In applying profenofos synthetic insecticide, farmers often did not use the recommended concentration as written on the label (1.5 ml L-1). Farmers usually apply insecticides at concentrations they predict would kill the insect pests. Based on the result of an interview with farmers, the concentration applied by farmers was 2 - 3 ml L-1 in order for a quicker death of the pest. The interval of spraying was 7 - 10 days depending on the rate of insect infestation in the field.