German Vargas

Dr. German Vargas

Entomological Society of America
+1

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 November 2022 in Neotropical Entomology
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Journal Article
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GVGerman Vargas
German Vargas
LRLeonardo F. Rivera-Pedroza
Leonardo F. Rivera-Pedroza
LGLuis Garcia
Luis Garcia
SJSimone Mundstock Jahnke
Simone Mundstock Jahnke

13 September 2017 in Neotropical Entomology
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Journal Article
Closed access
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GVGerman Vargas
German Vargas
LLL A Lastra
L A Lastra
GRG D Ramírez
G D Ramírez
MSM A Solís
M A Solís

10 January 2024 in Insects
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Journal Article
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LALivia M.S. Ataide
Livia M.S. Ataide
GVGerman Vargas
German Vargas
YVYisell Velazquez-Hernandez
Yisell Velazquez-Hernandez
IRIsamar Reyes-Arauz
Isamar Reyes-Arauz
PVPaola Villamarin
Paola Villamarin
ARAlexandra M Revynthi
Alexandra M Revynthi
In 2020, the invasive Thrips parvispinus (Karny) was first detected in Florida, United States. In response to the implemented regulatory restrictions, we conducted laboratory experiments under containment conditions. Thrips larvae and adults were exposed to 32 products (conventional and biorational insecticides) either directly or indirectly. Direct exposure was performed using a Spray Potter Tower, while indirect exposure was conducted by evaluating residue toxicity against the thrips. Water served as a control. We assessed mortality and leaf-feeding damage 48 h post-treatment. Among the conventional insecticides, chlorfenapyr, sulfoxaflor-spinetoram, and spinosad caused high mortality across all stages in both direct and residue toxicity assays. Pyridalyl, acetamiprid, tolfenpyrad, cyclaniliprole-flonicamid, acephate, novaluron, abamectin, cyantraniliprole, imidacloprid, cyclaniliprole, spirotetramat, and carbaryl displayed moderate toxicity, affecting at least two stages in either exposure route. Additionally, chlorfenapyr, spinosad, sulfoxaflor-spinetoram, pyridalyl, acetamiprid, cyclaniliprole, cyclaniliprole-flonicamid, abamectin, and acephate inhibited larvae and adult’s leaf-feeding damage in both direct and residue toxicity assays. Regarding biorational insecticides, mineral oil (3%) and sesame oil caused the highest mortality and lowest leaf-feeding damage. Greenhouse evaluations of spinosad, chlorfenapyr, sulfoxaflor-spinetoram, and pyridalyl are recommended. Also, a rotation program incorporating these products, while considering different modes of action, is advised for ornamental growers to avoid resistance and to comply with regulations.

5 September 2017 in PLOS ONE
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Journal Article
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GBGloria Barrera
Gloria Barrera
LVLaura Fernanda Villamizar
Laura Fernanda Villamizar
CECarlos Espinel
Carlos Espinel
EQEdgar Mauricio Quintero
Edgar Mauricio Quintero
MBMariano Nicolás Belaich
Mariano Nicolás Belaich
GVGerman Vargas
German Vargas
Diatraea spp. (Lepidoptera: Crambidae) are a group of insects that are agriculture pests in many economically relevant crops such as sugarcane, sorghum, corn and rice. Recognized species for this genus respond differentially to natural enemies used in their biological control, emphasizing the importance of species in a regional approach. Currently, identification is based on the male genitalia. However, the availability of specimens collected from field and subjectivity based on the character recognition can seriously hamper species identification, and therefore result in inadequate pest management. To overcome this, individuals of Diatraea spp. preliminarily classified male genitalia and obtained from reared conditions and the field (both derived from natural populations occurring in Colombia) were analyzed using genitalic morphometry and molecular biology specifically using a fragment of the cytochrome oxidase subunit II (CO II) mitochondrial gene. Although morphometric analysis did not show any overriding results regarding genitalia morphology, the bioinformatics analyses of CO II sequences resulted in an adequate classification of the individuals within the recognized species. It also, revealed that the occurrence of clades associated with geographical distribution may be associated with cryptic species. The latter was also confirmed by a Single-Strand Conformation Polymorphism (SSCP) methodology evaluating the same fragment of CO II. This experimental approach allows properly recognizing each species and in consequence is proposed as an effective tool in Diatraea species identification.

22 December 2021 in Insects
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Journal Article
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ARAlexandra M Revynthi
Alexandra M Revynthi
YVYisell Velazquez-Hernandez
Yisell Velazquez-Hernandez
MCMaria Canon
Maria Canon
AGA. Daniel Greene
A. Daniel Greene
GVGerman Vargas
German Vargas
CMCatharine M. Mannion
Catharine M. Mannion
Originating in northeastern Mexico and southern Texas, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell 1897, was discovered infesting China rose hibiscus (Hibiscus rosa-sinensis L.) in south Florida in May 2017. Although the biologies of the congeneric boll weevil, A. grandis Boheman 1843, and pepper weevil, A. eugenii Cano 1894 are well documented, no data are available regarding the biology of HBW. Here, we present a comprehensive study on the biology of this pest when reared at 10, 15, 27 and 34 °C and on different food sources. This weevil has three larval instars and its life cycle was completed only at 27 ± 1 °C. Weevil development was similar on an artificial diet when compared with a diet of hibiscus buds. Adult HBW could survive solely on pollen, but reproduction did not occur. Without water, HBW survived for ≈15 days; survival times reached nearly 30 days when water was accessible. Our results suggest that if left unmanaged, HBW has the potential to cause significant economic damage to the hibiscus industry. Given that a comprehensive understanding of a pest’s biology is critical for development of effective integrated pest management, our results provide a foundation for future research endeavors to mitigate the impact of this weevil in south Florida.

1 December 2017 in Florida Entomologist
Verified
Journal Article
Open access
VAViviana M. Aya
Viviana M. Aya
CEClaudia Echeverri
Claudia Echeverri
GBGloria Barrera
Gloria Barrera
GVGerman Vargas
German Vargas
Releases of the parasitoid Cotesia flavipes have been carried out since late 2014 in Colombia's Cauca River Valley to complement other biological control on sugarcane stem borers (Diatraea spp.). To confirm the identity of the species being released as well as those recovered in the field, including samples from the department of Santander in western Colombia, specimens were examined using a fragment of cytocrome oxydase I (COI). Results confirmed that the genetic identity of the specimens sequenced corresponded to C. flavipes, with a genetic divergence of 0.00 to 0.03 as compared with GenBank registers. In the Cauca River Valley, parasitoid distribution currently extends from La Virginia (Risaralda) to Palmira (Valle del Cauca), and is mainly associated to the geographical distribution of the new Diatraea species reported in the region, D. busckella and D. tabernella. Desde finales del año 2014 se ha venido liberando al parasitoide Cotesia flavipes en el valle del río Cauca de Colombia para complementar otros esfuerzos de control biológico de los barrenadores del tallo de la caña de azúcar (Diatraea spp.). Para confirmar la identidad tanto de los parasitoides que se han venido liberando como de aquellos recuperados en campo, incluso de aquellos provenientes del departamento de Santander al oeste de Colombia, se analizaron especímenes utilizando un fragmento de la citocromo oxidasa I (COI). Se confirmó que la identidad genética de los especímenes secuenciados corresponde a C. flavipes, con un estimativo de divergencia genética de 0.00 y 0.03 en comparación con los registros Genbank. En el valle del río Cauca la distribución del parasitoide se extiende actualmente entre La Virginia (Risaralda) y Palmira (Valle del Cauca), y es asociada principalmente a la distribución de las nuevas especies de Diatraea reportadas en la región, D. busckella y D. tabernella.