Field experiments were carried out in 2004–2006 at the Plant Breeding and Acclimatization Institute (IHAR) Bonin Branch and private farm in Niekłonice. The experiments with Pyrinex 480 EC (chlorpyriphos) in which the tested product was soil-applied were carried out on potato cv. Bryza (Niekłonice and Bonin). Treatments were performed by spraying the soil 2–3 days before potato planting at the dose 4 l/ha. It was revealed that soil-applied Pyrinex 480 SC considerably reduced the damage of cv. Bryza tubers by wireworms as compared to the untreated control.