Chemical protective practices are commonly used in maize crop and negative interactions between insecticides and herbicides seem possible. Some of these negative interactions have been observed in other crops in Brazil with a few studies related with maize. The main objective of this work was to study the interaction between imazapyr + imazapic herbicides and thiamenthoxan, thiodicarb, clorpirifos e fipronil, insecticides in maize. The experiment was carried out at field conditions, at "Fundação ABC" experimental area, Castro, Paraná State, Brazil during 2001/2002 season crop. The herbicide tolerant hybrid DKN 909 CL, under a no-tillage system, was used. Thiodicarb (120 mL ha-1) and thiamenthoxan (32 g ha-1) were mixed with the seeds while clorpirifos (1125 mL ha-1) and fipronil (96 g ha-1) were applied to the sowing lines. The herbicide treatments (imazapyr + imazapic) were applied at the 5-leaves stage (V5) in the doses of 0, 17.5 + 52.5, 35.0 + 105.0, 52.5 + 157.5 g ha-1 Crop phytotoxicity was evaluated at 7, 16 and 25 days after application (DAA). Harvesting for yield analysis and 1000 kernels mass was done at 131 DAA. No interactions were observed between insecticide treatments and herbicide doses. Clorpirifos insecticide and a proportional increase of the herbicide to 52.5+157.5 g ha-1 induced phytotoxicity symptoms; nevertheless no injuries were observed from 30 DAA on. Yield and 1000 kernels mass were not reduced by the different treatments.
corn; insecticide; herbicide; interaction; ALS inhibitor
