The whole genome sequence of a begomovirus (family Geminiviridae) infecting Muntingia calabura L.... more The whole genome sequence of a begomovirus (family Geminiviridae) infecting Muntingia calabura L. (family Muntingiaceae) from the province of Guayas in Ecuador was determined in this work. The major symptom observed on this plant species was yellow spots on leaves. The nucleotide sequences of three DNA-A clones and one DNA-B clone were compared to those of other begomoviruses. The DNA-A clones displayed the highest similarity to isolates of pepper leafroll virus (PepLRV), with 87.4 to 88.1% sequence identity. Likewise, the DNA-B clone showed the highest similarity (79.3-79.6% sequence identity) to PepLRV isolates. According to the demarcation criteria for begomovirus species, the begomovirus described in this work, for which we propose the name "muntingia yellow spot virus", represents a novel species. To our best knowledge, this is the first report of a begomovirus infecting a plant of the family Muntingiaceae.
Liriomyza sativae una especie minadora de hojas notoriamente polífaga, constituye una de las prin... more Liriomyza sativae una especie minadora de hojas notoriamente polífaga, constituye una de las principales causas de aplicaciones de insecticidas en frijol, Phaseolus vulgaris en Ecuador. No obstante, asociadas a este insecto existen varias especies de parasitoides las cuales generalmente regulan sus poblaciones cuando no existe interferencia debido a las aplicaciones de insecticidas. Para evaluar la magnitud del control biológico natural por estos parasitoides se realizaron dos estudios en el Centro Experimental “El Misionero” Guayas, Ecuador. En uno se observó la fluctuación poblacional de L. sativae y la incidencia de sus parasitoides en una parcela sin insecticidas. En el otro se evaluaron los mismos factores en un experimento comparando dos tratamientos: 1. sin aplicaciones de insecticidas y 2. con aplicaciones semanales de una formulación comercial de lambda cihalotrina + tiametoxam. En ambos casos se observó la diversidad de los parasitoides asociados con este minador. En el pr...
Abstract We investigated the survival of Mediterranean fruit fly (Medfly) larval stages on yellow... more Abstract We investigated the survival of Mediterranean fruit fly (Medfly) larval stages on yellow peppers stored for 21 d in cold environments (1.5, 4 and 7 °C), and the differences in larval mortality rates of Medflies exposed to 1.5 °C storage environments between yellow and red peppers. In addition, we investigated the effect of packing yellow peppers and exposing them to cold environments for 21 d on the quality of the fruits. The aim of the study was to investigate packing and shipping post-harvest protocols as a preliminary investigation to explore cold environments as a system to assure the export of quality peppers with low risks of surviving Medfly immature stages. This exploratory study showed that storing yellow peppers for 21 d in lined boxes (20-μm-thick macroperforated Xtend film) at 1.5 and 4 °C protected the quality of the fruit, and precluded the survival of Medfly eggs and larval stages (L1, L2 and L3). In contrast, peppers stored at 7 °C for 21 d did not completely kill immature stages of the Medfly. In addition, the study showed that Medfly larval stages exposed to 1.5 °C environments on yellow and red peppers have different tolerances to cold. Sensitivity to cold in red pepper was higher than in yellow for all larval stages. In addition, sensitivity to cold between larval stages varied between yellow and red peppers: for yellow, sensitivity preceded as follows L1 > L2 > L3, while in red peppers it was L2 > L1 > L3. Abilities to accumulate lipids and protein by feeding Medfly larvae suggest that palatability and nutrition may be partially responsible for the differences in cold tolerance.
The Ethiopian fruit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae), is a significant pest of c... more The Ethiopian fruit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae), is a significant pest of cucurbit crops in Asia and Africa and is currently controlled with insecticides. The sterilizing effect of gamma radiation on D. ciliatus adults was investigated to assess the suitability of sterile insect technique (SIT) for use as an alternative, non‐chemical strategy for the control of this pest. Late pupae (48 h before emergence) were irradiated with 60, 80, 100, 120, and 140 Gy of gamma rays emitted by a 60Co source. Following emergence, the biological characteristics of the experimental cohorts (including all possible male‐female combinations of irradiated and untreated flies) were recorded. No significant negative effects of irradiation on pupal eclosion or the ability of newly emerged flies to fly were observed. Samples of eggs at reproductive fly‐ages (12‐, 15‐, and 17‐day‐old pairs) were collected and their hatch rates were assessed. At 60 Gy, females were completely sterilized, whereas complete sterilization of the males was observed only at 140 Gy (a small amount of fertility persisted even at 120 Gy). In addition to the above experiments, three fruit infestation trials were conducted with zucchini [Cucurbita pepo L. (Cucurbitaceae)] as the plant host and the pupae produced in those trials were collected and recorded. We observed significant (ca. 10%) infestation following treatment with up to 120 Gy and zero progeny only at 140 Gy, mirroring the egg‐hatch results. Our findings support the feasibility of SIT for the control of D. ciliatus.
Los cuerpos de agua se encuentran sometidos a la contaminacion natural y a la de origen antropico... more Los cuerpos de agua se encuentran sometidos a la contaminacion natural y a la de origen antropico, siendo esta ultima la causante de los principales efectos adversos. Es necesario diagnosticar las situaciones puntuales para detener o prevenir la contaminacion. Con el fin de determinar, la calidad del agua en algunos puntos del rio Pajan, Provincia de Manabi incluyendo donde esta instalada una planta de tratamiento biologico de aguas residuales (PTBAR), se realizo este estudio durante noviembre 2016 - enero 2017. Se efectuaron cuatro muestreos de insectos, asi como, analisis fisico - quimicos en los puntos: aguas arriba, aguas abajo y en la salida de la PTBAR. Con los insectos colectados se determinaron las familias y se calcularon los indices de IBF y BMWP para cada punto. Fueron colectados 3349 insectos, en 35 Familias dentro de diez Ordenes, siendo las familias mas abundantes, Chironomidae (Diptera) y Baetidae (Ephemeroptera) sin diferencias entre puntos de muestreos (P>0,05). ...
espanolEl psilido asiatico de los citricos, Diaphorina citri (Hemiptera: Liviidae), es una plaga ... more espanolEl psilido asiatico de los citricos, Diaphorina citri (Hemiptera: Liviidae), es una plaga nueva en Ecuador detectada en el ano 2013. Su importancia radica en que es vector de la bacteria Candidatus Liberibacter, causante del huanglongbing, una devastadora enfermedad en citricos. Durante el periodo octubre 2016-marzo 2017 se estudio, en condiciones de laboratorio, su ciclo biologico, supervivencia, fertilidad y estadisticos poblacionales (Ro: tasa neta reproductiva, Tg: tiempo generacional, y rm: tasa intrinseca de desarrollo poblacional) sobre la planta hospedera (Murraya paniculata L.). Se evaluaron dos tratamientos: T1, plantas a raiz desnuda en agua y T2, plantas sobre suelo como sustrato. Ambas condiciones de cria fueron comparadas mediante la prueba de Wilcoxon. La duracion de ciclo presento diferencias (P≤0,05) entre ambos tratamientos, con una amplitud de 16,0 a 16,7 dias. El resto de las variables no mostro diferencias (P>0,05) entre los tratamientos. La longevidad...
Background The insect vector of Huanglongbing, Diaphorina citri Kuwayama, 1908 (Hemiptera: Livida... more Background The insect vector of Huanglongbing, Diaphorina citri Kuwayama, 1908 (Hemiptera: Lividae) was detected in Ecuador in 2013 and its main parasitoid Tamarixia radiata (Waterston, 1922) (Hymenoptera: Eulophidae) was reported for the first time in 2017. In the citrus production region of Manabí province, Ecuador, D. citri and T. radiata were reported for the first time on Murraya paniculata L. in 2016 and 2018, respectively. D. citri was first found infesting Citrus x aurantiifolia (Christm.) Swingle in Manabí province at the end of 2018. The present study was conducted between August 2018 and May 2021 to: (1) monitor D. citri populations on M. paniculata and C. x aurantiifolia and determine the parasitism rates of T. radiata on D. citri nymphs on both host plants, (2) establish the occurrence of T. radiata parasitizing D. citri on C. x aurantiifolia, and (3) calculate a predictive model for estimating the number of parasitized nymphs on a planting lot of M. paniculata and a C....
As part of the development of a sterile insect technique (SIT) application for the Ethiopian frui... more As part of the development of a sterile insect technique (SIT) application for the Ethiopian fruit fly, Dacus ciliatus, we studied the mating behaviour of a laboratory‐adapted strain (a 4‐year‐old colony kept for more than 40 generations) and a wild population. Effects of laboratory rearing and irradiation were assessed by carrying out mating compatibility and male mating competitiveness tests using a 1:1 ratio between irradiated (120 Gy) laboratory males and non‐irradiated wild males. Mating behaviour was studied on host and non‐host plants under field cage conditions. To assess the effect of mass rearing upon male performance, we repeated the mating competitiveness test using non‐irradiated laboratory insects. The findings indicated a high degree of compatibility among the two populations and satisfactory competitiveness of the irradiated laboratory males (ca. 35%). The competitiveness of non‐irradiated laboratory males was also ca. 35%, suggesting that no adverse effects resulted from their irradiation. Mating occurred only at twilight and mainly on the underside of leaves of non‐host plants (lemon trees). Findings are discussed in view of their implications for a future application of SIT against this fruit fly pest.
En el control de plagas agrícolas, los insecticidas representan la principal alternativa disponib... more En el control de plagas agrícolas, los insecticidas representan la principal alternativa disponible. Para analizar la magnitud de su uso, se realizaron 539 entrevistas a agricultotes en los siguientes cultivos: Cucurbitaceae: melón, Cucumis melo L. y sandía, Citrullus lanatus (Thunb.), Fabaceae: frijol, Phaseolus vulgaris L., Solanaceae: papa, Solanum tuberosum L., pimiento, Capsicum annuum L. y tomate, Solanum lycopersicum L., ubicados en las provincias: Chimborazo, El Oro, Guayas, Loja y Santa Elena. Se recabó información sobre plagas importantes, tipo de manejo y si resultaba plaguicida químico, se consignaba: nombre genérico, ingrediente activo, toxicidad aguda, dosificación aplicada, frecuencia de aspersiones, períodos de carencia y mezclas de productos. El total de los entrevistados manifestó utilizar mezclas de insecticidas, generalmente elevando las dosificaciones recomendadas sin tomar en cuenta los periodos de carencia. Además, señalaron realizar 2,6; 1,1; 0,5; 2,0 y 2,8 a...
The whole genome sequence of a begomovirus (family Geminiviridae) infecting Muntingia calabura L.... more The whole genome sequence of a begomovirus (family Geminiviridae) infecting Muntingia calabura L. (family Muntingiaceae) from the province of Guayas in Ecuador was determined in this work. The major symptom observed on this plant species was yellow spots on leaves. The nucleotide sequences of three DNA-A clones and one DNA-B clone were compared to those of other begomoviruses. The DNA-A clones displayed the highest similarity to isolates of pepper leafroll virus (PepLRV), with 87.4 to 88.1% sequence identity. Likewise, the DNA-B clone showed the highest similarity (79.3-79.6% sequence identity) to PepLRV isolates. According to the demarcation criteria for begomovirus species, the begomovirus described in this work, for which we propose the name "muntingia yellow spot virus", represents a novel species. To our best knowledge, this is the first report of a begomovirus infecting a plant of the family Muntingiaceae.
Liriomyza sativae una especie minadora de hojas notoriamente polífaga, constituye una de las prin... more Liriomyza sativae una especie minadora de hojas notoriamente polífaga, constituye una de las principales causas de aplicaciones de insecticidas en frijol, Phaseolus vulgaris en Ecuador. No obstante, asociadas a este insecto existen varias especies de parasitoides las cuales generalmente regulan sus poblaciones cuando no existe interferencia debido a las aplicaciones de insecticidas. Para evaluar la magnitud del control biológico natural por estos parasitoides se realizaron dos estudios en el Centro Experimental “El Misionero” Guayas, Ecuador. En uno se observó la fluctuación poblacional de L. sativae y la incidencia de sus parasitoides en una parcela sin insecticidas. En el otro se evaluaron los mismos factores en un experimento comparando dos tratamientos: 1. sin aplicaciones de insecticidas y 2. con aplicaciones semanales de una formulación comercial de lambda cihalotrina + tiametoxam. En ambos casos se observó la diversidad de los parasitoides asociados con este minador. En el pr...
Abstract We investigated the survival of Mediterranean fruit fly (Medfly) larval stages on yellow... more Abstract We investigated the survival of Mediterranean fruit fly (Medfly) larval stages on yellow peppers stored for 21 d in cold environments (1.5, 4 and 7 °C), and the differences in larval mortality rates of Medflies exposed to 1.5 °C storage environments between yellow and red peppers. In addition, we investigated the effect of packing yellow peppers and exposing them to cold environments for 21 d on the quality of the fruits. The aim of the study was to investigate packing and shipping post-harvest protocols as a preliminary investigation to explore cold environments as a system to assure the export of quality peppers with low risks of surviving Medfly immature stages. This exploratory study showed that storing yellow peppers for 21 d in lined boxes (20-μm-thick macroperforated Xtend film) at 1.5 and 4 °C protected the quality of the fruit, and precluded the survival of Medfly eggs and larval stages (L1, L2 and L3). In contrast, peppers stored at 7 °C for 21 d did not completely kill immature stages of the Medfly. In addition, the study showed that Medfly larval stages exposed to 1.5 °C environments on yellow and red peppers have different tolerances to cold. Sensitivity to cold in red pepper was higher than in yellow for all larval stages. In addition, sensitivity to cold between larval stages varied between yellow and red peppers: for yellow, sensitivity preceded as follows L1 > L2 > L3, while in red peppers it was L2 > L1 > L3. Abilities to accumulate lipids and protein by feeding Medfly larvae suggest that palatability and nutrition may be partially responsible for the differences in cold tolerance.
The Ethiopian fruit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae), is a significant pest of c... more The Ethiopian fruit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae), is a significant pest of cucurbit crops in Asia and Africa and is currently controlled with insecticides. The sterilizing effect of gamma radiation on D. ciliatus adults was investigated to assess the suitability of sterile insect technique (SIT) for use as an alternative, non‐chemical strategy for the control of this pest. Late pupae (48 h before emergence) were irradiated with 60, 80, 100, 120, and 140 Gy of gamma rays emitted by a 60Co source. Following emergence, the biological characteristics of the experimental cohorts (including all possible male‐female combinations of irradiated and untreated flies) were recorded. No significant negative effects of irradiation on pupal eclosion or the ability of newly emerged flies to fly were observed. Samples of eggs at reproductive fly‐ages (12‐, 15‐, and 17‐day‐old pairs) were collected and their hatch rates were assessed. At 60 Gy, females were completely sterilized, whereas complete sterilization of the males was observed only at 140 Gy (a small amount of fertility persisted even at 120 Gy). In addition to the above experiments, three fruit infestation trials were conducted with zucchini [Cucurbita pepo L. (Cucurbitaceae)] as the plant host and the pupae produced in those trials were collected and recorded. We observed significant (ca. 10%) infestation following treatment with up to 120 Gy and zero progeny only at 140 Gy, mirroring the egg‐hatch results. Our findings support the feasibility of SIT for the control of D. ciliatus.
Los cuerpos de agua se encuentran sometidos a la contaminacion natural y a la de origen antropico... more Los cuerpos de agua se encuentran sometidos a la contaminacion natural y a la de origen antropico, siendo esta ultima la causante de los principales efectos adversos. Es necesario diagnosticar las situaciones puntuales para detener o prevenir la contaminacion. Con el fin de determinar, la calidad del agua en algunos puntos del rio Pajan, Provincia de Manabi incluyendo donde esta instalada una planta de tratamiento biologico de aguas residuales (PTBAR), se realizo este estudio durante noviembre 2016 - enero 2017. Se efectuaron cuatro muestreos de insectos, asi como, analisis fisico - quimicos en los puntos: aguas arriba, aguas abajo y en la salida de la PTBAR. Con los insectos colectados se determinaron las familias y se calcularon los indices de IBF y BMWP para cada punto. Fueron colectados 3349 insectos, en 35 Familias dentro de diez Ordenes, siendo las familias mas abundantes, Chironomidae (Diptera) y Baetidae (Ephemeroptera) sin diferencias entre puntos de muestreos (P>0,05). ...
espanolEl psilido asiatico de los citricos, Diaphorina citri (Hemiptera: Liviidae), es una plaga ... more espanolEl psilido asiatico de los citricos, Diaphorina citri (Hemiptera: Liviidae), es una plaga nueva en Ecuador detectada en el ano 2013. Su importancia radica en que es vector de la bacteria Candidatus Liberibacter, causante del huanglongbing, una devastadora enfermedad en citricos. Durante el periodo octubre 2016-marzo 2017 se estudio, en condiciones de laboratorio, su ciclo biologico, supervivencia, fertilidad y estadisticos poblacionales (Ro: tasa neta reproductiva, Tg: tiempo generacional, y rm: tasa intrinseca de desarrollo poblacional) sobre la planta hospedera (Murraya paniculata L.). Se evaluaron dos tratamientos: T1, plantas a raiz desnuda en agua y T2, plantas sobre suelo como sustrato. Ambas condiciones de cria fueron comparadas mediante la prueba de Wilcoxon. La duracion de ciclo presento diferencias (P≤0,05) entre ambos tratamientos, con una amplitud de 16,0 a 16,7 dias. El resto de las variables no mostro diferencias (P>0,05) entre los tratamientos. La longevidad...
Background The insect vector of Huanglongbing, Diaphorina citri Kuwayama, 1908 (Hemiptera: Livida... more Background The insect vector of Huanglongbing, Diaphorina citri Kuwayama, 1908 (Hemiptera: Lividae) was detected in Ecuador in 2013 and its main parasitoid Tamarixia radiata (Waterston, 1922) (Hymenoptera: Eulophidae) was reported for the first time in 2017. In the citrus production region of Manabí province, Ecuador, D. citri and T. radiata were reported for the first time on Murraya paniculata L. in 2016 and 2018, respectively. D. citri was first found infesting Citrus x aurantiifolia (Christm.) Swingle in Manabí province at the end of 2018. The present study was conducted between August 2018 and May 2021 to: (1) monitor D. citri populations on M. paniculata and C. x aurantiifolia and determine the parasitism rates of T. radiata on D. citri nymphs on both host plants, (2) establish the occurrence of T. radiata parasitizing D. citri on C. x aurantiifolia, and (3) calculate a predictive model for estimating the number of parasitized nymphs on a planting lot of M. paniculata and a C....
As part of the development of a sterile insect technique (SIT) application for the Ethiopian frui... more As part of the development of a sterile insect technique (SIT) application for the Ethiopian fruit fly, Dacus ciliatus, we studied the mating behaviour of a laboratory‐adapted strain (a 4‐year‐old colony kept for more than 40 generations) and a wild population. Effects of laboratory rearing and irradiation were assessed by carrying out mating compatibility and male mating competitiveness tests using a 1:1 ratio between irradiated (120 Gy) laboratory males and non‐irradiated wild males. Mating behaviour was studied on host and non‐host plants under field cage conditions. To assess the effect of mass rearing upon male performance, we repeated the mating competitiveness test using non‐irradiated laboratory insects. The findings indicated a high degree of compatibility among the two populations and satisfactory competitiveness of the irradiated laboratory males (ca. 35%). The competitiveness of non‐irradiated laboratory males was also ca. 35%, suggesting that no adverse effects resulted from their irradiation. Mating occurred only at twilight and mainly on the underside of leaves of non‐host plants (lemon trees). Findings are discussed in view of their implications for a future application of SIT against this fruit fly pest.
En el control de plagas agrícolas, los insecticidas representan la principal alternativa disponib... more En el control de plagas agrícolas, los insecticidas representan la principal alternativa disponible. Para analizar la magnitud de su uso, se realizaron 539 entrevistas a agricultotes en los siguientes cultivos: Cucurbitaceae: melón, Cucumis melo L. y sandía, Citrullus lanatus (Thunb.), Fabaceae: frijol, Phaseolus vulgaris L., Solanaceae: papa, Solanum tuberosum L., pimiento, Capsicum annuum L. y tomate, Solanum lycopersicum L., ubicados en las provincias: Chimborazo, El Oro, Guayas, Loja y Santa Elena. Se recabó información sobre plagas importantes, tipo de manejo y si resultaba plaguicida químico, se consignaba: nombre genérico, ingrediente activo, toxicidad aguda, dosificación aplicada, frecuencia de aspersiones, períodos de carencia y mezclas de productos. El total de los entrevistados manifestó utilizar mezclas de insecticidas, generalmente elevando las dosificaciones recomendadas sin tomar en cuenta los periodos de carencia. Además, señalaron realizar 2,6; 1,1; 0,5; 2,0 y 2,8 a...
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