Epizootics caused by a nuclear polyhedrosis virus in populations ofspodoptera exiguain southern Spain

Abstract

A nuclear polyhedrosis virus (NPV) has been identified as the etiological agent causing epizootics in natural populations of Spodoptera exigua in the south of Spain. The incidence of this NPV has been determined from samples of larvae collected from sunflower fields and vegetable greenhouses at two sites located 500 km apart. The NPV was the only disease agent identified at both sites. Through the period surveyed the percentage of NPV-infected larvae increased from 4.3% to 23% and from 22.5% to 100% in S. exigua larvae collected from sunflower fields and vegetable greenhouses respectively. No mortality attributed to the NPV was found in Spodoptera littoralis, Heliothis armigera, Peridroma saucia and Plusia gamma larvae collected in the same survey from the same sites. This is the first report of epizootics caused by NPV in S. exigua populations in field and greenhouse crops in Europe.

Hierarchical spatial structure of genetically variable nucleopolyhedroviruses infecting cyclic populations of western tent caterpillars

“…They concluded that a single dominant genotype was responsible for all the epizootics monitored, although variants of this genotype were also collected. Similarly in Spain, the same RFLP variants of SeNPV were found in natural populations of S. exigua over several years (Caballero et al . 1992).…”

Functional response ofChelonus oculator(Hymenoptera: Braconidae) to temperature, and its consequences to parasitism

“…On the other hand, in the outdoor crops of the area, parasitoid and predator species (Cabello 1986, 1988, Caballero et al 1990, Guimaraes et al 1995, Torres-Villa et al 2000 as well as entomopathogens (Caballero et al 1992) are very abundant and provide very efficient control over the pest populations, with elimination rate of 33 and 100% (Cabello 1988), which does not happen in greenhouse crops (Cabello et al 1996). In the case of S. exigua, the parasitoid egglarval species that stands out is Chelonus oculator (F.) (Pino et al 2003) which could potentially be a control agent in greenhouse crops if increased.…”

Combined effect of nucleopolyhedrovirus and Microplitis pallidipes for the control of the beet armyworm, Spodoptera exigua

“…Another important biological control agent of the beet armyworm is S. exigua nucleopolyhedrovirus (SeNPV). Its virulence has been documented in the field and the laboratory, and the virus can cause natural epizootics in an S. exigua population 2–4. Nevertheless, it is unknown whether M. pallidipes is negatively affected by SeNPV, or whether their interaction could facilitate virus transmission among the hosts in the field.…”