Abstract
Colonies ofNeodiprion sertifer (Geoffroy) larvae infected by nuclear polyhedrosis virus were visited by parasitoids, predators, and scavengers. Six transmission pathways were studied in detail. Viable virus polyhedra (PIB) were isolated from external surfaces of parasitic wasps and faeces of tachinid flies, coccinellid larvae, and scavenging flies. Faeces of the scavenging flies remained infectious 9 months on foliage in the field. A bird fed on earthworms from contaminated soil passed infectious faeces. Raindrops on foliage below diseased larval colonies contained more than 108 PIB/ml. It was concluded that although there are numerous transmission pathways, only a few may be available at any one time. The stochastic nature of many pathways implies that the overall transmission rate is highly variable. These results are consistent with frequent observations of low transmission levels between larvae of the same generation.
Résumé
Des colonies de larves deNeodiprion sertifer (Geoffroy) infectées par le virus de la polyédrose nucléaire ont été visitées par des parasitoïdes, des prédateurs et des nécrophages. Six voies possibles de transmission ont été étudiées en détails. Des polyèdres viables du virus (PIB) ont été isolés des surfaces externes des hyménoptères parasites et des fecès des mouches tachinaires, des larves de Coccinellides et des mouches nécrophages. Les fecès des mouches nécrophages restaient infectieuses à l'extérieur durant 9 mois sur le feuillage. Un oiseau nourri de vers de terre d'un sol contaminé donnait des fecès infectées. Les gouttes de pluie sur un feuillage situé au-dessous de colonies de larves malades contenaient plus de 108 PIB/ml. On en concluait que malgré les nombreuses voies de transmission, peu pouvaient être disponibles chaque fois. La nature des différentes voies donne à penser que le taux total de transmission est très variable. Ces résultats sont cohérents avec les observations fréquentes des niveaux de faible transmission entre les larves de la même génération.
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Olofsson, E. Transmission agents of the nuclear polyhedrosis virus ofNeodiprion sertifer [Hym.: Diprionidae] . Entomophaga 34, 373–380 (1989). https://doi.org/10.1007/BF02372476
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DOI: https://doi.org/10.1007/BF02372476