Insecticide cocktail mixing practices and farmer knowledge scores across two delta regions of Vietnam

Abstract:

The practice of mixing multiple insecticide products into cocktail formulations is widespread among Vietnamese vegetable farmers, yet systematic comparison of this behavior across major production regions and its relationship to farmer knowledge levels remains limited. This research compared insecticide cocktail mixing patterns, knowledge scores, and economic outcomes between vegetable farmers in the Red River Delta (n = 150) and Mekong Delta (n = 150) of Vietnam during 2025-2026. Five cocktail combinations were identified, with organophosphate-pyrethroid (OP+PY) mixtures being most prevalent in the Red River Delta (28.5%) and organophosphate-carbamate (OP+CA) mixtures most common in the Mekong Delta (25.3%). Knowledge scores, assessed across a seven-point scale incorporating age group and education level variables, ranged from 1.8 (no education, age 56+) to 6.5 (tertiary, age 36-45). A significant positive linear relationship was established between over-application rate and seasonal economic loss (r = 0.72, p < 0.001), with farmers applying insecticides at rates exceeding label recommendations incurring substantially higher costs without proportional pest reduction benefits. These findings underscore the need for region-specific extension strategies that address the distinct cocktail mixing cultures of each delta while improving farmer knowledge and economic efficiency.