Responses (knock-down and mortality) of large pine weevil (Hylobius abietis L.) beetles to insecticides of different mechanism of action such as neonicotinoids (clotianidin, acetamiprid) acting on nicotinic receptors of acetylcholine (ACh), pyrethroids (deltamethrin, α-cypermethrin) blocking sodium channels in nerve cell membranes, organophosphates (chlorpiryfos) and carbamates (carbosulfan) both inhibiting acetylcholinesterase (AChE) activity and fenylpirazoles (fipronil) interfering with γ-butyric acid (GABA) receptors were studied. Taking into account speed of insect decay the order of examined groups of substances may be established as follows: first place is occupied by insecticides interferring with GABA receptors, second place by insecticides blocking AChE activity, and third place in parallel insecticides blocking sodium channels and those acting on nicotinic receptors of ACh.
The studies were performed on the isolated Ascaris lumbricoides suis preparation according to Baldwin's method (Ringer's fluid in the case of thermolability, 38 ± 0.5°, pH 6.8, passing nitrogen through the fluid, the time of experiment 95 minutes). The kymographic data were analysed by Feugeas' method calculating the coefficient A and T. The results were subjected to statistical analysis by means of Student's test. Alcohol extracts from dried fruits of 9 plants from Ericaceae were prepared conforming to Polish Farmacopea III. The strongest effect on the contractility of the isolated helminth preparation was exerted by Extr. Fructus Rhododendroni flavi, Extr. Vaccini vitis idaeae, Extr. Vaccinii uliginosi, Extr. Ericae tetralicis, Extr. Oxycocci quadripetali i Extr. Vaccinii myrtilli. The greatest depression of the preparation tonus was brought about by Extr. Ericeae tetralicis, Extr. Vaccii vitis idaeac, Extr. Callunae vulgaris, Extr. Vaccinii uliginosi. The results obtained are in keeping with the previous ones achieved by means of Student's test in Enchytraeus (Wiad. Parazytol., 1961).