The tawny crazy ant, Nylanderia fulva, has recently become one of the most notorious pests in southern US. One of the main goals of this project is to find the origin of invasive populations of the ant and to evaluate potential natural enemies to be used in biological control programs.

Nylanderia fulva recently invaded the US where it has become the dominant ant species in many ecosystems, displacing the native ants, as well as other invasive ants previously introduced such as the red imported fire ant Solenopsis invicta. Unfortunately, many control strategies typically used with other ants are not adequate for N. fulva.

In collaboration with scientists from Texas University A&M and the USDA, we are studying the biology of this ant, focusing on several lines of work: to determine the possible origin of the invasive populations in the US, to resolve the species status of N. fulva and find if it forms a species complex, possibly involving cryptic species, and to select genotypes of the decapitating phorid fly Pseudacteon convexicauda, a natural enemy found in Argentina, that is most suited to use in biological control of populations in the US.

Staff:
María Belén Fernández,Andrés Sánchez Restrepo,Luis Calcaterra

Cooperators:
Edward Vargo y Pierre-André Eyer, Universidad de Texas A & M
Viviana Confalonieri, GIFF, FCEN-UBA/CONICET
Christoph Bleidorn, Universidad de Göttingen.

HLB is a lethal disease produced by a bacterium of the Candidatus Liberibacter genus and transmitted by the psyllid Diaphorina citri that affects citrus, obstructing the transport of nutrients in the plant. The spread of the disease can be avoided by preventing its re-entry into the country and by biologically controlling populations of D. citri with its ectoparasitoid Tamarixia radiata.

Global citrus cultivation is currently threatened by the HLB. Argentina is the leading exporter of lemons and the eighth largest producer of citrus, generating an annual production of US$ 1,160 million and employing 250,000 workers.

HLB can be controlled with T. radiata, a parasitoid of D. citri. Both are established species in the country, while the phytosanitary condition of the bacteria is «Present Quarantine Pest» under official control. Genetic studies in Mexico have shown the presence of five mitochondrial haplotypes (COI) of T. radiata with different efficacy in their ability to reduce D. citri populations. So far, the haplotypes present in Argentina have not been determined; and only one mitochondrial haplotype for D. citri (COI) is known.

The objective is to genetically characterize the populations of T. radiata present in Argentina through the study of their population structure and correlation with the known population structure of the vector D. citri.

Staff:
Guillermo Logarzo, Nadia Jiménez

Collaborators:
Esteban Hasson, Daniel Poveda-Martinez; FCEyN, UBA
Juan Pedro Bouvet; EEA INTA Cooncordia
María Elena Schapovaloff, Alejandra Badaracco; EEA INTA Montecarlo
Máximo Raúl Alcides Aguirre; EEA INTA Bella Vista
Silvia Norma Tapia, EEA INTA Yuto

In search of a rational management of Citrus Variegated Chlorosis (CVC) disease in Argentina, we are conducting surveys of potential vectors (Hemiptera: Cicadellidae) of CVC in citrus agroecosystems of NOA and NEA, in order to select egg parasitoids for their biological control.

The Argentine citrus industry currently faces severe commercial limitations due to sanitary and environmental measures imposed by international markets. These limitations are given by the presence of quarantine pests, and the low levels of pesticide residue tolerance of importing countries. Through a Scientific and Technological Research Project (PICT-FONCyT) requested by FuEDEI and other national institutions (PROIMI-Conicet / FCNyM-UNLP / INTA), FuEDEI is participating in an integrated management plan for CVC. The aim of the project is to identify leafhoppers (Hemiptera: Cicadellidae: Proconiini, Cicadellini), potential CVC vectors, and select egg parasitoids (Hymenoptera) for their biological control in citrus agroecosystems of NOA and NEA.

Staff:
Guillermo Logarzo, Fernando Mc Kay, Laura Varone, Mariel Guala, María Belén Aguirre.

Cooperators:
Eduardo Virla (PROIMI-Conicet), Tucumán, Argentina.
Susana Paradell, Facultad de Ciencias Naturales y Museo, UNLP, La Plata, Buenos Aires, Argentina.
Pablo Cavigliasso, Dra. Ing. Agr. Beatriz Díaz, Ing. Agr. M. Sc. María Fernanda Rivadeneira, Jose Telayna y Mario Carmarán: INTA-Estación Experimental Agropecuaria Concordia, Entre Ríos.
Roxana Almonacid, Máximo Raúl Alcides Aguirre, Matías Rossoli y Sara Cáceres: INTA-Estación Experimental Agropecuaria Bella Vista, Corrientes.
Cristian Eric Stolar y Diana Oshashi: INTA-Estación Experimental Agropecuaria Cerro Azul, Misiones.

Hypogeococcus sp., a member of the H. pungens species complex “HCM”, is a serious pest of cacti in Puerto Rico, and a threat to cacti in the Caribbean, Mexico, and the United States. As the damage caused by this mealybug is extensive, a biological control program was initiated.

Hypogeococcus sp. nov. (Hemiptera: Pseudococcidae), an invasive species native to South America, is currently a pest of cacti in Puerto Rico. Initially, it was misidentified as H. pungens, whose host range includes species of the Cactaceae, Amaranthaceae, and Portulacaceae families. Studies on the biology, taxonomy, and genetics of this mealybug performed by FuEDEI, indicated that H. pungens is a complex of species, and that the Puerto Rican cacti pest is a new species restricted to Cactaceae. It was also found that the H. pungens complex is constituted by 4 species: H. pungens sensu stricto and 3 undescribed species.

In 2010, due to the extensive damage caused by this mealybug on native cacti in Puerto Rico, the United States Department of Agriculture (USDA) and FuEDEI initiated a biological control program. As part of this program, a survey of Hypogeococcus spp. and their natural enemies in South America was initiated. Two nymph parasitoids, Anagyrus cachamai Triapitsyn, Logarzo & Aguirre and A. lapachosus Triapitsyn, Aguirre & Logarzo (Hymenoptera: Encyrtidae), were selected as potential biological control agents. In 2017, both species were sent to the quarantine facility at the Center of Excellence for Quarantine and Invasive Species at University of Puerto Rico. Currently, specificity studies with A. cachamai and A. lapachosus are being conducted in their native range and in Puerto Rico.

Researchers:
Guillermo A. Logarzo, María Belén Aguirre, Daniel Poveda Martínez, Mariel Guala, María Violeta Tarrio.

Cooperators:
Hilda Díaz-Soltero, Caribbean Advisor to the APHIS Administrator, USDA, San Juan, Puerto Rico
Ron Weeks, USDA APHIS PPQ, Biological Control Program, Raleigh, NC.
Stephen Hight, Research Entomologist, USDA-ARS, Tallahassee, FL
Serguei Triapitsyn, Principal Museum Scientist and Quarantine Supervisor, Department of Entomology, University of California, Riverside
Lucía Claps, Instituto Superior de Entomología, Universidad de Tucumán, Argentina
Esteban Hasson, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires (UBA), Argentina
Octavio Bruzzone CONICET, INTA Bariloche, Río Negro.
Fabián Font, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires.
Marcelo Diniz Vitorino, Departamento de Engenharia Florestal, Programa de Pós-graduação em Engenharia Florestal – PPGEF. Lab. de Monitoramento e Proteção Florestal – LAMPF. Universidade Regional de Blumenau -FURB.

The little fire ant is a pest, not only in some places in its native range (Colombia and Brazil), but also in new invaded areas: Caribbean and Pacific Islands, Subtropical Atlantic Islands, the USA and West Africa.

Its presence has been associated with the reduction of the diversity of ants, the decrease of flying and arboreal insects, and the elimination of populations of arachnids, as well as attacks on native reptiles, birds and mammals. Currently, only toxic baits are used for its control. The only known natural enemy, a parasitoid micro-hymenopteran, was only found in the Caribbean islands, Costa Rica, Colombia, Ecuador, Venezuela, Guyana, and Suriname, and is therefore believed to be specific to the tropical lineage. Furthermore, its use has been questioned because it does not seem to control the abundance of the little fire ant and because of the damage caused to plant leaves that are used as oviposition substrates. Consequently, there is an immediate need to discover more effective agents or other factors that allow its control. The objectives of this project are (1) to focus the search for natural enemies in areas of greater genetic diversity of the subtropical-temperate lineage, (2) to determine if the two lineages are different cryptic species, and (3) to determine the main factors that determine its success as invader in its area of ​​introduction.

Staff:
Luis Calcaterra

Cooperators:
Steven Valles y David Oi, CMAVE, ARS-USDA; Viviana Confalonieri y Noelia Guzman, Grupo de Investigaciones en Filogenias Moleculares y Filogeografía (GIFF), FCEN-UBA/CONICET; Pablo Schilman e Ignacio Muñoz, Laboratorio de Ecofisiología de Insectos, FCEyN-UBA/CONICET; Lucila Chifflet, MACN Bernardino Rivadavia/CONICET.

The population density of fire ants in southern South America is several times lower than in the areas where they have been introduced: southern USA, Puerto Rico and California, Arizona and New Mexico. This species affects agriculture, wildlife and human populations, and causes a yearly 6-billion dollar damage in the US alone.

Over the past decade fire ants have become a global pest, with new introductions originating in the US that settled in Australia, Taiwan, mainland China, Mexico and the Caribbean islands. Parasitoids and pathogens from Argentina are being used to try to reduce their abundance in invaded sites to levels similar to those in South America. However, there are other factors, such as their higher competitive ability, that contribute to their success as invaders. The objectives of this project are (1) to continue with the release of pathogens and parasitoid flies from Argentina in the US, (2) to continue the search for new pathogens using genomic tools, (3) to study the evolution of the supergen (Gp-9) that determines that one species has one (monogyny) or more (polygyny) queens per colony in South American fire ants and (4) to perform a molecular phylogenetic analysis of parasitoid flies to understand the relationship between their species and delimit new cryptic species in order to select the most suitable genotypes for the control of each pest fire ant

Staff:
Luis Calcaterra
Andrés Sanches Restrepo

Cooperators:
R. Vander Meer, David Oi y Steven Valles, CMAVE, ARS-USDA; Dietrich Gotzek, Smithsonian Institution; DeWayne Shoemaker, Universidad de Tennessee, Marcos Pesquero, Universidad de Morrinhos, Brasil.

The use of gamma radiation in ants is currently an alternative that is being used to replace the use of conventional insecticides to control invasive and/or pest ants.

Low doses of ionizing radiation are used as a post-harvest treatment to control quarantine pests, such as invasive ants, in fresh agricultural products. The objectives of this project are (1) to determine the generic dose of radiation to sterilize the queens of the main invasive ants (for example, W. auropunctata, L. humile, S. invicta) that travel as stowaways in export products without affecting their quality and (2) to discover new chemical compounds produced by Poisson and Dufour glands with high repellency and/or toxicity in ants that coexist with invasive species in ant assemblies in southern South America to develop repellents and bioinsecticides against invasive and/or pest ants.

Staff:
Luis Calcaterra

Cooperators:
Peter Follett, ARS-Pacific Basin Agricultural Research Center, Hilo, Hawaii, EE.UU.
Chen, M. Grodowitz, ARS-BPRU, Stoneville, Mississipi, EE.UU.

Cactoblastis cactorum, the cactus moth, is native to South America and feeds on plants of the genus Opuntia. The larvae eat internal tissues gregariously, favoring secondary infections, exposing the plant to death. This pest threatens the unique diversity of cacti and the prickly pear industry, both in North America and Argentina.

The cactus moth was successfully used for the biological control of Opuntia spp. in Australia and South Africa, where no native cacti occur. It accidentally reached the United States, dispersing quickly, placing Mexico at risk.  Mexico possesses one of the greatest diversities of native cacti, and a large prickly pear based industry. This crop is widely used in arid areas as it has the advantage of not needing irrigation and has multiple uses (human food, fodder for livestock, soil stability, fence, wind protection). In Argentina, the cactus moth is the main pest of prickly pear plantations, causing heavy losses. Our research includes basic ecology studies of this pest, interaction with its host plants, and the damage it causes. We conduct searches for natural enemies; currently, we are mainly studying Apanteles opuntiarum, a specific parasitoid wasp, with great potential as a control agent. Genetic studies are being conducted to determine the dispersal pathways and population structuring of C. cactorum and its related species.

Staff:
Investigadora a cargo: Laura Varone
Personal técnico: Mariel Guala
Estudiantes de doctorado: Malena Fuentes Corona y Daniel Poveda Martínez

Cooperators:
Stephen Hight (USDA-ARS- CMAVE, Tallahassee, Florida, EE. UU.)
Mrittunjai Srivastava (Division of Plant Industry, Florida Department of Agriculture and Consumer Services, Gainesville, Florida).