Quality control of Trichogramma atopovirilia and Trichogramma pretiosum (Hym.: Trichogrammatidae) adults reared under laboratory conditions

The objective of this work was to assess the flight capacity, parasitism and emergence of Trichogramma atopoviriliaand two strains of T. pretiosum (Hymenoptera: Trichogrammatidae) (L1 and L2). The flight capacity of these species was assessed in test units consisting of a plastic PVC cylinder with a rigid transparent plastic circle on the upper part and an extruded polystyrene disk closing its bottom. A tube was placed in each test unit containing a card with 300 Anagasta kuehniella (Lepidoptera: Pyralidae) eggs parasitised by Trichogramma. These cards were assessed to determine the parasitism rate and adult emergence of these natural enemies. T. atopovirilia and T. pretiosum L1 presented adequate flight capacity and parasitism, in addition to high percentages of adults emerged

Interações entre formigas cortadeias, fungos endofíticos e plantas

The aim of this research was to study the interaction between two pairs of mutualistic and symbiotic organisms: forest plants (in this case Atlantic forest) and endophytic fungi on the one hand, and leafcutter ants and their fungal symbiont on the other. In this context, the first part of this thesis is a review and synthesis of interactions (known or predicted) between the plant-endophyte mutualism and the ant-fungus mutualism. In the second part, we verified the presence of endophytic fungi in vegetative fragments that were being carried and were in middens of Atta laevigata in five fortnightly collections. A high fungal diversity was found and some fungal genera were found more or less than expected in rejected midden material. The genera Glomerella, Mycelia sterilia sp. 22, Pestalotiopsis, Phomopsis sp. 1 and Xylaria were more prevalent in carried fragments while the genera Cylindrocladium, Drechslera, Epicoccum, Fusarium, Mycelia sterilia sp. 21, Trichoderma e Ulocladium and Ulocladium were found more in rejected fragments from middens. A new finding was the genera Ulocladium and Trichoderma as endophytes in leaves of tropical plants. We discuss the potential risks of these endophytes, in particular the mycoparasites Trichoderma and Epicoccum. In the third part, ten nocturnal collections were made according to the same scheme but with the ant Atta sexdens rubropilosa. In this instance, Trichoderma was found to be more prevalent in rejected midden material than expected, possible indicating active rejection of these fragments. The Trichoderma isolates found were paired off in in vitro experiments against the ants’ mutualist fungus Leucoagaricus gongylophorus. We found that L. gongylophorus inhibited the growth of all of the Trichoderma isolates, indicating a potentially important line of defence for the colonies. We also investigated the endophytism of ten of these Trichoderma isolates in the plants Ligustrum japonicum and Eucalyptus grandis. Generally, endophytism was weak in L. japonicum although an important observation was made of the presence of some isolates in the bud. This was not found in E. grandis but in this plant endophytism was more expressive. Importantly, some isolates were re-isoltaed from leaves above the inoculated area, indicating the potential for systemic infection of plants. In the final part of the thesis, an isolate of Trichoderma supposed mycoparasite was offered with rice to queenless mini-colonies of the A. sexdens rubropilosa. No effects were found of the presence of this fungus on foraging activity, the amount of rice or leaves harvested or the amount of waste produced. Although no effect was found on survival time of the colonies, there were few of these. There was however a reduction in the survival time of the workers from Trichoderma-infected. To conclude, perspectives are offered for future study of this system, focussing in particular on the potential use of Trichoderma in biological control of leafcutter ants.O objetivo deste trabalho foi estudar a interação entre dois pares de organismos simbióticos e mutualistas: as plantas florestais (neste caso, Mata Atlântica) e fungos endofíticos por um lado, e as formigas cortadeiras e seus fungos simbiontes no outro. Neste contexto, a primeira parte desta tese é uma análise e síntese de interações (conhecida ou presumida) entre o mutualismo planta-endófito e o mutualismo formiga- fungo. Na segunda parte, verificou-se a presença de fungos endofíticos em fragmentos vegetativos que estavam sendo carregados ou que estavam no lixo de Atta laevigata em cinco coletas quinzenais. A elevada diversidade fúngica foi encontrada e alguns gêneros de fungos foram encontrados mais ou menos do que o esperado em material rejeitado. Os gêneros Glomerella, Mycelia sterilia sp. 22, Pestalotiopsis, Phomopsis sp. 1 e Xylaria foram mais prevalentes em fragmentos carregados enquanto que os gêneros Cylindrocladium, Drechslera, Epicoccum, Fusarium, Mycelia sterilia sp. 21, Trichoderma e Ulocladium foram encontrados mais em fragmentos rejeitado do lixo. A nova descoberta foram os gêneros Ulocladium e Trichoderma como endofíticos em folhas de plantas tropicais. Discutimos os potenciais riscos desses endofíticos, em particular os micoparasitas Trichoderma e Epicoccum. Na terceira parte, dez coletas noturnas foram feitas de acordo com o mesmo esquema relatado anteriormente, mas com a formiga Atta sexdens rubropilosa. Neste exemplo, Trichoderma prevaleceu em material rejeitado, indicando possível rejeição ativa desses fragmentos. Os isolados de Trichoderma encontrados foram colocados em cultivos pareados em experimentos in vitro com Leucoagaricus gongylophorus, fungo mutualista das formigas cortadeiras. Descobrimos que L. gongylophorus inibiu o crescimento de todos os isolados de Trichoderma, indicando uma linha potencialmente importante na defesa em colônias de formigas cortadeiras. Também foi investigado o endofitismo de dez isolados de Trichoderma em plantas de Ligustrum japonicum e de Eucalyptus grandis. O endofitismo foi fraco em L. japonicum, embora uma observação importante foi feita em função da presença de alguns isolados na gema apical e que não foi encontrado em E. grandis, porem o endofitismo foi mais expressivo. Alguns isolados foram re-isolados de folhas acima da área inoculada, indicando o potencial para infecção sistêmica de plantas. Na parte final da tese, um isolado de Trichoderma supostamente micoparasita foi oferecido com arroz para mini-colônias sem rainha de A. sexdens rubropilosa. Nenhum efeito foi encontrado na atividade de forrageamento, na quantidade de arroz ou folhas forrageadas e a quantidade de lixo produzido. Embora nenhum efeito tenha sido encontrado no tempo de sobrevivência das colônias, houve, no entanto uma redução no tempo de sobrevivência das operárias em colônias infectadas com Trichoderma. Para concluir, há perspectivas quanto estudos futuro deste sistema, concentrando-se em particular sobre o uso potencial de Trichoderma no controle biológico de formigas cortadeiras.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Parasitism behavior by Acarophenax lacunatus and impact of its phoresy on Rhyzopertha dominica

Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) é um ácaro parasitóide de ovos de algumas famílias da classe Insecta, podendo ser uma ferramenta complementar no controle de pragas de produtos armazenados. Este ácaro tem preferência por parasitar ovos de Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), em cujos adultos realiza forésia, forma passiva de deslocamento. Estudos a respeito do comportamento são de fundamental importância para a compreensão de diversos aspectos da biologia de artrópodes; no entanto estudos mais detalhados a respeito do comportamento de parasitismo de A. lacunatus e de sua relação forética com R. dominica ainda são poucos. Desta forma estudou-se o comportamento de parasitismo de A. lacunatus em ovos de R. dominica, bem como sua relação forética com esse coleóptero. Para a realização deste trabalho foram feitos dois ensaios. O primeiro abordou o estudo do comportamento de parasitismo de A. lacunatus em ovos de R. dominica. O segundo ensaio foi realizado em dois testes: um para verificar se a forésia de A. lacunatus afetaria a iniciação de vôo de seu hospedeiro e o outro para averiguar se a carga forética prejudicaria o caminhamento do seu hospedeiro. No estudo do comportamento de parasitismo de A. lacunatus, o ácaro foi colocado em uma arena, juntamente com um ovo hospedeiro, sendo observado até o parasitismo. A partir destas observações, descreveu-se o comportamento de parasitismo com as seguintes categorias comportamentais: marcha exploratória inicial, marcha exploratória após o encontro do ovo e parasitismo propriamente dito. Para o teste da relação entre forésia e iniciação de vôo utilizou-se adultos não-sexados de R. dominica, com e sem ácaros foréticos. Estes coleópteros foram colocados em uma câmara de bioensaio que foi avaliada, em intervalos de 10 minutos, por uma hora, para verificar se os besouros que iniciaram vôo tinham ou não ácaros foréticos. Observou-se que a maior parte dos besouros que iniciaram vôo não tinha ácaros aderidos ao corpo. No teste da relação de cargas foréticas com o caminhamento de R. dominica, besouros contendo diferentes cargas foréticas (0, 2, 4, 6, 8, 11 e 23 ácaros/inseto) foram observados quanto à distância caminhada, ao tempo de caminhamento e o tempo sem caminhar. Besouros com cargas foréticas de dois, quatro e seis ácaros caminharam mais e ficaram menos tempo sem caminhar ao contrário do observado para besouros com cargas foréticas de oito, 11 e 23 ácaros, os quais tenderam a ter um padrão de caminhamento semelhante aos de besouros sem ácaros foréticos. Em conclusão, além de se verificar que há um padrão comportamental uniforme no parasitismo de A. lacunatus sobre ovos de R. dominica, verificou-se que a presença de ácaros foréticos esteve associada à baixa freqüência de iniciação de vôo do besouro, e que, dependendo da densidade de ácaros presos ao coleóptero, o caminhamento parece ser estimulado ou não afetado.Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) is a parasitoid mite on eggs of some Insecta; this could be a complementary tool for pest management in stored products. This mite has preference for eggs of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) attaching to the adult beetles for dispersion, a phenomenon referred to as phoresy. Behavioral studies are critical for the understanding of several aspects of arthropod biology. No investigation on the parasitism behavior of A. lacunatus on and its phoretic relationship with R. dominica has been conducted yet and thus it was the objective of this work. Two sets of studies were conducted: the first investigated the parasitism behavior of A. lacunatus on the egg of R. dominica, and the second investigated whether phoresy of A. lacunatus would affect flight initiation and if phoretic loads would affected the walking behavior of adult beetles. In the study of parasitism behavior of A. lacunatus, the mite was placed in an arena together with in one host egg and observed until the parasitism. Based on observations of several individuals, the parasitism behavior was described with the following behavioral categories: initial exploratory march, exploratory march after finding the host egg and parasitism. In the test of flight initiation, adults of R. dominica with and without phoretic mites were placed in a bioassay chamber, which was evaluated in 10-min intervals for one hour to verify whether or not there were mites attached to the beetles that initiated flight. Results showed that most beetles initiating flight had no mites attached to their bodies. In the second test involving phoresy, beetles with different phoretic loads (0, 2, 4, 6, 8, 11 and 23 mites/insect) were observed in a video-recorded arena so as to determine the distance walked, time spent walking and time without walking. Beetles with phoretic loads of two, four and six mites walked longer distances and stayed less time without walking unlike beetles with phoretic loads of 11 and 23 mites, which tended to show a walking pattern similar to beetles without phoretic mites. In addition to observing a uniform pattern in the parasitism behavior by A. lacunatus on eggs of R. dominica, the presence of phoretic mites was associated with low frequency of flight initiation by the beetle, and depending on the number of mites attached to coleopteran, walking was stimulated or unaffected.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Screening of Fungi for Biological Control of a Triatomine Vector of Chagas Disease: Temperature and Trypanosome Infection as Factors

Submitted by Nuzia Santos ([email protected]) on 2019-08-13T13:38:58Z No. of bitstreams: 1 Screening of Fungi for Biological Control of a Triatomine Vector of Chagas Disease.pdf: 7595171 bytes, checksum: bd969267c04cc94dc7f2de676b153d9f (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2019-08-13T13:41:57Z (GMT) No. of bitstreams: 1 Screening of Fungi for Biological Control of a Triatomine Vector of Chagas Disease.pdf: 7595171 bytes, checksum: bd969267c04cc94dc7f2de676b153d9f (MD5)Made available in DSpace on 2019-08-13T13:41:57Z (GMT). No. of bitstreams: 1 Screening of Fungi for Biological Control of a Triatomine Vector of Chagas Disease.pdf: 7595171 bytes, checksum: bd969267c04cc94dc7f2de676b153d9f (MD5) Previous issue date: 2016Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Entomopathogenic fungi have been investigated as an alternative tool for controlling various insects, including triatomine vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. Here we tested the pathogenicity and virulence of ten isolates of the fungi Metarhizium spp. and Beauveria bassiana against Rhodnius prolixus and found all of the isolates to be virulent. We used two isolates (URPE-11 Metarhizium anisopliae and ENT-1 Beauveria bassiana) for further screening based on their prolific sporulation in vitro (an important property of fungal biopesticides). We characterized their virulences in a dose-response experiment and then examined virulence across a range of temperatures (21, 23, 27 and 30°C). We found isolate ENT-1 to maintain higher levels of virulence over these temperatures than URPE-11. We therefore used B. bassiana ENT-1 in the final experiment in which we examined the survival of insects parasitized with T. cruzi and then infected with this fungus (once again over a range of temperatures). Contrary to our expectations, the survival of insects challenged with the pathogenic fungus was greater when they had previously been infected with the parasite T. cruzi than when they had not (independent of temperature). We discuss these results in terms of aspects of the biologies of the three organisms. In practical terms, we concluded that, while we have fungal isolates of potential interest for development as biopesticides against R. prolixus, we have identified what could be a critical problem for this biological tool: the parasite T. cruzi appears to confer a measure of resistance to the insect against the potential biopesticide agent so use of this fungus as a biopesticide could lead to selection for vector competence

Assessment of Trichogramma species (Hymenoptera: Trichogrammatidae) for biological control in cassava (Manihot esculenta Crantz)

Cassava is the sixth most important crop in the world, and it is attacked by many pests, such as Erinnyis ello (L.) (Lepidoptera: Sphingidae). This lepidopteran pest has natural enemies that can efficiently control its population, such as Trichogramma spp. (Hymenoptera: Trichogrammatidae). The objective of this research was to assess the flight capacity, parasitism and emergence of Trichogramma pretiosum, T. marandobai and T. demoraesi and to select the most efficient species among them for biological control programs. The flight capacity of these species was assessed in test units consisting of a plastic PVC cylinder with a rigid, transparent plastic circle on the upper portion of the cylinder and an extruded polystyrene disk to close the bottom of the cylinder. A tube was placed in each test unit containing a card with 300 Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs that had been parasitised by Trichogramma. These cards were later assessed to determine the parasitism rate and adult emergence of these natural enemies. Trichogramma pretiosum presented the highest flight capacity (68 ± 5%), parasitism (74 ± 2%) and percentage of adults emerged (91 ± 3%) in the laboratory, making this species suitable for mass rearing and release in biological control programs.A mandioca é a sexta cultura mais importante no mundo, sendo atacada por diversas pragas, incluindo Erinnyis ello (Linnaeus) (Lepidoptera: Sphingidae). Este lepidóptero apresenta inimigos naturais que podem controlar de forma eficiente sua população, destacando os parasitoides oófagos Trichogramma spp. (Hymenoptera: Trichogrammatidae). O objetivo deste trabalho foi avaliar Trichogramma pretiosum, T. marandobai e T. demoraesi quanto à sua capacidade de parasitismo, emergência e voo, visando selecionar a espécie mais eficiente para programas de controle biológico. Os parâmetros biológicos foram avaliados em unidades teste, consistindo de um cilindro de PVC com um circulo de plástico rígido e transparente no topo e um disco de poliestireno vedando a parte inferior. Um tubo de ensaio contendo 300 ovos de Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) parasitados por Trichogramma foi colocado no interior da unidade. Trichogramma pretiosum apresentou maior capacidade de voo (68 ± 5%) e porcentagens de parasitismo (74 ± 2%) e emergência de adultos (91 ± 3%) em laboratório, sendo indicado para criação e liberação em programas de controle biológico

Assessment of Trichogramma species (Hymenoptera: Trichogrammatidae) for biological control in cassava (Manihot esculenta Crantz)

Cassava is the sixth most important crop in the world, and it is attacked by many pests, such as Erinnyis ello (L.) (Lepidoptera: Sphingidae). This lepidopteran pest has natural enemies that can efficiently control its population, such as Trichogramma spp. (Hymenoptera: Trichogrammatidae). The objective of this research was to assess the flight capacity, parasitism and emergence of Trichogramma pretiosum, T. marandobai and T. demoraesi and to select the most efficient species among them for biological control programs. The flight capacity of these species was assessed in test units consisting of a plastic PVC cylinder with a rigid, transparent plastic circle on the upper portion of the cylinder and an extruded polystyrene disk to close the bottom of the cylinder. A tube was placed in each test unit containing a card with 300 Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs that had been parasitised by Trichogramma. These cards were later assessed to determine the parasitism rate and adult emergence of these natural enemies. Trichogramma pretiosum presented the highest flight capacity (68 ± 5%), parasitism (74 ± 2%) and percentage of adults emerged (91 ± 3%) in the laboratory, making this species suitable for mass rearing and release in biological control programs