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Yulin Gao - One of the best experts on this subject based on the ideXlab platform.
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optimization of the sex pheromone based method for trapping field populations of Phthorimaea operculella zeller in south china
Journal of Integrative Agriculture, 2021Co-Authors: Junjie Yan, Ruixia Meng, Stuart R Reitz, Xiangdong Mei, Jiawen Feng, Zhixu Lin, Yulin GaoAbstract:Abstract Despite the identification of the potato tuber moth Phthorimaea operculella (Zeller) sex pheromone, no effective application based on this pheromone has yet been developed and evaluated. This study investigated the effect of pheromone lures, trap densities, heights of trap deployment, and pheromone doses in Yunnan, China, for the purpose of increasing the control efficiency of P. operculella and improving the application of pheromone technology in the field. The results showed that lures made of corn oil and red PVC pipes attracted the highest number of moths (11.73±1.90 per trap per day). Sex pheromone loading of 100 µg was optimal for trapping moths, but higher doses of pheromone inhibited attraction. The density of traps did not affect capture rates; therefore, the optimum trap density was 30–40 traps ha–1. The optimum height of trap deployment was not above the height of the plant canopy. This study provides technical details necessary for the monitoring and control of potato tuber moth using sex pheromones.
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Identification and Functional Characterization of Two Putative Pheromone Receptors in the Potato Tuber Moth, Phthorimaea operculella.
Frontiers in physiology, 2021Co-Authors: Yajie Cai, Jinglei Zhu, Mengdi Zhang, Yadong Zhang, Zengrong Zhu, Wenwu Zhou, Guirong Wang, Yulin GaoAbstract:Pheromones are a kind of signal produced by an animal that evoke innate responses in conspecifics. In moth, pheromone components can be detected by specialized olfactory receptor neurons (OSNs) housed in long sensilla trichoids on the male antennae. The pheromone receptors (PRs) located in the dendrite membrane of OSNs are responsible for pheromone sensing in most Lepidopteran insects. The potato tuber moth Phthorimaea operculella is a destructive pest of Solanaceae crops. Although sex attractant is widely used in fields to monitor the population of P. operculella, no study has been reported on the mechanism the male moth of P. operculella uses to recognize sex pheromone components. In the present study, we cloned two pheromone receptor genes PopeOR1 and PopeOR3 in P. operculella. The transcripts of them were highly accumulated in the antennae of male adults. Functional analysis using the heterologous expression system of Xenopus oocyte demonstrated that these two PR proteins both responded to (E, Z)-4,7-13: OAc and (E, Z, Z)-4,7,10-13: OAc, the key sex pheromone components of P. operculella, whilst they responded differentially to these two ligands. Our findings for the first time characterized the function of pheromone receptors in gelechiid moth and could promote the olfactory based pest management of P. operculella in the field.
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potential of steinernema carpocapsae weiser as a biological control agent against potato tuber moth Phthorimaea operculella zeller lepidoptera gelechiidae
Journal of Integrative Agriculture, 2020Co-Authors: Junjie Yan, Shovon Chandra Sarkar, Ruixia Meng, Stuart R Reitz, Yulin GaoAbstract:Abstract The entomopathogenic nematode, Steinernema carpocapsae, was evaluated for control of the potato tuber moth, Phthorimaea operculella, under laboratory conditions. We evaluated different concentrations of S. carpocapsae for control of 2nd, 3rd, and 4th instar P. operculella. The median lethal concentration (LC50) of S. carpocapsae infective juveniles (IJs) to 2nd, 3rd and 4th instar larvae of P. operculella was 200, 363, 181 IJs mL−1, respectively. With the extension of treatment time, the cumulative mortality increased for 2nd, 3rd, and 4th instar larvae and pupae of P. operculella. Fourth instars were the most susceptible for all observation periods. Therefore, our results suggest that S. carpocapsae could be an effective biological control agent for P. operculella.
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sub lethal effects of beauveria bassiana balsamo on field populations of the potato tuberworm Phthorimaea operculella zeller in china
Journal of Integrative Agriculture, 2018Co-Authors: Huiguo Yuan, Zhongren Lei, Silvia I Rondon, Wu Shengyong, Yulin GaoAbstract:Abstract The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China. Several reports indicate that P. operculella could be controlled biologically by the use of beneficial fungus such as Beauveria bassiana (Bals.-Criv) Vuill. However, limited information is available under growing conditions in China. Thus, this study evaluated the sub-lethal effects of B. bassiana on the offspring of P. operculella by the age-stage, two-sex life table. First instar larva of P. operculella were treated with 1×107 conidia mL−1 of the fungus, and several biological parameters were evaluated. The fecundity, duration of the egg stage, all larval stages, pre-adult stage, and total pre-oviposition period, were significantly shorter than the control treatment. Offspring of treated parents, presented a net reproductive rate and mean generation time of 17.43 per day and 24.98 days, respectively, compared to 65.79 per day and 26.51 days for the untreated ones. This study provides basic information to help understanding the potential long-term effects of entomopathogenic fungi on P. operculella.
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potential of a strain of beauveria bassiana hypocreales cordycipitaceae for the control of the potato tuberworm Phthorimaea operculella zeller
International Journal of Pest Management, 2017Co-Authors: Huiguo Yuan, Zhongren Lei, Silvia I Rondon, Yulin GaoAbstract:The potato tuberworm, Phthorimaea operculella (Zeller), is one of the most important pests of potato, Solanum tuberosum L., worldwide. We evaluated six Beauveria bassiana strains with potential for...
M Lopezferber - One of the best experts on this subject based on the ideXlab platform.
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granulovirus formulations efficiently protect stored and field potatoes from Phthorimaea operculella and tecia solanivora in costa rica
Biocontrol, 2013Co-Authors: Yannery Gomezbonilla, M Lopezferber, Primitivo Caballero, Rosa Murillo, Delia MuñozAbstract: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.
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experimental mixtures of Phthorimaea operculella granulovirus isolates provide high biological efficacy on both Phthorimaea operculella and tecia solanivora lepidoptera gelechiidae
Journal of Invertebrate Pathology, 2012Co-Authors: Carlos Espinelcorreal, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M Lopezferber, Xavier LeryAbstract: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/mm2 to 0.10 OB/mm2) more pathogenic than isolate Peru applied alone. In T. solanivora they were between 2.3 and 4.9-fold (from 12.29 OB/mm2 to 1.25 OB/mm2) 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.
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genetic and biological analysis of colombian Phthorimaea operculella granulovirus isolated from tecia solanivora lepidoptera gelechiidae
Applied and Environmental Microbiology, 2010Co-Authors: Carlos Espinelcorreal, Xavier Lery, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M LopezferberAbstract:Tecia solanivora (Lepidoptera: Gelechiidae) is an invasive potato pest of the north of South America that recently colonized zones where Phthorimaea operculella (Lepidoptera: Gelechiidae), a taxonomically related insect, was established. Nowadays, both species can be found in most areas in different proportions. The Phthorimaea operculella granulovirus (PhopGV) was found to efficiently control P. operculella and was used as a biopesticide in storage conditions. However, no appropriate biological control methods exist for T. solanivora, and the use of granulovirus isolates would provide a solution. The Colombian Corporation for Agricultural Research (CORPOICA) carried out several T. solanivora larva samplings in Colombia with the aim of finding potential isolates. Five geographical granulovirus isolates from T. solanivora (VG001, VG002, VG003, VG004, and VG005) were found, and molecular analysis by REN profiles shows three different genotypic variants in Colombia. Analysis of their genomes revealed their relatedness to PhopGV. Two isolates exhibited submolar bands in their REN patterns, suggesting a mixture of viral genotypes. These data were confirmed by PCR amplification and sequencing of particular regions of the viral genomes. Their biological activity was assayed on both hosts, T. solanivora and P. operculella. A significantly higher pathogenicity in both hosts was observed with isolates VG001 and VG005 than with isolate VG003 or a Peruvian isolate (from P. operculella) used as a reference in the bioassay. Based on their molecular and biological activity characteristics, VG001 and VG005 isolates should be selected for further analysis in order to establish their potential as biological control agents.
Xavier Lery - One of the best experts on this subject based on the ideXlab platform.
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Responses of different geographic populations of two potato tuber moth species to genetic variants of Phthorimaea operculella granulovirus
Entomologia Experimentalis Et Applicata, 2013Co-Authors: Jean Louis Zeddam, Xavier Lery, Yannery Gómez-bonilla, Carlos Espinel-correal, David Páez, François Rebaudo, Miguel López-ferberAbstract:Phthorimaea 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.
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experimental mixtures of Phthorimaea operculella granulovirus isolates provide high biological efficacy on both Phthorimaea operculella and tecia solanivora lepidoptera gelechiidae
Journal of Invertebrate Pathology, 2012Co-Authors: Carlos Espinelcorreal, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M Lopezferber, Xavier LeryAbstract: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/mm2 to 0.10 OB/mm2) more pathogenic than isolate Peru applied alone. In T. solanivora they were between 2.3 and 4.9-fold (from 12.29 OB/mm2 to 1.25 OB/mm2) 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.
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Characterization of a Costa Rican granulovirus strain highly pathogenic against its indigenous hosts, Phthorimaea operculella and Tecia solanivora
Entomologia Experimentalis et Applicata, 2011Co-Authors: Yannery Gómez-bonilla, Xavier Lery, Miguel López-ferber, Primitivo Caballero, Delia MuñozAbstract:A 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 [LD50 = 17.9 occlusion bodies (OBs) mm−2] and Tecia solanivora (Povolny) (Lepidoptera: Gelechiidae) (LD50 = 69.1 OBs mm−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.
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genetic and biological analysis of colombian Phthorimaea operculella granulovirus isolated from tecia solanivora lepidoptera gelechiidae
Applied and Environmental Microbiology, 2010Co-Authors: Carlos Espinelcorreal, Xavier Lery, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M LopezferberAbstract:Tecia solanivora (Lepidoptera: Gelechiidae) is an invasive potato pest of the north of South America that recently colonized zones where Phthorimaea operculella (Lepidoptera: Gelechiidae), a taxonomically related insect, was established. Nowadays, both species can be found in most areas in different proportions. The Phthorimaea operculella granulovirus (PhopGV) was found to efficiently control P. operculella and was used as a biopesticide in storage conditions. However, no appropriate biological control methods exist for T. solanivora, and the use of granulovirus isolates would provide a solution. The Colombian Corporation for Agricultural Research (CORPOICA) carried out several T. solanivora larva samplings in Colombia with the aim of finding potential isolates. Five geographical granulovirus isolates from T. solanivora (VG001, VG002, VG003, VG004, and VG005) were found, and molecular analysis by REN profiles shows three different genotypic variants in Colombia. Analysis of their genomes revealed their relatedness to PhopGV. Two isolates exhibited submolar bands in their REN patterns, suggesting a mixture of viral genotypes. These data were confirmed by PCR amplification and sequencing of particular regions of the viral genomes. Their biological activity was assayed on both hosts, T. solanivora and P. operculella. A significantly higher pathogenicity in both hosts was observed with isolates VG001 and VG005 than with isolate VG003 or a Peruvian isolate (from P. operculella) used as a reference in the bioassay. Based on their molecular and biological activity characteristics, VG001 and VG005 isolates should be selected for further analysis in order to establish their potential as biological control agents.
Silvia I Rondon - One of the best experts on this subject based on the ideXlab platform.
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physiological responses of the potato tuberworm Phthorimaea operculella to potato solanum tuberosum germplasm
American Journal of Potato Research, 2021Co-Authors: Seyed Mozaffar Mansouri, Silvia I RondonAbstract:The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is an important field and storage pest of potato Solanum tuberosum L. Feeding indices and midgut digestive protease and amylase enzyme activities were measured under laboratory conditions in P. operculella larvae reared on leaves of eight potato genotypes including Agria, Ausonia, Khavaran, Kondor, Morene, Satina, Savalan, Sprint, and two Iranian potato selections PI396124 and PI397082–2. The highest amounts efficiency of conversion of ingested food, and efficiency of conversion of digested food, were recorded in larvae reared on Savalan, and the lowest amount of these indices found on Khavaran, Agria, and PI397082–2. There were significant positive correlations between coefficients of P. operculella with midgut protease enzyme activity, and no significant correlations between the indices and midgut amylase enzyme activity. Among tested potato genotypes, the highest proteolytic activity was found on Savalan (6.6 ± 0.07 U/mg), and the lowest activity observed on Khavaran (4.4 ± 0.09 Umg −1) and Agria (4.4 ± 0.14 Umg −1).
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decoding Phthorimaea operculella lepidoptera gelechiidae in the new age of change
Journal of Integrative Agriculture, 2020Co-Authors: Silvia I RondonAbstract:Abstract Arthropods and pathogens constantly challenge potato Solanum tuberosum L. production. Scenarios of climate variation have increased the possibility of changes in pests' biological and ecological patterns by increasing or reducing overwintering length, changes in population growth rates, number of generations, crop-pest relationship, and therefore affecting their expansion. Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae) is one of the main pests affecting potatoes worldwide. Adults oviposit single or multiple eggs in leaves, stems, and tubers, while the larvae in immature stage mine leaves or burrows into tubers turning them unmarketable. Traditional control methods are effective in controlling P. operculella, but many factors determine the success of the control chosen. This review provides key highlights of current information available that could be used as a resource to fight this pest.
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sub lethal effects of beauveria bassiana balsamo on field populations of the potato tuberworm Phthorimaea operculella zeller in china
Journal of Integrative Agriculture, 2018Co-Authors: Huiguo Yuan, Zhongren Lei, Silvia I Rondon, Wu Shengyong, Yulin GaoAbstract:Abstract The potato tuberworm Phthorimaea operculella Zeller, is one of the most important potato pests worldwide including China. Several reports indicate that P. operculella could be controlled biologically by the use of beneficial fungus such as Beauveria bassiana (Bals.-Criv) Vuill. However, limited information is available under growing conditions in China. Thus, this study evaluated the sub-lethal effects of B. bassiana on the offspring of P. operculella by the age-stage, two-sex life table. First instar larva of P. operculella were treated with 1×107 conidia mL−1 of the fungus, and several biological parameters were evaluated. The fecundity, duration of the egg stage, all larval stages, pre-adult stage, and total pre-oviposition period, were significantly shorter than the control treatment. Offspring of treated parents, presented a net reproductive rate and mean generation time of 17.43 per day and 24.98 days, respectively, compared to 65.79 per day and 26.51 days for the untreated ones. This study provides basic information to help understanding the potential long-term effects of entomopathogenic fungi on P. operculella.
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potential of a strain of beauveria bassiana hypocreales cordycipitaceae for the control of the potato tuberworm Phthorimaea operculella zeller
International Journal of Pest Management, 2017Co-Authors: Huiguo Yuan, Zhongren Lei, Silvia I Rondon, Yulin GaoAbstract:The potato tuberworm, Phthorimaea operculella (Zeller), is one of the most important pests of potato, Solanum tuberosum L., worldwide. We evaluated six Beauveria bassiana strains with potential for...
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screening of iranian potato germplasm for resistance to the potato tuberworm Phthorimaea operculella lepidoptera gelechiidae
American Journal of Potato Research, 2013Co-Authors: Seyed Mozaffar Mansouri, Seyed Ali Asghar Fathi, Bahram Naseri, Jabraeil Razmjou, Gadir Nouriganbalani, Silvia I RondonAbstract:The potato tuberworm, Phthorimaea operculella (Zeller), is an important insect pest of potato, Solanum tuberosum L., both in storage and in the field. In this research, tubers of eight commercial potato cultivars and four Iranian selections with equal weight and dormancy were exposed to 10 pairs of adult P. operculella in a climate chamber set at 25 ± 1 °C, 65 ± 5 % RH and total darkness. In a free-choice situation, oviposition was lower on 397082–2, Khavaran and Morene compared to the other germplasm that were exposed to adults of P. operculella. Number of mines per tuber, length of mines per tuber, time of development of larvae, number of pre-pupae produced per tuber, weight of pre-pupae and number of eggs developed in ovaries per female were counted and/or measured on each commercial cultivar and selection. There were fewer and shorter mines on tubers of 397082–2, Khavaran and Morene compared to the other potato germplasm. The number of pre-pupae produced per tuber and the weight of pre-pupae were lower when P. operculella was reared on tubers of 397082–2, Khavaran and Morene. Also the development, survival and fecundity were lower when P. operculella was reared on those same germplasm. Flesh firmness was negatively correlated with larval survival (r 2 = 0.87); in addition, the percentage of starch and macronutrient composition was low on these three germplasm. Thus, tuber flesh firmness of these germplasm could delay larval penetration and lower establishment 397082–2, Khavaran and Morene showed promising traits that can be integral component of potato breeding for resistance to P. operculella and pest management programs.
Carlos Espinelcorreal - One of the best experts on this subject based on the ideXlab platform.
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experimental mixtures of Phthorimaea operculella granulovirus isolates provide high biological efficacy on both Phthorimaea operculella and tecia solanivora lepidoptera gelechiidae
Journal of Invertebrate Pathology, 2012Co-Authors: Carlos Espinelcorreal, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M Lopezferber, Xavier LeryAbstract: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/mm2 to 0.10 OB/mm2) more pathogenic than isolate Peru applied alone. In T. solanivora they were between 2.3 and 4.9-fold (from 12.29 OB/mm2 to 1.25 OB/mm2) 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.
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genetic and biological analysis of colombian Phthorimaea operculella granulovirus isolated from tecia solanivora lepidoptera gelechiidae
Applied and Environmental Microbiology, 2010Co-Authors: Carlos Espinelcorreal, Xavier Lery, Laura Villamizar, Juliana Gomez, Jean Louis Zeddam, Alba Marina Cotes, M LopezferberAbstract:Tecia solanivora (Lepidoptera: Gelechiidae) is an invasive potato pest of the north of South America that recently colonized zones where Phthorimaea operculella (Lepidoptera: Gelechiidae), a taxonomically related insect, was established. Nowadays, both species can be found in most areas in different proportions. The Phthorimaea operculella granulovirus (PhopGV) was found to efficiently control P. operculella and was used as a biopesticide in storage conditions. However, no appropriate biological control methods exist for T. solanivora, and the use of granulovirus isolates would provide a solution. The Colombian Corporation for Agricultural Research (CORPOICA) carried out several T. solanivora larva samplings in Colombia with the aim of finding potential isolates. Five geographical granulovirus isolates from T. solanivora (VG001, VG002, VG003, VG004, and VG005) were found, and molecular analysis by REN profiles shows three different genotypic variants in Colombia. Analysis of their genomes revealed their relatedness to PhopGV. Two isolates exhibited submolar bands in their REN patterns, suggesting a mixture of viral genotypes. These data were confirmed by PCR amplification and sequencing of particular regions of the viral genomes. Their biological activity was assayed on both hosts, T. solanivora and P. operculella. A significantly higher pathogenicity in both hosts was observed with isolates VG001 and VG005 than with isolate VG003 or a Peruvian isolate (from P. operculella) used as a reference in the bioassay. Based on their molecular and biological activity characteristics, VG001 and VG005 isolates should be selected for further analysis in order to establish their potential as biological control agents.