Abstract: Chickpea wilt incited by Fusarium oxysporum f. sp. ciceris is one of the severe diseases causes heavy losses (20-100%) depending upon stage of infection and wilting. Minimizing this disease can only be accomplished by careful crop management. Biological control is currently being painstaking for an increasing number of crops and managed ecosystems as the crucial technique of pest control. In this context an investigation was conducted to diminish wilt of chickpea by use of integrated disease management. It was observed that in vitro condition (dual culture technique) Trichoderma viride was highest inhibiting the growth of Fusarium oxysporum f. sp. ciceris at the ratio 1:4 followed by 1:2 and 1:1 in poisoned food technique maximum inhibition under field condition was obtained by 0.3% followed by 0.2 and 0.1%, doses of carbendazim. After that carbendazim it was neem cake at concentrations 7% followed by 5 and 3% in that order which give maximum inhibition of test pathogen under field condition. Lowest percentage of incidence of wilt (19.0%) was found with T. viride (T2) followed by carbendazim (21.0%), neem cake (42.6%), carbendazim+neem cake (45.2%), carbendazim+T. viride (47.2%), neem cake+T. viride (48.2%). Pot culture studies revealed that the soil application of T. viride (4 g kg-1) was found most effective treatment in reducing the incidence of chickpea wilt. Thus, chickpea wilt could be managed by the integration of various practices like, seed treatment with chemicals, seed and soil application of bioagents and amendment of soils with neem cakes.
INTRODUCTION
Pulse crops are an important source of food proteins, vitamins, lipids and certain minerals and generally grown under risk prone marginal lands. They are important crops for providing a high value food and nutritional security of a large fraction of vegetarian people of the world and are generally known as poor man’s meat (Singh and Singh, 1992). Pulses being legume crops play a vital role in improving soil fertility and conserve natural resources which are essential for sustainable agriculture. Chickpea (Cicer arietinum L.) a self pollinating diploid (2n = 2x = 16) crop is the world’s third most important legume. India is the principle chickpea producing country followed by Pakistan and Turkey (FAO, 2008).
The wilt of Chickpea incited by Fusarium oxysporum f. sp. ciceris is one of the serious diseases (Gupta et al., 1986). This pathogen is soil borne (Singh et al., 2009) and seed borne (Haware et al., 1978) cause profound losses (20 to 100%) depending upon phase of illness and wilting (Haware and Nene, 1980). The spores of fungus enter in the plants passing through the roots. When the spores reach in vascular system they produce certain enzymes that disgrace the cell walls and obstruct the plant’s transport system. Discoloration occurs inside tissues from the roots to the aerial parts, yellowing and wilting of the foliage occur and finally there is necrosis (Brayford, 1998; Leslie and Summerell, 2006). Chemical management of its infection by systematic fungicides is extravagant but also causes ecological problem. Hence, scientists are steadily looking out for non perilous and eco-friendly measures for plant disease management. Previously, a number of workers study various management practices by means of biological and chemical agents (Khan et al., 2001; Sibtain et al., 2001; Inam-ul-Haq et al., 2003; Kaur et al., 2007). In this context Bendre and Barhate (1998) concluded that crop yield loss could be minimized by adjustment of cultural practices, optimum use of chemicals, use of beneficial biological agents resistant varieties. Thus, the present investigation was planned to Isolate, identify pathogen from infected plants of chickpea and evaluate in vitro and in vivo the efficacy of carbendazim vis-a-vis neem cake and Trichoderma viride against Fusarium oxysporum f. sp. ciceris.
MATERIALS AND METHODS
Experimental detail: The present experiment was conducted at Department of Plant Protection, Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad, India during Rabi 2009-10. The site of experiment is located at 25.87°N latitude and 81.54°E longitude and 98 m above sea level. This region has sub tropical climate with extremes of summer and winter. During winter season, especially in the month of December and January, the temperature drops down to as low as 2°C and during summer, it reaches up to 48°C. In laboratory all glass wares used were thoroughly cleaned with detergent, washed dried and sterilized at 150°C for 4 h and Potato Dextrose Agar (PDA) was used for isolation of fungus as method described by Aneja (2004). For isolation of fungus infected plants of wilt disease were cut into small bits of 2 mm surface sterilized by 0.1% mercuric chloride, rinsed 3 times by sterilized distilled water and transferred to petri plate containing PDA medium and incubated at 25°C. After 3 days, hyphal tip from periphery of colony growth was separated and transferred to another petri plates having medium to get pure culture. Identification of the pathogen was confirmed by studying morphological features of colony, spore characteristics and referring the relevant literature. Pathogenicity test and multiplication of F. oxysporum was done as per method of Nikam et al. (2007). Isolation and identification of fungal antagonists from rhizosphere soil was done as described by Rifai (1969). Incorporation of organic amendments into medium was done as mentioned by Jaganathan and Narsimhan (1988). Dual culture technique of Huang and Hoes (1976) was used for inoculation of antagonists of pathogen, where as poisoned food technique as described by Nene and Thapliyal (1979) was followed to determine percent mycelia inhibition. Field trial consisted of eight treatments one control and 3 replications with total number of 27 plots (each plot size 3x2 m). Treatments were carbendazim, T. viride, neem cake, carbendazim+neem cake, carbendazim+T. viride, neem cake+T. viride, carbendazim+neem cake+T. viride, uninoculated and inoculated control treatment in vitro experiment consisted of neem cake 3, 5 and 7% carbendazim 0.1, 0.2 and 0.3%. Each treatment was replicated 5 times. Dual culture technique consisted of treatments control, F. oxysporum+T. viride in 1:1 F. oxysporum+T. viride in 1:2 ratio, F. oxysporum+T. viride in 1:4 ratio. Each was replicated five times. Carbendazim was used at the rate of 2 g kg-1 seed through seed treatment (Nikam et al., 2007). Observations on disease intensity, plant growth parameters and yield were taken at 30, 60 and 90 Days After Sowing (DAS).
Statistical analysis: The data obtained on disease intensity, plant growth and yield parameters were analyzed statistically to test the significance of each character at 5% level of significance using procedure outlined by Fisher and Yates (1968).
RESULTS AND DISCUSSION
Biological control may be defined as the reduction in inoculums density producing activity of pathogen in its active or dormant state, by one or more organisms naturally or through manipulation of environment and host of the antagonists (Baker and Cook, 1974). Fungitoxic effect of three seed dressing fungicides alone and in combination was tested in vitro by applying poisoned food technique. The results obtained on the fungitoxicity of fungicides against F. oxysporum f. sp. ciceris in vitro are presented in Table 1. Our research finding indicates that maximum inhibition of pathogen was obtained by 7% neem cake (60.49%), followed by 5% neem cake (31.94%) and 3% neem cake (8.89%). The differences were significant compared to control. Similar results were reported by Nakkeeran et al. (2002) and Sharma and Gupta (2003).
Under in vitro condition maximum inhibition of F. oxysporum was done by 0.3% carbendazim (70.09%) followed by 0.2% carbendazim (50.69%), 0.1% carbendazim (25.92%), 7% of neem cake (20.38%), 5% neem cake (15%) and 3% neem cake (14%) and the difference in these were significant. T6 was significantly better than other treatment where as differences between 3% neem cake and 5% neem cake and between 7% neem cake and 0.1% carbendazim were not significant (Table 2). These observations are in line with the results of Gupta et al. (1997). Regarding population density of T. viride (CFUx105 g-1 soil) in rhizosphere of chickpea field on 90 DAS Table 3 revealed that its highest colonization (41.81%) was in T. viride (4 g kg-1 of seed treatment)followed by carbendazim (39.27), neem cake (31.28) carbendazim+neem cake (18.99), neem cake+T. viride (13.51), carbendazim+T. viride ( 12.88) uninoculated (11.1) and inoculated control (6.51).
| Table 1: | Percent inhibition of Trichoderma viride on radial growth (mm) of Fusarium oxysporum f. sp. ciceris at different intervals |
| Table 2: | Percent inhibition of neem cake and carbendazim on radial growth (mm) of Fusarium oxysporum f. sp. ciceris at different intervals |
| Table 3: | Population density of Trichoderma viride in rhizosphere of chickpea field at different intervals |
| Table 4: | Effect of carbendazim, neem cake and Trichoderma viride on dry shoot weight of chickpea (Cicer arietinum L.) at different intervals |
All the treatments were significantly different from each other and superior to control. Sugha et al. (1995) evaluated 12 fungicides against Fusarium wilt of chickpea in vitro and in vivo under glass house and field conditions and reported Carbendazim (50 WP and 25 DS) and thiram alone and in combination as highly effective in inhibiting in vitro mycelial growth of the pathogen and in reducing wilt incidence both under glass house and field conditions.
With regard to effect of carbendazim (T1) neem cake (T3) and T. viride (T2) on dry shoot weight (g), Table 4 shows that 90 DAS the highest dry weight of shoot was recorded in T. viride (8.35 g) followed by carbendazim (7.94 g) and neem cake (7.02 g), carbendazim+neem cake (6.68), carbendazim+T. viride (6.49), neem cake+T. viride (5.36), carbendazim+neem cake+T. viride (5.07), uninoculated (4.62) and control (3.95) and the differences in these were significant. This indicates a significant effect of treatments in dry shoot weight. T. viride was significantly effective but was at par with carbendazim Similar findings have been reported by Poddar et al. (2004) on fresh shoot weight in respect to various treatments on chickpea.
Regarding effect of treatments on dry root weight of chickpea, it was observed that highest mean dry root weight in neem cake (1.9 g) followed by carbendazim (1.38 g), carbendazim+T. viride (1.31 g), carbendazim+neem cake (1.30 g), neem cake+T. viride (1.15 g), carbendazim+neem cake +T. viride (1.13 g), uninoculated control (1.08 g), control (0.90 g) and carbendazim (0.09 g) and the differences in these were significant.
| Table 5: | Effect of carbendazim, neem cake and Trichoderma viride on dry root weight of chickpea at different intervals |
| Table 6: | Effect of carbendazim, neem cake and Trichoderma viride on yield per plot of chickpea |
All treatments were significantly effective compared to control except carbendazim (Table 5). Similar findings have been reported by Saralamma and Reddy (2005). Karthikeyan and Karunanithi (1996) who found neem cake effective for control of F. oxysporum.
Highest mean yield of chickpea per plot was recorded in T. viride (601.66 g) followed by carbendazim (566.66 g), neem cake (560 g) and carbendazim+neem cake (483.33 g). However, lowest yield was observed with control (286.66 g) followed by neem cake+T. viride (460 g), carbendazim+neem cake+T. viride (336.66 g) and un-inoculated control (323.33 g). Thus, it can be concluded that T. viride was the most effective treatment under field condition (Table 6). Similar findings have been reported by Jha and Jalali (2006). However, effect of these treatments on disease intensity revealed that the lowest percentage of incidence` of wilt (19.0%) was found with T. viride (T2) followed by carbendazim (21.0%), neem cake (42.6%), carbendazim+neem cake (45.2%), carbendazim+T. viride (47.2%), neem cake+T. viride (48.2%), carbendazim+neem cake+ T. viride (49.8%), uninoculated control (51.3%) and control (61.3%) and differences in these were significant T. viride was found most effective which is in accordant with reports of Pandey and Upadhyay (1999). De et al. (1996) found that coating of chickpea seeds with Carbendazim (0.2%) was more effective in reducing wilt and increasing seed yield by 25.9 to 42.6%. Gupta et al. (1997) screened 6 fungicides against F. oxysporum f. sp. ciceris and reported Carbendazim at the rate of 100 mg mL-1 as most effective in inhibiting the growth of fungus in vitro. Due to synergistic effects of both the chemicals seed treatment with Thiram (0.15%)+Carbendazim (0.1%) were found most effective against F. oxysporum f. sp. ciceris. Somasekhara et al. (1996) reported that bioagents like T. viride, Trichoderma harzianum and Trichoderma hamatum as effective in controlling pigeon pea wilt caused by F. oxysporum f. sp. udum. Kolte et al. (1998) effectively controlled chickpea wilt with seed treatment by Rhizobium, T. viride, T. harzianum and Azotobacter sp. Prasad et al. (2002) who had reported soil application of T. viride and T. harzianum 1 week before sowing as more effective in reducing wilt and wet root rot of chickpea. The consortium (T. viride+ T. harzianum +T. hamatum) found very effective for control of chickpea wilt due to synergistic effect.
CONCLUSION
Minimizing biotic stresses can only be accomplished by careful crop management. Biological control is now being considered for an increasing number of crops and managed ecosystems as the primary method of pest control. The present study revealed that carbendazim and neem cake in poisoned food technique inhibited highest growth of test pathogen at the rate of 0.3% followed by 0.2, 0.1 and 7% under field condition. T. viride at the rate of 4 g kg-1 was most effective treatment for minimizing wilt of chickpea. Thus, chickpea wilt could be managed by the integration of various practices like, seed treatment with chemicals, seed and soil application of biological agents and amendment of soils.