Biology of Trichogramma marandobai and T. manicobai (Hymenoptera: Trichogrammatidae) in eggs of Erinnyis ello (Lepidoptera: Sphingidae)

ABSTRACT Parasitoids of the genus Trichogramma are promising for the biological control of insect pests in several crops, including cassava, which is severely attacked by Erinnyis ello L., 1758 (Lepidoptera: Sphingidae). Evaluating the biological aspects of these parasitoids to understand their dynamics is an important step towards the implementation of this control strategy in the field. Thus, our objective was to evaluate the biology of Trichogramma manicobai Brun, Moraes & Soares, 1984, and T. marandobai Brun, Moraes & Soares, 1986 in E. ello eggs. The parasitoids were obtained by collecting E. ello eggs from a commercial production of cassava, and the host's eggs were obtained from laboratory and greenhouse rearings. The average duration of a generation (T), net reproduction rate (R0), intrinsic rate of increase (rm), and the finite rate of increase (λ) were estimated, and from these, the fertility life table was calculated. The results indicated that T. marandobai has both higher net reproduction rate and a higher intrinsic rate of increase as well as requires less time to double its population than T. manicobai. Thus, T. marandobai has potential for natural and conservative biological control of E. ello. In addition, its potential in applied biological control should be evaluated through studies on the viability of its mass rearing in alternative hosts and its dispersion behavior in the field.

Resistance of cassava genotypes to Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae)

ABSTRACT Vatiga manihotae (Drake 1922) (Hemiptera: Tingidae) is an important cassava pest due to the great potential damage and the increasing population in recent years. However, few studies about bioecology and control of the cassava lace bug have been conducted and their results don't provide adequate control strategies. An alternative to maintain the population below economic injury levels is through the adoption of host plant resistance. To improve the understanding about the bioecology and find new sources of resistance in cassava, the biological parameters and demographics of V. manihotae on five cassava genotypes (Santa Helena, MEcu 72, Col 22, Clone 02 and Clone 03) under controlled conditions (25±2°C, 14L/10D) were evaluated. Duration and viability of the stages, the period egg-adult, sex ratio, the pre-oviposition period, fecundity and longevity of male and female was determined, and a fertility life table was prepared. Insects fed on MEcu 72 showed increased nymphal, egg-adult, and pre-oviposition periods and reduced female fecundity and longevity in comparison to the other genotypes. Demographic parameters (Ro, rm, T, DT) showed a significant impact on the growth potential of V. manihotae fed on MEcu 72 indicating that the populations would diminish over time. The combined effect of these parameters indicated that MEcu 72 has resistance on V. manihotae specimens hindering their development.

Adequação do hospedeiro e parâmetros relacionados à aptidão de Cotesia glomerata L. (Hymenoptera: Braconidae) em diferentes ínstares de Ascia monuste orseis Godart (Lepidoptera: Pieridae) / Host suitability and fitness-related parameters of Cotesia glomerata L. (Hymenoptera: Braconidae) on different instars of Ascia monuste orseis Godart (Lepidoptera: Pieridae)

O estudo teve por objetivo adequar o ínstar do hospedeiro Ascia monuste orseis ao parasitismo de Cotesia glomerata e avaliar o desempenho do parasitoide. Foram oferecidas às fêmeas de C. glomerata lagartas de 2o, 3o, 4o e 5o ínstares de A. monuste orseis , permitindo-se o parasitismo por duas horas. Subsequentemente, acompanhou-se o desenvolvimento das lagartas que foram alimentadas com seções foliares de couve-manteiga. Foram avaliados: a duração de cada ínstar das lagartas, o peso da pupa com quatro dias de idade e a porcentagem de lagartas parasitadas e de mortalidade. Em relação ao parasitoide, foram avaliados: porcentagem de parasitismo; número de parasitoide por hospedeiro; porcentagem de emergência; razão sexual; peso médio da pupa; número de parasitoide por lagarta; período ovo-pupa (POP); período pupal (PP); período ovo-adulto (POA). Os resultados indicaram que o segundo ínstar do hospedeiro A. monuste oreseis é o mais apropriado para o parasitismo de C. glomerata por proporcionar maior porcentagem de parasitismo e maior número de descendentes por hospedeiro.(AU)

The study aimed to adapt the instar of host Ascia monuste orseis to the parasitism of Cotesia glomerata and evaluate the parasitoid performance. Females of C. glomerata were exposed to 2nd, 3rd, 4th and 5th instars larvae of A. monuste orseis , allowing parasitism for two hours. Subsequently, the development of caterpillars that were fed with leaf sections of kale was monitored. The duration of each caterpillar instar, the weight of four days-old pupae, the percentage of parasitized caterpillars and mortality were assessed. Despite parasitoids, the following parameters were assessed: percentage of parasitism; number of parasitoids per host; percentage of emergence, sex ratio; average weight of the pupae, number of parasitoids per caterpillar; period egg-pupae; pupal period; and period egg-adult. The results indicated that the second instar of host A. monuste oreseis is the most suitable for the parasitism of C. glomerata for providing highest percentage of parasitism and a larger number of offspring per host.(AU)

Ocorrência natural de Beauveria bassiana (Bals. ) Vuill. (Moniliales: Moniliaceae) e patogenicidade sobre Protortonia navesi Fonseca (Hemiptera: Monophlebiidae) na cultura da mandioca, em Marechal Cândido Rondon, Paraná / Natural occurrence of Beauveria bassiana (Bals. ) Vuill. (Moniliales: Moniliaceae) and pathogenicity on Protortonia navesi Fonseca (Hemiptera: Monophlebiidae) in cassava plantation, in Marechal Cândido Rondon, Paraná

O objetivo deste estudo foi registrar a primeira ocorrência natural e patogenicidade da associação entre Beauveria bassiana e Protortonia navesi na cultura da mandioca. Para isso, ninfas e adultos de P. navesi infectados foram coletados em amostragens realizadas quinzenalmente, na área do Instituto Agronômico do Paraná, em Marechal Cândido Rondon, de janeiro a dezembro de 2012. Amostras foram analisadas e, utilizando-se meio de cultura seletivo de aveia, foi isolado o fungo a partir dos cadáveres, sendo identificado como Beauveria bassiana (Bals.) Vuill., armazenado na Coleção de Fungos Entomopatogênicos do Laboratório de Biotecnologia Agrícola, sob o código Unioeste 78. Para comprovar sua patogenicidade, foi adotado o postulado de Koch, aplicando-se o fungo (10 9 conídios/mL) sobre ninfas e adultos de P. navesi obtidos da criação de laboratório. Após 10 dias de incubação, verificou-se 18% de mortalidade confirmada, sendo considerada baixa a atividade sobre a cochonilha P navesi.(AU)

The objective of this study was to record the first natural occurrence and pathogenicity of the association between Beauveria bassiana and Protortonia navesi in the cassava crop. Infected P. navesi nymphs and adults were collected in samples fortnightly in the Agronomic Institute of Paraná, in Marechal Cândido Rondon, from January to December 2012. Samples were analyzed at the Laboratory of Agricultural Biotechnology. The entomopathogenic fungus was isolated from corpses using selective oatmeal culture medium, and multiplied for sporulation being identified as Beauveria bassiana (Bals.) Vuill. The fungus was stored in the Collection of Entomopathogenic Fungi Laboratory of Agricultural Biotechnology, identified as Unioeste 78. To prove the pathogenicity of the found isolate, bioassays were performed following the postulate of Koch, the fungi suspension was sprayed (10 9 conídios mL), on nymphs and adults of P. navesi obtained from laboratory rearing. After 10 days of incubation there was 18% mortality confirmed, being considered low activity on mealybugs Protortonia.(AU)

Ocorrência de Aleurothrixus aepim (Goeldi, 1886) em mandioca na região Oeste do Paraná / Occurrence of Aleurothrixus aepim (Goeldi, 1886) on cassava in Western Paraná

Este trabalho registra a ocorrência de Aleurothrixus aepim Goeldi em plantas de mandioca na região Oeste do Paraná, Brasil. A espécie foi primeiramente encontrada em fevereiro de 2009, em área experimental da Universidade Estadual do Oeste do Paraná (UNIOESTE), em folhas de mandioca da variedade fécula branca. Os exemplares foram coletados recolhendo-se folhas infestadas com ninfas de mosca-branca, caracterizadas por apresentar corpo recoberto por filamentos cerosos de coloração branca. O material foi preservado em etanol a 70%, em frascos de vidro, e foram enviados para identificação. Novos surtos foram registrados no início de 2010 e 2011 em diferentes propriedades rurais localizadas no município de Marechal Cândido Rondon. Entretanto, a causa precisa da ocorrência de A. aepim nessa região não está totalmente clara. Nas demais regiões produtoras do Estado, esta espécie ainda não foi detectada.(AU)

This paper work recorded the occurrence of Aleurothixus aepim Goeldi in cassava plants in the West of Parana, Brazil. The species was first found in February, 2009, in an experimental area at Universidade Estadual do Oeste do Paraná (UNIOESTE), in cassava leaves of the white starch variety. The samples were collected by gathering leaves infested with whitefly nymphs, which are characterized for presenting body coated by white waxy filaments. The material was preserved in 70% ethanol, in glass bottles, and sent for identification. New outbreaks have been recorded in the beginning of 2010 and 2011 in different rural properties located in the city of Marechal Candido Rondon. However, the precise cause of the occurence of A. aepim in this region is not completely clear. In the other production regions of the State, this species has not yet been detected.(AU)

Seletividade de Beauveria bassiana e Metarhizium anisopliae a Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) / Selectivity of Beauveria bassiana and Metarhizium anisopliae to Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Trichogramma pretiosum Riley and the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae are efficient biological control agents and are thought to be used jointly. In here, we investigated if these entomopathogens could have any side-effects on T. pretiosum. Therefore, 1 x 8 cards containing sterilized eggs of Anagasta kuehniella (Zeller) that were sprayed with 0.2 ml of B. bassiana or M. anisopliae (1.0 × 10(9) conidia/ml) were offered to a T. pretiosum female for 24h (30 cards/fungus = 30 replicates). Afterwards, females were isolated in glass tubes. The control group was sprayed with sterile distillated water + Tween 80 (0.01 percent). In addition, 60 cards with sterilized eggs of A. kuehniella were submitted to parasitism by females of T. pretiosum for 24h. Of these cards, 30 were sprayed with B. bassiana or M. anisopliae and 30 with distillated water + Tween 80 (0.01 percent), and observed daily until parasitoid emergence. Metarhizium anisopliae decreased parasitoid emergence and caused confirmed mortality. Therefore, field and semi-field experiments should be conducted for a final assessment of the side-effects of these entomopathogens on Trichogramma as a ways to develop a control strategy in which both can be used.

O parasitóide Trichogramma pretiosum Riley e os fungos entomopatogênicos Beauveria bassiana e Metarhizium anisopliae são considerados eficientes agentes de controle biológico e podem ser empregados concomitantemente em algumas situações. O objetivo deste trabalho foi verificar quais os efeitos desses entomopatógenos sobre T. pretiosum. Foram usadas cartelas de 1 × 8 cm contendo ovos esterilizados de Anagasta kuehniella (Zeller) pulverizadas com 0,2 ml de B. bassiana ou M. anisopliae (1,0 × 10(9) conídios/ml) e mantidas individualmente com uma fêmea de T. pretiosum por 24h, totalizando 30 cartelas para cada fungo. Posteriormente, as fêmeas foram individualizadas em tubos de vidro. A testemunha consistiu na pulverização de água destilada estéril + Tween 80 (0,01 por cento). Paralelamente, 60 cartelas contendo ovos esterilizados de A. kuehniella foram submetidas ao parasitismo por fêmeas de T. pretiosum por 24h. Destas, 30 cartelas foram pulverizadas com B. bassiana ou M. anisopliae e 30 com água destilada estéril + 0,01 por cento, Tween 80, sendo os ovos observados diariamente até a emergência do parasitóide. Metarhizium anisopliae provocou diminuição na emergência de T. pretiosum e causou mortalidade confirmada. Assim, experimentos de campo e de semi-campo devem ser conduzidos para a avaliação final dos efeitos nocivos desses entomopatógenos a Trichogramma, para que estratégias de controle conjuntas possam ser desenvolvidas para esses agentes de controle.