Abstract
The false spruce webworm, Cephalcia abietis L., causes severe defoliation of Norway spruce in the central European uplands. A concept for its integrated control is proposed, with two kinds of control. Fencing wild boars in an outbreaks site for one year at a density of about 1 animal/ha has provided a 70% reduction of ecnymph density in the ground. The entomophilic nematode Steinernema kraussei Steiner, an indigenous parasite of Cephalia eonymphs and pupae, is sensitive to soil acidity. Values below pH 4.0 are detrimental, but ranges between pH 5.0 and 7.0 are favourable. Considering extreme soil acidification as the reason for continuous suppression of the parasitic nematodes, the application of neutralizing fertilizers was tested in the field as a method to augment nematode populations. Three months after fertilizer treatment, nematode density in soil and parasitization rate of Cephalcia econymphs increased significantly. The usefulness of these methods for IPM of Cephalcia abietis is briefly discussed.
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