ISSN:
1573-8248
Keywords:
Pauesia cedrobii
;
Cedrobium laportei
;
Cedrus atlantica
;
élevage au laboratoire
;
Pauesia cedrobii
;
Cedrobium laportei
;
Cedrus atlantica
;
laboratory rearings
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Description / Table of Contents:
Summary The aim of this study was to attempt a permanent rearing of the parasite:Pauesia cedrobii Stary et Leclant in order to make releases in natural conditions more easily than through direct introduction. The rearings were carried out for one year and a half under 9 different climatic conditions (temperature, humidity, photoperiod) upon the specific host:Cedrobium laportei Remaudière. This aphid was multiplied on a cedar plant grown in a container, which constituted a production unit easily moved to in natural conditions. In each of the climatised rooms, with constant temperature and humidity, 2 rearing chambers were set up with fluorescent lights, one of them with 8 hours lighting, the other one with 16 hours. During the “day-time” (despite the 2 fans used for air-extraction), the chamber temperature increased by about 3°C. The parasite rearing was impossible at 4°C. On the contrary, at 8°C the rearings were possible during a certain time. Nevertheless, the temperature was still too near the lower threshold of development of the parasite, while still above that of the host. The only permanent rearings were reached at 12°C. Under these conditions we observed a good balance between the parasite, which developed normally, and its host, which never disappeared. However the experimental results show, after about one year, that the cedar plant becomes less suitable for the development of aphid colonies and for the production of parasites. At 20°C, it was impossible to maintain the parasite on its host. During all the time of the test we observed at this temperature (and also at 25°C) a decaying of the cedar plant. It seems that the upper threshold of development is lower for the parasite than for its host. Generally speaking, long days are more suitable to rearings. On the basis of these results it is possible to consider a mass rearing ofP. cedrobii to make releases in natural conditions.
Notes:
Résumé Cette étude avait pour objectif la mise au point d'un élevage du parasitePauesia cedrobii Starý & Leclant sur son hôte spécifiqueCedrobium laportei Remaudière, ce dernier étant multiplié sur des jeunes plants de cèdreCedrus atlantica Manetti. Dans des chambres climatisées à température et humidité relative constantes, on a placé des enceintes d'élevage assurant respectivement 8 et 16 heures d'éclairement. Pendant la phase d'éclairement, et malgré 2 ventilateurs chargés d'assurer l'extraction de l'air, la température des enceintes a augmenté d'environ 3°C. Au total, 9 conditions climatiques ont été testées, chacune pendant un an et demi. A 4°C, le parasite ne s'est pas multiplié. A 8°C, il s'est maintenu pendant une année environ, mais cette température s'est montrée encore trop proche de son seuil inférieur de développement et de celui de son hôte. A 12°C, on a observé un bon équilibre entre le parasite, qui s'est développé normalement, et son hôte, qui n'a jamais disparu. A 20°C, les élevages ont eu un bon rendement pendant 6 mois, mais il n'a pas été possible de les maintenir pendant plus longtemps. A cette température, et plus encore à 25°C, les plants de cèdre ont présenté des symptômes de dépérissement. A 25°C, les résultats mettent en évidence une action défavorable de la température sur tous les niveaux trophiques. En règle générale, les jours longs ont été un peu plus favorables aux élevages.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02372477
Permalink
