A. K. Patibanda ¹, B. Sen ¹

Affiliations
1 Division of Plant Pathology, Indian Agricultural Research Institute (ICAR), Pusa, New Delhi, 110012, IN

Abstract

In vitro interactions of antagonist Aspergillus niger isolate AN 27 and muskmelon wilt pathogen Fusarium oxysporum f. sp. melonis isolate MM 37 revealed three distinct growth phases of A. niger AN 27-initial normal growth with black colony colour due to sporulation, suppressed growth and sporulation followed by revived growth and sporulation. Change in medium pigmentation from violet to pink and formation of abundant thick mycelial strands and chains of chlamydospores were observed in F. oxysporum f. sp. melonis MM 37. Change in medium pigmentation of MM 37 was attributed to the change in medium pH brought by AN 27 by constitutively producing organic acids. Mechanisms involved in AN 27 antibiosis were production of organic acids, antimicrobial substances (n-butanol extract) and extra cellular enzymes - all of which inhibited microconidial germination of MM 37. Seed coating with A. niger AN 27 spores or seedling dip in its spore suspension protected muskmelon seedlings from Fusarial wilt in Rapid Pathogenicity test.

Keywords

Aspergillus niger, Biological Control, Fusarium oxysporum f. sp. melonis, Muskmelon Wilt.

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A. K. Patibanda ¹, B. Sen ²

Affiliations
1 Agricultural Research Station, Tandur 501 141, Ranga Reddy District, Andhra Pradesh, IN
2 Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110012, IN

Abstract

Seven isolates of the antagonist Aspergillus niger van Teigh and three isolates of the muskmelon wilt pathogen Fusarium oxysporllm f. sp. melones were assayed for their in vitro interactions. The most virulent isolate of the pathogen was highly sensitive to antagonism compared to less virulent isolate. Variation existed among different A. niger isolates in their antagonistic potential. Observations on overgrowing ability of the antagonist, A. niger werc more useful in screening isolates compared to other parameters such as inhibition zone, radial growth of the test pathogen and I or of the test antagonist in A. niger Vs F. oxysporum r. sp. melonis system. Isolate AN 27 was found promising based on its biocontrol capabilities.

Keywords

Antagonism, Aspergillus niger, Fusarium oxysporum f. sp. melonis, Muskmelon, Wilt.

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