhibition in colony growth of the fungus. The colony growth was completely inhibited when PDA was amended with Bavistin 50 WP at all concentrations. Provax-200 gave 85.74, 87.58 and 89.26%, and Rovral 50 WP showed 82.96, 86.30 and 88.70% inhibition of radial colony growth at 100, 200 and 400 ppm, respectively (Table 1).
In case of F. oxysporum, significant inhibition of colony growth was obtained with treatments with all fungicides except Dithane M-45 at 100 ppm. The rate of inhibition varied with fungicides and their concentrations. Bavistin 50 WP gave 100% inhibition in mycelial growth of F. oxysporum at all concentrations. Provax-200 caused 50.55, 57.58 and 67.03%, and Rovral 50 WP gave 34.07, 53.89 and 63.70% growth inhibition at 100, 200 and 400 ppm, respectively. Three less effective fungicides, Cupravit, Ridomil MZ and Dithane M-45 showed only 8.70-19.81, 4.25-7.41-11.67 and 4.25-9.44% inhibition of radial growth of F. oxysporum at different concentrations (Tables 1).
All the plant extracts at all concentrations caused significant inhibition of the colony growth of the M. phaseolina and F. oxysporum compared to control. The maximum growth inhibition was achieved with garlic followed by ginger, onion and neem extracts. The botanicals gave 14.82-41.86, 11.86-24.64, 6.30-19.26 and 2.03-18.34% inhibition in colony diameter of M. phaseolina at 10, 20 40% concentrations, respectively. Amendment of PDA with extracts of ginger, garlic, neem and onion at 10, 20 and 40% concentrations also significantly inhibited the growth of F. oxysporum. The inhibition was corroborated with concentration of each botanical. Ginger, onion and neem extracts gave 67.97-87.78, 61.47-85.19 and 45.56-82.97% inhibition of colony growth of F. oxysporum at 10, 20 and 40% concentrations, respectively (Tables 2).
Results of the present experiments reveal that among six fungicides Bavistin 50 WP, Rovral 50 WP and Provax-200 are effective to reduce in vitro colony growth of M. phaseolina and F. oxysporum at all concentrations. Bavistin 50 WP gave 100% growth inhibition of both fungi on amended PDA. Provax-200 caused 50.55, 57.58 and 67.03%, and Rovral 50 WP gave 34.07, 53.89 and 63.70% growth inhibition at 100, 200 and 400 ppm, respectively. Similar findings have also been reported by other investigators. Islam (2011) found complete inhibition of the fungus due to application of Bavistin 50 WP at 100 to 400 ppm concentrations. He also reported that Bavistin inhibited the radial growth of F. oxysporum about 95%. Ahmad et al. (1991) demonstrated inhibitory effect of Bavistin against M. phaseolina. Khan and Fakir (1995) and Haque and Gaffar (1995) demonstrated that Vitavax-200 is an effective fungicide against M. phaseolina. It is well established fact that Bavistin and Provax-200 are effective seed treating fungicides (Vidhyasekaran and Thiagarajan 1981.
Findings of other experiments with four botanicals reveal that all of the botanicals at 10, 20 and 40% are effective to inhibit radial colony diameter of M. phaseolina as well as F. oxysporum on amended PDA. Among the botanicals, the most effective one was extract of garlic which gave 14.82-41.86% reduction in colony diameter of M. phaseolina and 64.64-89.45% reduction in F. oxysporum. Similar findings have also been reported by Ahmed and Sultana (1984), Dubey and Dwivedi (1991) and Islam (2011). They found that inhibition of mycelial growth and spore germination of M. phaseolina. Khan and Fakir (1995) and Rahman et al. (1999) reported that extract of garlic is effective in controlling seed-borne infection of F. oxysporum of jute seed.
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