A large number of pathogens are able to infect arthropods, including fungi, viruses, microsporidia and bacteria. Saprophytic true insect pathogens are generally not problematic in sanitised insectaries although outbreaks may occur under certain circumstances. Of more importance are those pathogens that cause chronic, debilitating disease and have the potential to affect insect fitness. Baculoviruses are DNA viruses that primarily infect Lepidoptera and some Hymenoptera. There are two main groups, the nucleopolyhedroviruses (NPV) and the granuloviruses (GV). These viruses can cause acute infections in mass reared arthropods; examples being Douglas fir tussock moth Orygia pseudotsugata, codling moth Cydia pomonella, cabbage looper Trichoplusia ni and Beet armyworm Spodoptera exigua. The Centre for Ecology & Hydrology has reared several species of Lepidoptera for more than 20 years in a specialised insectary. In the early 1990’s a persistent baculovirus infection was discovered in a culture of cabbage moth Mamestra brassicae. The virus was shown to be actively transcribed but individual insects did not succumb to infection. The culture has been continuously reared since this time with 100% infection in each generation but with extremely rare mortality due to the virus and little apparent fitness costs in the hosts. We discuss the methods by which these insect cultures are maintained and examine another example from a large insect facility, rearing codling moth for an orchard codling moth suppression programme. We will also examine how these persistent infections may be triggered into fully overt disease and the implications that this has for mass rearing of insects
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.