Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 525500
Title Morphologie en biologie van de schildluis Chionaspis salicis L.
Author(s) Dinther, J.B.M. van
Source University. Promotor(en): W.K.J. Roepke. - Wageningen : Veenman - 80
Publication type Dissertation, internally prepared
Publication year 1950
Keyword(s) coccidae
Categories Hemiptera / Animal Anatomy and Morphology
Abstract To help fill the gap in information on scale insects in the Netherlands, a study was made on C. salicis, a species mainly infesting willows. It was considered useful to become familiar with scale insects because of the danger of the San Jos_- scale (a fruit-tree pest) spreading northwards from France and Germany.
All stages of C.salicis were described, distribution and recorded food plants were reviewed, literature on toxicity of insecticides against scale insects were summarized.

C. salicis overwintered as egg. Minimum hatching temperature was 17°-18°C. Experiments with temperatures from -1° to 13°C (90 % r.h.) showed temperature- sensitive egg stages; temperature below zero was not necessary for later development.

Young nymphs appeared in April, winged and wingless adult males in July; females oviposited in September, reproduction being mainly parthenogenetic. Sterility in the female was observed and an inverse relation between fertility and population density was found.

In experiments with other food plants, males developed on many, but females reached maturity and oviposited only on poplars.

C. salicis was parasitized, twice a year, by Aphytis fuscipennis to a total of 14%.
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