EN
This study provides the results of research conducted at the Sośnicowice Branch of Institute of Plant Protection, which analyses the influence of number of sprayings with certain insecticides on the effectiveness of control aplied against pollen beetle (Meligethes aeneus F.) and cabbage stem weevil (Ceutorhynchus pallidactylus Marsh.) and yield of winter oilseed rape plants in conjunction with weather conditions occurring during the experimental period. Plots were sprayed once or twice with following insecticides: 2008 and 2009 – Decis 2,5 EC (deltamethrin), Mospilan 20 SP (acetamiprid), Proteus 110 OD (tiachloprid 100, deltamethrin 10), 2010 – Mospilan 20 SP, Proteus 110 OD, Karate Zeon 050 CS (lambda-cyhalothrin 50). The crucial factor for the control applied against pollen beetle and cabbage stem weevil on winter oilseed rape was air temperature spread during budding, which, along with long-term duration of certain insecticide treatments was a decisive factor affecting the effectiveness of control applied against various stages of development of cabbage stem weevil. The type of insecticides used and weather conditions after spraying were the crucial determinants for the amount of seed yield obtained.