Blattlausschäden im Jahre 1961 und Auftreten der Fichtenröhrenlaus Liosomaphis abietina Walker in der Schweiz

Injuries by Aphids in 1961 and Appearance of the Spruce Aphid Liosomaphis abietina Walker in Switzerland

Birmensdorf

1961

2 Abb., 1 Karte, 19 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

1265

200157568

A striking appearance of Aphids was noted in the Swiss forests, especially on conifers, in spring 1961 which had been preceded by an unusually mild winter. O several localties the larches suffered from a heay attack ba the Spruce Gall Aphid Adelges laricis Vall., so that the needles turned completely brown. The treatment with a mist solution of concentrated mineral oil, applied in quantites of 22 litres per hectare, against the over-wintering larvae, showed a 100% kill. Liosomaphis abietina Walker, the Spruce Aphid, which was hitherto unknown in Switzerland, was found since 1960, and espacially in the current year, on different localities of the country. On spruce, with some exceptions, the population density was not high. On blue spruce (Picea pungens Engelm., Picea alba Lk.) however, an outbreak could nearly always be observed. The present knowledge of this new pest of the Swiss forests is resumed.