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stigmatias Loew Euxesta stigmatias Loew, 1868: 310. Causton et al. 2006: 135 [introduced species]. Distribution. Introduced. Nearctic, Neotropical; Galápagos: Floreana (ICCDRS), Isabela (ICCDRS), San Cristóbal, Santa Cruz, Seymour. Material examined. Galápagos: San Cristóbal: Cerro Mundo, guava thicket, 550 m, 13–23.ii.1989, Malaise, S.B. Peck & B.J. Sinclair (4 ♀, CNC). Santa Cruz: Los Gemelos, 600 m, Scalesia forest, 31.i.1989, B.J. Sinclair (3 ♀, CNC); El Cascajo, Finca Aguirre, 11.xi.2001, B.J. Sinclair (3 ♁, CNC). Seymour: MV-light, 23.i.1989, B.J. Sinclair (1 ♁, 2 ♀, CNC). Remarks. This species is known as the corn silk fly and was first recorded from the islands in the 1980s. It is known from the arid to humid zones. undetermined species Distribution. Not determined. Galápagos: San Cristóbal. Material examined. Galápagos: San Cristóbal: Casetta, 560 m, pampa, dung trap, 16–19.ii.1989, B.J. Sinclair (1 ♁, CNC); same data except, dry Scalesia, 400 m, 23.ii.1989 (1 ♀, CNC); Cerro Mundo, guava thicket, 550 m, 13–23.ii.1989, MT, S.B. Peck & B.J. Sinclair (1 ♀, CNC); Baquerizo, arid zone, 10 m, MT, 11–23.ii.1989, S. Peck (2 ♁, 5 ♀, CNC); same data except, 150 m, 12–13.ii.1989 (3 ♁, 2 ♀, CNC); 11.x.2001, A. Tye, ex. Calandrinia galapagosa (5 ♁, 1 ♀, ICCDRS). Remarks. Adults of this species were reared from stems of the rare plant Calandrinia galapagosa H. St. John., Published as part of Sinclair, Bradley J., 2023, An annotated checklist of the Diptera of the Galápagos Archipelago (Ecuador), pp. 1-102 in Zootaxa 5283 (1) on page 43, DOI: 10.11646/zootaxa.5283.1.1, http://zenodo.org/record/7912667, {"references":["Loew, H. (1868) Die amerikanischen Ulidina. Berliner Entomologische Zeitschrift, 11, 283 - 326. [1867] https: // doi. org / 10.1002 / mmnd. 18670110308","Causton, C. E., Peck, S. B., Sinclair, B. J., Roque-Albelo, L., Hodgson, C. J. & Landry, B. (2006) Alien insects: threats and implications for conservation of Galapagos Islands. Annals of Entomological Society of America, 99 (1), 121 - 143. https: // doi. org / 10.1603 / 0013 - 8746 (2006) 099 [0121: AITAIF] 2.0. CO; 2"]}

Fresh market sweet corn (Zea mays L., convar. saccharata var. rugosa, Poales: Poaceae) ears produced in Florida are damaged by the larvae of Euxesta stigmatias Loew, Euxesta eluta Loew, and Chaetopsis massyla Walker (Diptera: Ulidiidae) that renders ears unmarketable. No standard lure exists for monitoring these pests. Oviposition substrate and attractant bioassays were designed to identify attractive substrates for further semiochemical investigation. Frass from the fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), was more attractive than other ovipositional substrates tested for E. eluta and C. massyla, and resulted in greater ovipositional output. Tassel-derived armyworm frass was more attractive than leaf-derived frass for oviposition. Frass also resulted in greater oviposition output by two species. In attraction bioassays, frass was generally preferred over the corresponding corn tissue, and only C. massyla demonstrated a preference for silk-frass over tassel-frass. The most promising substrates were then evaluated by electroantennography (EAG) to quantify olfactory responses. Frass volatiles also elicited greater antennal responses than corn volatiles. With tassel-frass, greater amplitude EAG responses were recorded from immature E. eluta female antennae, while mature female E. stigmatias exhibited greater responses. Equivalent antennal response to silk-frass was observed from E. eluta. Overall, silk-frass elicited the greatest EAG responses among all three fly species. Our results indicate that armyworm frass is an important resource in the chemical ecology of corn-infesting silk flies, and this substrate warrants further investigation for potential attractants that may facilitate development of novel management tools for these pests.

The 'cornsilk fly,' Euxesta stigmatias Loew, is an attractive, dark metallic green fly with distinctive wing patterns and wing flapping behavior commonly found throughout southern Florida agricultural communities. Its normally saprophytic life style belies its destructive nature when it comes to its preference for sweet corn ears. Entire fields may have to be passed up for harvest if they went untreated for this destructive pest or if individual treatments were missed due to weather, time or other constraints. This document is EENY-224, one of a series of the Department of Entomology and Nematology, UF/IFAS Extension. Original publication date August 2001. Revised July 2005. EENY-224/IN381: Cornsilk Fly (suggested common name), Euxesta stigmatias Loew (Insecta: Diptera: Otitidae) (ufl.edu)

Florida sweet corn is intensively treated to prevent infestation from the corn-infesting picture-winged fly complex (hereafter referred to as silk flies, Diptera: Ulidiidae). Previous bioassays performed on Euxesta stigmatias Loew demonstrated some pyrethroids performed weakly, while others were more efficacious and with longer-lasting residual activity. Since the last published bioassays, new active ingredients have been made available, other species in the complex discovered, and label restrictions increased for some products. For these reasons, topical bioassays were performed on the three most common species to assess insecticide efficacy of current commercial products labeled for either silk fly or fall armyworm ( Spodoptera frugiperda (J.E. Smith), Lepidoptera: Noctuidae) control. Bioassays were conducted using formulated product mixed in water and applied using a Generation III Research Spray Booth. The median lethal concentration ratio (LC 50 ) of beta-cyfluthrin with and without the pyrethroid synergist piperonyl butoxide was investigated. Acetamiprid, chlorantraniliprole, carbaryl, and flubendiamide did not result in high mortality to any species tested. Euxesta eluta Loew was susceptible to all other insecticides tested, and exhibited the lowest LC 50 to beta-cyfluthrin. Both Chaetopsis massyla Walker and E. stigmatias recovered from several pyrethroid treatments. Euxesta stigmatias also had the highest beta-cyfluthrin LC 50 , and piperonyl butoxide restored beta-cyfluthrin efficacy and lowered the LC 50 s of all three species.

Injury caused by picture-winged flies or corn silk flies (Diptera: Ulidiidae) is a major limiting factor of corn (Zea mays L.: Poales: Poaceae) yields in Florida. Growers have relied heavily on chemical insecticides for control of these pests. However, we are exploring other methods, such as the use of biological control by predatory arthropods, which may be factors in an integrated pest management (IPM) program. Thus, information on the distribution of the flies and their predators and responses of the predators to the flies is potentially useful. Taylor's Power Law, Iwao's Patchiness Regression, and the Index of Dispersion were used to study distribution patterns of arthropods found on sweet corn ears in 2010. Arthropod groups included eggs and larvae of Euxesta stigmatias (Loew), E. eluta (Loew), E. annonae F. (Diptera: Ulidiidae), nymphs and adults of Orius insidiosus (Say) (Hemiptera: Anthocoridae), and larvae of Anotylus insignitus (Gravenhorst) (Coleoptera: Staphylinidae). In each season i...

Since the 1960s, the USA has led all other countries in the production of sweet corn (Zea mays L.), and Florida has often led the nation, such as from 2004 to 2009. Picture-winged flies, or corn silk flies, including Euxesta stigmatias Loew, E. eluta Loew, E. annonae F., and Chaetopsis massyla Walker (Diptera: Ulidiidae), are serious pests of field and sweet corn in southern Florida. Control has focused on the use of chemical insecticides, but efforts have begun to explore other control methods, such as using predatory arthropods. We studied the timing, abundance, identification, and predatory status of ulidiids and other arthropod species associated with corn ears growing in the field in the spring, summer, and fall of 2010. Predators of ulidiids included Orius insidiosus Say (Hemiptera: Anthocoridae), Anotylus insignitus (Gravenhorst) (Coleoptera: Staphylinidae), Chrysoperla carnea Smith (Neuroptera: Chrysopidae), Zelus longipes (L.) (Hemiptera: Reduviidae), and potentially other arthropod species. Larvae of A. insignitus, C. carnea, and nymphs and adults of O. insidiosus consumed eggs and larvae of ulidiids in laboratory no-choice tests. Other than ulidiid eggs and/or larvae, O. insidiosus was the most abundant arthropod species in the silking (R1) stage of corn in all 3 seasons. Sap beetle larvae or adults (Coleoptera: Nitidulidae) were the most abundant arthropod groups in the spring blister stage (R2) and in milk stages (R3) of the spring and fall. The most abundant groups in the summer R2 and R3 stages included A. insignitus larvae and sap beetle larvae and adults, and in the summer R2, also O. insidiosus. The most abundant groups in the fall R2 were O. insidiosus, sap beetle adults, Thrips sp. (Thysanoptera: Thripidae), and mites. Chrysoperla carnea was found only in the summer, and Z. longipes only in the fall. In all 3 seasons, ulidiid eggs were more abundant than larvae in the R1 stage, but larvae usually outnumbered eggs in the R2 and R3 stages. Each of the groups, O. insidiosus and eggs and larvae of ulidiids, were most abundant in the summer followed by the fall and least abundant in the spring. These findings may help in determining spatial distributions and functional responses of these predators to further evaluate their potential to control ulidiid flies.

El complejo de moscas de los estigmas Euxesta stigmatias (Loew), Chaetopsis massyla (Walker) y Eumecosommyia nubila (Wiedemann) han adquirido importancia como plagas en el cultivo de maíz en Sinaloa, y sus daños están asociados a pudriciones que afectan la calidad del elote y el rendimiento del grano. Este trabajo tiene por objetivo presentar el resultado de la búsqueda de enemigos naturales (parasitoides, depredadores y nematodos entomopatógenos) con potencial para el control biológico de este complejo de moscas. El trabajo se realizo durante el ciclo agrícola primavera verano de 2011. Se hicieron 8 muestreos semanales con red entomológica y colecta de frutos, en la etapa de fructificación y maduración del grano en lotes de maíz sembrados con el hibrido Asgrow Garañon, predominando dos avispas del orden Hymenoptera de las familias Pteromalidae y Eurytomidae, que parasitan a la mosca de los estigmas en el estado de pupa; Spalangia spp., se observó con mayor frecuencia ejerciendo un parasitismo natural del 47 % sobre Euxesta stigmatias (Loew) durante las etapas de fructificación y maduración de los frutos. La chinche pirata Orius insidiosus (Say) estuvo presente durante los meses de marzo a julio depredando a huevecillos y larvas de la mosca. Por otro lado, se realizaron muestreos de suelos para aislar e identificar poblaciones de nematodos entomopatógenos, utilizando al insecto trampa Galleria melonella (L)., se aislaron poblaciones en tres sitios sembrados con maíz localizados en el CIIDIR-IPN Unidad Sinaloa, en los ejidos Guasave y Maximiliano R. López, todos ubicados en el municipio de Guasave. Los nematodos encontrados en los sitios pertenecen a especies de la familia Rhabtitidae, la identificación a nivel de género está en proceso. Los enemigos naturales encontrados se caracterizan por tener potencial para evaluarse como agentes de control biológico del complejo de moscas de los estigmas. .

Eleven species of picture-winged flies (Diptera: Ulidiidae: Lipsanini) have been reported attacking maize [Zea mays L. (Poaceae)] ears in the Americas. Four of these species are sweet corn pests in America north of Mexico: Chaetopsis massyla (Walker), Euxesta annonae (Fabricius), E. eluta Loew, and E. stigmatias Loew. Adults of these four species appear at the beginning of each season following maize-free periods, suggesting other plants act as food sources for maintenance and development of these flies. Studies were conducted in Florida, USA, to evaluate the suitability of several crop and non-crop plants commonly occurring near maize plantings as developmental hosts for these flies. Laboratory trials were conducted using laboratory colonies of C. massyla, E. eluta ,a ndE. stigmatias to determine their developmental rates and pupal survivorship on roots, stems, leaves, or fruits of 14 cropandweedspecies.Allthreeflyspeciescompleteddevelopment onalltestedcrops(Brassicaoleracea L., Capsicum chinense Jacquin, Capsicum annum L., Carica papaya L., Persea americana Mill., RaphanussativusL.,SaccharumofficinarumL., andSolanumlycopersicumL.)andweedspecies [Amaranthus spinosus L., Portulaca oleracea L., Sorghum halepense (L.), and Typha spp.], except for Daucus carota L. roots and Solanum tuberosum L. tubers. Findings of the current study suggest that the presence of multiple host crops in areas surrounding maize fields may help explain the occurrence of thesemaize-infestingulidiidsimmediatelyafterprolongedabsencesofmaize.

The aim of this study was to comparatively characterize the monthly variation and the sex ratio of Euxesta stigmatias (Loew) and Euxesta sororcula (Wiedermann) populations from a natural reserve and from a guava orchard. It was also investigated whether density and the climate factors affected the individuals' size and fluctuating asymmetry (FA). In both environments, E. sororcula predominated over E. stigmatias. The number of individuals of E. sororcula collected in the ecological station was significantly lower than the number of individuals caught in the orchard. However, the number of captured individuals of E. stigmatias did not differ between environments. Significant sex ratio differences were detected between the collection sites. Female's frequency of E. stigmatias was significantly higher than male's frequency in the ecological station, but not in the orchard. An opposite pattern was encountered for E. sororcula population, showing a significant larger number of females only in the orchard. The species populations also differed in the degree of asymmetry presented. Euxesta stigmatias individuals showed no change on size or on FA along the captures and between environments. Moreover, E. sororcula tended to be more susceptible to climatic variations, considering the significant observed correlation between temperature and body size and the expressive body size and FA variations. This study illustrates the influence of the environment in some structural and dynamic parameters of the studied populations.

Several species of Ulidiidae (Diptera) are primary pests of maize (Zea mays L.). The ability to distinguish their immature stages would be useful for biological studies where their distributions overlap. Morphology of the immature stages was examined for three Ulidiidae that attack maíze in the southeastern United States: Chaetopsis massyla (Walker), Euxesta eluta Loew, and Euxesta stigmatias Loew. Egg, larval, and pupal characters were measured and described with the aid of light and scanning electron microscopy. Because of considerable overlap in character states, only a few traits in each stage could be used to separate these three species. C. massyla eggs had pores restricted to the posterior end, but the pores were evenly distributed in the two Euxesta species. Eggs of the two Euxesta species could not be differentiated. Larval mouth hooks of C. massyla had a distinct tooth on their ventral surface, whereas this tooth was lacking in E. eluta and E. stigmatias. Fewer oral ridges were observed on C. massyla larvae than on E. eluta or E. stigmatias. Posterior spiracular slits were apparent in E. stigmatias versus obscure in E. eluta larvae. The length and spinule arrangements on creeping welts could be used to separate E. eluta and E. stigmatias larvae. Posterior spiracular plates of C. massyla puparia were trapezoidal versus ovoid in the two Euxesta species. Puparium color varied significantly among the three species.

The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn (Zea mays L.) in Florida since 1930. Several other species in the family are known to infest corn grown in the Caribbean, Central America, and South America. Surveys were conducted throughout Florida to evaluate species richness and distribution of corn-infesting Ulidiidae. Adults were sampled with sweep nets and reared from fly larvae-infested corn ears collected from representative corn fields in 16 and 27 counties in 2007 and 2008, respectively. Four Ulidiidae species were found in corn fields using both sampling techniques. Euxesta eluta Loew and Chaetopsis massyla (Walker) were found throughout the state on field and sweet corn. Euxesta stigmatias was only found in Martin, Miami-Dade, Okeechobee, Palm Beach, and St. Lucie Counties on field and sweet corn. Euxesta annonae (F.) was found in sweet corn in Miami-Dade, Okeechobee, and Palm Beach Counties, but field corn was not sampled in the...

The picture-winged fly Euxesta stigmatias Loew (Diptera: Ulidiidae) has been a serious pest of sweet corn in Florida since the 1930s and had been considered the only fly infesting Florida corn. In a sweet corn variety trial to evaluate E. stigmatias resistance in 2007, adult Chaetopsis massyla (Walker) (Diptera: Ulidiidae) was reared from the ears. Choice and no-choice trials were conducted in 2007 and 2008 to determine the pest nature of C. massyla on corn. In no choice tests, C. massyla pairs were caged on uninfested corn ears in green house and field trials. In choice tests, field collected corn ears were held for fly emergence. No choice tests showed that C. massyla could infest and complete development in ears that had no previous damage. Chaetopsis massyla emerged from corn ears with and without prior infestation by other insect species in choice tests. Subsequently, C. massyla were reared from corn ears collected from locations throughout the major sweet corn growing region of southern Flo...

Field trials using Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and Euxesta stigmatias Loew (Diptera: Ulidiidae) were conducted to evaluate resistance and potential damage interactions between these two primary corn, Zea mays L., pests against Lepidoptera-resistant corn varieties derived from both endogenous and exogenous sources. The endogenous source of resistance was maysin, a C-glycosyl flavone produced in high concentrations in varieties 'Zapalote Chico 2451' and 'Zapalote Chico sh2'. The exogenous resistance source was the Bacillus thuringiensis (Bt)11 gene that expresses Cry1A(b) insecticidal protein found in 'Attribute GSS-0966'. Damage by the two pests was compared among these resistant varieties and the susceptible 'Primetime'. Single-species tests determined that the Zapalote Chico varieties and GSS-0966 effectively reduced S. frugiperda larval damage compared with Primetime. E. stigmatias larval damage was less in the Zapalote Chico varieties than the other varieties in single-species tests. E. stigmatias damage was greater on S. frugiperda-infested versus S. frugiperda-excluded ears. Ears with S. frugiperda damage to husk, silk and kernels had greater E. stigmatias damage than ears with less S. frugiperda damage. Reversed phase high-performance liquid chromatography analysis of nonpollinated corn silk collected from field plots determined that isoorientin, maysin, and apimaysin plus 3'-methoxymaysin concentrations followed the order Zapalote Chico sh2 > Zapalote Chico 2451 > Attribute GSS-0966 = Primetime. Chlorogenic acid concentrations were greatest in Zapalote Chico 2451. The two high maysin Zapalote Chico varieties did as well against fall armyworm as the Bt-enhanced GSS-0966, and they outperformed GSS-0966 against E. stigmatias.

Damage by Euxesta stigmatias Loew larvae to sweet corn renders the ears unmarketable. This report evaluates the efficacy of insecticides labeled for armyworm control in Florida sweet corn against E. stigmatias adults. Tests were performed in controlled settings by using direct contact and dried plant residues of esfenvalerate, cyfluthrin, lambda-cyhalothrin, chlorpyrifos, methyl parathion, methomyl, and thiodicarb. Direct application of all insecticides except thiodicarb quickly killed or caused incapacitating sublethal affects (uncoordinated movement, uncontrolled twitching, and hyperextension of mouthparts and ovipositor) to >75% of the flies. Low rates (0.56 kg [AI]/ha) of chlorpyrifos and methyl parathion provided the most efficient control, killing 100 and 93%, respectively, within 2 h of direct contact. Low rates of pyrethroids induced low mortality but high sublethal effects that together immobilized nearly 100% of adults within 1 h of exposure. Mortality reached 95% within 2 h of direct contact in flies treated with high rates of pyrethroids. Methomyl killed as many as 94%, but required 24 h to reach this level after direct treatment. Residues on dipped leaves and field-treated plants of all tested insecticides except methyl parathion were less effective at killing adults compared with direct contact tests. Pyrethroid residues (particularly cyfluthrin) on field planted sweet corn induced significantly higher levels of sublethal effects (57–70%), and for a longer period of time, compared with materials in the other classes of chemistry.

The milkweed assassin bug, Zelus longipes (L.) (Hemiptera: Reduviidae), is a generalist predator and a potential biological control agent of picture-winged flies (Diptera: Ulidiidae), which cause considerable economic damage to sweet corn yields in Florida. We studied the potential of Z. longipes as a biocontrol agent of four ulidiid pests in corn fields: Euxesta stigmatias Loew, Euxesta eluta Loew, Euxesta annonae F., and Chaetopsis massyla Walker. Within-plant and within-field distributions of Z. longipes and ulidiids and functional responses of Z. longipes to ulidiid prey were determined. Highest numbers of Z. longipes and ulidiids in the R1, R2, and R3 corn stages were generally in the basal or middle leaves at 09:00 h EST, ears at 13:00 h EST, and top and tassel at 17:00 h EST. Hence, there seemed to be a coordinated migration of Z. longipes and ulidiids from the lowest to the highest parts of the corn plant during the day. Within the corn field, aggregated (clumped) distributions were most common for Z. longipes and ulidiids especially in the later R2 and R3 stages based on Taylor's power law, Iwao's patchiness regression, index of dispersion, and Lloyd's patchiness indices of dispersion. However, predator and prey populations were lower in the R1 stage, and there were inconsistent results for dispersion indices among times of day and between predators and prey. Ulidiid distributions in R1 were mostly regular (uniform) at 13:00 h EST, but aggregated at 09:00 h and 17:00 h. However, Z. longipes R1 distributions were mostly aggregated at 13:00 h, but random or regular at 09:00 h and 17:00 h EST. Handling times for male and female Z. longipes were 1.0-1.39 h and 0.67-0.97 h, respectively, and each had a type II functional response to E. stigmatias, E. eluta, and E. annonae and consumed about five flies per day. Although the population abundance of Z. longipes can vary between seasons, it appears to be a promising biocontrol agent of ulidiid flies in corn.

The corn silk fly, Euxesta stigmatias Loew (Diptera: Otitidae), and related otitid species can cause severe crop losses to sweet corn, Zea mays L., grown in tropical and subtropical regions. In Florida, the fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), and E. stigmatias are two debilitating insect pests on the sweet corn ear that are considered the most costly and difficult to control. Our purpose was to search for resistance to the corn silk fly in a diverse set of maize germplasm that included sweet, floury, field and popcorn, and to determine if any empirical relationship existed between E. stigmatias damage and S. frugiperda infestation in corn ears. The overall means across two sites, 3 yrs and 16 genotypes was 1.77 for corn silk fly damage, rated on a 0 to 4 prototype scale, and 30.1% for fall armyworm infestation. Clear differences existed between the sweet and popcorn types when compared to the field and floury types. The field and floury corns sustained significantly less damage by the corn silk fly than the sweet and popcorn types (0.91 vs 3.33). Five of these genotypes, CEW-R58, DDSB, GT-RI4, Mp704 and ‘Zapalote Chico 2451’, had both lower corn silk fly damage ratings and lower levels of fall armyworm infestation. Across this broad germplasm base no statistical relationship was identified between corn silk fly damage and fall armyworm infestation, suggesting that each insect species responds independently to different maize genotypes. Husk extension was partly related to reduced S. frugiperda infestation, and tip tightness was partly related to reduced E. stigmatias damage. These results indicate that field corn could possibly serve as source of resistance to the corn silk fly for the improvement of sweet corn.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Morphometric methods associated with multivariate statistical analysis are adequate tools to elucitade biological questions related to character variations within and between populations. Besides, these methods allow to verify the effects of the available resources amount for food suply, the climatic fluctuations and the presence of predators and orher natural enemies in some individual characteristics such as size and symmetry. The aim of this dissertation was to investigate the climatic and the density of occurrence effects on the the size and on the fluctuating asymmetry (FA) of individuals from distinct populations. It was considered on the analysis two Euxesta species (Otitidae = Ulidiidae) from the biological reserve of the Estação Ecológica do Panga and form a guava orchad located at Água Limpa Farm, and also, populations of the aphid Brevicoryne brassicae (L.) (Aphididae) and its associated microhymenopteran hyperparasitoid Alloxysta fuscicornis (Hartig) (Figitidae) in the Glória Experimental Farm, all sites belonging to the Universidade Federal de Uberlândia. The results demonstrate that the temperature variations produce body sizes variations, although it not generates marked effects over the individual s symmetry. Euxesta sororcula (Wiedemann) and Euxesta stigmatias (Loew) (Otitidae = Ulidiidae) populations showed distinct population dynamics strucutures even habiting togheter the same environments. E. sororcula for being more susceptibile to show size and FA variations presents a promissor potential use as a biological indicator of environmental stress. The temperature also affected the density and the size of B.brassicae in the studied system and, once altered these characteristic of this primary host, changes on size and on FA of the hiperasitoids were also produced. Adjustments on the individual and population levels contribute to the population dynamics regulation of investigated species. Métodos morfométricos associados às análises estatísticas multivariadas são ferramentas adequadas para elucidar questões biológicas relacionadas às variações de caracteres dentro e entre populações. Além disto, tais métodos permitem que sejam verificados os efeitos da quantidade de recursos disponíveis para alimentação, as flutuações climáticas e a presença de predadores ou outros inimigos naturais em algumas características individuais tais como o tamanho e a simetria corpóreos. Esta dissertação investigou os efeitos climáticos e da densidade de ocorrência na determinação do tamanho e da assimetria flutuante dos indivíduos em populações distintas. Foram consideradas nas análises duas espécies de dipteros Euxesta (Otitidae = Ulidiidae) da reserva biológica da Estação Ecológica do Panga e de um pomar de goiabas da Fazenda Água Limpa e, ainda, uma população do pulgão Brevicoryne brassicae (L.) (Aphididae) e do microhimenóptero hiperparasitóide Alloxista fuscicornis (Hartig) (Figitidae) da Fazenda Experimental do Glória, todos os locais pertencentes à Universidade Federal de Uberlândia (UFU). Os resultados monstraram que as mudanças de temperatura produzem variações no tamanho do corpo, embora não tenham efeito marcante sobre a simetria dos organismos. Euxesta sororcula (Widemann) e Euxesta stigmatias (Loew) (Otitidae = Ulidiidae) apresentaram distintas estruturas populacionais mesmo co-ocorrendo nos dois ambientes estudados. E. sororcula, por ser mais sucetível a apresentar variações de tamanho e na assimetria flutuante possui promissor uso como bioindicador de estresse ambiental. A temperatura também afetou a densidade de B. brassicae no sistema estudado e, uma vez alteradas as características deste pulgão hospedeiro, modificações no tamanho e na assimetria do hiperparasitóide A. fuscicornis foram produzidas. Tais ajustes a nível individual e populacional contribuem para a regulação da dinâmica populacional das espécies investigadas. Mestre em Ecologia e Conservação de Recursos Naturais

FAW is a serious pest of sweet corn in Florida that normally requires intensive management with insecticides during vegetative and reproductive stages to produce a marketable crop. CEW typically attacks the ears later in the season and frequently requires insecticide treatments in the spring months throughout the state. Euxesta stigmatias larvae attack the corn silk, ears and cob rendering the ears unmarketable. The purpose of this trial was to compare two newer insecticides against standard insecticides for control of the above pests. The trial was conducted at the Everglades Research and Education Center, Belle Glade, FL in a Lauderhill organic soil (i.e., euic, hyperthermic Lithic Medisaprists). Yellow sweet corn seeds (Novartis Seeds ‘GSS 5771’) were planted 20 Aug 2003, 9 inches apart on 30-inch centers using a John Deere Max Merge planter. The study was arranged in a RCB design with four replicates. Plots were 30 ft long, six rows wide, and separated by 5 ft planted, untreated buffers. Blocks were separated on all sides by 15 ft of unplanted buffers. Treatments for naturally occurring FAW were begun once infestation levels reached above a 20% threshold level. Insecticides were applied on 10, 17, 24 Sep, and 1, 8, 14 and 17 Oct using a compressed air spray system mounted on a high clearance spider spray track tractor at 40 psi (nozzle pressure) using 8005 EVS TeeJet nozzles at 15-inch centers across the six-row boom. Insecticides were applied in spray volumes of 30 gpa on the first four dates and 55 gpa on the last three dates. Induce spray adjuvant was added at 0.25% v/v to all treatments, including the water check. Pretreatment (8 Sep) and post treatment samples to evaluate the treatments consisted of examining 10 randomly selected plants in each of the center three rows in each plot (30 plants per treatment replicate) for live FAW larvae. Thirty ears per treatment plot were harvested on 20 Oct and examined for FAW, CEW and E. stigmatias damage. Data were subjected to ANOVA and means were separated using LSD (P ≤ 0.05).

The cornsilk fly, Euxesta stigmatias Loew, is found in tropical and subtropical areas of the western hemisphere. It occurs throughout the Caribbean Islands, Mexico, Central and South America south to Bolivia and Paraguay, and in Florida. Historically it has been a pest in the United States only in southernmost Florida, Puerto Rico, and the Virgin Islands. However, in recent years cornsilk fly has become a serious pest in south-central Florida, and there are sporadic reports of its occurrence from a few other states. This document is EENY-224, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: August 2001. EENY-224/IN381: Cornsilk Fly (suggested common name), Euxesta stigmatias Loew (Insecta: Diptera: Otitidae) (ufl.edu)

EUMECOSOMYIA NUBILA (WIDEMANN), A NEW OTITID IN PUERTO RICO, WITH NOTES ON THE HABITS OF THE DIPTERAN SPECIES COMPLEX OF CORN