Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz (1996) 69, 59-63

C. Sengonca and T. Faber (1996)
Studies on developmental stages of the horse chestnut scale insect, Pulvinaria regalis Canard (Hom., Coccidae), in the open land and in the laboratory
Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 69 (3), 59-63
Abstract: In the presented paper the development of horse chestnut scale insect, Pulvinaria regalis Canard, was studied on red horse chestnut (Aesculus x carnea) in the urban area of Bonn. Secondly, the scale insect growth was determined on sycamore maple (Acer pseudoplatanus) and horse chestnut (Aesculus hippocastanum) at different temperatures in the laboratory.
The field population displayed an insignificant linear increase in body length between July and beginning of December. No growth was observed between December and March but between mid of March and beginning of May the body size increased exponentially. By setting up a frequency distribution of the anal plate length and by simultaneous measurement of new and old anal plate during molting it was possible to separate different developmental stages. The length of the anal plates of first instar crawlers/settlers ranged between 0.030 and 0.054 mm, that of the second and third instar nymphs between 0.066 and 0.090 mm and 0.102 to 0.150 mm, respectively. The anal plate length of fourth instar adult females differed between 0.162 and 0.246 mm, whereas those of male puparians ranged between 0.075 and 0.098 mm. Since the cuticula of P. regalis is very extensible, the separation of different developmental stages was only reliable by using the measure of the strongly sclerosed anal plate. Until 12. August first instar crawlers/settlers and till 29. September second instar nymphs were observed on red horse chestnut in the field. Female third instar nymphs were noticed between 9. September and 28. April and fourth instar adult females from 31. March on.
In the laboratory P. regalis individuals on horse chestnut and sycamore maple did only grow at 18°C and fluctuating temperature of 20/14°C (16/8 h). The growth was heavily affected at warm temperatures of 26°C and scale insects lived only a few weeks. Only at the fluctuating temperature of 20/14°C (16/8 h) some females laid eggs on horse chestnut and sycamore maple from the 49. and 48. week onwards.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Cetin Sengonca

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pulvinaria regalis	Lime tree/linden (Tilia)