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Varone L.,USDA ARS South American Biological Control Laboratory | Heraty J.M.,University of California at Riverside | Calcaterra L.A.,USDA ARS South American Biological Control Laboratory
Biological Control | Year: 2010

Parasitoid wasps of the genus Orasema Cameron have been considered as potential candidates for biological control of imported fire ants in the United States. Surveys were conducted for their occurrence in fire ant colonies across southern South America. In Argentina, 443 ant colonies were excavated at 57 sites and 11 positive sites were revisited to monitor the field persistence. In Paraguay, Bolivia and Uruguay, 288 colonies were examined in the field in 16 sites. Orasema simplex Heraty was the most abundant species, and found in 63.7% of the total parasitized colonies (n= 72). Orasema xanthopus (Cameron) and Orasema salebrosa Heraty were found at four sites in Argentina. In Bolivia, Orasema pireta Heraty was found at one site and parasitizing an unidentified Solenopsis species. Two new host species for Orasema were discovered, Solenopsis quinquecuspis Forel and Solenopsis macdonaghi Santschi. In addition, Orasema aenea Gahan was found parasitizing fire ants for the first time. The parasitoids persisted at 36.4% of the positive sites, most of them in rural habitats. © 2010.


Logarzo G.A.,USDA ARS South American Biological Control Laboratory | Zamar M.I.,National University of Jujuy | Richman D.,New Mexico State University | Bruzzone O.,CONICET
Florida Entomologist | Year: 2012

We examined plant used versus plant availability by a thysanopteran community on 13 woody and perennial native plants in the Chihuahua Desert. Individual plants were sampled with sticky-traps on 8 dates from May 1997 to August 1998. We sampled 5,040 adult thrips from 26 species in 19 genera, of which 16 could be identified to species. Four families were represented, Thripidae (17 species comprised 98.2 % of the collected specimens), Phlaeothripidae (5 species comprised 1.6%), Aeolothripidae (2 species comprised 0.1%) and Heterothripidae (1 species comprised 0.1%). A total of 16 species (84.2%) were phytophagous on flowers and leaves, 2 (10.5%) were predators, one (5.2%) was mycophagous. Feeding habits for 7 species are unknown. Thrips abundance was positively correlated with plant volume, but not with insect richness. Strikingly for a natural area, Frankliniella occidentalis accounted for 73.6% of the total collection of the sampled thrips, which together with Chirothrips falsus, Microcephalothrips abdominalis, Frankliniella gossypiana, and Neohydatothrips signifier, comprised 94.0% of the total number of collected thrips. Main abundances, considering all thrips species, occurred in fall and spring; no thrips were collected during winter. This seasonal pattern of occurrence was observed for the most abundant thrips species. In summary, the results of this study were: 1) few thrips species were found to be specialists; only 2 thrips species out of 12 studied, showed strong preference for host plants, 2) presence of a high percentage of positive associations, and a low percentage of negative associations, 3) the role of plant volume explained more than 80% of variance of thrips abundance. These results suggest that the studied thrips community has low plant specificity and the pattern of plant use observed could be the consequence of generalist feeding diets.


Martinez J.J.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Berta C.,National University of Tucuman | Varone L.,USDA ARS South American Biological Control Laboratory | Logarzo G.,USDA ARS South American Biological Control Laboratory | And 4 more authors.
Invertebrate Systematics | Year: 2012

The gregarious species of Apanteles that attack cactus-feeding phycitine moths (Lepidoptera:Pyralidae) from Argentina are identified using DNA barcodes and morphological data. Sequences of specimens from 10 different populations were generated. Corrected genetic divergences showed two clusters of specimens separated by COI divergences higher than 6%. Our morphological examinations were congruent with the molecular evidence and therefore two species were confidently identified: Apanteles alexanderi Brèthes and a new species, Apanteles opuntiarum Martínez & Berta, sp. nov., which we describe and illustrate. Despite these two taxa being considered to represent a single polyphagous species for at least 50 years, they can be easily distinguished by the length of their ovipositor sheaths. A key to the species of microgastrine parasitoids of cactus-feeding Lepidoptera in South America is provided. The recognition of the new species reveals a narrower host range for the species involved in this system, making it necessary to re-evaluate their potential as biocontrol agents of the prickly pear moth. © CSIRO 2012.


Paradell S.L.,National University of La Plata | Virla E.G.,CONICET | Logarzo G.A.,USDA ARS South American Biological Control Laboratory | Dellape G.,National University of La Plata
Journal of Insect Science | Year: 2012

The American tribe Proconiini (Hemiptera: Cicadellidae: Cicadellinae) is one of the largest groups of xylem-feeding insects and includes the majority of the known vectors of xylem-born phytopathogenic organisms. The significance of the pathogens that this group transmits gives them an important role as pests, mostly for citrus fruit, grapes, and almonds. Knowledge of these Hemiptera in Argentina is insufficient and fragmentary. Thus one of the aims of this paper is to summarize the available information of the Proconiini sharpshooters in Argentina. In addition, 14 species are mentioned for the first time in the country, and new distributional data are given for 18 species. Thirty-four new associations between sharpshooters and host plants are recorded. New records of egg parasitoids are given for Dechacona missionum, Molomea consolida, M. lineiceps, and Tapajosa similis.


Brooks C.P.,Mississippi State University | Ervin G.N.,Mississippi State University | Varone L.,USDA ARS South American Biological Control Laboratory | Logarzo G.A.,USDA ARS South American Biological Control Laboratory
Ecology | Year: 2012

Environmental niche models (ENMs) have gained enormous popularity as tools to investigate potential changes in species distributions resulting from climate change and species introductions. Despite recognition that species interactions can influence the dynamics of invasion spread, most implementations of ENMs focus on abiotic factors as the sole predictors of potential range limits. Implicit in this approach is the assumption that biotic interactions are relatively unimportant, either because of scaling issues, or because fundamental and realized niches are equivalent in a species' native range. When species are introduced into exotic landscapes, changes in biotic interactions relative to the native range can lead to occupation of different regions of niche space and apparent shifts in physiological tolerances. We use an escaped biological control organism, Cactoblastis cactorum (Berg.), to assess the role of the environmental envelope as compared with patterns of host-herbivore associations based on collections made in the native range. Because all nonnative populations are derived from a single C. cactorum ecotype, we hypothesize that biotic interactions associated with this ecotype are driving the species' invasion dynamics. Environmental niche models constructed from known native populations perform poorly in predicting nonnative distributions of this species, except where there is an overlap in niche space. In contrast, genetic isolation in the native range is concordant with the observed pattern of host use, and strong host association has been noted in nonnative landscapes. Our results support the hypothesis that the apparent shift in niche space from the native to the exotic ranges results from a shift in biotic interactions, and demonstrate the importance of considering biotic interactions in assessing the risk of future spread for species whose native range is highly constrained by biotic interactions. © 2012 by the Ecological Society of America.


Mc Kay F.,USDA ARS South American Biological Control Laboratory | Oleiro M.,USDA ARS South American Biological Control Laboratory | Fourie A.,Plant Protection Research Institute | Simelane D.,Plant Protection Research Institute
International Journal of Tropical Insect Science | Year: 2010

Exploratory field surveys of the natural enemies associated with balloon vine Cardiospermum grandiflorum Swartz, an environmental weed in South Africa, Australia and other countries, were conducted in northern Argentina from 2005 to 2009. The surveys included other plant species in the genus Cardiospermum and other native Sapindaceae, permitting an assessment of the distribution and host range of the natural enemies. Seventeen phytophagous insects in five orders and ten families, and two fungal pathogens were found. The nature of the potential agents' damage, their field distribution and abundance, and the results of preliminary host-specificity testing indicated that the seed-feeding weevil Cissoanthonomus tuberculipennis (Coleoptera: Curculionidae) and the fruit-galling midge Contarinia sp. (Diptera: Cecidomyiidae) were the most promising biological control agents for C. grandiflorum outside of its native range. Copyright © ICIPE 2010. This is a work of the US Government and is not subject to copyright protection in the United States.


Dellape G.,National University of La Plata | Logarzo G.A.,USDA ARS South American Biological Control Laboratory | Virla E.G.,PROIMI Biotecnologia | Paradell S.L.,National University of La Plata
Florida Entomologist | Year: 2011

Xylella fastidiosa is endemic to the Americas, it causes economically important diseases in a variety of different crops, and is transmitted by xylem-feeding sharpshooters. This paper provides new geographic records for Proconiini sharpshooters in South America which helps to better understand their distribution. To develop these new records, we examined material from 3 of the main entomological collections held in Argentina. As a result, 5 species are cited for the first time from Paraguay; 4 for Perú; 3 for Bolivia; 2 for Ecuador; and 1 each for Uruguay and Brazil. Some of the species could be vectors of X. fastidiosa because congeners of the species studied here are known to transmit this bacterium.


De Remes Lenicov A.M.M.,National University of La Plata | Hernandez M.C.,USDA ARS South American Biological Control Laboratory | Brentassi M.E.,National University of La Plata | Defea B.,National University of La Plata
Journal of Insect Science | Year: 2012

Descriptions of the immature stages of Taosa (Cuernavaca) longula Remes Lenicov (Hemiptera: Fulgoroidea: Dictyopharidae) and a key for their identification is provided for specimens collected on the water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Commelinales: Pontederiaceae), in northeastern Argentina and Peru. Newly emerged nymphs from eggs collected in the field were reared in rearing chambers, and each stage was fixed to microscopic examination and illustration. Fifth nymphal instars can be easily recognized from congeners by the brown marked pattern coloration, shorter vertex, and the distinguishable median carina along the frons. Information on behavior and developmental time is also included.

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