Neues über die Tannentrieblaus (Dreyfusia nüsslini C. B.)

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Der heutige Stand der Bekämpfung und Abwehr der WeißtannenlausDreyfusia nüsslini C. B.

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Zur makroskopischen Unterscheidung der beiden WeißtannenläuseDreyfusia nüsslini C. B. (nordmannianae Eckst.) undDreyfusia piceae Ratz.

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Untersuchungen über Fichtengallenläuse, Dreyfusia spp. (Hom., Adelgidae) und deren Predatoren in der Nord-Türkei

In the East Pontic mountains at Giresun (Black Sea shore) three species of the genus Dreyfusia have been established: D. nordmannianae Eckst. and D. prelli Grosm. on Abies nordmanniana Link. and Picea orientalis Link. and Dreyfusia nov. spec. on A. nordmanniana. The latter species, earlier known from Greece and the Balkans, but not yet described is most probably unholocyctic on fir.In the Zigana mountains between Trabzon and Gümüsane a species producing plenty galls on young P. orientalis trees and closely resembling D. merkeri Eichh. has been observed. Further investigations are necessary to evaluate whether or not it lives unholocyclic on spruce.In the West Pontic mountains near Bolu D. nordmannianae was intensively studied in twig infestations on A. bornmülleriana Mattf. The pattern of attack differs greatly from the one experienced in central Europe in that almost exclusively the current year's shoots are attacked whereas the leader and the older twig axis remain free of attack. In Europe all parts of the trees are colonized.Considering the known facts about generation- and morph sequences, morph determination and phenological behaviour of D. nordmannianae the characteristics of their population dynamics in Turkey and the interactions of the curious mode of attack and the extraordinary efficiency of their special predators have been completely evaluated.     

Neues über die Kiefernnadelscheidengallmücke,Thecodiplosis (Cecidomyia) brachyntera Schwaegr

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