Protection of seedlings afforded by Supersect 10EC alone and Supersect 10EC mixed with Nu-Film 17 against pine weevil feeding was evaluated in field experiments in northern part of Romania. The seedlings, mainly of Norway spruce, but also European larch and black pine, have been treated by dipping into insecticide solution (% Supersect or 1 % Supersect plus 1 % Nu-Film) just before planting of the seedlings in three new clear-cutting areas. The efficacy of the treatment was evaluated after 3-5 months. The frequency of attack in Norway spruce seedlings was reduced by 21.4-61.1.% when Supersect was used together with Nu-Film, but only by 0-35.5 % when it was used alone. For the same species, the intensity of attack was diminished by 62.4-83.2 % when the treatment was done with Supersect and Nu-Film, and by 48.7-63.3 % when it was used only Supersect. For the other two species, the efficacy of treatment was generally lower. The tests showed that in new clear-cuttings, where the weevil population level is very high and the weevils are active for a long time, the treatment could be efficiently enough only during the first 2-3 months especially during the years with rainy weather. Consequently, additional protective measure should be applied in such situations. In order to achieve a good efficiency, the stems of the seedlings should be clear and dry before the treatment, and after the treatment the seedlings should be protected against the rain until the insecticide dries up on them. Higher concentrations of insecticides could give better results, but this should be proved in other tests.
Keywords: conifer seedling, Hylobius abietis, chemical protection, Supersect 10EC, Nu-Film 1 7