Guillermo Cabrera Walsh

Guillermo Cabrera Walsh
Fundación Para El Estudio De Especies Invasivas

PhD

About

55
Publications
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Introduction
My area of interest is ecology and management of invasive plants, especially in the orbit of biological control. I've also worked with semiochemicals of agricultural pests.

Publications

Publications (55)
Article
The aquatic macrophyte Cabomba caroliniana A. Gray is a major invasive weed in Australia and several other countries. A classical biological control program was initiated in Australia in 2003 and native range explorations in Argentina that year led to the discovery of the aquatic weevil Hydrotimetes natans Kolbe feeding on C. caroliniana, making it...
Article
A gall midge, Prodiplosis hirsuta Kolesik sp. nov., is described whose larvae feed on shoot tips of Jatropha gossypiifolia and Jatropha clavuligera in Paraguay and Bolivia. Morphology and the mitochondrial COI gene sequence of the new species are given. Field survey and preliminary no‐choice host specificity tests showed that the host plant range o...
Article
Exotic water primroses are aggressive invaders in both aquatic and riparian ecosystems worldwide. Water primrose [Ludwigia hexapetala (Hook. & Arn.) Zardini, Gu & P. H. Raven], floating primrose-willow [Ludwigia peploides (Kunth) P. H. Raven subsp. peploides], floating primrose-willow [Ludwigia peploides (Kunth) P. H. Raven subsp. montevidensis (Sp...
Article
Full-text available
Hedychium coronarium (Zingiberales: Zingiberaceae), native to the Himalayas and southern China, has become an environmental weed in many countries around the world. Reported in several provinces of Argentina, H. coronarium constitutes a serious environmental problem especially in the wetlands of natural areas of Misiones Province, such as the Iguaz...
Article
Full-text available
Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of t...
Article
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The genus Diabrotica has over 400 described species, the majority of them neotropical. However, only three species of neotropical Diabrotica are considered agricultural pests: D. speciosa, D. balteata, and D. viridula. D. speciosa and D. balteata are polyphagous both as adults and during the larval stage. D. viridula are stenophagous during the lar...
Article
The host range of the thrips Liothrips ludwigi was investigated using single- and multi-generational no-choice nymphal development and oviposition tests. Development, oviposition, and egg viability were quantified when L. ludwigi were fed three exotic Ludwigia species and seven USA native plant species. Liothrips ludwigi completed development and o...
Article
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The leaf-mining fly Hydrellia egeriae Rodrigues-Junior (Diptera: Ephydridae) was evaluated under quarantine conditions as a candidate biological control agent of the invasive aquatic weed Egeria densa Planchon (Hydrocharitaceae) in California, U.S.A. The objective of this study was to test the fly’s feeding preference for E. densa as compared to th...
Poster
During the last hundred years, plants from Argentina (e.g. water hyacinth and alligator weed) have been accidentally or deliberately transported to other countries where they became invasive weeds. In 1962, the Agriculture Research Service (ARS) of the United States Department of Agriculture established the South American Biological Control Laborat...
Poster
Cuernavaca longula is a phloem‐feeding insect associated with the aquatic invasive weed Eichhornia crassipes, and is distributed in South America from Peru to Northern Argentina. It was studied and proposed as a potential biocontrol agent demonstrating its host affinity to water hyacinth through host specificity and damage studies. However, the com...
Article
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Vector control has been the most effective preventive measure against malaria and other vector-borne diseases. However, due to concerns such as insecticide resistance and budget shortfalls, an integrated control approach will be required to ensure sustainable, long-term effectiveness. An integrated management strategy should entail some aspects of...
Article
Full-text available
Classical biological control –or biocontrol- is a form of pest management comprising the release of specialized natural enemies (biocontrol agents) of an exotic pest. Classical biocontrol agents are scientifically selected from among the natural enemies the pest has in its native region. However biological control is firmly resisted in many countri...
Article
Full-text available
Saltcedars are woody plants in the genus Tamarix L. (Caryophyllales: Tamaricaceae) and are native to Eurasia and Africa. Several species have become invasive in the Americas, Australia and South Africa. In Argentina there are four species of Tamarix distributed in arid, semi-arid and coastal areas of most provinces. The taxonomic isolation of Tamar...
Article
Hydrocotyle ranunculoides (Araliaceae) is an aquatic plant native to the Americas and invasive in Europe. This work reports laboratory and garden studies on the host range of its main natural enemy, the weevil Listronotus elongatus (Hustache) (Coleoptera: Curculionidae). The genus Hydrocotyle is in a disputed phylogenetic situation such that both A...
Article
Descriptions of the immature stages of the planthopper Lepidelphax pistiae Remes Lenicov (Fulgoromorpha), a specialist herbivore of Pistia stratiotes L. (Alismatales) from Argentina, are provided for the first time. P. stratiotes, or water lettuce, is an important weed in fresh water bodies of the tropics and subtropics. Newly emerged nymphs from e...
Article
Pistia stratiotes L. (Araceae) is an important weed in many waterways worldwide. The South American weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) and the planthopper Lepidelphax pistiae Remes Lenicov (Hemiptera: Delphacidae) are specific herbivores of P. stratiotes. Both species, plus the oligophagous moth Samea multiplicalis Gu...
Article
Full-text available
The South American water primroses, Ludwigia grandiflora (Michx.) Greuter & Burdet, L. grandiflora subsp. hexapetala (Hook. & Arn.) G.L. Nesom & Kartesz, Ludwigia peploides (Kunth) P.H. Raven, and L. p. subsp. montevidensis (Spreng.) P.H. Raven (Onagraceae, Section Oligospermum), have become invasive in several watersheds of the United States and E...
Article
Full-text available
A two-component pheromone, (3S,6S,7R,10S)- and (3S,6S,7R,10R)-10,11-epoxy-1-bisabolen-3-ol (murgantiol), present in emissions from adult male harlequin bugs, Murgantia histrionica, is most attractive in field bioassays to adults and nymphs in the naturally occurring ratio of ca. 1.4:1. Each of the two individual synthetic stereoisomers is highly at...
Article
Pistia stratiotes L. (Araceae) is an important weed in many waterways around the world. The South American weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae) is a successful biocontrol agent for this weed but additional agents are needed for some areas. The planthopper Lepidelphax pistiae Remes Lenicov (Hemiptera: Delphacidae) is a s...
Article
Full-text available
The reported male-produced aggregation pheromone of the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), identified as a mixture of (3S,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol and (3R,6S,7R,10S)-10,11-epoxy-1-bisabolen-3-ol, offers new opportunities for its management. We found that black pyramid traps deployed along...
Article
Full-text available
Cucurbitacin-rich extracts are phagostimulants for both male and female Luperini, but field trials reveal that males are far more attracted to them than females. The sex ratio and number of beetles killed by an application of cucurbitacin-based toxic baits was assessed at two different scales: small areas of 100 m2, and a larger area of 10,000 m2....
Article
Full-text available
The delphacid Lepidelphax pistiae was found on water lettuce in Argentina. Nymphs and adults did not survive past seven days on 29 species of test plants, and no progeny were produced. In contrast, survival and reproduction were high on water lettuce. Results suggest that L. pistiae is monospecific to water lettuce.
Article
Cucurbitacins are plant defensive chemicals that attract many species of adapted insect herbivores such as luperine leaf beetles, and they have been employed in traps and toxic baits. Male and female beetles feed avidly on baits containing these compounds, but field trials have revealed that males find them far more attractive than females. A wind-...
Article
A new delphacid genus and species from Argentina, Lepidelphax pistiae Remes Lenicov, gen. et sp. nov.(Hemiptera: Fulgoromorpha: Delphacidae: Delphacini), is described and illustrated, and biological, distribution and experimental host range data are provided. Males of the new genus are easily distinguished from all other Neotropical Delphacini by b...
Article
Hydrocotyle ranunculoides is a perennial macrophyte that forms dense interwoven mats on stagnant or slow moving waters. It is native to the Americas, but has become invasive in many countries. Its rapid and thick growth can block watercourses interfering with their economic and ecological functions. The ecology of H. ranunculoides and of some of it...
Article
Background Diabrotica speciosa (Germar) is an important pest in South America. Both the adults and the larvae are polyphagous, and its most susceptible host is maize. Factors behind the appearance of adults in the field and geographical variations in voltinism are unknown. This hinders the chances of implementing rational control strategies. Result...
Article
Full-text available
Taosa longula Remes Lenicov (Hemiptera: Dictyopharidae), a planthopper native to South America, is a candidate for the biological control of water hyacinth, Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae), a serious weed worldwide. Biological control requires agents that are not only specific but also effective. Damage caused by sap-suc...
Article
Full-text available
Egeria densa (Hydrocharitaceae) is a submerged macrophyte from South America that is a weed in several countries. It crowds out native plants and hinders water use, causing economic and environmental damage. The leafminer fly Hydrellia sp. 1 (Diptera: Ephydridae), was found feeding in E. densa throughout its Argentine distribution, and is currently...
Article
Full-text available
Taosa longula Remes Lenicov (Hemiptera: Dictyopharidae) is a planthopper from the South American tropics that feeds on water hyacinth, Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae). The biology of T. longula was studied in the laboratory and field to evaluate it as a potential biological control agent for this widespread aquatic weed....
Article
Full-text available
Cabomba caroliniana, otherwise known as cabomba, is a submerged, rooted macrophyte with heavily dissected leaves that produces flowers that extend above the water surface. It has been disseminated around the world by aquarium traders and enthusiasts, and has become a noxious weed in numerous countries, including Australia, where it often produces d...
Article
The new species Diabrotica collicola Cabrera & Cabrera Walsh is described and illustrated based on specimens collected from Balcozna, Catamarca Province (Argentina). A full description is provided and includes adding morphological characters of the mouthparts, hind wing venation, binding patch, metendosternite, and details of male and female genita...
Article
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Chaenusa aurantium Kula and Martinez, new species and Chaenusa steineri Kula, new species, both from the Neotropical Region, are described. The former species was reared from an undescribed species of Hydrellia Robineau-Desvoidy (Diptera: Ephydridae) in Argentina under evaluation for control of Egeria densa (Planch.) (Alismatales: Hydrocharitaceae)...
Article
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Hydrelliaeucoila egeria (Hymenoptera: Cynipoidea: Figitidae), a new genus and species obtained from pupae of Hydrellia sp. (Diptera: Ephydridae) mining in Egeria densa Planchon (Hydrocharitaceae), is described. Diagnostic photographs and data about the biology of this parasitoid are included.
Article
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Brazilian peppertree (Schinus terebinthifolius Raddi, Anacardiaceae) is a perennial tree native to Argentina, Brazil, and Paraguay. The plant was introduced into the USA before 1900. Originally grown as an ornamental, Brazilian peppertree is now considered an noxious plant in Hawaii and Florida, where it is ranked among the most important threats t...
Article
The species composition and abundance of coprophilous predatory Staphylinidae in two sites of temperate and subtropical Argentina are presented and discussed in terms of their hypothetical effect on the dung breeding fly community. Specimens of Staphylinidae were collected from cow manure by flotation. Dung breeding fly puparia were also collected...
Article
Full-text available
Diabroticina is a speciose subtribe of New World Chrysomelidae (Subfamily Galerucinae: Tribe Luperini) that includes pests such as corn rootworms, cucumber beetles and bean leaf beetles (e.g. Diabrotica, Acalymma, Cerotoma species). The evolution and spread of pesticide resistance, the European invasion of Diabrotica v. virgifera LeConte, and possi...
Article
A reliable marking technique was needed for a mark-release-recapture experiment with adults of Diabrotica speciosa (Germar). Four marking techniques, acrylic paint (spattered or brushed on the surface of the insect); and fluorescent pigments (dusted on surfaces or mixed with diet to produce an ingested marker), were tested. Fluorescent pigment dura...
Article
Toxic baits and traps for Diabroticina, based on bitter cucurbit extracts, have been utilized for a number of years with inconsistent results. Four species of bitter Cucurbitaceae were compared in the field for their attractancy to species of Diabroticina in Argentina and the United States. The comparisons were made with polyester fabrics treated w...
Article
Full-text available
The subtribe Diabroticina is a large group of New World Chrysomelidae that includes corn rootworms, cucumber beetles and other pests. Recent introductions of Diabrotica virgifera virgifera LeConte into Europe, and the development of resistances to current management practices of rootworms in the USA have increased interest in new sustainable option...
Article
Full-text available
Cabomba caroliniana is a submerged aquatic plant from South America that is becoming a serious weed worldwide. It spreads by seed and by fragmentation and has an extremely wide climatic range, invading lakes and ponds from tropical (Darwin, Australia: latitude 12°) to cold temperate regions (Peterborough, Canada: latitude 45°). There are currently...
Article
The new species Diabrotica calchaqui Cabrera Walsh is described and illustrated based on specimens collected from Cachi, Salta Province, Argentina. This new species is assigned to the Diabrotica virgifera group, subtribe Diabroticina, tribe Luperini. D. calchaqui is recognized by the combined characters of elytra green with yellow vittae in some sp...
Article
The genus Diabrotica (Coleoptera: Chrysomelidae) includes a great number of pest species, including some of the most important crops pests of the Americas. However, only five parasitoid species have been recorded for it. The parasitoid Celatoria bosqi Blanchard was the first parasitoid described from Diabrotica spp. in South America, where substant...
Article
The genus Diabrotica includes a large number of pest species, including some of the most important crop pests of the Americas. The parasitoid Centistes gasseni Shaw is the first braconid to be described parasitizing Diabrotica in South America, and high natural infestations are reported. Field and experimental observations on the host range, distri...
Article
The reproductive biology, and larval and adult host range of Diabrotica speciosa (Germar), Diabrotica viridula (F.), Acalymma spp. (Coleoptera: Chrysomelidae: Galerucinae), and other Diabroticina are described. These Diabroticina are pests of several crops in South and Central America. The adult feeding hosts were compared, among species, and withi...
Article
The species composition and abundance of coprophilous predatory Staphylinidae in two sites of temperate and subtropical Argentina are presented and discussed in terms of their hypothetical effect on the dung breeding fly community. Specimens of Staphylinidae were collected from cow manure by flotation. Dung breeding fly puparia were also collected...
Article
Dung-inhabiting pest flies are one of the main problems associated with the accumulation of cattle dung. This work analyzes the diversity and dynamics of a coprophilous community from northern Buenos Aires, Argentina, in a search for potential biocontrol agents. Thirty-six dung pads of 3 age categories and 4 microhabitats were collected on each sam...
Article
Cattle dung accumulation presents problems of pasture fouling, nutrient loss, intestinal parasitosis, and pest fly development. These problems have been confronted, with variable success, with the introduction of coprophagous scarabs (Coleoptera: Scarabaeidae). This work reports the results of field collections and laboratory culture of immature an...
Article
Paracoprid scarabs (Scarabaeidae: Scarabaeinae) dig tunnels under or near various animals droppings, portions of which the beetles store to feed on or use to build nests for their larvae. These nests have been classified into 3 main patterns, based mainly on the structure of the nest, egg cell, and the existence of parental care. Pattern I nests ar...
Article
Full-text available
Paraganaspis egeria, a new genus and species obtained from pupae of Sarcophagula occidua (F.) (Diptera: Sarcophagidae) is described. Diagnostic figures and a brief description of the biology of this parasitoid are included.

Projects

Projects (4)
Project
Our project has three main goals: 1) Investigate the feasibility of biological control of invasive Ludwigia spp. in the USA. 2) In collaboration with colleagues from FuEDEI (Argentina) and INIA (Uruguay), import potential biological control agents into our Quarantine in Albany, CA, where we will rear, study the biology, and conduct host-range tests. 3) Establish collaborations to help us acquire non-target (native) plants to use in the host-range trials.
Project
Ludwigia grandiflora, L.g.subsp. hexapetala and L.peploides are native in Argentina and have 17-20 spp of associated insects species. The objectives are: 1-Found insect species associated with L.g.hexapetala. 2-Select potential candidates for biocontrol, study and test them. 3- Morphological and cytological taxonomy of the host plant and related species in Ludwigia genus.