Effect of concomitant application of Pseudomonas fluorescens and Purpureocillium lilacinum in carrot fields infested with Meloidogyne hapla

Abstract

Root-knot nematode, Meloidogyne hapla remains a major limiting factor to obtain the estimated yield and quality of carrots in many countries. Effective use of nematode antagonistic bio-agents is a potentially important component of the eco-friendly agro-farming. The effect of seed treatment (ST) with liquid Pseudomonas fluorescens at 100 ml/kg seeds and soil drenching (SD) with Purpureocillium lilacinum at 5 l/ha, singly and jointly, was studied to minimise the damage caused by M. hapla in carrot plants under field conditions. The concomitant application of P. fluorescens ST + P. lilacinum SD reduced 70% of second stage juvenile (J2) population in soil, 71% of female population in root and 74% of egg numbers in roots. The carrot plants from P. fluorescens ST + P. lilacinum SD plots were 36% taller with 39% more leafs and 30% longer leaves than untreated plants. The yield was also 29% higher in concomitant application. There was no significant difference in the root colonisation of P. fluorescens and P. lilacinum in solo and combined treatments. It concludes that the concomitant application of P. fluorescens ST and P. lilacinum SD is more effective to suppress M. hapla infection and enhance the yield of carrot.

Keywords:

• Carrot
• root-knot nematode
• biological control
• liquid formulations
• integrated approach

Acknowledgements

The author thanks the technicians of Horticultural Research Station, Kodaikanal for execution of field trials, nematode extraction work and other lab works.