Evaluation of arbuscular mycorrhiza and other biocontrol agents in managingFusarium oxysporumf. sp.Cubenseinfection in banana cv. Neypoovan

Abstract

Panama wilt of banana caused by Fusarium oxysporum f. sp. cubense (race 1) is a serious disease devastating the important cultivar Neypoovan (syn Elakki Bale AB) in southern India. Chemical control methods are not very effective in controlling the disease. The objective of this study was to evaluate biocontrol agents (BCAs) under controlled and field conditions for their efficacy against the pathogen and to detect and quantify the reduction in FOC population. Arbuscular mycorrhizal (AM) fungi, Trichoderma harzianum and Pseudomonas fluorescens were inoculated at the time of planting in single, dual and tripartite combinations allowing colonization up to 0, 45 and 90 days. Plants were challenged thereafter with 50 g of FOC inoculum multiplied on sorghum grains containing 1.5 )10 6 cfu g (1 . Uninoculated plants and those inoculated with pathogen only were controls. Plant growth parameters were measured and structural modifications in the roots were studied. FOC populations in the roots were determined by ELISA every month and final yield was recorded. At the end of 7 months, plants pre-inoculated with BCAs i.e., G. mosseae'T. harzianum and challenged with Fusarium under field conditions could sustain 61 and 70% improvement in plant height and girth, respectively, and 75% in bunch weight over plants not precolonised with BCAs but challenged with FOC which finally succumbed to the disease. ELISA study revealed Fusarium population was reduced to 0.58 OD in 7 months in G. mosseae and T. harzianum treatment compared to a level of 1.9 OD in Fusarium alone treated plants. Beneficial effect of BCAs may be due to the over all protection provided by them by causing physical modifications in the cell wall, growth promotion and through induction of disease resistance.

Biological Control Agents Against Fusarium Wilt of Banana

“…Maçã, especially under low concentration of Foc inoculum (Borges et al, 2007). Also, the pathogen population in roots of banana plants at 7 months after treatment with a combination of G. mosseae and T. harzianum was significantly reduced, as measured by ELISA (Mohandas et al, 2010). In the field, banana plants pre-treated in the nursery with G. clarum had higher biomass than untreated plants, and showed lower FWB incidence (67%), compared to the untreated control (88%).…”

Management of Fusarium wilt of banana: A review with special reference to tropical race 4

“…In the decade since biocontrol work on Fusarium wilt of banana was last reviewed (Ploetz, 2004), the above trends have continued, as few field studies have been reported and most publications describe only lab and greenhouse research (Borges et al, 2007;Fishal et al, 2010;Forsyth et al, 2006;Lian et al, 2008;Mohandas et al, 2010;Nel et al, 2006a,b;Sun et al, 2011;Thangavelu and Jayanthi, 2009;Thangavelu and Mustaffa, 2012;Ting et al, 2010;Wang et al, 2013;Weber et al, 2007;Wu et al, 2013;Zacky and Ting, 2013). In two exceptional situations, field results were reported: the best treatment of Thangavelu and Jayanthi (2009) resulted in a nonsustainable incidence of 20% after 8 months, and in another study, promising greenhouse treatments failed in the field; in it, Belgrove et al (2011) noted that "… neither the nonpathogenic F. oxysporum, P. fluorescens, nor combinations thereof reduced Fusarium wilt development significantly."…”

Non-Synergistic Effect of Trichoderma harzianum and Glomus spp. in Reducing Infection of Fusarium Wilt in Banana

“…Height and stem diameter increment/loss were computed as the difference between the final and initial data taken during the experiment. The effectiveness of the artificially induced suppressive soil was assessed based on disease incidence (%) and disease progression, estimated by using the area under the disease progress curve (AUDPC) which was compared statistically among treatments [15] every week on a six-week period. Sample plants were sectioned longitudinally to confirm the presence of vascular lesions characteristic of FocR4 infection.…”