ABSTRACT
Endosymbiont bacteria can affect biological parameters and reduce the effectiveness of natural enemies in controlling the target insect. The objective of this work was to identify endosymbiont bacteria in Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), the main natural enemy used to manage Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). Genomic DNA from six A. nitens populations was extracted and polymerase chain reactions (PCR) were performed with the primers to detect endosymbiont bacteria in this insect. The PCR products were amplified, sequenced, and compared with sequences deposited in the GenBank for the bacteria identification. All A. nitens populations had the bacterium Yersinia massiliensis (Enterobacteriales:Enterobacteriaceae). This bacterium was originally described as free-living, and it is associated with and composes part of the A. nitens microbiota. This is the first report of Y. massiliensis in an insect host.
As bactérias endossimbiontes podem afetar os parâmetros biológicos e reduzirem a eficácia de inimigos naturais no controle do inseto alvo. O objetivo deste trabalho foi identificar bactérias endossimbiontes em Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), o principal inimigo natural usado no manejo de Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). O DNA genômico de seis populações de A. nitens foi extraído e as reações em cadeia da polimerase (PCR) realizadas com os primers para detectar bactérias endossimbiontes neste inseto. Os produtos de PCR foram amplificados, sequenciados e comparados com as sequências depositadas no GenBank para identificação das bactérias. Todas as populações de A. nitens tinham a bactéria Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). Esta bactéria foi originalmente descrita como de vida livre e está associada e compõe parte da microbiota de A. nitens. Este é o primeiro relato de Y. massiliensis em um hospedeiro.
Subject(s)
Animals , Pest Control, Biological , Polymerase Chain Reaction/veterinary , Wasps/genetics , YersiniaABSTRACT
Abstract Endosymbiont bacteria can affect biological parameters and reduce the effectiveness of natural enemies in controlling the target insect. The objective of this work was to identify endosymbiont bacteria in Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), the main natural enemy used to manage Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). Genomic DNA from six A. nitens populations was extracted and polymerase chain reactions (PCR) were performed with the primers to detect endosymbiont bacteria in this insect. The PCR products were amplified, sequenced, and compared with sequences deposited in the GenBank for the bacteria identification. All A. nitens populations had the bacterium Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). This bacterium was originally described as free-living, and it is associated with and composes part of the A. nitens microbiota. This is the first report of Y. massiliensis in an insect host.
Resumo As bactérias endossimbiontes podem afetar os parâmetros biológicos e reduzirem a eficácia de inimigos naturais no controle do inseto alvo. O objetivo deste trabalho foi identificar bactérias endossimbiontes em Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), o principal inimigo natural usado no manejo de Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). O DNA genômico de seis populações de A. nitens foi extraído e as reações em cadeia da polimerase (PCR) realizadas com os primers para detectar bactérias endossimbiontes neste inseto. Os produtos de PCR foram amplificados, sequenciados e comparados com as sequências depositadas no GenBank para identificação das bactérias. Todas as populações de A. nitens tinham a bactéria Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). Esta bactéria foi originalmente descrita como de vida livre e está associada e compõe parte da microbiota de A. nitens. Este é o primeiro relato de Y. massiliensis em um hospedeiro.
ABSTRACT
Endosymbiont bacteria can affect biological parameters and reduce the effectiveness of natural enemies in controlling the target insect. The objective of this work was to identify endosymbiont bacteria in Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), the main natural enemy used to manage Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). Genomic DNA from six A. nitens populations was extracted and polymerase chain reactions (PCR) were performed with the primers to detect endosymbiont bacteria in this insect. The PCR products were amplified, sequenced, and compared with sequences deposited in the GenBank for the bacteria identification. All A. nitens populations had the bacterium Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). This bacterium was originally described as free-living, and it is associated with and composes part of the A. nitens microbiota. This is the first report of Y. massiliensis in an insect host.
As bactérias endossimbiontes podem afetar os parâmetros biológicos e reduzirem a eficácia de inimigos naturais no controle do inseto alvo. O objetivo deste trabalho foi identificar bactérias endossimbiontes em Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), o principal inimigo natural usado no manejo de Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). O DNA genômico de seis populações de A. nitens foi extraído e as reações em cadeia da polimerase (PCR) realizadas com os primers para detectar bactérias endossimbiontes neste inseto. Os produtos de PCR foram amplificados, sequenciados e comparados com as sequências depositadas no GenBank para identificação das bactérias. Todas as populações de A. nitens tinham a bactéria Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). Esta bactéria foi originalmente descrita como de vida livre e está associada e compõe parte da microbiota de A. nitens. Este é o primeiro relato de Y. massiliensis em um hospedeiro.
Subject(s)
Animals , Weevils , Hymenoptera/genetics , Yersinia/genetics , Enterobacteriaceae/geneticsABSTRACT
Abstract The ages of parasitoid females and their hosts can have substantial effects on parasitism and parasitoid efficacy. This relationship has been investigated over the last few decades and found to vary among species. To our knowledge, it was virtually unknown for Trichogramma pretiosum wasps that parasitize Anticarsia gemmatalis eggs. Therefore, the influence of parasitoid and host age on the parasitism of T. pretiosum on eggs of A. gemmatalis was here evaluated in three independent bioassays. Neither the number of parasitized eggs nor that of emerged parasitoids differed between T. pretiosum females of different age. The number of parasitoids per egg and the sex ratio were higher for 5-day-old females. Regarding host age, the number of parasitized eggs was highest for A. gemmatalis eggs aged 24 h (9.60), followed by eggs aged 48 h (1.00), while no parasitism was observed for eggs aged 72 h. The number of parasitoids per egg and sex ratio were not influenced by host age. Preference was significantly higher for host eggs aged 24 h (79.67%), followed by eggs aged 48 h (16.99%) and 72 h (3.33%). Accordingly to these results, the key challenge for a successful T. pretiosum release to control A. gemmatalis in the field is to synchronize the presence of up to 5-day-old adults with the most susceptible phase of the host eggs (1 day).
ABSTRACT
The tomato is a crop of great importance for Brazilian agriculture. Among the most damaging pests, the small tomato borer, Neoleucinodes elegantalis Guenée (Lepidoptera: Crambiadae) has caused great losses, since they directly reach the fruits to be commercialized, being used for its handling a large volume of insecticides. In this way, the use of alternative techniques that help in the management of this pest becomes of great importance. Among them, the use of the egg parasitoid Trichogrammaspp. has been promising. Thus, the present study aimed to evaluate the performance of Trichogrammaspecies and/or strains in N. elegantalisby selection of strains. The selection was made based on four lineages maintained in the Nucleus of Scientific and Technological Development in Phytosanitary Management of Pests (NUDEMAFI), being three strains of the species T. pretiosumand one of T. galloispecies. The parameters evaluated were percentage of parasitized eggs, egg viability, number of individuals per eggs, sex ratio and number of Trichogrammaspp. to be released. The T. galloi(T. g1) showed the best parameters for selection of the strain. Estimating the optimal number of T. g1 in eggs of small-fruit-borerwas 82 individuals per egg parasitoid. Therefore, this strain wasselected for the management of the small tomato-borer, whose eggs presented favorable physicochemical characteristics for the development of the parasitoid.
Subject(s)
Animals , Pest Control, Biological , Lepidoptera/parasitology , WaspsABSTRACT
Abstract Wolbachia (Hertig) endosymbionts are extensively studied in a wide range of organisms and are known to be transmitted through the egg cytoplasm to the offsping. Wolbachia may cause several types of reproductive modifications in arthropods. In Trichogramma species, parthenogenesis-inducing Wolbachia bacteria allow females wasps to produce daughters from unfertilized eggs and these bacteria are present in at least 9% of all Trichogramma species. Phylogenetic studies have led to the subdivision of the Wolbachia clade in five supergroups (A, B, C, D and E) and Wolbachia from Trichogramma belong to supergroup B. Here, using the wsp gene, four groups of Wolbachia that infect Trichogramma species were distinguished and the addition of a new group "Ato" was suggested due to the addition of Wolbachia from Trichogramma atopovirilia (Oatman and Platner). Specific primers were designed and tested for the "Ato" group. Seventy-five percent of all evaluated Wolbachia strains from Trichogramma fell within "Sib" group.
Resumo Endosimbiontes do gênero Wolbachia (Hertig) são extensivamente estudados em uma ampla gama de organismos e são conhecidos por serem transmitidos via citoplasma do ovo hospedeiro para seu descendente. Wolbachia pode causar vários tipos de alterações reprodutivas nos artrópodes. Nas espécies de Trichogramma, a reprodução partenogenética induzida por Wolbachia, possibilita as fêmeas dos parasitoides a produção de fêmeas a partir de ovos não fertilizados e estas bactérias estão presentes em pelo menos 9% de todas as espécies de Trichogramma. Estudos filogenéticos têm levado a subdivisão do clado Wolbachia em cinco supergrupos (A, B, C, D and E). Wolbachia em Trichogramma pertence ao supergrupo B. Com o gene wsp foi possível se distinguir quatro grupos de Wolbachia que infectam Trichogramma e adicionar um novo grupo (Ato) devido a inclusão de Wolbachia detectada em Trichogramma atopovirilia (Oatman and Platner, 1983). Primers específicos foram construídos e testados para o grupo "Ato". Setenta e cinco por cento de todas as linhagens de Wolbachia que infectam Trichogramma se enquadraram dentro do grupo "Sib".
Subject(s)
Animals , Female , Bacterial Outer Membrane Proteins/metabolism , Wasps/microbiology , DNA Primers/genetics , Alphaproteobacteria/metabolism , Wolbachia/genetics , Genes, Bacterial/genetics , Phylogeny , Reproduction , Species Specificity , Symbiosis , Wasps/geneticsABSTRACT
The European pepper moth Duponchelia fovealis (Zeller, 1847) (Lepidoptera: Crambidae), despite being among the principal pests of strawberries in Brazil. However, biological control methods are rarely documented for this pest. In the current study, the goal was to select promising Trichogramma strains to enable the control of D. fovealis and to determine the acceptance of different ages of host eggs by the parasitoid. In the first bioassay, evaluations were done on the biological parameters of five strains of Trichogramma pretiosum Riley and one of Trichogramma galloi Zucchi (Hymenoptera: Trichogrammatidae). The best performance came from the strains, Tp18 (T. pretiosum) and Tg (T. galloi), showing parasitism and viability higher than 50 and 90%, respectively. Another bioassay revealed the acceptance of both these species (Tp18 and Tg) for different ages of D. fovealis eggs. All host ages were accepted by T. pretiosum (Tp18) and T. galloi, with a preference for younger eggs (65% parasitism). Adult emergence, number of individuals per egg and sex ratio revealed no significant differences with respect to the host age. The current study provides pertinent data on the selection and performance of Trichogramma species on D. fovealis eggs of different ages.
A traça do morangueiro Duponchelia fovealis (Zeller, 1847) (Lepidoptera: Crambidae) é uma das principais pragas da cultura do morango no Brasil. Entretanto, métodos de controle biológico desta praga são raramente documentados. Este trabalho teve como objetivo selecionar linhagens de Trichogramma e avaliar o parasitismo de diferentes idades de ovos de D. fovealis. Foram avaliados os parâmetros biológicos de cinco linhagens de Trichogramma pretiosum Riley e uma de Trichogramma galloi Zucchi (Hymenoptera: Trichogrammatidae). As espécies/linhagens com melhor desempenho foram Tp18 (T. pretiosum) e Tg (T. galloi), com taxas de parasitismo e viabilidade acima de 50 e 90%, respectivamente. Em seguida, foi avaliada a suscetibilidade das duas espécies (Tp18 e Tg) em diferentes idades de ovos de D. fovealis. Todas as idades do ovo hospedeiro avaliadas foram aceitas pelos dois parasitoides e houve uma maior tendência a parasitar ovos mais jovens. Em todas as idades do hospedeiro houve emergência de parasitoides adultos, e sem diferença significativa entre idades. As variáveis número de indivíduos por ovo e razão sexual não apresentaram diferença significativa quanto à idade do hospedeiro. O atual estudo fornece informações sobre a seleção e o desempenho de espécies de Trichogramma em diferentes idades de ovos de D. fovealis.
Subject(s)
Animals , Pest Control, Biological , Hymenoptera/parasitology , Lepidoptera/parasitologyABSTRACT
This study evaluated the parasitism of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) on eggs of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) at different ages and densities. The rates of parasitism and emergence, the number of parasitoids emerged per egg and sex ratio of offspring were evaluated in both experiments. Eggs of H. armigera up to 36 hours provided greater parasitism and emergence of adults compared to eggs up to 60 hours old. The number of parasitoids, which emerged per host egg, was greater than one and the sex ratio remained around 80% of females, regardless of the egg development stage. Females of T. pretiosum responded with superior rates of parasitism, emergence and number of parasitoids per egg at the densities of 20 and 25 eggs of H. armigera . These results indicate that T. pretiosum parasite with superior performance in eggs of up to 36h of age and densities of 20 eggs per female day- 1 in laboratory conditions. These results will help to establish the intervals between releases of parasitoids, aiming to control this pest, when adjusted with knowledge of the survival of the parasitoids in the field and in pest infestation.
Este trabalho avaliou o parasitismo de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) em ovos de Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) em diferentes idades e densidades. As taxas de parasitismo e emergência, número de parasitoides emergidos por ovo e razão sexual dos descendentes foram avaliados em ambos os experimentos. Ovos de H. armigera de até 36 horas proporcionaram maior parasitismo e emergência dos adultos em comparação com ovos com até 60 horas de idade. O número de parasitoides, que emergiram por ovo hospedeiro, foi superior a 1 e a razão sexual permaneceu em torno de 80% de fêmeas, independentemente do estágio de desenvolvimento do ovo. Fêmeas de T. pretiosum responderam com taxas superiores de parasitismo, emergência e número de parasitoides por ovo nas densidades de 20 e 25 ovos de H. armigera. Estes resultados indicam que T. pretiosum parasita com desempenho superior em ovos de até 36h de idade e densidades de 20 ovos por fêmea dia-1 em condições laboratoriais. Estes resultados ajudarão a estabelecer os intervalos entre as liberações de parasitoides, visando o controle desta praga, quando ajustado com o conhecimento da sobrevivência dos parasitoides no campo e na infestação de pragas.
Subject(s)
Host-Parasite Interactions , Parasites , Pest Control, BiologicalABSTRACT
Abstract Wolbachia (Hertig) endosymbionts are extensively studied in a wide range of organisms and are known to be transmitted through the egg cytoplasm to the offsping. Wolbachia may cause several types of reproductive modifications in arthropods. In Trichogramma species, parthenogenesis-inducing Wolbachia bacteria allow females wasps to produce daughters from unfertilized eggs and these bacteria are present in at least 9% of all Trichogramma species. Phylogenetic studies have led to the subdivision of the Wolbachia clade in five supergroups (A, B, C, D and E) and Wolbachia from Trichogramma belong to supergroup B. Here, using the wsp gene, four groups of Wolbachia that infect Trichogramma species were distinguished and the addition of a new group Ato was suggested due to the addition of Wolbachia from Trichogramma atopovirilia (Oatman and Platner). Specific primers were designed and tested for the Ato group. Seventy-five percent of all evaluated Wolbachia strains from Trichogramma fell within Sib group.
Resumo Endosimbiontes do gênero Wolbachia (Hertig) são extensivamente estudados em uma ampla gama de organismos e são conhecidos por serem transmitidos via citoplasma do ovo hospedeiro para seu descendente. Wolbachia pode causar vários tipos de alterações reprodutivas nos artrópodes. Nas espécies de Trichogramma, a reprodução partenogenética induzida por Wolbachia, possibilita as fêmeas dos parasitoides a produção de fêmeas a partir de ovos não fertilizados e estas bactérias estão presentes em pelo menos 9% de todas as espécies de Trichogramma. Estudos filogenéticos têm levado a subdivisão do clado Wolbachia em cinco supergrupos (A, B, C, D and E). Wolbachia em Trichogramma pertence ao supergrupo B. Com o gene wsp foi possível se distinguir quatro grupos de Wolbachia que infectam Trichogramma e adicionar um novo grupo (Ato) devido a inclusão de Wolbachia detectada em Trichogramma atopovirilia (Oatman and Platner, 1983). Primers específicos foram construídos e testados para o grupo Ato. Setenta e cinco por cento de todas as linhagens de Wolbachia que infectam Trichogramma se enquadraram dentro do grupo Sib.
ABSTRACT
ABSTRACT: The micro-hymenopterans of genus Trichogramma are eggs parasitoids used in the biological control of lepidopteran pests. The objectives of this study was to record the interaction of species of Trichogramma and their hosts on crops in the Mid-North, in the states of Maranhão and Piauí, Brazil. Lepidopteran eggs were sampled on crops and non-crops. Trichogramma atopovirilia , T. manicobai , T. galloi and T. pretiosum occur naturally in eggs of eight lepidopteran species. Natural parasitism shown by Trichogramma species reveals the importance of these parasitoids as agents for biological control in the Mid-North region.
RESUMO: Os micro-himenópteros do gênero Trichogramma são parasitoides de ovos utilizados no controle biológico de lepidópteros. Os objetivos deste estudo foram registrar as interações de espécies de Trichogramma e seus hospedeiros em culturas agrícolas do Meio-Norte, nos estados do Maranhão e Piauí. Foram amostrados ovos de lepidópteros em culturas agrícolas e plantas não cultivadas. Trichogramma atopovirilia, T. manicobai, T. galloi e T. pretiosum ocorreram naturalmente parasitando ovos de oito espécies de lepidópteros. O parasitismo natural evidencia a importância das espécies de Trichogramma como agente de controle biológico de pragas na região do Meio-Norte.
ABSTRACT
ABSTRACT In two independent bioassays, size and flight ability of parasitoids reared on eggs of Corcyra cephalonica for 19 generations and parasitoids reared on a natural host (Spodoptera frugiperda eggs) for 250 generations were compared as fast quality control procedures for insect rearing. The size of parasitoids was examined by morphometric analysis using a stereoscope. Length and width of the wings, right hind tibia, and the body of 20 individuals (males and females) were measured. In the analysis of flight ability, parasitoids were divided into three groups: individuals able to fly ("flyers"), individuals that did not fly but had no visible deformation ("walkers"), and individuals with visible deformation ("deformed"). We observed that parasitoids were larger when reared on the natural host than on the factitious host for all evaluated morphological characters. However, there was no significant difference between the treatments regarding the number of "flyers", "walkers" or "deformed" parasitoids. This indicates that even though the rearing of T. remus on a factitious host affects parasitoid size, it does not necessarily affect its flight ability and therefore suggests that C. cephalonica is suitable as a factitious host for mass rearing of T. remus. Other biological parameters still need to be evaluated, such as host finding ability, parasitism capacity, and parasitoid field efficacy in order to provide a more complete picture of the effects caused by a host change. However, because fast laboratory tests are needed in rearing facilities, the one used in this study might be useful to rapidly assess parasitoid quality.
ABSTRACT
Abstract ITS2 (Internal transcribed spacer 2) sequences have been used in systematic studies and proved to be useful in providing a reliable identification of Trichogramma species. DNAr sequences ranged in size from 379 to 632 bp. In eleven T. pretiosum lines Wolbachia-induced parthenogenesis was found for the first time. These thelytokous lines were collected in Peru (9), Colombia (1) and USA (1). A dichotomous key for species identification was built based on the size of the ITS2 PCR product and restriction analysis using three endonucleases (EcoRI, MseI and MaeI). This molecular technique was successfully used to distinguish among seventeen native/introduced Trichogramma species collected in South America.
Resumo Sequências do Espaço Transcrito Interno 2 (ITS2) têm sido utilizadas em estudos taxonômicos e sua utilidade constatada pela confiabilidade que o método confere à identificação das espécies de Trichogramma. Esta técnica molecular foi bem sucedida em distinguir dezessete espécies nativas e introduzidas de Trichogramma, coletadas na América do Sul. As sequências do DNAr variaram de 379 a 632 pb. Em 11 linhagens de T. pretiosum estudadas, o endosinbionte Wolbachia foi detectado pela primeira vez. Estas linhagens telítocas foram encontradas no Peru (9), Colômbia (1) e Estados Unidos (1). Uma chave dicotômica para identificação de espécies foi construída baseada no tamanho do produto da PCR do ITS2 e em análises de restrição utilizando-se três endonucleases (EcoRI, MseI and MaeI).
Subject(s)
Animals , Wasps/classification , Wasps/physiology , DNA, Ribosomal Spacer/genetics , Molecular Sequence Data , Parthenogenesis , Sequence Analysis, DNA , South America , Wasps/genetics , Wasps/microbiology , Wolbachia/physiologyABSTRACT
No impact of Bt soybean that express Cry1Ac protein on biological traits of Euschistus heros (Hemiptera, Pentatomidae) and its egg parasitoid Telenomus podisi (Hymenoptera, Platygastridae). Biological traits of the stink bug Euschistus heros and its main biological control agent Telenomus podisi were evaluated under controlled environmental conditions (25 ± 2ºC; 60 ± 10% RH; and 14/10 h photoperiod) by placing first instar nymphs into Petri dishes with pods originating from two soybean isolines (Bt-soybean MON 87701 × MON 89788, which expresses the Cry1Ac protein, and its near non-Bt isoline A5547) where they remained until the adult stage. Due to gregarious behavior exhibited by first instar nymphs, they were individualized only when at the second instar. Adults were separated by sex and weighed, and pronotum width of each individual was subsequently measured. They were placed into plastic boxes containing soybean grains of the same soybean isoline as food source. Egg viability and female fecundity were assessed in adult individuals. Adult females of T. podisi (up to 24h old) were placed with eggs of E. heros from mothers reared on both soybean isolines. Nymphal development time, insect weight, pronotum width, sex ratio, female fecundity, and egg viability (% emergence) of Euschistus heros did not differ between treatments. Eggto-adult development time, female longevity, sex ratio, and percentage of parasitized eggs were not impacted by the Bt-soybean (expressing Cry1Ac protein). Results indicate that the Bt-soybean, MON 87701 × MON 89788, has no direct significant impact on the two studied species.
ABSTRACT
O sucesso das liberações de Trichogramma spp. depende basicamente do conhecimento das características bioecológicas do parasitoide e da sua interação com o hospedeiro alvo. Assim, o objetivo deste trabalho foi avaliar a preferência hospedeira de T. pretiosum entre os ovos de S. frugiperda, S. albula, S. eridania, A. gemmatalis, P. includens, D. saccharalis e A. kuehniella. Para os testes de preferência, foram instaladas arenas com garrafas de polietileno e, em cada uma delas, foi colocada uma cartela com ovos de duas espécies de hospedeiros e uma fêmea do parasitoide por 24 horas. Os parâmetros avaliados foram o parasitismo ( por cento) e a emergência ( por cento). As fêmeas de T. pretiosum apresentaram preferência pelos ovos de A. kuehniella. No entanto, nos ensaios com A. gemmatalis X P. includens e D. saccharalis X S. frugiperda, não ocorreram diferenças no parasitismo. Assim, pode-se afirmar que, nos teste de livre escolha, na ausência do hospedeiro em que os parasitoides foram multiplicados (A. kuehniella), as fêmeas não apresentaram preferência ao parasitismo, o que indica a existência de condicionamento pré-imaginal do parasitoide. Os resultados da viabilidade dos ovos parasitados por T. pretiosum variaram entre os diferentes hospedeiros testados.
The success of Trichogramma spp. releases in biological control programs relies upon the knowledge of the parasitoid bio-ecological characteristics and the parasitoid interaction with the target pest. Therefore, this research aimed to evaluate T. pretiosum host preference among eggs of S. frugiperda, S. albula, S. eridania, A. gemmatalis, P. includens, D. saccharalis and A. kuehniella. Polyethylene cages were set to test host preference of T. pretiosum comparing each two groups of host species. The evaluated parameter was parasitism ( percent) and parasitoid emergence ( percent). T. pretiosum females parasitized preferably A. kuehniella eggs. However, in the bioassay with A. gemmatalis X P. includens and D. saccharalis X S. frugiperda there was no difference in the parasitism. Then, in the free choice test, in the absence of the host in which the parasitoid was reared (A. kuehniella), T. pretiosum shows no host preference indicating the existence of pre-imaginal conditioning acquired during larval development. The parasitism viability results were variable among the different tested hosts.
ABSTRACT
As altas produtividades na cultura do milho têm sido alcançadas em função de vários fatores técnicos, sendo o controle de pragas um dos mais importantes. Nesse sentido, o objetivo deste trabalho foi avaliar a persistência de agrotóxicos utilizados na cultura do milho ao parasitoide Trichogramma pretiosum. Foram avaliadas as persistências de sete inseticidas e três fungicidas, os quais foram diluídos separadamente em 200L de água e pulverizados sobre folhas de videira. Essas folhas foram levadas ao laboratório e utilizadas dentro de gaiolas aos 3, 10, 17, 24 e 31 dias, onde permaneceram confinados os adultos do parasitoide para contaminação. A mortalidade dos adultos de T. pretiosum foi mensurada indiretamente em função do menor número de ovos parasitados do hospedeiro alternativo Anagasta kuehniella. Os resultados foram comparados com o tratamento testemunha e os agrotóxicos classificados conforme categorização da IOBC. Foram utilizadas quatro repetições para cada tratamento. Os fungicidas Opera, Priori Xtra e Folicur 200 EC foram de vida curta (classe 1). Os inseticidas Match EC e Sumithion 500 CE foram de vida curta (classe 1); Lorsban 480 BR e Safety foram moderadamente persistentes (classe 3) e Engeo Pleno, Karate Zeon 50 CS e Tracer foram persistentes (classe 4) aos adultos de T. pretiosum.
The high yields in corn have been achieved due to various technical factors, being the pest control one of the most important. In this way, the objective was to evaluate the persistence of the pesticides used in corn field to the parasitoid Trichogramma pretiosum. It was evaluated the persistence of seven insecticides and three fungicides, which were separately diluted to 200L of water and sprayed on the vine leaves. These leaves were taken to the laboratory and used into cages at 3, 10, 17, 24 and 31 days, where remained confined the adults of the parasitoids to contamination. The adult mortality of T. pretiosum was measured according to the lower number of parasitized eggs of alternative host Anagasta kuehniella. The results were compared with the witness treatment and pesticides classified according to IOBC categorization. Four replicates for each treatment were used. The fungicides Opera, Priori Xtra and Folicur 200 EC were short life (class 1). The insecticides Match EC and Sumithion 500 CE were short life (class 1); Lorsban 480 BR and Safety were moderately persistent (class 3), and Engeo Pleno, Karate Zeon 50 CS and Tracer were persistent (class 4) to adults of T. pretiosum.
ABSTRACT
The effects of the egg density of Diaphania hyalinata (L.) on several biological parameters of Trichogramma exiguum Pinto & Platner and T. pretiosum Riley were investigated. For that, 24h-old egg masses were isolated in glass tubes (15 replicates; 1 egg mass = 1 replicate), and offered to parasitization by a newly-emerged female of T. pretiosum or T. exiguum 24h at the proportion of one female to 5, 10, 15, 20, 25, 30, 35 and 40 eggs of D. hyalinata. The following parameters were evaluated: number of parasitized eggs, number of individuals per egg, viability and sex ratio. Trichogramma exiguum parasitized more eggs than T. pretiosum when more than 25 eggs were available per female. The percentage of emergence was satisfactory to T. pretiosum in densities up to 15 eggs/female and up to 20 eggs/female for T. exiguum. The number of individuals per egg was not statistically different in both species except in the density of 25 eggs/female. It can be concluded that T. exiguum performed better than T. pretiosum at larger clutch sizes, as T. exiguum parasitization capacity increased as a result of the size of the host clutch size.
Subject(s)
Animals , Female , Clutch Size , Hymenoptera/physiology , Lepidoptera/parasitology , Ovum/parasitologyABSTRACT
Trichogramma spp. (Hymenoptera: Trichogrammatidae) parasitam ovos de Anticarsia gemmatalis (Lepidoptera: Noctuidae), o principal desfolhador de soja no Brasil. O objetivo deste trabalho foi avaliar o parasitismo de onze espécies/linhagens de Trichogramma em cartelas de cartolina com vinte ovos de A. gemmatalis por fêmea desse parasitoide durante 24 horas. A linhagem de Trichogramma atopovirilia (Hymenoptera: Trichogrammatidae) de Sete Lagoas, Minas Gerais, apresentou melhor desempenho com 19 ovos de A. gemmatalis parasitados por fêmea em 24 horas, viabilidade de 98% e razão sexual de 0,84. A linhagem de Trichogramma pretiosum de Cristalina, Goiás, parasitou 11,9 ovos de A. gemmatalis por fêmea com 98% de viabilidade e razão sexual de 0,65. Esse trabalho confirma a importância de se avaliar linhagens de Trichogramma antes de programas de controle biológico, pois diferentes linhagens de uma mesma espécie desse parasitoide apresentam resultados distintos.
Several Trichogramma (Hymenoptera: Trichogrammatidae) species parasitize Anticarsia gemmatalis (Lepidoptera: Noctuidae) eggs, the major soybean desfoliator in Brazil. The objective of this work was to evaluate the parasitism of eleven Trichogramma species/strains in cardboards with twenty eggs of A. gemmatalis by this parasitoid female for 24 hours. The strain trat - 2 Trichogramma atopovirilia (Hymenoptera: Trichogrammatidae) of Sete Lagoas, Minas Gerais, showed better performance with 19 A. gemmatalis eggs parasitized by female in 24 hours, 98% viability and sex ratio of 0.84. The strain Trichogramma pretiosum of Crystalline, Goiás, parasitized 11.9 A. gemmatalis eggs per female with 98% viability and sex ratio of 0.65. This work confirms the importance of evaluating Trichogramma strains before biological control programs, because different strains of the same species of parasitoid have distinct results.
Subject(s)
Glycine max/parasitology , Pest Control, Biological/methods , Hymenoptera , Lepidoptera/physiologyABSTRACT
Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis are commonly found in avocado and persimmon orchards in northern Parana state. However, their abundance depends on whether insecticides are used or not to control the key lepidopteran pests Stenoma catenifer (Wals.) (Lepidoptera: Elachistidae) and Hypocala andremona (Stoll) (Lepidoptera: Noctuidae), respectively. The aim of this work was to evaluate the effects of an aqueous neem seed extract (ANSE) at 15, 3 and 1.5 percent, and of an emulsifiable concentrate neem oil (ECNO) at 2.5, 0.5 and 0.25 percent on lifetime parameters of these trichogrammatids as a way of testing the feasibility of integrating the biological and chemical control methods. Chemicals were applied on Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs before or after parasitization (one, three or five days). ANSE was more deleterious to both parasitoid species than ECNO, regardless of the concentration and the time of application. The chemicals acted on a concentration and time dependent manner. Treating the host with neem before parasitism was less deleterious to wasp emergence, especially for T. annulata. Pre-treatments (24h) of the host eggs with ECNO at concentrations varying from 0.5 percent to 0.25 percent did not affect T. pretiosum longevity, but 2.5 percent reduced T. annulata survival. Feeding wasps with honey mixed with 0.25 percent ECNO negatively affected T. annulata survival.
Subject(s)
Animals , Azadirachta , Glycerides/pharmacology , Hymenoptera/drug effects , Pest Control, Biological/methods , Plant Extracts/pharmacology , Terpenes/pharmacologyABSTRACT
Foram avaliadas características biológicas de fêmeas de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) linhagem bonagota com três idades sobre ovos deBonagota salubricola (Meyrick) (Lepidoptera: Tortricidae) com cinco períodos de desenvolvimento embrionário. Ovos de B. salubricola com 0-24, 24-48, 48-72, 72-96, 96-120 horas de desenvolvimento embrionário foram oferecidos ao parasitismo por fêmeas de T. pretiosum com 0-24, 24-48 e 48-72 horas de idade, por 24 horas à 25 ± 1º C, 70 ± 10% de umidade relativa e 14 horas de fotofase. Fêmeas do parasitoide com 0-24 horas de vida apresentaram melhores taxas de parasitismo em ovos do hospedeiro com 24-48 horas de desenvolvimento embrionário. Fêmeas com 24-48 e 48-72 horas de vida apresentaram preferência por ovos com 0-24 horas de desenvolvimento embrionário. O percentual de emergência variou entre 20,0 e 60,0%, a razão sexual entre 0,56 e 0,85 e o número de parasitoides/ovo foi superior a um, sem diferença significativa. O ideal para programas de controle biológico de B. salubricola é utilizar o parasitoide na idade de 0-24 horas.
Biological characteristics ofTrichogramma pretiosumRiley (Hymenoptera: Trichogrammatidae) strain bonagota with three ages on eggs of Bonagota salubricola (Meyrick) (Lepidoptera: Tortricidae) at five embryonic developmental stages was studied under laboratory conditions (25 ± 1º C, 70 ± 10% of relative humidity and 14 hours of photophase). B. salubricola eggs with 024, 2448, 4872, 7296, 96120 hours of embryonic developmental stages were offered to T. pretiosum during 24 hours using parasitoid females with 024, 2448 and 4872 life hours. Parasitoid females with age of 0 24 hours showed a higher parasitism rate in eggs of B. salubricola with 2448 hours of embryonic development. Females with age of 2448 and 4872 hours, showed a preference for eggs with 0 24 hours of embryonic development. Adult emergence and sex ratio ranged from 20.0 to 60.0% and from 0.56 to 0.85 respectively. The number of parasitoids/egg was always more than one, ranging from 1.03 to 1.14. The ideal for a biological control program of B. salubricola using T. pretiosum strain bonagota is to use parasitoids with a maximum of 24 hours of age.
Subject(s)
Parasites , Malus/parasitology , Hymenoptera/physiology , Lepidoptera/embryologyABSTRACT
Oviposition site preference of Plutella xylostella (L.) and the parasitism by Trichogramma pretiosum Riley on cabbage plants at pre- and post-head formation were investigated in commercial cabbage field. Groups of six plants were randomly caged. In each cage three pairs of 24h-old P. xylostella moths were released, followed by 1,200 T. pretiosum females released 12h later. After 48h from parasitoid release, plants were harvested and fully inspected with the oviposition mapped according to the leaf position and their parts (basal, median and border) and upper and bellow leaf surfaces. Moth oviposition and egg parasitism were equally distributed across the plant leaves at the pre-head formation stage. At this stage, the basal part and the upper leaf surface were the preferred places for oviposition and egg parasitism, respectively. Cabbage plants at the post-head formation stage exhibited greater oviposition and egg parasitism in the inner leaf attached to the head. At this stage, the leaf border and the upper leaf surface were the preferred places for oviposition and egg parasitism, respectively. The infestation of P. xylostella on cabbage can be determined by egg counting at the pre- and post-head formation stages at the basal part of the leaves or at the border of the leaf attached to the head, respectively. And, in both plant stages parasitized eggs by T. pretiosum are more likely to be found at the upper leaf surface.