Spontaneous reactivation of baculovirus has been postulated as the main cause to explain outbreaks in laboratory insect cultures that have never been exposed to virus and in the development of epizootics in natural populations. Recent studies have reported a high prevalence of baculovirus covert infections in lepidopteran populations, such as Spodoptera exigua. Hence, reactivation may be considered as a potential strategy in biological control programs provided the factors involved in triggering patent infections can be elucidated. The aim of this study is to evaluate the effect of different stress factors on covertly infected S. exigua larvae in terms of virus reactivation. For this, adult survivors that had ingested occlusion bodies of S. exigua multiple nucleopolyhedrovirus (SeMNPV) were mated and the subsequent generation (F1) tested for virus reactivation in the second instar. A number of treatments were tested: i) chemical stressors: 1-01.% copper sulfate, 1% iron sulfate, 1-0.1% hydroxylamine, 2% Tinopal, 1 ppm paraquat dichloride, 1 ppm sodium selenite; ii) inoculation with: SeMNPV-US2, Chryxodeisis chalcites NPV (non permissive) and Bacillus thuringiensis (spores and crystals); and iii) rearing temperatures of 18 ºC and 28ºC.

Trabajo presentado en el 44th Annual Meeting of Society for Invertebrate Pathology, celebrado en Halifax (Nova Scotia, Canadá) del 7 al 11 de agosto de 2011.

Peer Reviewed