Studies on integrated management of wilt and root rot complex of chickpea (Cicer arietinum L.) caused by Fusarium spp. and Rhizoctonia solani
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Date
2014
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MPUAT, Udaipur
Abstract
The present investigation were undertaken to develop an effective strategy for the integrated management of wilt and root rot complex diseases of chickpea (Cicer arietinum L.), which is widely prevalent in moderate to high severity in different parts of Rajasthan.
The pathogens were isolated from disease chickpea plants showing typical wilt and root rot symptoms collected from farmer’s field of different chickpea growing areas of Rajasthan viz., Udaipur, Bikaner, Tivari, Pali, Sirohi and Banswara. Fusarium oxysporum f.sp. ciceri (one isolate), Fusarium solani (five isolates) and Rhizoctonia solani (six isolates) were isolated and their pathogenicity were confirmed by growing chickpea in pathogen inoculated soil.
The isolates of F. solani and R. solani exhibited considerable variations in growth, colony character, spore and sclerotial size. The in vitro physiological studies revealed that the maximum mycelium growth and sporulation of the isolates of F. solani, Foc and R. solani were recorded at 300C temperatures and pH 7 though considerable variations were recorded among isolates of F. solani and R. solani.
Assessment of losses caused by wilt and root rot complex were studied on field for two years at varied disease levels. Results showed the disease severity increased with combined inoculation of two (R. solani + Foc) and three (Foc + F. solani +R. solani) pathogens as compared to that of the individual (R. solani).
Five fungicides were tested, in vitro condition at three concentrations (250, 500 & 1000 ppm). The isolates showed variations in sensitivity to various fungicides but Tebuconazole was highly effective against all the isolates of Foc, F. solani and R. solani at all the concentrations so it was taken for further field experiment. Neem oil at 0.2 % concentration was effective in suppressing the growth of the pathogens Among the fungal and bacterial biocontrol agents, T. harzianum ICRISAT-25 and T. viride ICAR-95, P. fluorescens UDP Pf-1 and B. subtilis Br II showed good suppression of the three pathogens. These were than tested in pot culture and showed good effects. The biocontrol agent T. harzianum ICRISAT-25 showed highest efficacy in suppressing the isolates of the pathogens by dual culture method and was further tested in the field.
In order to find host plant resistance to wilt and root rot complex, ten popular varieties were evaluated in pot culture under inoculations of all the three pathogens. The cultivar Avrodhi was highly resistant, GNG-469, RAJ-1581, P-1080 and Pratap Chana-1 were moderately resistant, while BG-1053, BGD-72, BG-391 and RSG-888 were moderately susceptible. The popular cultivar Dahod Yellow was found to be highly susceptible. Alteration of different dates with late sown on 29th Nov showed less incidence of the disease as compared to early sowing on 15th Oct.
The fungicides, botanicals and biocontrol agents found effective in vitro, were further evaluated in field for two consecutive seasons as seed treatment individually as well as in combinations for suppression of wilt and root-rot complex of chickpea. It was found that combined treatments were superior in terms of better germination, lower mortality and higher yield as compared to the individual treatments. The most effective treatment was seed treatment with Tebuconazole + T. harzianum followed by Vitavax + T. harzianum as compared to control as well as other treatments. T. harzianum applied as seed treatment effectively established in chickpea rhizosphere and reached high population densities, at 90 DAS while the population of the pathogens was low in the rhizosphere as significant disease suppression was recorded.
Description
Studies on integrated management of wilt and root rot complex of chickpea (Cicer arietinum L.) caused by Fusarium spp. and Rhizoctonia solani
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Citation
Padamini, Rajkumari and Mathur. Kusum