Evaluation of Non-Toxic Visible Dyes as Markers for Microtermes obesi and Odontotermes lokanandi

Workers and soldiers of Microtermes obesi Holmgren and Odontotermes lokanandi Chatarjee and Thakur (Blattodea: Termitidae) were force-fed on different concentrations of Nile blue-A and Sudan red-7B. Results showed that 0.5% Nile blue-A caused 100 % mortality in M. obesi on 15th day in M. obesi and on 9th day, whereas 0.5% Sudan red caused 100% mortality in M. obesi on 9th day in O. lokanandi, on 5th day M. obesi and O. lokanandi were released on baits containing different concentrations of Nile blue-A. M. obesi got colour at 100% relative humidity after day 10 at all concentrations, while at 92 and 76% relative humidity they got colour at high concentration only. However, O. lokanandi was found sensitive to Nile blue. M. obesi and O. lokanandi released on baits of Sudan red-7B, did not get any colour under all tested relative humidities.Nile blue-A and Sudan red at medium and low concentrations remained in bodies of more than 90% M. obesi for 25 and 10 days, respectively. After 60 days, maximum of 59.33% termites were blue with low concentration of Nile blue. All M. obesi stained with Sudan red were dead by day 60.