Pea moth (Cydia nigricana F.) is one of the most important pea pests. To achieve high efficiency of pea moth control by chemical methods it is essential to have an information about correct date of insecticide application. The aim of the study was to determine the optimum date of insecticide application to control of pea moth occurring on pea using pheromone traps for pest monitoring. The experiment was conducted in 2012 in the experimental fields of the Research In-stitute of Horticulture in Skierniewice and the Agricultural School in Powiercie. The results showed that in Polish weather conditions the optimal moment to start the treatment is about 10 days after the confirmation of the presence of the first pea moth males in the traps.