The effect of the presence of organic amendment on the activity of two selected strains of Pochonia chlamydosporia var. catenulata (Kamyschko ex Barron and Onions) Zare & Gams on Meloidogyne enterolobii Yang & Eisenback was evaluated. The fungal strains studied were IMID SD 187 from Cuba and CG1006 from Brazil. The experiment was carried out in Embrapa-Cenargen, Brasilia-DF (Brazil), under greenhouse conditions during February-April, 2011. An agricultural soil (sterilized and not sterilized) was used and combined with the presence-absence of organic amendment (Bioplant) (1:1 v/v). Four treatments were prepared inoculating polyethylene bags with 4kg of substrate with 5000 chlamydopores.g-1 of substrate of each of the strains, leaving non-inoculated bags as controls. Then, a chicory plant was transplanted into each bag, and 5000 juveniles/eggs of M. enterolobii were added. Colonization of both strains of P. chlamydosporia var. catenulata was in the order of 10³-10(4) UFC,g-1 in the soil and roots. The percentages of egg mass colonization and egg parasitism of the strain CG1006 were higher, between 77-92% and 71-78%, than those of IMI SD 187, which were 58-89% and 37-74%, respectively. Although the galling index of M. enterolobii was not reduced by the effect of none of the fungi, the number of healthy egg was reduced compared with the control. The results indicated that the presence of organic amendment did not influence the activity of the native strain significantly, but it did influence that of the foreign strain (IMI SD 187), fundamentally in natural soil. Therefore, the pertinence of studies in non- sterilized soils was ratified for offering more reliable information for the selection of promising strains as biological control agents of nematodes and their use within nematode management strategies.

Se evaluó el efecto de la presencia de abono orgánico sobre la actividad de dos cepas seleccionadas de Pochonia chlamydosporia var. catenulata (Kamyschko ex Barron y Onions) Zare y Gams (IMI SD 187 y CG1006) de Cuba y Brasil, respectivamente, frente a Meloidogyne enterolobii Yang y Eisenback. El experimento se realizó en Embrapa-Cenargen, Brasilia-DF (Brasil) y se mantuvo en casa de vegetación durante los meses de febrero-abril de 2011. Se utilizó un suelo agrícola y se combinó la presencia-ausencia de abono orgánico (Bioplant) (1:1 v/v) con suelo natural (no esterilizado y esterilizado). Se prepararon cuatro tratamientos con cada cepa donde se inocularon 5000 clamidosporas.g-1 de sustrato y cuatro grupos controles (sin Pochonia), en bolsas de polietileno con 4kg de sustrato, donde se trasplantó una postura de achicoria y se añadieron 5000 juveniles/huevos de M. enterolobii. Se comprobó que el desarrollo saprofítico de ambas cepas de P. chlamydosporia var. catenulata estuvo en el orden de 10³-10(4) UFC.g-1 en el suelo y las raíces. El porcentaje de colonización de masas de huevos y el parasitismo de huevos de la cepa CG1006 fue superior, con valores entre 77-92% y 71-83%, comparado a la IMI SD 187 que logró 58-89 y 37-74%, respectivamente. Aun cuando ambos hongos no redujeron el índice de agallas de M. enterolobii, disminuyó el número de huevos sanos, respecto al control. Los resultados indicaron que la presencia de abono orgánico no influyó significativamente en la actividad de la cepa nativa, pero sí de la cepa foránea (IMI SD 187) fundamentalmente en el suelo natural. Se ratifica la pertinencia de estudios en suelos no esterilizados, al ofrecer información más confiable en la selección de cepas promisorias como agentes de control biológico de nematodos y su empleo dentro de estrategias de manejo.

La perla de tierra Eurhizococcus brasiliensis es el insecto plaga más importante en las uvas de Brasil. La presencia natural y actividad biológica de hongos entomopatógenos (HE) contra esta plaga son poco conocidas. En este estudio se evaluó la presencia de E. brasiliensis asociada a HE en suelos y la virulencia de una cepa de Isaria fumosorosea proveniente de la perla de la tierra contra quistes bajo condiciones de laboratorio. No se logró identificar ningún HE en los quistes durante una evaluación inicial conducida en un área de producción de uva al sur de Brasil. Sin embargo, el 6% de las hembras móviles que emergieron de los quistes estaban infectadas con Metarhizium brunneum, el cual es el primer reporte del aislamiento de este patógeno sobre perlas de la tierra en Brasil. Los quistes sin su capa de cera protectora fueron inoculados por inmersión a una suspensión de conidios de I. fumosorosea. Se describieron los síntomas y signos de la infección. Los quistes infectados tenían un color amarillo oscuro y una consistencia de "huevo cocido" cuando rotos, en contraste a un color amarillo claro y una consistencia de "huevo crudo" de los quistes vivos. Las células fúngicas vegetativas se encontraron dentro de los quistes sintomáticos, y más tarde se hizo visible la conidiación en la parte externa. La CL25 para los quistes protegidos por su capa de cera e inoculados por inmersión fue de 1,31 x 10(7) conidios.mL-1. Sin embargo, la presencia de estructuras del hongo no se observó en los individuos sintomáticos. Teniendo en cuenta la inmovilidad de los quistes y la ausencia de signos patológicos para la evaluación de mortalidad, los síntomas descritos pueden ayudar en estudios futuros sobre el control de E. brasiliensis utilizando I. fumosorosea.

The Brazilian ground pearl Eurhizococcus brasiliensis is the most prevalent insect pest of grapes in Brazil. The natural occurrence and biological activity of entomopathogenic fungi (EF) against this pest are poorly known. In this study, we evaluate the presence of E. brasiliensis-associated EF in soil and the virulence of a ground pearl-derived strain of Isaria fumosorosea against cysts under laboratory conditions. EF were not identified on cysts in an initial survey performed in a grape-producing area in southern Brazil. However, 6% of mobile females that had emerged from cysts were infected by Metarhizium brunneum, which was the first report of this insect pathogen on ground pearls in Brazil. Cysts without the protective wax layer were inoculated with I. fumosorosea conidia suspension by immersion. The symptoms and the signs of the disease were described. Infected cysts had a yellow-ochre color and "hard-boiled egg" consistency when broken, in contrast to the intense bright yellow color and "raw egg" consistency of living cysts. Vegetative fungal cells were present inside symptomatic cysts, and later, outside conidiation was visible. The LC25 for the cysts protected with the wax layer and also inoculated by immersion was 1.31 x 10(7) conidia·mL-1. However, the presence of fungal structures was not observed on symptomatic individuals. Considering the motionlessness of cysts and the absence of disease signs for mortality assessment, the symptoms described may be helpful for further studies on E. brasiliensis control using I. fumosorosea.

Recently, Pochonia chlamydosporia (Goddard) Zare y Gams was isolated from parasitized eggs of Meloidogyne enterolobii Yang y Eisenback (syn. jun. Meloidogyne mayaguensis Rammah y Hirschmann) in guava (Psidium guajava L.) plantations, at the northeast of Brazil. Due to the potential danger of this pest for a large group of crops, including vegetable crops, a greenhouse experiment was conducted with two repetitions in time. The aim was to evaluate the saprophytic and parasitic activities of three brazilian strains (CG1003, CG1006 and CG1041) and the cuban strain (IMI SD 187) of P. chlamydosporia against M. enterolobii in a tomato (Solanum lycopersicum L.)- lettuce (Lactuca sativa L.) crop sequence. At the end of the cultivation, 6 month after the application, colonization of P. chlamydosporia was in the order of 10(4) CFU.g-1 of soil and 10³ CFU.g-1 of root, with exception of the strain CG1041 (10² CFU.g-1 of root). Egg mass percentage was higher than 60% in all treatments, while parasitized egg percentage was between 45-55%. These results validated the cuban strain against a nematode target under different conditions from those it originally came from; the brazilian strain potential as biocontroler of M. enterolobii was also demonstred. Future investigation perspectives with those fungi are opened for their use as biological control agents for nematode pest management strategies.

Recientemente se informaron aislamientos de Pochonia chlamydosporia (Goddard) Zare y Gams parasitando huevos de Meloidogyne enterolobii Yang y Eisenback (syn. jun. Meloidogyne mayaguensis Rammah y Hirschmann) en plantaciones de guayaba (Psidium guajava L.), al nordeste de Brasil. Teniendo en cuenta el peligro potencial de esta plaga para numerosos cultivos incluyendo las hortalizas, se realizó un experimento en casa de vegetación con dos repeticiones en el tiempo. El objetivo fue evaluar las actividades saprofítica y patogénica de tres cepas brasileñas (CG1003, CG1006 y CG1041) y una cubana (IMI SD 187) de P. chlamydosporia frente a M. enterolobii, en una sucesión de cultivos tomate (Solanum lycopersicum L.)- lechuga (Lactuca sativa L.). Al finalizar el ciclo de los cultivos, 6 meses después de la aplicación, se comprobó que la colonización de P. chlamydosporia se mantuvo en el orden de 10(4) UFC.g-1 de suelo y mayor de 10³ UFC.g-1 en las raíces, excepto para la cepa CG1041 (10² UFC.g-1 de raíz). El porcentaje de colonización de estos hongos sobre las masas de huevos fue superior al 60% en todos los tratamientos, mientras que los porcentajes de parasitismo de huevos estuvieron entre 45 y 55%. Estos resultados validaron la cepa cubana frente a una diana y en condiciones diferentes a las que es originaria y se demostró que las cepas brasileñas son potenciales biocontroladores de M. enterolobii, abriéndose así futuras perspectivas de investigación como agentes de control biológico integrados para el manejo de este nematodo.

O nematóide das galhas, Meloidogyne mayaguensis, causa sérias perdas econômicas em plantações de goiaba no Brasil. Fungos parasitas de ovos de M. mayaguensis ainda não foram estudados no Brasil, mas essas informações podem servir de base para estudos futuros de controle biológico em campo. Os fungos parasitas de ovos, Pochonia chlamydosporia var. chlamydosporia, P.chlamydosporia var. catenulata e Lecanicillium psalliotae foram isolados em ovos de M. mayaguensis e analisados quanto às suas características morfológicas e culturais. Para os isolados de P. chlamydosporia a melhor temperatura para crescimento e esporulação variou entre 24 e 28 ºC. Para o isolado de L. psalliotae, a melhor temperatura para crescimento foi 30 ºC. Em estado sólido, os isolados de P. chlamydosporia produziram entre 3,5 e 5,2 x 10(6) chlamidosporos por g de substrato colonizado, enquanto que o isolado de L. psalliotae produziu 8,5 x 10(8) conídios por g de substrato colonizado. Há necessidade de estudos futuros para mostrar o potencial desses fungos como agentes de controle biológico de M. mayaguensis.

The root-knot nematode, Meloidogyne mayaguensis, causes serious economic loss to guava plantation in Brazil. Fungi associated with eggs of M. mayaguensis in Brazilian soil have not been studied yet, but this knowledge could form the basis for future field studies on biological control of this nematode. The egg parasitic fungi, Pochonia chlamydosporia var. chlamydosporia, P.chlamydosporia var. catenulata and Lecanicillium psalliotae, were isolated from M. mayaguensis eggs and analyzed based on their cultural and morphological characteristics. The optimum temperature for growth and spore production ranged between 24 and 28ºC for P. chlamydosporia isolates. For the isolate of L. psalliotae, the best growth was at 30ºC. In solid state fermentation, P. chlamydosporia isolates produced between 3.5 and 5.2 x 10(6) chlamydospores per g of colonized substrate, whereas L. psalliotae isolate produced 8.5 x 10(8) conidia per g of colonized substrate. Future studies are required to clarify the potential of these fungi as biological control agents of M. mayaguensis.

Amplified fragment length polymorphism (AFLP) was used to investigate polymorphism among 43 Hirsutella thompsonii isolates (33 from Thailand) obtained from various mite species. The outgroups were an unidentified Hirsutella isolate along with Hirsutella nodulosa and Hirsutella kirchneri. Phylogenetic analyses of the AFLP data showed significant variation among isolates and the existence of three H. thompsonii clades. We also investigated the isolates using PCR with specific primers for the Hirsutella exotoxin gene Hirsutelin A (HtA) and 18 of these isolates were used for sequencing of the partial beta-tubulin gene. Phylogenetic analyses of beta-tubulin sequences showed two distinct H. thompsonii clades, one of which included AFLP clades I and II. For both markers grouping of the H. thompsonii isolates was not related to either host mite species or geographical origin, although for the HtA gene one clade contained only isolates with no detectable HtA band. These results confirm the high intraspecific polymorphism of H. thompsonii, and maximum likelihood analysis showed no monophyletic group within this species. To refine the taxonomy of this genus other studies should be undertaken using additional molecular markers and several other Hirsutella isolates.

A phylogenetic analysis of the 5.8S rDNA and internal transcribed spacer (ITS1 and ITS2) sequences from some entomogenous Paecilomyces species supports the polyphyly of the genus and showed the existence of cryptic species. In the Eurotiales, anamorphs Paecilomyces variotii and Paecilomyces leycettanus were related to the teleomorphs Talaromyces and Thermoascus. In the Hypocreales, three major ITS subgroups were found, one of which included Paecilomyces viridis, Paecilomyces penicillatus, Paecilomyces carneus and isolates identified as Paecilomyces lilacinus and Paecilomyces marquandii. However, the majority of the P. lilacinus and P. marquandii isolates formed a distinct and distantly related subgroup, while the other major subgroup contained Paecilomyces farinosus, Paecilomyces amoeneroseus, Paecilomyces fumosoroseus and Paecilomyces tenuipes.

Quarenta e nove isolados brasileiros de Dicyma pulvinata foram analisados quanto a características morfológicas, análises de RFLP, RAPD e AFLP. Este fungo é um micoparasita do Microcyclus ulei, o agente causal da mais importante doença da seringueira (Hevea brasiliensis), o mal-das-folhas. Estes isolados foram comparados com isolados indianos obtidos a partir de lesões de Cercosporidium sp., com um isolado proveniente da França obtido a partir de lesões de Cladosporium fulvum e com um isolado de D. ampullifera proveniente de Papua-Nova Guiné. A análise de parâmetros morfológicos confirmou a identificação dos isolados brasileiros. As representações gráficas das matrizes de distância de cada marcador molecular mostraram resultados semelhantes. Os isolados de D. pulvinata obtidos de M. ulei mostraram-se intimamente relacionados. Por outro lado, os isolados - referência, incluídos nestes estudos, mostraram-se bastante dispersos. De acordo com a análise de variância molecular, considerando todos os marcadores, os isolados de D. pulvinata obtidos de M. ulei, apresentaram diferença significativa entre isolados procedentes de áreas de cultivo de seringueira favoráveis à ocorrência do mal-das-folhas (regiões norte e nordeste do Brasil) e aqueles de áreas de escape da doença (Mato Grosso).

Forty-nine Brazilian Dicyma pulvinata isolates were examined by morphological traits and RFLP, RAPD and AFLP analyses. This fungus is a mycoparasite of Microcyclus ulei, the causal agent of the most devastating rubber (Hevea brasiliensis) disease, known as "South American Leaf Blight" (SALB). These isolates were compared with an Indian isolate from Cercosporidium sp., and a French isolate from Cladosporium fulvum. They were also compared with Dicyma ampullifera from Papua New Guinea. The morphological parameters analyzed confirmed the identification of the Brazilian isolates. The graphic representations of the distance matrices of each molecular marker showed similar results. Dicyma pulvinata isolates from M. ulei were closely related, whereas the reference isolates examined were dispersed. Among the D. pulvinata isolates obtained from M. ulei, a significant pairwise distance was obtained, for all the molecular markers, between the isolates from the areas favorable to the occurrence of SALB (North and Northeast of Brazil) and the region of escape for the disease (Mato Grosso State).

Field tests were carried out during the rainy season of 2001/2002 in São Luís de Montes Belos, Goiás, Brazil, to evaluate the potential of the entomopathogenic fungus, Beauveria bassiana, against peridomestic Triatoma sordida. An oil-water formulation of the isolate CG 14 (Embrapa) was applied in triatomine infested hen houses of four farms at a final concentration of 10(6) conidia/cm². Numbers of T. sordida decreased over the next 25 days, after application of the fungus, and B. bassiana developed on dead insects in one hen house. A high number of B. bassiana colonies was detected in substrates collected in treated hen houses 24 h after application of CG 14. In the following three months the presenceof B. bassiana declined to values found before treatment.

O fungo entomopatogênico Nomuraea rileyi (Farlow) Samson pode produzir epizootias em populações de lagarta-da-soja, Anticarsia gemmatalis Hübner, controlando essa praga naturalmente. No entanto, o fenômeno nem sempre ocorre a tempo de evitar que populações de A. gemmatalis atinjam o nível de dano econômico na cultura. Observações sobre a produção de conídios em cadáveres de A. gemmatalis em condições de campo mostraram que alta umidade relativa e precipitação são fatores determinantes na cinética da esporulação do fungo in vivo. O início da esporulação foi retardado e a produção de conídios diminuída quando cadáveres de A. gemmatalis infectados com N. rileyi foram submetidos a períodos longos de estresse hídrico (umidade relativa de 25-30%). Observações no campo também demonstraram que a viabilidade de conídios de N. rileyi pode permanecer elevada (>75% germinação) por períodos de até 10 dias na superfície de cadáveres, servindo como fonte de inóculo durante esse período.

The entomopathogenic fungus Nomuraea rileyi (Farlow) Samson produces epizootics on populations of the velvetbean caterpillar, Anticarsia gemmatalis Hübner, resulting in its natural control. However, sometimes this phenomenon does not occur soon enough to prevent pest population outbreaks and damage to the crop. Observations of N. rileyi conidial production on the surface of A. gemmatalis cadavers in the field showed that high relative humidity and precipitation determine the sporulation dynamics. In fact, initiation of sporulation is delayed and conidia production is reduced when A. gemmatalis cadavers infected with N. rileyi are exposed to water stress (relative humidity 25-30%) in the laboratory. Field observations also demonstrated that N. rileyi conidial viability remain high (>75% germination) until 10 days on A. gemmatalis cadaver surface, acting as an inoculum source for this period.

Os fungos entomopatogênicos Paecilomyces fumosoroseus e P. lilacinus foram transformados com o plasmídio pBT6, contendo o gene de <FONT FACE="Symbol">b</font>-tubulina modificado, isolado do fungo Neurospora crassa, o qual confere resistência ao fungicida benomil. Transformantes resistentes ao benomil, obtidos da P. lilacinus, apresentaram tolerância a concentrações superiores a 30 <FONT FACE="Symbol">m</font>g/ml, enquanto transformantes da P. fumosoroseus apresentaram tolerância a 20 <FONT FACE="Symbol">m</font>g/ml. Após 5 passagens seriadas dos transformantes em meio contendo benomil e 5 passagens seriadas em meio não seletivo, 100% dos transformantes da P. lilacinus apresentaram estabilidade mitótica, através do teste de germinação de conídios. Em contraste, somente 4 dos 9 transformantes obtidos para P. fumosoroseus foram mitoticamente estáveis. Análise de Southern blot dos DNA genômicos de ambas as espécies sugere que o mecanismo de transformação foi por substituição alélica do gene de <FONT FACE="Symbol">b</font>-tubulina, para todos os transformantes obtidos. As seqüências não homólogas do vetor não foram detectadas nos genomas dos transformantes.

The entomopathogenic fungi Paecilomyces fumosoroseus and P. lilacinus have been transformed to resistance to the fungicide benomyl by a polyethylene glycol (PEG)-mediated procedure using a mutant <FONT FACE="Symbol">b</font>-tubulin gene from Neurospora crassa carried on plasmid pBT6. Benomyl-resistant transformants of P. lilacinus were obtained that could tolerate greater than 30 µg/ml benomyl and P. fumosoroseus transformants were obtained that could tolerate 20 µg/ml benomyl. Following 5 serial passages of transformants on benomyl-containing media and 5 serial passages on non-selective media, 100% of P. lilacinus transformants were found to be mitotically stable by a conidial germination test. In contrast, only 4 out of 9 transformants of P. fumosoroseus were mitotically stable. Southern blot analysis of genomic DNA from both species suggested that the mechanism of transformation in all transformants was by gene replacement of the <FONT FACE="Symbol">b</font>-tubulin allele. Non-homologous vector sequences were not detectable in the genomes of transformants.

O fungo Beauveria bassiana (Bals.) Vuill., isolado CG 306, foi testado contra o Triatoma infestans (Klug) através de aplicação indireta por contato do inseto com papel filtro tratado com conídios. O patógeno foi aplicado sobre papel filtro através de filtragem a vácuo de uma suspensão de conídios. Foram feitas estimativas do tempo médio de sobrevivência entre 15 e 21 dias nas densidades de 3x10(6) e 10(7) conídios/cm², respectivamente, sem diferenças significativas entre as concentrações. A concentração de 2,4x10(6) conídios/cm² de CG 306 foi necessária para matar 50% de ninfas de terceiro ínstar de T. infestans 25 dias após inoculação e incubação a 25°C e 50% de umidade relativa. A CL50 foi estatisticamente maior (2,0x10(7) conídios/cm²) quando os insetos foram expostos por uma hora aos conídios distribuídos sobre papel filtro. Um emulsificante à base de óleo mineral (2%) não afetou a germinação de conídios in vitro. Um número menor de conídios foi necessário para matar 50% dos insetos após exposição constante ao papel filtro tratado, em comparação com os conídios não formulados com o emulsificante. Quando a exposição foi limitada a 1 h, os conídios não formulados foram mais efetivos do que conídios formulados. Após aplicação de B. bassiana (10(7) conídios/cm²) em pequenas casas experimentais de madeira, seguida de liberação de ninfas de terceiro ínstar de T. infestans, o nível de infecção de insetos recuperados 25 dias após aplicação com o fungo foi significativamente inferior as encontrado na casa-testemunha. A mortalidade atribuída a infecção fúngica de insetos recuperados e mantidos em laboratório foi de 38,1 a 93,8%. A mortalidade de insetos expostos ao papel filtro tratado e mantido em copos cobertos com gaze dentro das casas, foi de 35 a 78,8% 25 dias após aplicação. A persistência dos conídios foi superior a 98% durante os experimentos de campo. Não houve desenvolvimento de B. bassiana sobre cadáveres originados de infecção provocada em laboratório e posteriormente expostos às condições de campo no interior das casas.

Beauveria bassiana (Bals.) Vuill., isolate CG 306, was assayed against Triatoma infestans (Klug) using indirect application by contact with a treated filter paper. The fungus was deposited on filter paper by vacuum-filtration of a conidial suspension. Estimates of 50% survival time of insects were between 15 and 21 days at 3x10(6) and 10(7) conidia/cm² of treated support, respectively, without significant difference between concentrations. A concentration of 2.4x10(6) conidia/cm² of CG 306 was necessary to kill 50% of T. infestans third instar nymphs 25 days after inoculation at 25°C and 50% relative humidity, when insects were continuously exposed to conidia. The LC50 was significantly higher (2.0x10(7) conidia/cm²) when insects were exposed for 1 h to the treated filter paper, than with continuous exposure. A mineral oil based emulsifier (2%) had no effect on germination of conidia in vitro. Fewer formulated conidia were necessary to kill 50% of insects after constant exposure to the treated surface, compared with unformulated conidia. After a 1 h exposure, unformulated conidia were more effective than formulated. After spraying B. bassiana (10(7) conidia/cm²) and releasing third instar nymphs of T. infestans in small wooden test houses, the rate of insect recovery after 25 days was significantly lower in the fungus treated houses compared to the control house. Mortality due to fungal infection of recovered insects transferred to the laboratory was between 38.1 and 93.8%, compared with no mortality in the control group. The rate of mortality of insects exposed to treated filter paper in gauze covered cups in the houses was between 35 and 78.8% after 25 days. Persistence of conidia on filter paper exposed inside the houses was > 98% during the field tests. There was no development of CG 306 on cadavers originating from laboratory infection and exposed to field conditions in the houses.

Foi avaliada a ação do inseticida deltametrina sobre a capacidade de germinação e virulência do fungo entomopatogênico Beauveria bassiana (Bals.) Vuill. contra ninfas de 3° estádio de Triatoma infestans (Klug) (Hemiptera: Reduviidae). Após 12 horas em cultura submersa, observou-se uma diminuição significativa da germinação de conídios de B. bassiana em proporção ao aumento da concentração do inseticida. Na mais alta dose aplicada, 550 mmg/ml, foi observado retardamento da germinação com 24 e 36 horas e interrupção do desenvolvimento do fungo após esse tempo. A exposição de ninfas de 3° estádio a concentrações subletais de deltametrina não alterou de forma significativa a virulência de B. bassiana.

Twenty three isolates of Beauveria bassiana and 13 isolates of Metarhizium anisopliae were tested on third instar nymphs of Triatoma infestans, a serious vector of Chagas disease. Pathogenicity tests at saturated humidity showed that this insect is very susceptible to fungal infection. At lower relative humidity (50%), conditions expected in the vector microhabitat, virulence was significantly different among isolates. Cumulative mortality 15 days after treatment varied from 17.5 to 97.5%, and estimates of 50% survival time varied from 6 to 11 days. Maintaining lower relative humidity, four B. bassiana and two M. anisopliae isolates were selected for analysis of virulence at different conidial concentrations and temperatures. Lethal concentrations sufficient to kill 50% of insects (LC50) varied from 7.1x105 to 4.3x106 conidia/ml, for a B. bassiana isolate (CG 14) and a M. anisopliae isolate (CG 491) respectively. Most isolates, particularly B. bassiana isolates CG 24 and CG 306, proved to be more virulent at 25 and 30°C, compared to 15 and 20°C. The differential virulence at 50% humidity observed among some B. bassiana isolates was not correlated to phenetic groups in cluster analysis of RAPD markers. In fact, the B. bassiana isolates analyzed presented a high homogeneity (> 73% similarity).

Parasitóides de ovos (Hymenoptera: Scelionidae) do complexo de percevejos da soja (Glycine max L.) são candidatos potenciais a agentes de controle nos programas de manejo integrado de pragas da soja no Brasil. A correta identificação de espécies e/ou raças desses parasitóides é importante para implementação do uso do controle biológico. A técnica de "random amplified polymorphic DNA" (RAPD) foi usada para analisar indivíduos machos de Telenomus podisi Ashmead e Trissolcus spp. coletado em uma área de soja em Brasília em 1996. A análise de 18 oligonucleotídeos usados para os indivíduos de Trissolcus spp. revelou diferentes perfis de RAPD entre as espécies, indicando a possibilidade de utilizar esses marcadores para diferenciar T. teretis Johnson, T. urichi Crawford e T. basalis (Wollaston). Os 13 oligonucleotídeos usados para analisar 33 indivíduos de uma população de T. podisi produziram 103 bandas. Foram observados diferentes genótipos nessa população, que pela análise fenética com os dados de RAPD se agruparam com alta homogeneidade (similaridade >78,2%).

The solitary egg parasitoids (Hymenoptera: Scelionidae) of Pentatomidae species complex are potential candidates for soybean (Glycine max L.) integrated pest management programs in Brazil. The correct identification of species and strains of these parasitoids is necessary to implement the use of biological control. Polymerase chain reaction (PCR) was used to generate random amplification of polymorphic DNA (RAPD) from male individuals of Telenomus podisi Ashmead and Trissolcus spp. collected in a soybean field in Brasília, Brazil in 1996. The analysis of 18 primers used to screen Trissolcus spp. individuals revealed different patterns related to the species analyzed. These results indicate the potential of RAPD markers to differentiate T. teretis Johnson, T. urichi Crawford and T. basalis (Wollaston). The 13 selected primers used to analyze T. podisi individuals produced 103 clear polymorphic scorable markers. Different genotypes were observed within this population analyzed, although the cluster analysis applied to the RAPD data showed high homogeneity (similarity >78.2%) among individuals.