Studies were carried out in years 2006-2010 in south-eastern Poland in Krzeczowice near Przeworsk (49°59’ N; 22°27’ E). In the experiment, insecticide formulations were used that contained imidacloprid (Gaucho 600 FS and Couraze 350 FS) and methiocarb (Mesurol 500 FS). During the years of the research, the percentage of plants damaged by frit fly larvae in the control plots varied from 13.5% to 38.2%. All insecticides in the studied doses showed high efficiency in limiting the harmfulness of the above species. By applying formulations that contained imidacloprid, the number of plants damaged by larvae was limited by 69.6%-98.1%, while in the case of the insecticide that contained methiocarb, by 65.1%-96.2%. The pre-sowing treatment of maize grain with the studied insecticides also resulted in higher grain yield. Following the application of imidacloprid, the increase in grain yield ranged from 3.1% to 17.3%, while in the case of methiocarb, from 1.5% to 10.4%.

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