34 research outputs found
New associations between Phasiinae (Diptera: Tachinidae) and Pentatomidae (Hemiptera: Heteroptera) phytophagous insects in the rolling pampa (Argentina) and description of Dallasimyia bosqi Blanchard male
Las relaciones entre parasitoides Phasiinae (Diptera: Tachinidae) y sus huéspedes Pentatomidae (Hemiptera: Heteroptera) son escasamente conocidas en la Argentina. Se presentan nuevas asociaciones hospedador-parasitoide en la pampa ondulada, y se describe por primera vez el macho adulto de Dallasimyia bosqi Blanchard. Se efectuaron muestreos quincenales de hemípteros adultos durante primavera-verano de 2005, 2006 y 2012 en áreas de vegetación espontánea y cultivos de trébol rojo y soja en campos de los partidos de La Plata, Magdalena y Chivilcoy (Buenos Aires). Los hemípteros capturados se criaron bajo condiciones controladas, los que tenían huevos de parasitoides pegados en el corion se mantuvieron hasta su muerte, y aquellos sin evidencia de parasitismo se mantuvieron hasta 25-30 días. Cada huésped muerto fue depositado en un recipiente con tierra húmeda y cubierto con una malla de nylon. Los parasitoides adultos emergidos fueron acondicionados para su identificación. Se registraron cinco nuevas asociaciones: E. meditabunda - Cilindromyia brasiliana y Homogenia sp., D. furcatus - Trichopoda argentinensis y Dallasimyia bosqi, y C. armigera - Trichopoda giacomellii, y la ya conocida N. viridula - Trichopoda giacomellii. Colecciones de referencia se encuentran depositadas en el Museo de La Plata, Argentina (MLP) y en el Museu de Zoologia da Universidade de São Paulo, Brasil (MZSP).The relationships between Phasiinae (Diptera:Tachinidae) parasitoid flies and their Pentatomidae (Hemiptera: Heteroptera) hosts are little known in Argentina. We present new host-parasitoid associations in the rolling pampa, and describe for the first time the adult male of Dallasimyia bosqi Blanchard. Adult Hemiptera were sampled biweekly during spring-summer 2005, 2006 and 2012 in areas of natural vegetation and crops of red clover and soybean, in fields in La Plata, Magdalena and Chivilcoy counties (Buenos Aires province). The Hemiptera were reared under controlled conditions; those with parasitoid macrotype eggs stuck on the corium were kept till death, and those with no signs of parasitism were kept for up to 25-30 days. Each dead host was placed in a container with damp soil and covered with a nylon mesh. The adult parasitoids emerged were conditioned for identification. Five new associations were recorded: E. meditabunda - Cilindromyia brasiliana (Townsend) and Homogenia sp., D. furcatus - Trichopoda argentinensis (Blanchard) and Dallasimyia bosqi, and C. armigera - Trichopoda giacomellii (Blanchard) as well as the already known N. viridula - Trichopoda giacomellii. Reference collections are deposited in the Museo de La Plata, Argentina (MCNLP) and in the Museu de Zoologia da Universidade de São Paulo, Brazil (MZSP).Centro de Estudios Parasitológicos y de Vectore
Numerical variations of Diaphorina citri Kuwayama (Sternorrhyncha: Psyllidae) and the Ectoparasitoid Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) in a orange grove of Entre Ríos, Argentina
Diaphorina citri es vector de la bacteria
que produce la enfermedad HLB en cítricos, una
de las más destructivas. En lotes comerciales
de naranja dulce en Entre Ríos se analizó
la abundancia espacio-temporal de adultos
de D. citri y del ectoparasitoide Tamarixia
radiata. Quincenalmente y durante tres años se
colectaron adultos en 10 trampas cromotrópicas
y los datos obtenidos fueron relacionados con el
porcentaje medio de brotación de otra plantación.
El número de D. citri/trampa/quincena se analizó
mediante Kruskal-wallis y prueba de Mantel y la
respuesta de agregación de T. radiata mediante
correlación. Ambas poblaciones exhibieron la
mayor abundancia el primer año: las frecuentes
aplicaciones de abamectina en el segundo y
tercero provocaron una marcada reducción.
Espacialmente, la diferencia numérica de D. citri
entre árboles no estuvo asociada a su cercanía
pero la correlación entre ellos fue significativa.
Temporalmente se evidenciaron cuatro picos
de abundancia: tres asociados a brotación
(invernal, primaveral y estival), y un cuarto no
asociado a brotación. La mayor abundancia
de T. radiata ocurrió en los árboles con mayor
abundancia de D. citri y hubo una significativa
correlación espacial entre ambas especies.
El enrollamiento anti-horario del gráfico entre
D. citri - T. radiata en árboles individuales
sugiere una interacción huésped- parasitoide,
estructurada como poblaciones locales.Diaphorina citri is a vector of the bacterium
that produces the HLB disease in citrus, one of
the most destructive. In commercial plantations
of sweet orange in Entre Ríos analyzed spatialtemporal
abundance of D. citri adults and the
ectoparasitoid Tamarixia radiata. Fortnightly and
in three successive years we collected adults
with 10 yellow sticky traps, and data were related
to the mean shooting percentage from another
plantation. The number of D. citri/trap/ fortnight
was analyzed by Kruskal-Wallis and the Mantel
test and the aggregation response of T. radiata
by correlation. Both populations exhibited
greater abundance in the first year: frequent
abamectine applications in the second and
third years produced a marked abundance
reduction. Spatially, D. citri dissimilarity between
trees was not associated with their distance, but
correlation between the number of D. citri/ trap
was significant. Chronologically D. citri exhibited
four peaks of abundance associated with
winter, spring and summer flush. The greater
T. radiata abundance occurred in those trees
with greater D. citri abundance, and both species
were spatially correlated. The anti clock-wise
spiraling in D. citri - T. radiata diagram in single
trees suggests a host- parasitoid interaction,
structured as local populations.Fil: Liljesthröm, Gerardo Gustavo.
Universidad Nacional de La PlataFil: Bouvet, Juan Pedro Raúl.
Instituto Nacional de Tecnología Agropecuaria (Argentina). Estación Experimental Agropecuaria Concordia
Cold-storage of Piezodorus guildinii (Hemiptera: Pentatomidae) eggs for rearing Telenomus podisi (Hymenoptera: Platygastridae)
Piezodorus guildinii (Hemiptera: Pentatomidae) is an important soybean pest, and one of its main natural enemies is Telenomus podisi (Hymenoptera: Platygastridae). Rearing of the parasitoid is constrained by the hosts' egg quality, which deteriorates after few generations in laboratory, therefore, cold-stored host eggs utilization could be a useful tool for augmentative biological control. Thus, the objective was to evaluate the quality of P. guildinii cold-stored eggs, on the performance of parental and F1 generation of T. podisi. Hosteggs 24 hour old were stored at -18°C for one (N= 53), two (N= 28) or three months (N= 29), and approximately 40 host eggs were offered to a T. podisi female per treatment, for 48 hours. The control treatment consisted of 24-hour-old non-frozen host eggs, obtained and kept at 24°C (N= 55). Parental generation parasitism and progeny´s emergence on frozen eggs was significantly lower than on non-frozen eggs, even for the shorter storage period. Male proportion and preimaginal development time of the progeny increased with freezing period. However, parasitism proportion caused by adults of F1, and emergence, male proportion, and preimaginal development time of F2 were not affected. Although the performance of T. podisi on frozen P. guildinii eggs was significantly lower than on nonfrozen ones, host eggs storage for up to two months allowed obtaining a parasitism rate of 40% with a high emergence rate. This could be helpful enough to maintain mass rearings, mainly during the host hibernation period, and to enhance field parasitism when host is scarce.Centro de Estudios Parasitológicos y de Vectore
Parasitismo de huevos de Piezodorus guildinii y Nezara viridula (Hemiptera: Pentatomidae) en soja, alfalfa y trébol rojo
Piezodorus guildinii Westwood and Nezara viridula (L.) (Hemiptera: Pentatomidae) are important soybean pests. P. guildinii causes more injury and is less susceptible to insecticides compared to N. viridula. N. viridula egg parasitoids are well studied; however, little is known about parasitoids of P. guildinii. Alfalfa, soybean and red clover were sampled during several seasons to characterize the abundance of both stink bugs, to determine their egg parasitoids, and to estimate parasitoids impact. In the field, Telenomus podisi (Ashmead),Trissolcus urichi (Crawford) and Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) emerged from P. guildinii, while only T. basalis (Wollaston) (Hymenoptera: Platygastridae) emerged from N. viridula. The proportions of parasitized eggs (i. e., the parasitoid impact) and egg masses, as well as the number of parasitized eggs/total number of eggs of the parasitized egg masses, were similar for alfalfa and soybean. Parasitism was not observed in red pclover. Parasitoid impact was lower during the dry growing seasons. Although P. guildinii field parasitism by T. urichi was less significant, laboratory experiments from the bibliography indicate that this wasp species performs well on this host. Trissolcus urichi would be an important biological control agent against P. guildinii, principally when the stink bug is more abundant.Piezodorus guildinii Westwoody Nezara viridula (L.) (Hemiptera: Pentatomidae) son importantes plagas en soja. P. guildinii causa mayores daños y es menos susceptible a los insecticidas. Los parasitoides oófagos de N. viridula fueron ampliamente estudiados, pero poco se conoce sobre los de P. guildinii. Se muestreó alfalfa, soja y trébol rojo durante varias temporadas para caracterizar la abundancia de ambas chinches, identificar sus parasitoides y estimar el impacto de los mismos. Telenomus podisi (Ashmead), Trissolcus urichi (Crawford) y Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) emergieron de P. guildinii, mientras que solo T. basalis (Wollaston) (Hymenoptera: Platygastridae) emergió de N. viridula. Las proporciones de huevos (impacto del parasitoide) y de posturas parasitadas, y el número de huevos parasitados/número total de huevos de las posturas parasitadas, fueron similares para alfalfa y soja. En trébol rojo no se registró parasitismo. El impacto del parasitoide fue menor durante las temporadas secas. Si bien el parasitismo de P. guildinii por T. urichi a campo fue poco significativo, los antecedentes de la bibliografía indican que su desempeño en el laboratorio sobre este hospedador es muy bueno. T. urichi podría ser un potencial agente de control biológico de P. guildinii, principalmente en situaciones de mayor abundancia de la chinche
Evaluation of <i>Mesocyclops annulatus</i> (Copepoda: Cyclopoidea) as a control agent of <i>Aedes aegypti</i> (Diptera: Culicidae) in Argentina
We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.Facultad de Ciencias Naturales y Muse
Parasitismo de huevos de Piezodorus guildinii y Nezara viridula (Hemiptera: Pentatomidae) en soja, alfalfa y trébol rojo
Piezodorus guildinii Westwood and
Nezara viridula (L.) (Hemiptera: Pentatomidae)
are important soybean pests. P. guildinii causes
more injury and is less susceptible to insecticides
compared to N. viridula. N. viridula egg parasitoids
are well studied; however, little is known about
parasitoids of P. guildinii. Alfalfa, soybean
and red clover were sampled during several
seasons to characterize the abundance of both
stink bugs, to determine their egg parasitoids,
and to estimate parasitoids impact. In the field,
Telenomus podisi (Ashmead),Trissolcus urichi
(Crawford) and Trissolcus basalis (Wollaston)
(Hymenoptera: Platygastridae) emerged from
P. guildinii, while only T. basalis (Wollaston)
(Hymenoptera: Platygastridae) emerged from
N. viridula. The proportions of parasitized eggs
(i. e., the parasitoid impact) and egg masses,
as well as the number of parasitized eggs/total
number of eggs of the parasitized egg masses,
were similar for alfalfa and soybean. Parasitism
was not observed in red pclover. Parasitoid
impact was lower during the dry growing
seasons. Although P. guildinii field parasitism
by T. urichi was less significant, laboratory
experiments from the bibliography indicate that
this wasp species performs well on this host.
Trissolcus urichi would be an important biological
control agent against P. guildinii, principally when
the stink bug is more abundant.Piezodorus guildinii Westwoody
Nezara viridula (L.) (Hemiptera: Pentatomidae)
son importantes plagas en soja. P. guildinii
causa mayores daños y es menos susceptible
a los insecticidas. Los parasitoides oófagos de
N. viridula fueron ampliamente estudiados, pero
poco se conoce sobre los de P. guildinii. Se
muestreó alfalfa, soja y trébol rojo durante varias
temporadas para caracterizar la abundancia de
ambas chinches, identificar sus parasitoides y
estimar el impacto de los mismos. Telenomus
podisi (Ashmead), Trissolcus urichi (Crawford)
y Trissolcus basalis (Wollaston) (Hymenoptera:
Platygastridae) emergieron de P. guildinii,
mientras que solo T. basalis (Wollaston)
(Hymenoptera: Platygastridae) emergió de
N. viridula. Las proporciones de huevos (impacto
del parasitoide) y de posturas parasitadas, y el
número de huevos parasitados/número total
de huevos de las posturas parasitadas, fueron
similares para alfalfa y soja. En trébol rojo no se
registró parasitismo. El impacto del parasitoide
fue menor durante las temporadas secas. Si
bien el parasitismo de P. guildinii por T. urichi a
campo fue poco significativo, los antecedentes
de la bibliografía indican que su desempeño en
el laboratorio sobre este hospedador es muy
bueno. T. urichi podría ser un potencial agente de
control biológico de P. guildinii, principalmente en
situaciones de mayor abundancia de la chinche.Fil: Cingolani, María Fernanda.
Universidad Nacional de La PlataFil: Greco, Nancy Mabel.
Universidad Nacional de La PlataFil: Liljesthröm, Gerardo Gustavo.
Universidad Nacional de La Plat
Life history traits and life table analysis of <i>Lobiopa insularis</i> (Coleoptera: Nitidulidae) fed on strawberry
Lobiopa insularis is a newly reported pest of strawberry in Argentina. We investigated characteristics of its biology in the laboratory, including survivorship and reproduction. We also estimated population growth for L. insularis fed ripe strawberry fruits. Lobiopa insularis was not observed ovipositing on strawberry fruits. A higher proportion of egg masses were recorded from a depth of 1 cm within the soil than on either the soil surface or deeper than 1cm (i.e. between 1and 2 cm) within the soil. The duration of preimaginal developmental stages represented ∼18.5% of the total life cycle, while the adult stage represented 81.5%. Survival from egg to adult was 64.20% and mean longevity of females and males adults was 121.84, (SE = 8.86) and 118.58 (SE = 5.90) days, respectively. Females laid eggs only when they were with a male, so reproductive period was dependent on male presence. The number of eggs/female/day was 18.01 (SE = 1.71); and total fecundity was 1655 (ES = 249.53) eggs/female. The long life span of adults and high reproductive output, i.e high fecundity and long reproductive period, indicate that availability and concentration of suitable developmental resources are important factors in the population dynamics of Lobiopa insularis associated with strawberry crops.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse
Cold-storage of Piezodorus guildinii (Hemiptera: Pentatomidae) eggs for rearing Telenomus podisi (Hymenoptera: Platygastridae)
Piezodorus guildinii (Hemiptera: Pentatomidae) is an important soybean pest, and one of its main natural enemies is Telenomus podisi (Hymenoptera: Platygastridae). Rearing of the parasitoid is constrained by the hosts' egg quality, which deteriorates after few generations in laboratory, therefore, cold-stored host eggs utilization could be a useful tool for augmentative biological control. Thus, the objective was to evaluate the quality of P. guildinii cold-stored eggs, on the performance of parental and F1 generation of T. podisi. Hosteggs 24 hour old were stored at -18°C for one (N= 53), two (N= 28) or three months (N= 29), and approximately 40 host eggs were offered to a T. podisi female per treatment, for 48 hours. The control treatment consisted of 24-hour-old non-frozen host eggs, obtained and kept at 24°C (N= 55). Parental generation parasitism and progeny´s emergence on frozen eggs was significantly lower than on non-frozen eggs, even for the shorter storage period. Male proportion and preimaginal development time of the progeny increased with freezing period. However, parasitism proportion caused by adults of F1, and emergence, male proportion, and preimaginal development time of F2 were not affected. Although the performance of T. podisi on frozen P. guildinii eggs was significantly lower than on nonfrozen ones, host eggs storage for up to two months allowed obtaining a parasitism rate of 40% with a high emergence rate. This could be helpful enough to maintain mass rearings, mainly during the host hibernation period, and to enhance field parasitism when host is scarce.Centro de Estudios Parasitológicos y de Vectore
Variaciones numéricas de Diaphorina citri Kuwayama (Sternorrhyncha: Psyllidae) y del Ectoparasitoide Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) en una plantación de naranjos de Entre Ríos, Argentina = Numerical variations of Diaphorina citri Kuwayama (Sternorrhyncha: Psyllidae) and the Ectoparasitoid Tamarixia radiata (Waterston) (Hymenoptera: Eulophidae) in a orange grove of Entre Ríos, Argentina
Diaphorina citri es vector de la bacteria que produce la enfermedad HLB en cítricos, una de las más destructivas. En lotes comerciales de naranja dulce en Entre Ríos se analizó la abundancia espacio-temporal de adultos de D. citri y del ectoparasitoide Tamarixia radiata. Quincenalmente y durante tres años se colectaron adultos en 10 trampas cromotrópicas y los datos obtenidos fueron relacionados con el porcentaje medio de brotación de otra plantación. El número de D. citri/trampa/quincena se analizó mediante Kruskal-wallis y prueba de Mantel y la respuesta de agregación de T. radiata mediante correlación. Ambas poblaciones exhibieron la mayor abundancia el primer año: las frecuentes aplicaciones de abamectina en el segundo y tercero provocaron una marcada reducción. Espacialmente, la diferencia numérica de D. citri entre árboles no estuvo asociada a su cercanía pero la correlación entre ellos fue significativa. Temporalmente se evidenciaron cuatro picos de abundancia: tres asociados a brotación (invernal, primaveral y estival), y un cuarto no asociado a brotación. La mayor abundancia de T. radiata ocurrió en los árboles con mayor abundancia de D. citri y hubo una significativa correlación espacial entre ambas especies. El enrollamiento anti-horario del gráfico entre D. citri - T. radiata en árboles individuales sugiere una interacción huésped- parasitoide, estructurada como poblaciones locales.Diaphorina citri is a vector of the bacterium that produces the HLB disease in citrus, one of the most destructive. In commercial plantations of sweet orange in Entre Ríos analyzed spatialtemporal abundance of D. citri adults and the ectoparasitoid Tamarixia radiata. Fortnightly and in three successive years we collected adults with 10 yellow sticky traps, and data were related to the mean shooting ercentage from another plantation. The number of D. citri/trap/ fortnight was analyzed by Kruskal-Wallis and the Mantel test and the aggregation response of T. radiata by correlation. Both populations xhibited greater abundance in the first year: frequent abamectine applications in the second and third years produced a marked abundance reduction. Spatially, D. citri dissimilarity between trees was not ssociated with their distance, but correlation between the number of D. citri/ trap was significant. Chronologically D. citri exhibited four peaks of abundance associated with winter, spring and summer flush. The greater T. radiata abundance occurred in those trees with greater D. citri abundance, and both species were spatially correlated. The anti clock-wise spiraling in D. citri - T. radiata diagram in single trees suggests a host- parasitoid interaction, structured as local populations.EEA ConcordiaFil: Liljesthrom, Gerardo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Bouvet, Juan Pedro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; Argentin
Life history traits and life table analysis of <i>Lobiopa insularis</i> (Coleoptera: Nitidulidae) fed on strawberry
Lobiopa insularis is a newly reported pest of strawberry in Argentina. We investigated characteristics of its biology in the laboratory, including survivorship and reproduction. We also estimated population growth for L. insularis fed ripe strawberry fruits. Lobiopa insularis was not observed ovipositing on strawberry fruits. A higher proportion of egg masses were recorded from a depth of 1 cm within the soil than on either the soil surface or deeper than 1cm (i.e. between 1and 2 cm) within the soil. The duration of preimaginal developmental stages represented ∼18.5% of the total life cycle, while the adult stage represented 81.5%. Survival from egg to adult was 64.20% and mean longevity of females and males adults was 121.84, (SE = 8.86) and 118.58 (SE = 5.90) days, respectively. Females laid eggs only when they were with a male, so reproductive period was dependent on male presence. The number of eggs/female/day was 18.01 (SE = 1.71); and total fecundity was 1655 (ES = 249.53) eggs/female. The long life span of adults and high reproductive output, i.e high fecundity and long reproductive period, indicate that availability and concentration of suitable developmental resources are important factors in the population dynamics of Lobiopa insularis associated with strawberry crops.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse