6.119
BIOCONTROL OF STOLON AND ROOT ROT (Rhizoctonia bataticola) IN MENTHA WITH Gliocladium virens
BIOCONTROL OF STOLON AND ROOT ROT (Rhizoctonia bataticola) IN MENTHA WITH Gliocladium virens PK MISHRA 1 and AN MUKHOPADHYAY2 l UAL, SECUNDERABAD, 2AAU, JORHAT- 785013, INDIA Background and Objectives A major constraint in the cultivation of Mentha arvensis widely used in the pharmaceutical and cosmetic industries, is stolon and root rot disease caused by Rhizoctonia bataticoia (Taub) Briton-Jones[l]. Control options are currently limited to the use of long crop rotations and the presowing drenching of the soil with chemicals, which are impractical and economically not viable. Therefore, biological control is considered worthy of investigation. The objectives of the present work were to evaluate an isolate of Giiociadium virens Miller, Giddens and Foster for control of Rhizoctonia bataticola on Mentha suckers, to study the mechanism of biocontrol and the effect of sucker treatment in the development of root system. Results and Conclusions Biocontrol fungus Gliociadium virens was proved highly antagonistic to Rhizoctonia bataticoia in culture. The mechanism being operative in disease control were antibiosis and mycoparasitism. The antibiosis was demonstrated by producing toxin and enzymes. Endochitinase with molecular weight of approximately 41KDa was detected from the culture filtrate of G. virens. Mycoparasitism by G. virens was performed by coiling of hyphae around the pathogen, penetration and lysis of hyphae. A formulation of G.virens was developed by solid state fermentation technology using agriwaste products@I.Significant disease control was obtained by the sucker treatment of mentha with powder, preparation of G. virens (3g/kg Sucker) under field conditions. In fields experiments, disease incidence was reduced from 67% to 22.2%. G. virens applied on sucker did not affect the growth and development rill' the root system. The incorporation of a bioagent preparation into our basic object at the and root rot towards reducing the disease and levels of fungicide residue. References [1]Kumar S, Kahol AP, Pat"a DD, Rar,,i M, Sin_qii S, Tyagi BR. 1997 Cultivation of Menthol Mint in India. Farm i3u]letin No.4:pp!3-20.[CIMAP,LUCKNOW]. [2]Mishra PK, Mukhopadhyay AN 1996. Proceedings Second lnt. Crop Science Congress, New Delhi, India, 14(8):348pp.