Responses of Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) to Rice and Corn Plants, Fed and Oviposited by Spodoptera frugiperda (Lepidoptera: Noctuidae).

The search behavior and parasitism of trichogrammatids can be affected by volatile compounds emitted by plants under herbivory and/or oviposition. Our aim was to evaluate the chemotactic behavior and parasitism rates of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) females against two varieties of corn and one of rice that underwent herbivory or oviposition by Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). In a glass Y-tube olfactometer, the parasitoids were given the choice between plants damaged by either herbivory or oviposition, with and without sentinel eggs, against those without damage. We also evaluated the average of parasitized eggs and the parasitoid emergence in sentinel eggs, which were next to plants that underwent herbivory contrasted with eggs next to undamaged plants. Trichogramma pretiosum was more attracted to rice and corn plants evaluated 24 h after herbivory compared to undamaged plants. Parasitoids preferred oviposited rice plants over control plants. Oviposited corn plants after 48 h were more attractive than non-oviposited plants without sentinel eggs. In the presence of sentinel eggs on the olfactometer tests, there was no difference in oviposition preference in corn. Parasitism was higher in sentinel eggs located near plants damaged by herbivory. This suggested that the egg parasitoid T. pretiosum not only uses chemical clues from rice and corn plants, damaged by herbivory, but also uses them as a strategy to search and increase parasitism in S. frugiperda eggs. However, the results of oviposition tests showed that plants of different species and varieties might respond differently to this type of damage.

Can Anastrepha fraterculus larval feeding influence chemotaxis and parasitism of Diachasmimorpha longicaudata and Aganaspis pelleranoi?

Anastrepha fraterculus (Diptera: Tephritidae) is a major barrier to fruit production and exportation. In Brazil, the native parasitoid Aganaspis pelleranoi (Hymenoptera: Figitidae) and the exotic parasitoid Diachasmimorpha longicaudata (Hymenoptera, Braconidae) stand out as biological control agents. Knowledge of the factors that affect interactions among parasitoids, A. fraterculus, and host fruits may enhance the use of these agents in biological control programmes. This study evaluated the chemotaxis and parasitism of A. pelleranoi and D. longicaudata females reared on A. fraterculus larvae and kept on an artificial diet, red guava (Psidium guajava) or apple (Malus domestica). Females of both parasitoid species that emerged from larvae raised on artificial diet, guava or apple, were tested to Y olfactometer choice tests. In the parasitism tests, both parasitoid species were made to choose between A. fraterculus larvae brushed with water, apple pulp or guava pulp. D. longicaudata females from artificial diet (control) did not distinguish between fruit odours; however, females of D. longicaudata from larvae kept in apple or guava directed to the odours of their original fruit. The greatest parasitism for D. longicaudata occurred in the units that contained the pulp in which the larvae grew. A. pelleranoi from artificial diet preferred guava odours, including the females kept in apple. Similar results were observed in the parasitism bioassays. Our results found that A. fraterculus larval feeding influenced search behaviour and parasitism of D. longicaudata, whereas A. pelleranoi rearing experience did not affect its host choices.

Field Responses of Rice Stalk Stink Bug, Tibraca limbativentris, to Synthetic Sex Pheromone and Isomers of 1,10-Bisaboladien-3-ol.

The rice stalk stink bug, Tibraca limbativentris Stål, is an important rice pest in Brazil, causing significant damage to rice plants and consequently yield losses, with a high invasive potential in Mexico and USA. The male-produced sex pheromone of this species was recently identified as a 7:3 mixture of (3S,6S,7R)-1,10-bisaboladien-3-ol (1) and (3R,6S,7R)-1,10-bisaboladien-3-ol (5) (a.k.a. zingiberenols). The aim of this study was to evaluate field responses of T. limbativentris females to the racemic mixture and stereoisomers of 1,10-bisaboladien-3-ol, including the male-produced sex pheromone. The results obtained in two rice-producing areas of Brazil (Rio Grande do Sul and Santa Catarina) showed that traps baited with the main component 1 alone, the racemic mixture, and a mixture of 1 and 5 were attractive to females of T. limbativentris. The minor component 5 was unable to attract females when used alone. The results indicate that the sex pheromone of T. limbativentris and racemic mixture of 1,10-bisaboladien-3-ol were equally attractive to co-specific females in rice fields, and they could be a tool to incorporate in rice stalk stink bug management programs.

Effects of exogenous methyl jasmonate and salicylic acid on rice resistance to Oebalus pugnax.

BACKGROUND: After herbivore attack, plants express inducible resistance-related traits activated by hormones, mainly jasmonic acid (JA) and salicylic acid (SA). Methyl jasmonate (MeJa) is a biologically active methyl ester of JA. Exogenous applications of JA, SA, and MeJa induce responses similar to herbivory by insects. In this study, rice, Oryza sativa L. (Poaceae), plants were treated with two concentrations of MeJa (2 and 5 mmol L-1 ), two concentrations of SA (8 and 16 mmol L-1 ) and herbivory to evaluate effects of elicitation and herbivory on resistance to the rice stink bug (RSB) Oebalus pugnax Fabricius, 1775 (Hemiptera: Pentatomidae), an injurious insect pest of rice in the United States. RESULTS: Nymphs developing on plants treated with SA 16 mmol L-1 took longer to reach adulthood than nymphs developing on check plants. Grains per panicle were higher in plants treated with SA 16 mmol L-1 and MeJa in both concentrations than in check treatment. Plants treated with SA emitted five of six volatile compounds identified in equal or higher amounts than plants subjected to previous herbivory, particularly methyl salicylate, a known defense-related compound. Salicylic acid 16 mmol L-1 was the treatment that elicited the highest amount of all volatiles. In the field assay, plots treated with SA 16 mmol L-1 showed lower spikelet sterility and a tendency for fewer bugs to be found in plots. CONCLUSION: Rice plants possess defense mechanisms that can be elicited using hormones as elicitors, mainly SA 16 mmol L-1 , to induce resistance against RSB. © 2018 Society of Chemical Industry.

Novel nanoscale pheromone dispenser for more accurate evaluation of Grapholita molesta (Lepidoptera: Tortricidae) attract-and-kill strategies in the laboratory.

BACKGROUND: Nanotechnology has recently allowed the production of formulations for controlled release of active ingredients. In the present study, the electrospinning technique was used to produce nanoscale dispensers for attract-and-kill strategies. Non-woven nanofibres containing insecticide (cypermethrin) and (E)-8,(Z)-8-dodecenyl acetate and (Z)-8-dodecanol (0.87 mg L-1 ), the main components of Grapholita molesta (Lepidoptera: Tortricidae) (Busck) pheromone, were evaluated in laboratory experiments. Male electroantennographic (EAG) responses and mortality (tarsal-contact and attract-and-kill behavioural cages) bioassays were performed for nanofibres (with and without insecticide) exposed for different periods (21, 42, 63 and 84 days) in controlled and non-exposed conditions. RESULTS: There were no significant differences in G. molesta male EAG responses based on the time of exposure within treatments. Nanofibres with pheromone only and with pheromone plus insecticide elicited equal EAG responses. Mortality in tarsal-contact bioassays was greater than 87% after exposure for 84 days. In the attract-and-kill bioassays, mortality ranged from 28.4 to 56.6%, although no difference was observed on insect mortalities over time (24, 48 and 72 h). CONCLUSION: Incorporation of cypermethrin in nanofibres did not interfere with G. molesta attractiveness. Both aspects of the strategy, the attractant and killing effects, were recorded using innovative nanofibres, and long-term effects suggest a controlled release of pheromone and insecticide. © 2017 Society of Chemical Industry.

Influência da idade do hospedeiro e da aprendizagem no comportamento quimiotáxico e no parasitismo de Trichogramma pretiosum / Influence of host age and learning on chemotactic behavior and parasitism of Trichogramma pretiosum

Trichogramma pretiosum Riley, 1879 mantido em ovos de Ephestia kuehniella Zeller, 1879, tem sido utilizado no controle biológico de Spodoptera frugiperda (J. E. Smith, 1797). No entanto, fatores como idade do hospedeiro e experiência prévia, podem influenciar o parasitismo e o comportamento do parasitoide. Esse estudo avaliou a influência da idade dos ovos e da experiência em ovos e extrato de ovos de S. frugiperda no comportamento quimiotáxico e no parasitismo de T. pretiosum. Ovos de S. frugiperda com 24, 48 e 72 horas, foram expostos a fêmeas de T. pretiosum. Também foi avaliado o tempo de experiência do parasitoide, no mesmo hospedeiro, por 1, 3, 4, 5, 6 e 24 horas, assim como, seu tempo de exposição (1, 2, 3 e 24 horas). As respostas quimiotáxicas de T. pretiosum (experiente e não experiente) em extrato de ovos de S. frugiperda foram observadas em olfatômetro tipo Y. As taxas de parasitismo foram registradas em teste de escolha, com insetos experientes e inexperientes com ovos e extrato de ovos de S. frugiperda. O parasitismo em S. frugiperda foi significativamente maior em ovos com 24 horas de idade. Fêmeas inexperientes e experientes por 1, 3 e 4 horas, apresentaram uma menor taxa de parasitismo, quando comparadas a fêmeas expostas por 5, 6 e 24 horas. Não houve diferença de parasitismo em fêmeas expostas por 2, 3 e 24 horas, comparadas às expostas por uma hora. Fêmeas experientes foram mais atraídas ao extrato de ovos de S. frugiperda, do que ao controle (hexano). A porcentagem de parasitismo, em fêmeas inexperientes, foi maior em ovos de E. kuehniella (hospedeiro de origem), no entanto, o mesmo resultado não foi observado em fêmeas experientes.

Trichogramma pretiosum Riley, 1879 reared on Ephestia kuehniella Zeller, 1879 eggs, have been used in biological control of Spodoptera frugiperda (J. E. Smith, 1797). However, host age and experience just after emergence might have some influence on parasitism and parasitoid behavior. This study evaluated the influence of S. frugiperda host age and egg odor experience, on chemotactic behavior and parasitism of T. pretiosum. Spodoptera frugiperda eggs with 24, 48 and 72 hours were exposed to T. pretiosum females. Parasitoid time experience, in the same host, was evaluated within 1, 3, 4, 5, 6 and 24 hours, as well as, its host exposed time (1, 2, 3 and 24 hours). Chemotactic responses of T. pretiosum (experienced and inexperienced females) to S. frugiperda egg extracts were recorded in Y-tube olfactometer. We also observe parasitism rates (choice tests) in insects with and without experience. The parasitism average was higher in S. frugiperda eggs with 24 hours. Inexperienced females and those experienced for 1, 3 and 4 hours, parasitized less S. frugiperda eggs compared to those for 5, 6 and 24 hours. There was no difference in parasitism from females exposed for 2, 3 and 24 hours when compared to those exposed for one hour. Experienced females were more attracted to S. frugiperda eggs odor than to control (hexano). Parasitism percentage, by inexperienced parasitoids, was greater in E. kuehniella eggs (original host) than in S. frugiperda, however it was not observed in experienced females.

Flutuação populacional e estimativa do número de gerações de Anastrepha fraterculus (Diptera: Tephritidae) em pomar de macieira em Caçador, Santa Catarina, Brasil / Population fluctuation and estimate of generations number of Anastrepha fraterculus (Diptera: Tephritidae) in apple orchard in Caçador, Santa Catarina, Brazil

Este estudo teve como objetivos avaliar a flutuação populacional e estimar o número de gerações por ano de Anastrepha fraterculus (Diptera: Tephritidae), com base nas variáveis meteorológicas de Caçador, Santa Catarina, Brasil. O estudo foi conduzido em pomar orgânico de macieira, de outubro de 2009 a abril de 2012. O número de moscas-das-frutas foi aferido semanalmente, com quatro armadilhas do tipo McPhail iscadas com Torula®. A associação entre o número de adultos capturados e as variáveis meteorológicas (temperaturas máxima, mínima e média, precipitação pluviométrica e umidade relativa do ar) foi feita pelo coeficiente de correlação de Pearson (p < 0,05). Para o período de entressafra (maio a setembro), os valores médios diários das variáveis meteorológicas foram calculados pelos testes F ou de Kruskal-Wallis (p < 0,05). O número de gerações/ano foi estimado utilizando-se os dados de temperatura mínima de 2009 até 2012, constante térmica e temperatura basal estabelecidos para A. fraterculus. Verificou-se que a mosca-das-frutas sul-americana ocorreu de novembro a abril, com picos populacionais em janeiro ou fevereiro. Apenas na safra 2010/2011 houve correlação entre o número médio de adultos capturados e as temperaturas máxima, média e mínima. Estimou-se que podem ocorrer em torno de oito gerações de A. fraterculus por ano em Caçador, Santa Catarina.(AU)

This study aimed to evaluated the population fluctuation and estimate the number of Anastrepha fraterculus (Diptera: Tephritidae) generations per year, based on meteorological variables in Caçador, SC, Brazil. The work was carried out in an organic apple orchard from October/2009 to April/2012. The fruit flies numbers were weekly recorded with four McPhail traps baited with Torula®. The association between the number of adults captured and meteorological variables (maximum, average and minimum temperatures, rainfall and relative humidity) was calculated using Pearson's correlation coefficient (p < 0.05). In off-season crop (May to September), the daily average of the meteorological variables were evaluated calculated by F or Kruskal-Wallis tests (p < 0.05). The number of generations per year was estimated based on minimum temperature from 2009 to 2012, thermal constant and basal temperature, established for A. fraterculus. The South American fruit fly occurred from November to April, with population peaks in January or February. We observed, only in 2010/2011 crop season, correlation between average number of adults captured and maximum, average and minimum temperatures. It was estimated that may occur about eight A. fraterculus generations per year in Caçador, Santa Catarina.(AU)

Volatiles Mediating Parasitism of Euschistus conspersus and Halyomorpha halys Eggs by Telenomus podisi and Trissolcus erugatus.

This study identified chemicals found on the eggs of two stink bug species, one native to western North America, Euschistus conspersus, and an invasive species from Asia, Halyomorpha halys. The responses of two scelionid egg parasitoids, Trissolcus erugatus and Telenomus podisi, toward natural stink bug egg volatiles, and synthetic reconstructions of egg volatiles, were tested in bioassays. A compound, methyl (2E,4Z)-2,4-decadienoate, previously identified as the major component of the male-produced aggregation pheromone of E. conspersus, was the major volatile identified from extracts of E. conspersus eggs. In contrast, for H. halys, the sesquiterpenoids that compose the male-produced aggregation pheromone of this species were not detected on eggs, whereas the presence of hexadecanal, octadecanal, and eicosanal was detected. In laboratory olfactometer tests, both Tr. erugatus and Te. podisi females were attracted to extracts of E. conspersus eggs, and to synthetic methyl (2E,4Z)-2,4-decadienoate. However, female Tr. erugatus and Te. podisi wasps were repelled, both by extracts of H. halys eggs and by a blend of the aldehydes identified from H. halys eggs. A follow-up field study, using hexane-washed and intact E. conspersus as sentinel eggs, showed that the parasitoids Trissolcus erugatus and Gryon obesum emerged from these eggs. Sentinel hexane-washed eggs treated with 3 ng of methyl (2E,4Z)-2,4-decadienoate were parasitized more by these two species than were hexane-washed or unwashed eggs, whereas hexane-washed eggs treated with a comparable dose of the C16,18,20 aldehyde mixture were avoided by these parasitoids. In a further field experiment, Trissolcus basalis was the primary parasitoid found in sticky traps baited with methyl (2E,4Z)-2,4-decadienoate, indicating that this species was attracted to, but either did not oviposit or develop in the E. conspersus sentinel eggs in the previous experiment.

Revisiting the Male-Produced Aggregation Pheromone of the Lesser Mealworm, Alphitobius diaperinus (Coleoptera, Tenebrionidae): Identification of a Six-Component Pheromone from a Brazilian Population.

The lesser mealworm, Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae), is a cosmopolitan insect pest affecting poultry production. Due to its cryptic behavior, insecticide control is usually not efficient. Thus, sustainable and effective methods would have an enormous and positive impact in poultry production. The aim of this study was to confirm the identity of the male-produced aggregation pheromone for a Brazilian population of A. diaperinus and to evaluate its biological activity in behavioral assays. Six male-specific compounds were identified: (R)-limonene (1), (E)-ocimene (2), 2-nonanone (3), (S)-linalool (4), (R)-daucene (5), all described before in an American population, and a sixth component, (E,E)-α-farnesene (6), which is apparently exclusive to a Brazilian population. Y-Tube bioassays confirmed the presence of a male-produced aggregation pheromone and showed that all components need to be present in a similar ratio and concentration as emitted by male A. diaperinus to produce a positive chemotactic response.

Aprendizagem e memória de Telenomus podisi (Hymenoptera, Platygastridae) / Learning and memory in Telenomus podisi (Hymenoptera, Platygastridae)

The egg parasitoid Telenomus podisi Ashmead, 1893 is an important natural control agent of stink bugs. Its success as a parasitoid depends on its host-locating ability, which may be influenced by learning and memory. This study used lemongrass [Cymbopogon citratus (DC.) Stapf. (Poales, Poaceae)] extract to assess the capacity for learning and memory retention time of T. podisi at different developmental stages of the immature phase. Eggs of Euschistus heros (Fabricius, 1798) (Hemiptera, Pentatomidae) parasitized by T. podisi and at different parasitoid juvenile developmental stages were isolated in glass tubes containing filter paper with lemongrass extract or acetone solvent (control). After emergence, T. podisi females were tested in a Y-tube olfactometer containing both scents. Inexperienced females were subjected to the same scents as experienced. To assess memory, females that emerged from eggs that were in contact with lemongrass extract throughout the immature developmental stage were given a choice between lemongrass extract and acetone when they were 24, 48, 72, and 96 hours old. Females that had contact with the lemongrass during the juvenile phase preferred lemongrass, while inexperienced females or those exposed to acetone chose the solvent. The presence of lemongrass all through the immature developmental stage altered the chemotaxic orientation of T. podisi and prompted learning in these organisms that lasted for up to 72 hours.

O parasitoide de ovos Telenomus podisi Ashmead, 1893 é um importante agente de controle natural de percevejos e seu sucesso de parasitismo está associado à habilidade para a localização do hospedeiro, sendo a aprendizagem e a memória um dos fatores que podem influenciar esta interação. O trabalho avaliou a capacidade de aprendizagem e tempo de retenção da memória de T. podisi ao extrato de capim-limão [Cymbopogon citratus (DC.) Stapf. (Poales, Poaceae)], em diferentes estágios do desenvolvimento da fase imatura. Ovos de Euschistus heros (Fabricius, 1798) (Hemiptera, Pentatomidae) parasitados por T. podisi foram individualizados em tubos de vidro contendo papel filtro com extrato de capim-limão ou solvente acetona (controle) e mantidos em diferentes estágios do desenvolvimento jovem dos parasitoides. Após a emergência, fêmeas de T. podisi foram testadas em olfatômetro tipo "Y" aos odores de ambos tratamentos. Fêmeas inexperientes foram submetidas aos mesmos odores das experientes. Para avaliar a memória, fêmeas oriundas de ovos que permaneceram em contato com o extrato de capim-limão por todo o desenvolvimento do estágio imaturo, foram testadas, após 24, 48, 72 e 96 horas de idade ao odor de capim-limão e acetona. Fêmeas que permaneceram em contato com o capim-limão por toda a fase jovem, direcionaram-se preferencialmente para este extrato, diferente das inexperientes ou das expostas à acetona, as quais preferiram o solvente. A presença do capim-limão, durante todo o estágio do desenvolvimento imaturo, alterou a orientação quimiotáxica de T. podisi, desencadeando aprendizagem nestes organismos, a qual se manteve por até 72 horas.

Aprendizagem e memória de Telenomus podisi (Hymenoptera, Platygastridae) / Learning and memory in Telenomus podisi (Hymenoptera, Platygastridae)

The egg parasitoid Telenomus podisi Ashmead, 1893 is an important natural control agent of stink bugs. Its success as a parasitoid depends on its host-locating ability, which may be influenced by learning and memory. This study used lemongrass [Cymbopogon citratus (DC.) Stapf. (Poales, Poaceae)] extract to assess the capacity for learning and memory retention time of T. podisi at different developmental stages of the immature phase. Eggs of Euschistus heros (Fabricius, 1798) (Hemiptera, Pentatomidae) parasitized by T. podisi and at different parasitoid juvenile developmental stages were isolated in glass tubes containing filter paper with lemongrass extract or acetone solvent (control). After emergence, T. podisi females were tested in a Y-tube olfactometer containing both scents. Inexperienced females were subjected to the same scents as experienced. To assess memory, females that emerged from eggs that were in contact with lemongrass extract throughout the immature developmental stage were given a choice between lemongrass extract and acetone when they were 24, 48, 72, and 96 hours old. Females that had contact with the lemongrass during the juvenile phase preferred lemongrass, while inexperienced females or those exposed to acetone chose the solvent. The presence of lemongrass all through the immature developmental stage altered the chemotaxic orientation of T. podisi and prompted learning in these organisms that lasted for up to 72 hours.(AU)

O parasitoide de ovos Telenomus podisi Ashmead, 1893 é um importante agente de controle natural de percevejos e seu sucesso de parasitismo está associado à habilidade para a localização do hospedeiro, sendo a aprendizagem e a memória um dos fatores que podem influenciar esta interação. O trabalho avaliou a capacidade de aprendizagem e tempo de retenção da memória de T. podisi ao extrato de capim-limão [Cymbopogon citratus (DC.) Stapf. (Poales, Poaceae)], em diferentes estágios do desenvolvimento da fase imatura. Ovos de Euschistus heros (Fabricius, 1798) (Hemiptera, Pentatomidae) parasitados por T. podisi foram individualizados em tubos de vidro contendo papel filtro com extrato de capim-limão ou solvente acetona (controle) e mantidos em diferentes estágios do desenvolvimento jovem dos parasitoides. Após a emergência, fêmeas de T. podisi foram testadas em olfatômetro tipo "Y" aos odores de ambos tratamentos. Fêmeas inexperientes foram submetidas aos mesmos odores das experientes. Para avaliar a memória, fêmeas oriundas de ovos que permaneceram em contato com o extrato de capim-limão por todo o desenvolvimento do estágio imaturo, foram testadas, após 24, 48, 72 e 96 horas de idade ao odor de capim-limão e acetona. Fêmeas que permaneceram em contato com o capim-limão por toda a fase jovem, direcionaram-se preferencialmente para este extrato, diferente das inexperientes ou das expostas à acetona, as quais preferiram o solvente. A presença do capim-limão, durante todo o estágio do desenvolvimento imaturo, alterou a orientação quimiotáxica de T. podisi, desencadeando aprendizagem nestes organismos, a qual se manteve por até 72 horas.(AU)

Parasitismo de ovos de Tibraca limbativentris Stål (Hemiptera: Pentatomidae) em lavoura de arroz irrigado, Eldorado do Sul, RS

The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is an important pest of rice in Brazil. This study aimed to register egg parasitoids of T. limbativentris in irrigated rice crop in Eldorado do Sul (state of Rio Grande do Sul, Brazil). The area (603 m2) was inspected weekly from 01/21/2010 to 03/03/2010 and rice stem stink bug eggs were collected. It was observed only the occurrence of Telenomus podisi (Ashmead) (Hymenoptera: Platygastridae) as egg parasitoid and the parasitism rate was 75%. This is the first record of T. podisi in rice stem stink bug eggs collected in rice fields in the state of Rio Grande do Sul.

O percevejo-do-colmo, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), é uma importante praga da cultura do arroz no Brasil. O presente trabalho objetivou registrar a ocorrência de parasitoides de ovos de T. limbativentris em lavoura de arroz irrigado, situada no município de Eldorado do Sul, Rio Grande do Sul. A área (603 m2) foi vistoriada semanalmente, de 21/01/2010 a 03/03/2010, coletando-se posturas do percevejo-do-colmo. Constatou-se somente a ocorrência de Telenomus podisi(Ashmead) (Hymenoptera: Platygastridae) como parasitoide de ovos, sendo o índice de parasitismo de 75%. Este é o primeiro registro de T. podisi em ovos do percevejo-do-colmo em lavouras de arroz no Rio Grande do Sul.

Parasitismo de ovos de Tibraca limbativentris Stål (Hemiptera: Pentatomidae) em lavoura de arroz irrigado, Eldorado do Sul, RS / Egg parasitism of Tibraca limbativentris Stål (Hemiptera: Pentatomidae) in irrigated rice crops, Eldorado do Sul, RS

O percevejo-do-colmo, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), é uma importante praga da cultura do arroz no Brasil. O presente trabalho objetivou registrar a ocorrência de parasitoides de ovos de T. limbativentris em lavoura de arroz irrigado, situada no município de Eldorado do Sul, Rio Grande do Sul. A área (603 m2 ) foi vistoriada semanalmente, de 21/01/2010 a 03/03/2010, coletando-se posturas do percevejo-do-colmo. Constatou-se somente a ocorrência de Telenomus podisi (Ashmead) (Hymenoptera: Platygastridae) como parasitoide de ovos, sendo o índice de parasitismo de 75%. Este é o primeiro registro de T. podisi em ovos do percevejodo-colmo em lavouras de arroz no Rio Grande do Sul.

The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is an important pest of rice in Brazil. This study aimed to register egg parasitoids of T. limbativentris in irrigated rice crop in Eldorado do Sul (state of Rio Grande do Sul, Brazil). The area (603 m2 ) was inspected weekly from 01/21/2010 to 03/03/2010 and rice stem stink bug eggs were collected. It was observed only the occurrence of Telenomus podisi (Ashmead) (Hymenoptera: Platygastridae) as egg parasitoid and the parasitism rate was 75%. This is the first record of T. podisi in rice stem stink bug eggs collected in rice fields in the state of Rio Grande do Sul.

Age and multiple mating effects on reproductive success of Grapholita molesta (Busck) (Lepidoptera, Tortricidae) / Efeito da idade e de múltiplos acasalamentos no sucesso reprodutivo de Grapholita molesta (Busck) (Lepidoptera, Tortricidae)

The reproductive success of the oriental peach moth was evaluated in four experiments: 1) assessment of the mating duration, fecundity, fertility and longevity of females paired with virgin and immediately mated males; 2) mating duration, spermatophore size, fecundity, fertility and longevity in females paired with virgin and up to four times mated males; 3) receptivity of females to additional copulations after mating with virgin or mated males, and the effects of this behavior in female fecundity, fertility and longevity; 4) influence of insects age in the reproductive output. Males (33%) could copulate immediately after a previous copula. They were fertile until the fourth mating, but only in the first copula they transferred the longest (1.43 ± 0.10 mm) and widest (0.83 ± 0.11 mm) spermatophore, presenting the fastest mating duration (34.8 ± 2.62 min). A high proportion of females copulated by non-virgin males (84%) was receptive to other copulas, in comparison to those copulated by virgin males (32.4%). However, the fecundity, fertility, and longevity were similar among females that copulate once or more. The age was the most important factor affecting reproductive variables, where one and three day old insects had a significant higher fecundity, fertility and presented a shorter mating duration in comparison with older individuals. Results pointed out that the reproductive capacity of Grapholita molesta changes a little with respect to the analyzed factors, highlighting the elevated biotic potential of the species.

O sucesso reprodutivo da mariposa-oriental foi avaliado em quatro bioensaios: 1) avaliação do tempo de cópula, fecundidade, fertilidade e longevidade de fêmeas pareadas com machos virgens e imediatamente acasalados; 2) tempo de cópula, tamanho do espermatóforo, fecundidade, fertilidade e longevidade em fêmeas pareadas com machos virgens e acasalados até quatro vezes; 3) receptividade de fêmeas a cópulas adicionais após o acasalamento com machos virgens ou acasalados, e o efeito deste comportamento na fecundidade, fertilidade e longevidade das fêmeas; 4) influência da idade dos insetos no sucesso reprodutivo. Machos (33%) foram capazes de copular logo após o primeiro acasalamento. Os machos foram igualmente férteis até o quarto acasalamento, mas somente na primeira cópula transferiram espermatóforo com maior comprimento (1,43 ± 0,10 mm) e na largura (0,83 ± 0,11 mm), e apresentaram cópula de menor duração (34,8 ± 2,62 min). Uma maior proporção de fêmeas copuladas por machos não virgens (84%) foram receptivas a novos acasalamentos em comparação as pareadas com virgens (32,4%). No entanto, a fecundidade, fertilidade e longevidade foram semelhantes entre as fêmeas que copularam uma ou várias vezes. A idade foi o fator que mais afetou as variáveis reprodutivas, onde insetos de um e três dias de idade foram significativamente mais fecundos, férteis e apresentaram menor tempo de cópula que os mais velhos. Os resultados apontam que a capacidade de reprodução de G. molesta altera-se pouco com relação aos fatores analisados, ressaltando assim, elevado potencial biótico da espécie.

First records of Glyphepomis adroguensis (Hemiptera, Pentatomidae) and its parasitoid, Telenomus podisi (Hymenoptera, Platygastridae), on irrigated rice fields in Rio Grande do Sul, Brazil / Primeiros registros de Glyphepomis adroguensis (Hemiptera, Pentatomidae) e seu parasitoide, Telenomus podisi (Hymenoptera, Platygastridae), em arroz irrigado no Rio Grande do Sul

First records of Glyphepomis adroguensis (Hemiptera, Pentatomidae) and its parasitoid, Telenomus podisi (Hymenoptera, Platygastridae), on rice fields in Rio Grande do Sul, Brazil. Eggs, nymphs, and adults of Glyphepomis adroguensis Berg, 1891 (Hemiptera, Pentatomidae) were observed for the first time on rice fields (Oryza sativa L.) in Charqueadas (29º59'S, 51º31'W) and Eldorado do Sul (30º02'S, 51º23'W) of Rio Grande do Sul state, Brazil. Telenomus podisi Ashmead, 1893 (Hymenoptera, Platygastridae) was found in G. adroguensis eggs.

Primeiros registros de Glyphepomis adroguensis (Hemiptera, Pentatomidae) e seu parasitoide, Telenomus podisi (Hymenoptera, Platygastridae), em arroz irrigado no Rio Grande do Sul. Ovos, ninfas e adultos de Glyphepomis adroguensis Berg, 1891 (Hemiptera, Pentatomidae) foram observados pela primeira vez no Rio Grande do Sul, Brasil, em lavouras de arroz irrigado (Oryza sativa L.) em Charqueadas (29º59'S, 51º31'W) e Eldorado do Sul (30º02'S, 51º23'W). Telenomus podisi Ashmead, 1893 (Hymenoptera, Platygastridae) foi encontrado em ovos de G. adroguensis.

The influence of prior experience with artificial fruits on the ovipositioning behavior of Anastrepha fraterculus (Diptera, Tephritidae)

The South American fruit fly, Anastrepha fraterculus (Wiedemann, 1830) (Diptera, Tephritidae), is a leading pest of Brazilian fruit crops. This study evaluated how prior experience with artificial fruits containing peach and/or guabiroba pulp influenced the ovipositing behavior of A. fraterculus. Insects 15-21 days old were exposed to four treatments: 1) experience with guabiroba, Campomanesia xanthocarpa O. Berg (Myrtaceae); 2) experience with peach, Prunus persica (L.) Batsch (Chimarrita cultivar; Rosaceae); 3) experience with both fruits; and 4) no experience (naive). Naive females and females experienced with guabiroba pulp and with both fruits (peach and guabiroba) oviposited and showed dragging and puncturing behavior on substrates containing guabiroba, but females that were only exposed to peach pulp did not show a preference for any substrate. The study shows that prior experience with substrate influences ovipositing behavior in A. fraterculus.

A mosca-das-frutas-sul-americana, Anastrepha fraterculus (Wiedemann,1830) (Diptera, Tephritidae) é uma das principais pragas da fruticultura no Brasil. O trabalho objetivou avaliar a influência da experiência prévia com frutos artificiais contendo polpa de pêssego e/ou guabiroba no comportamento de oviposição de A. fraterculus. Foram utilizados insetos entre 15 e 21 dias de idade, expostos a quatro tratamentos: 1) experiência com guabiroba, Campomanesia xanthocarpa O. Berg (Myrtaceae); 2) com pêssego, Prunus persica (L.) Batsch (cultivar Chimarrita) (Rosaceae); 3) com ambos; 4) inexperientes. Fêmeas inexperientes, assim como as experientes com polpa de guabiroba e com ambas (pêssego e guabiroba) ovipositaram e apresentaram comportamentos de arraste e punctura nos substratos que continham guabiroba, porém, as fêmeas previamente expostas somente à polpa de pêssego não apresentaram preferência por qualquer um dos substratos. O presente estudo indica que a experiência prévia com o substrato influencia o comportamento de oviposição de A. fraterculus.

The influence of prior experience with artificial fruits on the ovipositioning behavior of Anastrepha fraterculus (Diptera, Tephritidae)

The South American fruit fly, Anastrepha fraterculus (Wiedemann, 1830) (Diptera, Tephritidae), is a leading pest of Brazilian fruit crops. This study evaluated how prior experience with artificial fruits containing peach and/or guabiroba pulp influenced the ovipositing behavior of A. fraterculus. Insects 15-21 days old were exposed to four treatments: 1) experience with guabiroba, Campomanesia xanthocarpa O. Berg (Myrtaceae); 2) experience with peach, Prunus persica (L.) Batsch (Chimarrita cultivar; Rosaceae); 3) experience with both fruits; and 4) no experience (naive). Naive females and females experienced with guabiroba pulp and with both fruits (peach and guabiroba) oviposited and showed dragging and puncturing behavior on substrates containing guabiroba, but females that were only exposed to peach pulp did not show a preference for any substrate. The study shows that prior experience with substrate influences ovipositing behavior in A. fraterculus.

A mosca-das-frutas-sul-americana, Anastrepha fraterculus (Wiedemann,1830) (Diptera, Tephritidae) é uma das principais pragas da fruticultura no Brasil. O trabalho objetivou avaliar a influência da experiência prévia com frutos artificiais contendo polpa de pêssego e/ou guabiroba no comportamento de oviposição de A. fraterculus. Foram utilizados insetos entre 15 e 21 dias de idade, expostos a quatro tratamentos: 1) experiência com guabiroba, Campomanesia xanthocarpa O. Berg (Myrtaceae); 2) com pêssego, Prunus persica (L.) Batsch (cultivar Chimarrita) (Rosaceae); 3) com ambos; 4) inexperientes. Fêmeas inexperientes, assim como as experientes com polpa de guabiroba e com ambas (pêssego e guabiroba) ovipositaram e apresentaram comportamentos de arraste e punctura nos substratos que continham guabiroba, porém, as fêmeas previamente expostas somente à polpa de pêssego não apresentaram preferência por qualquer um dos substratos. O presente estudo indica que a experiência prévia com o substrato influencia o comportamento de oviposição de A. fraterculus.

[Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone]. / Efeito de fatores endógenos na percepção química de Grapholita molesta(Busck) (Lepidoptera: Tortricidae) ao feromônio sexual.

The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of field results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control.

Efeito de fatores endógenos na percepção química de Grapholita molesta(Busck) (Lepidoptera: Tortricidae) ao feromônio sexual / Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone

The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of field results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control.

Percepção química e visual de Anastrepha fraterculus (Diptera, Tephritidae) em laboratório

The South American fruit fly Anastrepha fraterculus (Wiedemann, 1830) is one of the greatest threats to the fruit growing industry in Brazil. During the feeding process, the larvae build galleries within the fruit, altering the flavor and damaging its production and commercialization. The present work had as its objective to study the factors involved in the choice of the host by A. fraterculus. Electroantennographic responses of the males and females to the ethanolic extracts of the fruits of the peach tree - Prunus persica, cultivar Chimarrita (Rosaceae), Surinam cherry tree - Eugenia uniflora (Myrtaceae), Guabirobeira tree - Campomanesia xanthocarpa (Myrtaceae) and Brazilian guava tree - Psidium cattleianum (Myrtaceae) were considered. Also recorded was the influence of the color (yellow, green and red) and the composition of the substratum of oviposition (pulps of Brazilian guava, Guabiroba, Surinam cherry and peaches) in the fecundity. Electroantennographic responses of the females were distinct to the extracts of the unripe and ripe Guabiroba, ripe Brazilian guava and unripe Surinam cherry. In antennae of the males, the greatest depolarization average was registered in the responses to the extracts of ripe and unripe Guabiroba, ripe and unripe Brazilian guava and unripe Surinam cherry. Electrophysiologic responses did not differ statistically between the sexes for all the treatments. The colors of the substratum of oviposition did not affect the fecundity. The females ovipositioned more on the substratum containing pulp of peaches and of Guabiroba, when compared to the respective controls.

A mosca-das-frutas-sul-americana, Anastrepha fraterculus (Wiedemann, 1830), é uma das principais pragas da fruticultura no Brasil. Durante a alimentação, as larvas fazem galerias nos frutos, alterando o sabor e prejudicando a produção e comercialização dos mesmos. O presente trabalho teve como objetivo estudar fatores envolvidos na escolha do hospedeiro por A. fraterculus. Foram avaliadas as respostas eletroantenográficas de machos e fêmeas a extratos etanólicos de frutos verdes e maduros de pessegueiro - Prunus persica, cultivar Chimarrita (Rosaceae), pitangueira - Eugenia uniflora (Myrtaceae), guabirobeira - Campomanesia xanthocarpa (Myrtaceae) e araçazeiro - Psidium cattleianum (Myrtaceae). Foram também observadas as influências da cor (amarela, verde e vermelha) e da composição do substrato de oviposição (polpas de araçá, guabiroba, pitanga e pêssego) na fecundidade da espécie. As respostas eletroantenográficas de fêmeas foram significativamente distintas para os extratos de guabiroba verde e madura, araçá maduro e pitanga verde. Em antenas de machos, as maiores despolarizações médias foram registradas em resposta aos extratos de guabiroba verde e madura, araçá verde e maduro e pitanga verde. As respostas eletrofisiológicas geradas não diferiram estatisticamente entre os sexos, para todos os tratamentos. A cor do substrato não afetou a oviposição. As fêmeas ovipositaram mais nos substratos contendo polpa de pêssego e de guabiroba, quando comparados aos respectivos controles.