Bio-efficacy evaluation of slow release nanoformulations of Mancozeb against phytopathogenic fungi Rhizoctonia bataticola, R. solani, Fusarium oxysporum and Macrophomina phaseolina

Controlled release (CR) nanoformulations of mancozeb (manganese-zinc double salt of N, N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory synthesized poly(ethylene glycols) (PEGs) based functionalized amphiphilic copolymers without using any surfactants or external additives. The bio efficacy evaluation of developed mancozeb CR formulations were studied and compared with that of commercially available 42% Suspension Concentrate (SC) and 75% Wettable Powder (WP). The in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi, R. bataticola, M. phaseolina, R. solani and F. oxysporum by poison food technique. ED₅₀ values of the developed formulations varied from 1.83 to 4.73 mg L⁻¹ for R. bataticola (4.47 mg L⁻¹ for SC and 4.27 mg L⁻¹ for WP), 2.88 to 3.73 mg L⁻¹ for M. phaseolina (4.91 mg L⁻¹ for SC and 3.72 mg L⁻¹ for WP), 1.59 to 3.86 mg L⁻¹ for R. solani (3.64 mg L⁻¹ for SC and 4.36 mg L⁻¹ for WP) and 1.81 to 3.23 mg L⁻¹ for F. oxysporum (4.50 mg L⁻¹ for SC and 3.99 mg L⁻¹ for WP). Also, the developed formulations offer slow release of mancozeb, which may have longer duration of efficacy as compared to commercial formulations.