Erica Luft Albarracin

Diversity of Egg Parasitoids Attacking Dalbulus maidis (Hemiptera: Cicadellidae) Populations at Low and High Elevation Sites in Mexico and Argentina

ABSTRACT The corn leafhopper, Dalbulus maidis (DeLong & Wolcott), is one of the most important pests of maize in Latin America because of its efficiency as a vector of 3 species of plant pathogens. In spite of its significance, however, little is known about its egg parasitoids. In this study, we present new data on D. maidis egg parasitoids in Mexico and Argentina. We surveyed the egg parasitoids in 2 locations: Mexico and Argentina, representing the farthest expansion of the D. maidis populations from Mexico. Using maize plants with sentinel eggs, parasitoids were surveyed in central Mexico and northwestern Argentina, at both low (<1,000) and high (>1,000) elevation sites, during 2 maize-growing wet seasons. Parasitoids of the families Mymaridae and Trichogrammatidae were found in both countries. Argentinean sites showed the highest richness, with 10 species, whereas in Mexico we found 6 species. Also, the Shannon diversity index was 1.6 times greater in Argentina than in Mexico. Higher percentages of parasitized eggs were recorded at the low elevation sites in both Mexico and Argentina. Anagrus breviphragma Soyka, a generalist parasitoid, was the only species found attacking eggs of D. maidis in both Mexico and Argentina at both high and low elevations.

Egg Parasitoids of Dalbulus maidis (Hemiptera: Cicadellidae) in Jalisco State, Mexico

L., in Latin America (Nault1990), and causes great losses to corn crops be-cause of its capacity to transmit efficiently cornstunt spiroplasma (CSS), maize bushy stunt phy-toplasma (MBSP), and maize rayado fino virus(MRFV) (Nault & Ammar 1989).Egg parasitoids are the most important natu-ral enemies of leafhoppers (Freytag 1985). Theknown egg parasitoids of

A New Host Record for the Egg Parasitoid Anagrus nigriventris (Hymenoptera: Mymaridae) of the Corn Leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae)

Fil: Luft Albarracin, Erica Beatriz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina

Egg Parasitoids of the Leafhoppers Dalbulus maidis and Dalbulus elimatus (Hemiptera: Cicadellidae) in Two Maize Habitats

Maize plants with similar numbers of Dalbulus maidis (DeLong & Wolcott) and Dalbulus elimatus (Ball) (Hemiptera: Cicadellidae) eggs were exposed to egg parasitoids in seasonal and perennial maize habitats. Both leafhopper species were parasitized by Paracentrobia tapajosae Viggiani (Hymenoptera: Trichogrammatidae), Anagrus breviphragma Soyka (Hymenoptera: Mymaridae), Aphelinoidea semifuscipennis Girault (Hymenoptera: Trichogrammatidae), and Pseudoligosita longifrangiata (Viggiani) (Hymenoptera: Trichogrammatidae). All parasitoids that attacked D. elimatus eggs are reported for the first time. Both leafhopper species showed similar number of parasitized eggs and similar percentages of parasitism. The parasitoids reached the adult stage. The levels of parasitism varied among the 2 habitats; a higher level of parasitism was observed in the perennial maize habitat compared with the seasonal maize habitat. Plantas de maiz con similar numero de huevos de D . maidis y D. elimatus fueron expuestos a los parasitoides. Ambas especies de chicharritas fueron parasitadas por Paracentrobia tapajosae Viggiani (Hymenoptera: Trichogrammatidae), Anagrus breviphragma Soyka (Hymenoptera: Mymaridae), Aphelinoidea semifuscipennis (Hymenoptera: Trichogrammatidae) y Pseudoligosita longifrangiata (Viggiani) (Hymenoptera: Trichogrammatidae). Todas las especies de parasitoides que atacan a los huevos de D. elimatus son reportadas por primera vez. Ademas, en ambas especies de chicharritas se encontro un numero similar de huevos parasitados y porcentaje de parasitismo, y los parasitoides encontrados llegaron a su estado adulto. La tasa total de parasitismo depende del tipo de habitat; en el habitat donde se cultiva maiz todo el ano, una alta tasa de parasitismo fue encontrada, mientras que en el habitat con maiz estacional, la tasa de parasitismo fue baja. View this article in BioOne

Description and biological traits of a new species of Paracentrobia (Hymenoptera: Trichogrammatidae), an egg parasitoid of the sharpshooter Tapajosa rubromarginata (Hemiptera: Cicadellidae) in Argentina.

During a survey of egg parasitoids of sharpshooters (Cicadellidae: Cicadellini and Proconiini), an undescribed species of Paracentrobia Howard was detected. It is here described and illustrated, and laboratory data on its life cycle are reported. Paracentrobia tapajosae sp. n. is a primary parasitoid of Agalliana ensigera Oman and Tapajosa rubromarginata (Signoret). Sixty‐seven percent of the exposed host eggs were parasitized by P. tapajosae sp. n., and eggs with well‐developed sharpshooter embryos were successfully attacked. The developmental cycle from egg to adult was 21.3±2.3 days. Adult longevity was 6.8±4.5 days, with females living longer than males. The sex ratio, considering only mated females, was 1:2.2 (males/females). Under laboratory conditions, P. tapajosae is a facultatively gregarious parasitoid. Laboratory data suggest a likely potential of this species as a biological control agent. Durante la búsqueda de parasitoides de huevos de chicharritas (Cicadellidae: Cicadellini y Proconiini), se obtuvo una especie no descrita de Paracentrobia Howard, la cual se describe e ilustra en esta contribución aportando además datos sobre su ciclo de vida. Paracentrobia tapajosae sp. n. es un parasitoide primario de huevos de Agalliana ensigera Oman y Tapajosa rubromarginata (Signoret). La tasa de parasitoidismo obtenida en laboratorio fue del 67% de los huevos expuestos, y huevos en avanzado estado de desarrollo también fueron exitosamente atacados. El tiempo medio de desarrollo fue de 21,3±2,3 días. La longevidad de los adultos fue de 6,8±4,5 días, y las hembras vivieron más que los machos. La proporción de sexos, considerando solo hembras fecundadas, fue 1:2.2 (machos/hembras). En condiciones de laboratorio, P. tapajosae se comportó como facultativamente gregario. Los datos de laboratorio sugieren que esta especie tiene un buen potencial como agente de control biológico.

Host range of Gonatocerus sp. near tuberculifemur ‘Clade 1’ in Argentina, an egg parasitoid newly associated to the glassy-winged sharpshooter, Homalodisca vitripennis (Hemiptera: Cicadellidae), and candidate for its biological control in California, USA

The South American egg parasitoid Gonatocerus sp. near tuberculifemur “Clade 1” (G. sp. “Clade 1”) (Hymenoptera: Mymaridae) is a new association of the glassy-winged sharpshooter (GWSS), Homalodiscavitripennis (Germar) (Cicadellidae) and a candidate for its biological control in California, USA. In Argentina, G. sp. “Clade 1” was screened in the laboratory (no-choice tests) and in the field (multiple choice tests) against eggs of 32 Auchenorrhyncha host species and other four potential hosts unrelated to sharpshooters. In no-choice assays, it parasitized only eggs within the leafhopper tribe Proconiini. In contrast, in the long term field tests, it emerged not only from eggs of the Proconiini but also from two species of Cicadellini at low numbers (five wasps out of 698 exposed eggs). Two interpretations arise from the results: (1) Host associations of G. sp. “Clade 1” are restricted to the Proconiini whereas field parasitization of the Cicadellini species were false positive, or (2) G. sp. “Clade 1” parasitizes also some Cicadellini species and its rejection in the laboratory was a false negative. Both interpretations are discussed. Insect motivation could be the explanation for the negative results in the no-choice tests. On the other hand, in the more natural field situations, the host selection process and oviposition behavior should not have been affected and host range would be more realistic. The parasitism of the Cicadellini species would be indicative of a potential non-target effect on the sharpshooters in the USA.

Trichogramma (Hymenoptera: Trichogrammatidae) species, egg parasitoids of Diatraea saccharalis (Lepidoptera: Crambidae) on sugarcane (Poales: Poaceae) in Argentina.

Summary The aim of this study was to identify egg parasitoids of Diatrea saccharalis F., sensu Guenée (Lepidoptera: Crambidae) in sugarcane in Tucumán, Argentina. We report a new host—parasitoid association of Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) attacking D. saccharalis and the first record of Trichogramma galloi Zucchi from Argentina. Additionally, Trichogramma pretiosum Riley was recorded in this survey. Sumario El objetivo de este estudio fue identificar los parasitoides de huevos de Diatraea saccharalis F., sensu Guenée (Lepidoptera: Crambidae) en caña de azúcar en Tucumán, Argentina. Se reporta una nueva asociación hospedero parasitoide de Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) sobre D. saccharalis y es el primer registro de Trichogramma galloi Zucchi para Argentina. Además, se registró la presencia Trichogramma pretiosum Riley en este relevamiento.