The pot experiments concerning the response of different weed species to two formulation of iodosulfuron methyl sodium and amidosulfuron mixture applied at different air temperature, relative humidity and soil moisture conditions were investigated in controlled environment chamber. The response of Anthemis arvensis L., Galium aparine L. and Thlaspi arvense L.  was examined. Two levels of each climate factors were investigated: for temperature – 24/12 and 12/6°C, for humidity – 40 and 70%, for soil moisture – 30 and 60%. The herbicide was applied at a recommended dose of 3.75 g ha-1 iodosulfuron methyl sodium + 15 g ha-1 amidosulfuron and at two herbicide formulations – water dispersible granules (WG) and oil dispersion (OD).

Response of the weed species to herbicide formulation was determined based on plant biomass reduction. T. arvense control did not depend on herbicide formulation, but it was affected by soil moisture, whereas G. aparine was strongly affected by relative humidity, soil moisture and herbicide formulation. Among the examined species, only A. arvensis response to herbicide was related to temperature. Effi cacy of the WG formulation was more influenced by climate conditions, especially relative humidity and soil moisture. Plants of G. aparine and A. arvensis were moresensitive to OD than WG formulation, regardless of the climate factor