Development of Controlled Release Formulations of Triazophos and Evaluation of their Efficacy against Meloidogyne incognita

Controlled release (CR) formulations of insecticide triazophos have been prepared using commercially available rosin and polystyrene polymers. Kinetics of triazophos release in soil from the different formulations was studied in comparison with the commercially available 40 EC. Incorporation of triazophos in polymer matrix reduced the rate of release. The diffusion exponent (n value) of triazophos in soil ranged from -0.062 to 0.69 in the tested formulations. The half release (t_½) of triazophos in rosin and polystyrene was 12.2 and 46.3 days and the period of maximum availability of triazophos was 27.3 and 65.7 days, respectively. The mean EC₅₀ of the commercial formulation against Meloidogyne incognita was quite high as compared to CR formulations. Effective euration (t_e) of triazophos from commercial formulations was 11.7 days in comparison with rosin (23.9 days). The bioassay studies revealed that with the rosin polymer, the dose of triazophos could be reduced to half of its recommended dose for nematode control.