Effect of pH and Viscosity of Gel Carrier and Lipid Metabolism Arresting Adjuvants on Shelf Life of Entomopathogenic Nematodes Mukhopadhyay A1, Singh A1,*, Somvanshi VS2, Manna S1, Rudra SG3, Kundu A1, Phani V2, Singh PK1 1Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India 2Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India 3Division of Food Science and Post Harvest Technology, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India *Corresponding author E-mail: anupama.chikara@gmail.com
Online published on 8 January, 2020. Abstract Random choice of generic carriers without proper understanding of biocontrol agent's behaviour and physiology in the existing formulations is a serious constraint leading to poor quality of bioformulations in general. This study reports the effect of gel carrier quality markers viz. pH and viscosity on the shelf life of an indigenous thermo-tolerant entomopathogenic nematode, Steinernema thermophilum. The pH of swollen gel matrix when less than 6 and more than 7 was detrimental to the biocontrol agent. Gel viscosity, in terms of consistency of the matrix at par with reference formulation ‘Pusa Nemagel’ was optimum to prolong shelf life of S. thermophilum. Among the thirteen test lipid metabolism arrestants (LMA), A1-derivative of benzoic acid was the o most promising against this EPN. Stored at 35C for three months, infective juveniles (IJs) exhibited maximum survival (50%) in the aqueous suspension treated with 10 ppm of A1 as compared to the aqueous suspension (36.89%). The finding was confirmed by Oil Red O staining technique, wherein the maximum number of stained IJs indicating stored lipid reserve in nematode body, were observed in A1 (10 ppm) treated suspension, thus establishing its efficiency as an effective lipid metabolism arrestant adjuvant for EPN formulations. Top Keywords Entomopathogenic nematode, Steinernema thermophilum, pH, viscosity, lipid metabolism arrestant. Top |