title: Experimental mixtures of Phthorimaea operculella granulovirus isolates provide high biological efficacy on both Phthorimaea operculella and Tecia solanivora (Lepidoptera: Gelechiidae).
abstract: The Guatemalan potato moth Tecia solanivora (Povolny) recently invaded part of South America, colonizing zones where Phthorimaea operculella (Zeller), another potato moth species belonging to the same group, was previously established. T. solanivora is now the major insect pest of potato in this area encompassing Venezuela, Colombia and Ecuador. P. operculella granulovirus (PhopGV) (Betabaculovirus) is a biocontrol agent to be considered for the simultaneous management of these two potato pests, instead of classical chemical insecticides. In a previous work, five PhopGV isolates were isolated in Colombia from T. solanivora and were tested against larvae of the same species showing variable efficacies. Infections with mixtures of different genotypes of Baculoviruses had been carried out in a wide range of species and several showed interesting results. In the present study, the effect of sequential passages of PhopGV in P. operculella and T. solanivora larvae was analyzed through biological assays. Three different mixtures containing a Peruvian PhopGV isolate (Peru) adapted to P. operculella and a Colombian PhopGV isolate (VG003) adapted to T. solanivora were tested. A preliminary analysis of the correlation between the genotypic marker egt gene and the level of pathogenicity after a variable number of replication cycles was made. Mixtures of virus isolates showed a higher efficacy in both hosts compared to individual PhopGV isolates. This higher pathogenicity was maintained through passages. In P. operculella the mixtures were between 2.8 and 23.6-fold (from 7.15 OB/mm(2) to 0.10 OB/mm(2)) more pathogenic than isolate Peru applied alone. In T. solanivora they were between 2.3 and 4.9-fold (from 12.29 OB/mm(2) to 1.25 OB/mm(2)) more pathogenic than isolate VG003 alone. Viral biopesticide containing a mixture of selected genotypes active against each hosts seemed suitable for the development of a biopesticide aimed to simultaneously control P. operculella and T. solanivora.
authors.affiliation: EMA, Centre LGEI, 6 Avenue de Clavières, 30319 Alès, France.
authors.forename: Carlos
authors.initials: C
authors.lastname: Espinel-Correal
authors.forename: Miguel
authors.initials: M
authors.lastname: López-Ferber
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Zeddam
authors.forename: Laura
authors.initials: L
authors.lastname: Villamizar
authors.forename: Juliana
authors.initials: J
authors.lastname: Gómez
authors.forename: Alba Marina
authors.initials: AM
authors.lastname: Cotes
authors.forename: Xavier
authors.initials: X
authors.lastname: Léry
mesh_terms: D000818:Animals; D001681:Biological Assay; D018797:Cell Cycle Proteins / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D014644:Genetic Variation; D025722:Granulovirus / Q000235:genetics / Q000472:pathogenicity*; D007304:Insect Viruses / Q000235:genetics / Q000302:isolation & purification*; D007306:Insecticides; D007814:Larva / Q000821:virology; D007915:Lepidoptera / Q000502:physiology / Q000821:virology*; D007928:Lethal Dose 50; D010572:Pest Control, Biological; D012692:Serial Passage
chemical_list: D018797:Cell Cycle Proteins; D004279:DNA, Viral; D007306:Insecticides