EN
Scentless chamomile Matricaria maritima (L.) ssp. inodora (L.) Dostal and common poppy Papaver rhoeas (L.) are species which very often infest winter cereal and winter rape crops. Inhibitors of acetolactate synthase (ALS) are commonly used for control of these weeds. The herbicides are characterised by a single site of action in the plant, which has an influence on selection of the weed population and may result in a rapid development of resistance. In 2012, five seed samples of scentless chamomile and five samples of common poppy were collected from five winter wheat crop fields in Żuławy Gdańskie where the weed species were very poorly controlled. Results of greenhouse experiments showed that two biotypes of scentless chamomile and common poppy were resistant to tribenuron methyl. It was not possible to control resistant biotypes even after use of tribenuron methyl at a dose four times higher than recommended in Poland, it is the first reported case of scentless chamomile and common poppy biotypes’ resistance to herbicides. It is not of economic importance but it does prove the growing problem of weed resistance in the country.