Herbicide Resistant Weeds

Herbicide resistance in Denmark.

Andreasen, C. and J. E. Jensen. 1994. Herbicide resistance in Denmark. SP Rapport. 1994, presented at the 11th Danish plant protection conference on the side effect of pesticides used on weeds. 6: 261-270.

A project in Denmark showed some biotypes of Chenopodium album, Conyza canadensis, Epilobium ciliatum, Poa annua, Senecio vulgaris and Solanum nigrum to be resistant to atrazine and 1 biotype of Stellaria media to be resistant to chlorsulfuron. Positive and negative cross-resistance was found for some resistant biotypes. In competition experiments, atrazine-resistant biotypes were less competitive than sensitive biotypes if they were grown in unsprayed environments. The chlorsulfuron-resistant biotype of S. media was as competitive as the sensitive one. The inheritance of atrazine resistance in S. nigrum was maternal. Recommendations on how to avoid herbicide resistance problems are made.