Potato Crops in Costa Rica are efficently protected from Phthorimaea operculella and Tecia solanivora by an indigineous granulovirus strain

Trabajo presentado en el 13th European Meeting Biological Control in IPM Systems, celebrado en Innsbruck (Austria) del 19 al 23 de junio de 2011.The control efficiency of a Phthorimaea operculella granulovirus isolate from Costa Rica (PhopGV-CR1) against the insect pests P. operculella and Tecia solanivora under field conditions was evaluated. The virus reduced damage between 50 and 80% in fields compared with the untreated controls. These data favor the inclusion of PhopGV-CR1 formulations in IPM programs.Peer Reviewe

Stored potatoes in Costa Rica are efficently protected from Phthorimaea operculella and Tecia solanivora with an indigineous granulovirus strain

Trabajo presentado en el 13th European Meeting Biological Control in IPM Systems, celebrado en Innsbruck (Austria) del 19 al 23 de junio de 2011.The control efficiency of a Phthorimaea operculella granulovirus isolate from Costa Rica (PhopGV-CR1) against the insect pests P. operculella and Tecia solanivora under storage and field conditions was evaluated. The virus reduced damage by over 70% compared with the untreated controls. These data favour the inclusion of PhopGV-CR1 formulations in IPM programs.Peer Reviewe

Costa Rican soils contain highly insecticidal granulovirus strains against Phthorimaea operculella and Tecia solanivora

The aim of this work was to isolate and characterize novel Phthorimaea operculella granulovirus (PhopGV) strains from Costa Rican soils. Three novel strains, named PhopGV-CR3, PhopGV-CR4 and PhopGV-CR5, were isolated from three locations in Costa Rica, Alvarado, Zarcero and Abangares, respectively, by means of soaking potato tubers with diluted soil samples. An additional strain, PhopGV-CR2, was identified from diseased larvae from a Tecia solanivora laboratory culture. Restriction fragment length polymorphisms obtained for each isolate with six restriction endonucleases (RENs) allowed their identification as four distinct PhopGV strains. Both REN and Polymerase chain reaction analyses indicated the existence of an array of genotypic variants present in all isolates. Bioassays in P. operculella and T. solanivora showed that PhopGV-CR3 was well adapted to the two coexisting hosts with high levels of pathogenicity against both pest species. The mean lethal dose values of this strain were 2.8OBs/mm 2 for P. operculella and less than 0.5OBs/mm 2 for T. solanivora. We conclude that PhopGV-CR3 shows great promise for soil application against these pests in Costa Rican potato crops. © 2011 Blackwell Verlag, GmbH.Yannery Gomez-Bonilla was the recipient of scholarships from the Spanish National Institute of Agricultural Research (INIA), the Costa Rican Ministry of Science and Technology (MICIT- CONICIT) and INTA. We are very grateful to Trevor Williams for his help with the English and the editing of this paper as well as for his constant support.Peer Reviewe

Granulovirus formulations efficiently protect stored and field potatoes from Phthorimaea operculella and Tecia solanivora in Costa Rica

The control efficiency of a Phthorimaea operculella granulovirus isolate from Costa Rica (PhopGV-CR1) against the concurrent insect pests P. operculella (Zeller) and Tecia solanivora (Povolny) (Lepidoptera: Gelechiidae) was evaluated. In warehouses, the best control efficiency was achieved with a powder formulate applied inside bags, which reduced injury over 70 % compared with the untreated controls. In the field, liquid and powder virus formulations significantly reduced injury between 56.2 and 81.7 % compared with the untreated controls, and were as efficient as chemical treatments. The efficiency of formulations stored at −20 °C for six months (liquid) or at ambient temperature for three months (powder) was maintained, but higher temperatures and/or longer exposure times resulted in loss of pathogenicity. The data presented here favor the inclusion of granulovirus formulations of PhopGV-CR1 in Integrated Pest Management programs against tuberworms in Costa Rica and give clues on storage conditions for the growers in this country.Project Plantón-Pacayas (INTA, Costa Rica)This research was financed with funds from the Project Plantón-Pacayas (INTA, Costa Rica).INTA, Costa RicaPeer reviewe

Characterization of a costa rican granulovirus strain highly pathogenic against its indigenous hosts, phthorimaea operculella and tecia solanivora

9 p., 2 figures, 5 tables and referencesA granulovirus isolate collected from diseased Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) larvae in Costa Rican potato [Solanum tuberosum L. (Solanaceae)] crops was characterized at the molecular and biological level. Restriction endonuclease analysis identified this isolate as a novel P. operculella granulovirus (PhopGV) (Baculoviridae: Betabaculovirus) strain and was designated as PhopGV-CR1. In addition, PCR amplification of four specific variable genomic regions yielded multiple amplicons for two open reading frames, revealing the presence of different genotypic variants within the virus population. Biologically, PhopGV-CR1 was highly pathogenic for its two indigenous hosts, although significant differences of up to four-fold were detected against P. operculella [LD 50=17.9occlusion bodies (OBs)mm -2] and Tecia solanivora (Povolny) (Lepidoptera: Gelechiidae) (LD 50=69.1OBsmm -2). The two P. operculella colonies, from Costa Rica and France, were equally susceptible to PhopGV-CR1. Serial passage of PhopGV-CR1 over four generations in T. solanivora increased its pathogenicity by five-fold in three generations, suggesting an ongoing adaptation to its alternate host.Yannery Gómez-Bonilla was the recipient of scholarships from the Spanish National Institute of Agricultural Research (INIA) and the Costa Rican Ministry of Science and Technology (CONICIT-MICIT)Peer reviewe

Responses of different geographic populations of two potato tuber moth species to genetic variants of Phthorimaea operculella granulovirus

International audiencePhthorimaea operculella granulovirus (PhopGV) belongs to the genus Betabaculovirus of the arthropod-infecting Baculoviridae. PhopGV is able to infect several gelechiid species. Among them are the potato tuber moths Phthorimaea operculella Zeller and Tecia solanivora Povolny (both Lepidoptera: Gelechiidae). In various South American countries, PhopGV-based biopesticides are used to control either P. operculella or T. solanivora. Many trials have indicated that a particular viral isolate can exhibit very distinct pathogenicity when infecting different host species or different populations of one host species. In this study, we compared host–pathogen interactions using various PhopGV isolates and various populations of P. operculella and T. solanivora. Virus isolates from P. operculella were more pathogenic against their original host species than against T. solanivora. A PhopGV isolated from T. solanivora was less efficient against P. operculella. In addition, virus isolates differed in pathogenicity toward their hosts (i.e., lethal concentrations of isolates ranged from low to high). Unexpectedly, we also found that host populations of one species from distinct geographic origins did not differ significantly in susceptibility to the same PhopGV isolate. This was the case for both host species and for five PhopGV isolates. Comparative restriction fragment length polymorphism (RFLP) analyses of 11 isolates including those used in bio-assays indicated three main regions of variation in the genome of PhopGV, corresponding to the regions of open reading frame PhopGV046, gene PhopGV129 (egt), and repeat 9 (located between open reading frames PhopGV083 and PhopGV084). Comparison of the nucleotide sequences of the insertions/deletions present in these regions were carried out for the most variable isolate, JLZ9f. The results are discussed in the context of the production and use of PhopGV as a biological agent against these two pest species