Wrażliwość trzeciego stadium pędraków chrabąszczy (Melolontha spp.) na kontaktowe działanie insektycydów neonikotynoidowych

Experiments were conducted on the susceptibility of third instar Melolontha spp. white grubs to the contact action of neonicotinoid insecticides under laboratory conditions. The insecticides used were: a) SP and WG (water suspension) formulations: acetamiprid (Mospilan 20 SP containing the active substance at 200 g l -1 ), clothianidin (Apacz 50 WG containing the active substance at 500 g kg -1 ); b) GR (granular) forms: clothianidin (traditional formulation containing the active substance at 10 g kg -1 ), imidacloprid (slow release form containing the active substance at 50 g kg -1 ); and carbosulfan as a standard insecticide (GR slow release form containing the active substance – Marshal Suscon 10 CG – at 100 g kg -1 ). The experiments confirmed the low sensitivity of third instar Melolontha white grubs to the contact action of these insecticides. Insecticides of SP and WG formulations applied to the soil at a dose of 25 mg active substance kg -1 soil did not cause 100% mortality after 28 days of exposure. In the case of clothianidin, mortality after 28 days was 40% and in the case of imidacloprid it was 80%. GR forms containing clothianidin (traditional formula) used at a dose of 50 mg kg -1 soil, and imidacloprid (slow release form) used at a dose of 250 mg kg -1 soil, caused 70-80% mortality after 28 days. Carbosulfan GR (slow release form), used as a standard at a dose of 500 g active substance kg -1 soil, caused 100 % mortality after 28 days.