Predatory capacity and intraguild interaction between aphidophagous predators in the control of rose bush aphids

ABSTRACT Chrysoperla externa (Hagen) and Hippodamia convergens (Guérin-Meneville) are voracious generalist predators, and important aphid control agents. In an environment containing a complex of species, the occurrence of intraguild interactions can interfere in the predator behavior and consumption. The aim of this work was to know the number of nymphs of Rhodobium porosum (Sanderson) and Macrosiphum rosae (Linnaeus) consumed by larvae of C. externa and H. convergens, and the interaction between these predators when confined together. First, second and third instar nymphs of R. porosum and M. rosae were provided in Petri dishes containing rose leaflets and second instar larvae of the predators. Intraguild interaction was studied in Petri dishes containing first instar nymphs of both aphid species and a second instar larva of C. externa plus one of H. convergens. A third treatment consisted of dishes containing a second instar larva of both predators maintained in the absence of prey. The evaluations took place throughout the entire instar of the predators. C. externa consumed a greater number of R. porosum nymphs and H. convergens a greater number of M. rosae nymphs. For both species of prey, the highest consumption was verified on the last day of evaluation. There was a positive interaction when the predator's larvae were confined in the presence of aphid nymphs, with no mortality observed for any of them. In the absence of prey, there was 70% mortality of H. convergens larvae due to intraguild predation.

Is a diet of Planococcus citri nymphs and adults suitable for Chrysoperla externa for use in biological control?

ABSTRACT Several studies have shown that the survival and reproduction of lacewings varies depending on the type of prey they consumed, especially during the first instar. In this study, we evaluated the effect of a diet consisting of Ephestia kuehniella (EK) and/or Planococcus-citri (PC) eggs offered to first instar Chrysoperla externa on subsequent development and survival. Larvae supplied only with P. citri (PC) nymphs had extended immature development, low survival, adults with lower weight and longevity, low fecundity and egg viability, and lower net reproduction rate (R0). Larvae submitted to the treatment EK+PC responded positively to the diet, showing results similar to those obtained in the control-EK treatment. Therefore, this mealybug supports suitable development and reproduction of C. externa when it is provided to second instar larvae after they fed on E. kuehniella eggs as first instars. As far as we know, this is the first report that demonstrates the effect of natural prey and alternatives on different larval stages of lacewings. This information is valuable in developing protocols for use of C. externaas a pest control agent.

Trophic relationship between Chrysoperla externa (Neuroptera: Chrysopidae) and Planococcus citri (Hemiptera: Pseudococcidae) associated with rose bushes

ABSTRACT This study aimed to determine the consumption of Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) nymphs and the predator:prey ratio required for high predatory efficacy and survival of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) larvae under different densities of prey, reared in rose bushes. Consumption by first-, second-, and third-instar larvae of C. externa was assessed. The predatory efficiency and survival of the predator were calculated for larvae in the second instar under densities of 20, 40, 80, 120, and 160 nymphs of P. citri and predator:prey ratios of 1:5, 1:10, and 1:20. The assessments were performed after 24 and 48 hours of exposure between species. There was increasing consumption throughout the larval development of C. externa. The predator:prey ratios 1:5 and 1:10 were the most efficient for P. citri population reduction, but the 1:5 ratio led to lower survival of larvae than the 1:10 and 1:20 ratios. There was a positive correlation between C. externa larval density and cannibalism (ρ = 0.45) and a negative correlation between predator density and P. citri population density (ρ = -0.81). Third-instar larvae consume more P. citri nymphs than second-instar larvae. Second-instar larvae of this lacewing released at a 1:20 ratio caused total mortality of mealybug nymphs within 48 hours, regardless the density of P. citri, with high larvae survival of C. externa.

Compatibility between the predators Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) and Chrysoperla externa (Neuroptera: Chrysopidae) in the control of Planococcus citri (Hemiptera: Pseudococcidae) associated with rose crop

ABSTRACT Rose crops are attacked by many pests, including mealybugs. Although Planoccocus citri is not registered as a main pest of roses in Brazil, it is an increasing problem on roses inside greenhouses. Chrysoperla externa and Cryptolaemus montrouzieri are options against P. citri and other pests on roses, however using two predators in biological control programs may face problems like intraguild predation. This work aimed to assess the consumption of 1st instar nymphs and adult females of P. citri by adults of C. montrouzieri and 3rd instar larvae of C. externa, as well as the interaction between these predators when confined together. The following treatments were performed with ten replications in a completely randomized design: 1 - C. externa + 200 nymphs of P. citri; 2 - C. externa + 10 adults of P. citri; 3 - C. montrouzieri + 500 nymphs of P. citri; 4 - C. montrouzieri + 15 adults of P. citri. Each replication was set on rose leaflets inside a Petri dish (9cm Ø). Intraguild interaction was assessed by releasing both predators inside dishes containing 700 nymphs of P. citri. Before the releases, predators stayed 24 hours without food. We evaluated the prey consumption and intraguild predation for three hours. C. externa consumed significantly less (85,4±2,99) nymphs than did C. montrouzieri (387,0±3,02). There was no difference in adult mealybugs consumed, with an average of 1,85±0,19. No intraguild predation was observed, and an increase of 11,8% in consumption was observed when predators were released together compared to the scenario of no competition.

Inter - and intraspecific relationships between Macrosiphum rosae (Hemiptera: Aphididae) and Chrysoperla externa (Neuroptera: Chrysopidae)

ABSTRACT The predator Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) is a polyphagous species that has, among its wide range of acceptable prey, the aphid Macrosiphum rosae (Linnaeus, 1758) (Hemiptera: Aphididae), an important pest of rose plants. We assessed the consumption of nymphs and adults of M. rosae by C. externa larvae, the predatory efficiency, and larval survival under different predator:prey ratios, densities of aphids, and ages of aphids. The bioassays were performed at 25 ± 1°C and 70 ± 10% RH under a 12-hour photoperiod, with aphids taken from roses of the cultivar Avalanche. Consumption was assessed by making young aphids (2nd and 3rd instars) and more developed aphids (4th instar and adult) available throughout the larval stage of the predator. The predatory efficiency and survival were studied for second-instar larvae offered M. rosae nymphs at densities of 20, 40, 80, 120, and 160 using predator:prey ratios of 1:5, 1:10, and 1:20. The assessments were performed 24, 48, and 72 hours after putting the species together. All of the C. externa instars consumed younger than older aphids. Larvae in the third instar consumed 80% of the young aphids and 77% of the older aphids. The higher the predator:prey ratio and larval density, the higher the predatory efficiency and the lower the larval survival. The ratios 1:5 and 1:10 led to the elimination of younger and older aphid populations 72 hours into the interaction between species.

Oxidação de fármacos por cloro e formação de subprodutos em amostras aquosas em escala de bancada / Pharmaceuticals oxidation by chlorine and byproducts formation in aqueous matrices in bench scale

RESUMO Fármacos e desreguladores endócrinos são encontrados em águas naturais brasileiras, incluindo alguns mananciais de abastecimento, também em função da baixa cobertura de coleta e tratamento de esgotos no Brasil. Nesse cenário, o presente trabalho intentou avaliar a remoção de três fármacos - sulfametoxazol (SMX), diclofenaco (DCF) e 17β-estradiol (E2) - em água destilada por meio da oxidação com cloro (hipoclorito de sódio), variando-se a dose de cloro e o tempo de contato em ensaios de batelada. As soluções cloradas foram analisadas, ainda, por cromatografia acoplada à espectrometria de massas para identificação de eventuais subprodutos de oxidação. Para tempo de contato de 10 min e dose de cloro de 1,5 mg.L-1, foi observada remoção média de 61% para DCF, 36% para E2 e 33% para SMX. Apenas para o DCF verificou-se diferença estatisticamente significativa (α=0,05) para dose de cloro de 3,0 mg.L-1. A oxidação seguiu modelo cinético de pseudossegunda ordem, com valores de k2 de 0,0168 L.µg.min-1 para SMX (para ambas doses testadas), de 0,0133 e 0,0798 L.µg.min-1 para DCF, e de 0,0326 e 0,0289 L.µg.min-1 para E2, para doses de cloro de 1,5 e 3,0 mg.L-1, respectivamente. Por fim, verificou-se que o aumento do tempo de contato favoreceu a oxidação dos fármacos, ainda que com a perspectiva de formação de subprodutos para SMX e E2.

ABSTRACT Pharmaceuticals and endocrine disrupting compounds are found in Brazilian natural waters, including some water sources for public supply, also due to the low coverage of sewage collection and treatment in Brazil. This study investigated the removal of three pharmaceutical compounds - sulfamethoxazole (SMX), diclofenac (DCF) and 17β-estradiol (E2) - from aqueous solutions by means of chlorine oxidation (sodium hypochlorite) by varying the dose of chlorine and contact time in batch tests. The chlorine solutions were examined by chromatography attached to the mass spectrometry in order to identify the oxidation by-products. For 10 min contact time, mean removal values of 61% were observed for DCF; 36% for E2; and 33% for SMX, when the chlorine dose was 1.5 mg L-1. Just for DCF there was a statistically significant difference (α=0.05) in the removal efficiency when increasing the chlorine dose to 3.0 mg.L-1. The oxidation followed the kinetic model of pseudo-second order, with k2 values of 0.0168 L.µg.min-1 for SMX (at both chlorine doses tested); 0.0133 and 0.0798 L.µg.min-1 to DCF; and 0.0326 and 0.0289 L.µg.min-1 to the E2 at chlorine doses of 1.5 and 3.0 mg L-1, respectively. Finally, it was verified that an increase of the contact time favored the oxidation of all pharmaceuticals tested, although with the perspective of by-products formation for SMX and E2.

Primeiro registro de ocorrência de Hemerobius gaitoi Monserrat, 1996 e Hemerobius hernandezi Monserrat, 1996 (Neuroptera: Hemerobiidae) para o estado de Minas Gerais, Brasil / First report of the occurrence of Hemerobius gaitoi Monserrat, 1996 and Hemerobius hernandezi Monserrat, 1996 (Neuroptera: Hemerobiidae) for the state of Minas Gerais, Brazil

O presente estudo relata, pela primeira vez, a ocorrência de Hemerobius gaitoi Monserrat, 1996 e Hemerobius hernandezi Monserrat, 1996 (Neuroptera: Hemerobiidae) para o estado de Minas Gerais, Brasil.(AU)

The present study reports for the first time the occurrence of Hemerobius gaitoi Monserrat, 1996 and Hemerobius hernandezi Monserrat, 1996 (Neuroptera: Hemerobiidae) in the state of Minas Gerais, Brazil.(AU)

Influência de diferentes cultivos e fatores climáticos na ocorrência de crisopídeos em sistema agroecológico / Influence of different crops and climate factors on the occurrence of green lacewings in agroecological system

Os insetos predadores da família Chrysopidae têm sido relatados tanto em ecossistemas naturais como nos agroecossistemas, sejam eles cultivos consorciados ou monocultivos. Porém, são escassas as informações sobre o comportamento das populações desses insetos nos agroecossistemas diversificados, como aqueles de base agroecológica. O presente trabalho teve o objetivo de determinar a riqueza de espécies de crisopídeos e avaliar a influência de diferentes cultivos agrícolas, assim como de fatores climáticos na abundância desses insetos em sistema de produção orgânica diversificada. O estudo foi conduzido de setembro de 2008 a agosto de 2009, por meio de amostragens semanais de adultos de Chrysopidae em áreas do Sistema Integrado de Produção Agroecológica, em Seropédica (RJ), cada qual com um tipo de sistema de cultivo (rotação milho-mucuna/olerícolas, cafeeiros sombreados e rotação cana-de-açúcar/pastagem de braquiária). Um total de 424 espécimes de crisopídeos foi coletado, sendo distribuídos em três espécies: Chrysoperla externa (98,1%), Ceraeochrysa cubana (1,7%) e Ceraeochrysa paraguaria (0,2%). Não houve diferença no número de adultos coletados em função dos diferentes cultivos, embora a análise de correlação evidencie que as rotações com poáceas favoreçam o aumento da sua abundância. A abundância dos crisopídeos foi influenciada pelo clima apenas no sistema de cafeeiros sombreados, sendo correlacionada negativamente com a temperatura média do ar e a com a precipitação pluvial acumulada.(AU)

The green lacewings (Chrysopidae) have been reported in natural ecosystems as well in agroecosystems, intercropping or monocropping. However, the knowledge on their behavior on different agroecosystems is scarce. The present work aimed to determine the diversity of green lacewing species and to evaluate the influence of different agricultural crops, as well as climate factors, on the abundance of these insects in an agroecologically-based organic production system. The study was conducted from September 2008 to August 2009, by performing weekly sampling of Chrysopidae adults in areas of the Integrated Production Agroecological System (SIPA) in Seropédica (RJ), each with one type of cropping system (corn-mucuna rotation/vegetable crops; shaded coffees and sugar cane/brachiaria pasture rotation). A total of 424 adult specimens were collected, belonging to three species: Chrysoperla externa (98.1%), Ceraeochrysa cubana (1.7%) and Ceraeochrysa paraguaria (0.2%). There were no differences on the number of green lacewing adults collected in the crops, although the correlation analysis showed that the crop rotations with grasses favor their abundance. The abundance of green lacewings was also influenced by the climate conditions only in the system of shaded coffees, being negatively correlated with mean air temperature and accumulated rainfall.(AU)

Dinâmica espaço-temporal de taxocenoses de crisopídeos (Neuroptera: Chrysopidae) em ecossistemas naturais / Spatio-temporal dynamic of green lacewings (Neuroptera: Chrysopidae) taxocenosis on natural ecossystems

In order to study the interactions of green lacewings toxocenosis on natural ecossystems, samplings were carried out in the Parque Ecológico Quedas do Rio Bonito, located in Lavras, Alto Rio Grande region, South of Minas Gerais, Brazil. The species inventory was accomplished in two vegetation types: semi-evergreen forest and open field formations, including areas of montane grassland, rocky montane grassland and "cerrado". Insects were captured with a butterfly net during 2h, walking through each vegetation formation. Sampling resulted in 1,948 specimens belonging to 30 species, of which 14 were Chrysopini and 16 Leucochrysini. Representatives of these tribes were observed both in forest and in open field formations. Species of the genera Ceraeochrysa, Chrysoperla, Chrysopodes, Plesiochrysa and Leucochrysa were found in forests and in open field formations, except for Plesiochrysa. The highest richness and diversity of species were observed in the forest. The similarity index among the communities of green lacewings in the studied areas was 27 percent.

Can larval lacewings Chrysoperla externa (Hagen): (Neuroptera, Chrysopidae) be reared on pollen? / Larvas de Chrysoperla externa (Hagen): (Neuroptera, Chrysopidae) podem ser criadas com pólen?

The aim of this study was to verify the viability of exclusive use of elephant grass pollen, Pennisetum purpureum (Schum), to feed larvae of the lacewing Chrysoperla externa (Hagen, 1861). The insects were kept at 24ºC and the duration and survival rate of each instar and the larval and pupal phases were recorded. The diet provided complete development of the larvae. The average duration of the first and second instars was the same (6.9 days), while the third instar lasted an average of 10.0 days and the pupal phase 13.2 days. The average survival of the larvae was above 80 percent for the first, second and third instars, and 70.0 percent and 33.3 percent for the larval and pupal phase, respectively. These results indicate that the exclusive use of elephant grass pollen can provide complete development of the immature stages of this predator.

O objetivo do presente estudo foi verificar a viabilidade do uso exclusivo de pólen de capim-elefante Pennisetum purpureum (Schum) como dieta para larvas de Chrysoperla externa (Hagen, 1861). Os insetos foram mantidos a 24ºC, avaliando-se a duração e a sobrevivência em cada instar e em todo o estágio larval e pupal. Verificou-se que a dieta proporcionou o desenvolvimento completo das larvas do crisopídeo, que apresentaram a mesma duração média para o primeiro e segundo ínstares (6,9 dias) e permaneceram 10,0 e 13,2 dias no terceiro instar e no estágio pupal, respectivamente. A sobrevivência média das larvas de C. externa foi superior a 80 por cento para o primeiro, segundo e terceiro ínstares, e de 70,0 por cento e 33,3 por cento para o estágio larval e pupal, respectivamente. Verificou-se que o uso exclusivo de pólen de capim-elefante como alimento para larvas de C. externa proporcionou o completo desenvolvimento dos estágios imaturos do predador.

Tabela de esperança de vida e de fertilidade de Sipha flava (Forbes) (Hemiptera, Aphididae) alimentado com capim-elefante em diferentes temperaturas / Life expectancy and fertility tables of Sipha flava (Forbes) (Hemiptera, Aphididae) fed elephant grass at different temperatures

Objetivou-se estimar as tabelas de esperança de vida e de fertilidade para Sipha flava (Forbes, 1884) alimentados com capim-elefante, em diferentes temperaturas. Foram utilizadas câmaras climatizadas a 12, 16, 20, 24, 28 e 32ºC, UR 70 ± 10 por cento e fotofase de 12 horas, contendo 150 insetos em cada condição térmica. Foi constatada mortalidade gradual em todas as temperaturas. A maior longevidade e maior esperança de vida dos afídeos foi a 12ºC. As taxas líquidas de reprodução (Ro) e o tempo necessário para a população duplicar em número (TD) também foram maiores a 12ºC. A sobrevivência (l x) começou a diminuir a partir de 3,5 dias a 24ºC e a partir do primeiro dia nas demais temperaturas, seguindo uma redução gradativa com o desenvolvimento do inseto. O intervalo de tempo entre cada geração (T) diminuiu com o aumento da temperatura, até 28ºC. A maior fertilidade específica (m x) e a maior fecundidade total média ocorreram a 24ºC. A capacidade inata de aumentar em número (r m) foi menor a 12ºC. A razão finita de aumento (λ) foi maior a 20 e 24ºC. A temperatura de 24ºC mostrou-se mais adequada para o desenvolvimento de S. flava em capim-elefante por proporcionar maiores valores para os parâmetros reprodutivos.

The objective of this study was to estimate the life expectancy and fertility tables of Sipha flava (Forbes, 1884) fed with elephant grass at different temperatures. The investigations were conducted in climate controlled chambers at 12, 16, 20, 24, 28 and 32ºC, UR 70 ± 10 percent and 12-hour photophase, with 150 insects at each temperature. There was gradual mortality at all temperatures studied. The longest life expectancy and longevity values for the aphids were at 12ºC. The highest net reproduction rates (Ro) and longest population doubling time (DT) were also found at 12ºC. The survival (l x) started to diminish after 3.5 days at 24ºC and after the first day at the other temperatures, gradually declining with the development of the insect. The time interval between each generation (T) decreased as the temperature increased up to 28ºC. The highest specific fertility (m x) and total fecundity were recorded at 24ºC. The smallest value for innate capacity to increase in number (r m) were at 12ºC. The finite increase ratio (λ) were highest at 20 e 24ºC. The temperature of 24ºC is most suitable for the population density of S. flava to increase on elephant grass because it provides the highest values for the reproductive parameters.

Desenvolvimento e reprodução de Sipha flava (Forbes) (Hemiptera: Aphididae) em diferentes temperaturas / Development and reproduction of Sipha flava (Forbes) (Hemiptera: Aphididae) at different temperatures

O afídeo Sipha flava (Forbes) ocasiona injúrias em capim-elefante e sua biologia é pouco conhecida. O objetivo deste trabalho foi avaliar o efeito da temperatura no desenvolvimento, sobrevivência e reprodução de S. flava alimentada com Pennisetum purpureum. Ninfas com até 12h de idade foram individualizadas sobre seções foliares de capim-elefante e mantidas em condições controladas (12, 16, 20, 24, 28 e 32ºC ± 1ºC, UR 70 ± 10 por cento e fotofase de 12h). O total de 150 ninfas foi usado por tratamento, divididas em 30 repetições, em delineamento inteiramente casualizado. A temperatura base (Tb) foi de 0,83, 1,05, 3,01 e 4,98 para ninfas de primeiro, segundo, terceiro e quarto ínstares, respectivamente, indicando exigências térmicas distintas para os diferentes estádios de desenvolvimento. A Tb foi de 2,08 para a fase ninfal, verificando-se a tolerância a baixas temperaturas. Em temperaturas elevadas (28 e 32ºC), constatou-se redução significativa na sobrevivência. Embora tenha sido constatado maior período reprodutivo e longevidade a 12ºC, quando comparado às temperaturas mais altas, a fecundidade total foi substancialmente reduzida. A duração do ciclo de vida foi cerca de duas vezes maior a 12ºC em relação a 24ºC. A maior produção diária e total de ninfas foi a 24ºC. As temperaturas de 20ºC e 24ºC foram as mais favoráveis para o desenvolvimento e reprodução de S. flava.

The aphid Sipha flava (Forbes) is a pest on elephant grass, but little is known about its biology. The objective of this work was to evaluate the temperature effects on the development, survival and reproduction of S. flava fed on Pennisetum purpureum. Twelve-hour-old nymphs were individualized on sections of elephant grass blades and maintained at 12, 16, 20, 24, 28 and 32ºC ± 1ºC, UR 70 ± 10 percent and 12h photophase. A total of 150 nymphs were used per treatment divided in 30 replicates, using a totally random design. The lower threshold temperatures (LTT) for first, second, third and fourth instars were 0.83, 1.05, 3.01 and 4.98ºC, respectively, indicating a change in thermal requirements as the development progress. The LTT for the whole nymphal stage was 2.08ºC, pointing to the tolerance of this species to low temperatures. A significant reduction in survival was observed at high temperatures (28 and 32ºC). Although the reproductive periods were longer and insects lived longer at 12ºC as compared with those at higher temperatures, the total fecundity was substantially reduced. The overall life cycle duration was almost twice as long at 12ºC than at 24ºC. The greatest daily production of nymphs and greatest number of nymphs produced overall occurred at 24ºC. The temperatures of 20ºC and 24ºC were more suitable to S. flava development and reproduction.

Aspectos biológicos de Chrysoperla externa (Hagen, 1861)(Neuroptera: Chrysopidae) alimentada com Planococcus citri (Risso, 1813)(Hemiptera: Pseudococcidae) e Toxoptera citricida (Kirkaldy, 1907) (Hemiptera: Aphididae) / Bipogical aspects of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) fed with Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) and Toxoptera citricida (Kirkaldy, 1907) (Hemiptera: Aphididae) (Hemiptera: Aphididae)

O ecossistema citrícola abriga muitas espécies de inimigos naturais, entre eles Chrysoperla externa (Hagen, 1861) que apresenta um grande potencial como agente de controle biológico de pragas. Neste trabalho, objetivou-se avapar o efeito das presas Planococcus citri (Risso, 1813) e Toxoptera citricida (Kirkaldy, 1907) sobre o desenvolvimento das fases de larva e pupa de C. externa. O ensaio foi conduzido em sala cpmatizada a uma temperatura de 25±1ºC, 70±10 por cento UR e fotofase de 12 horas, sendo os tratamentos constituídos pelo fornecimento contínuo e alternado dessas duas presas em cada ínstar do predador, além de ovos de Anagasta kuehniella (Zeller, 1879), utilizados para fins de comparação. Foram avaliados o tempo de vida e a viabilidade das fases de larva, pupa e do período larva-adulto de C. externa. Constatou-se que T. citricida fornecido isoladamente ao longo do desenvolvimento larval ou em dois ínstares consecutivos do predador, não foi uma presa adequada, constatando-se 100 por cento de mortalidade no período larva-adulto. Quando as larvas alimentaram-se de P. citri fornecida em dois ínstares do predador, a viabilidade no período larva-adulto foi semelhante à dieta constituída por apenas ovos de A. kuehniella, exceto quando se alimentaram de T. citricida no primeiro ínstar.

The citrus-growing ecosystem houses a great deal of species of natural enemies, among them Chrysoperla externa (Hagen, 1861), which presents a great potential for use in the bipogical contrp of pests. The aim of this work was to evaluate the effects of the preys Planococcus citri (Risso, 1813) and Toxoptera citricida (Kirkaldy, 1907) on the development of larva and pupa of C. externa. The trial was carried out in an accpmatized room at 25±1ºC, 70±10 percent RH and 12-hour photophase, the treatments consisting of the continuous and alternate supply of those two preys in each instar of the predator, in apition to eggs of Anagasta kuehniella (Zeller, 1879) utilized for comparison purposes. Both the white mealybug and the aphids were given in sufficient amounts to the C. externa larvae to be able to feed ad libitum. The pfetime and the survival rate of the phases of larva, pupa and the larval-adult period of C. externa were evaluated. It was found that T. citricida given either singly along the larval development or in two consecutive instars of the predator was not an adequate prey, 100 percent of mortapty over the larval-adult period being found. When the larvae fed on P. citri, given in two instars of the predator, the survival rate in the larval-adult period was similar to the diet constituted of only A. kuehniella eggs, except when fed with T. citricida in the first instar.

Biologia de Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) em abobrinha cultivar caserta (Cucurbita pepo L. ) em diferentes temperaturas / Biology of Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) on squash cultivar caserta (Cucurbita pepo L. ) in different temperatures

As cucurbitáceas apresentam grande demanda no mercado mundial e uma das principais pragas que atacam essas culturas é o pulgão Aphis gossypii. Assim, objetivou-se estudar aspectos da biologia desse afídeo em função da temperatura na cultivar de abobrinha Caserta (Cucurbita pepo L.). Utilizaram-se discos foliares (2,5cm de ∅) acondicionados, com a face abaxial para cima, em placas de Petri (5cm de ∅) contendo uma lâmina de ágar-água. Em cada placa foi deixada uma ninfa recém-nascida, acompanhandose o seu desenvolvimento ao longo de todo o ciclo de vida, em diferentes temperaturas (18, 21, 24, 27 e 30±1ºC), 70±10 por cento UR e fotofase de 12 horas. O delineamento foi inteiramente casualizado, com 60 repetições. Verificou-se que as temperaturas afetaram o desenvolvimento de A. gossypii. Menor duração do período ninfal e maior produção diária de ninfas foram observadas a 24 e 27ºC. A temperatura de 30ºC provocou efeito deletério, causando 68 por cento de mortalidade na fase ninfal.

The cucurbitaceous plants are always on demand in world market and one of the main pests on these crop is the aphid Aphis gossypii. This work aimed to study the biological aspects of A. gossypii on the Caserta (Cucurbita pepo L.) cultivar in different temperatures. To determine the biological aspects of A. gossypii, nymphs were kept on leaf disks (2.5 cm ∅) with the abaxial side up in Petri dishes (5 cm ∅) containing a thin layer of agar-water. Each dish contained one nymph of the first instar of the aphid. The development and the other biological parameters were evaluated in different temperatures (18, 21, 24, 27 e 30±1ºC), 70±10 percent RH and 12h photophase. The experiments were complete randomized design with 60 replicates. The results showed that the temperature influenced the development of A. gossypii. The shorter nymphal period and higher daily nymph s production were observed at 24 and 27 ºC. The temperature of 30 ºC was deleterius inducing to 68 percent of mortality at the nymphal stage of A. gossypii.

Aspectos biológicos e capacidade predatória de Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae) alimentada com Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) em diferentes temperaturas / Biological aspects and predatory capacity of Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae) fed on Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) under different temperatures

Avaliou-se alguns aspectos biológicos e a capacidade predatória em três temperaturas de larvas de Ceraeochrysa cubana (Hagen) alimentadas com ninfas de terceiro e quarto ínstares de Aphis gossypii Glover. Os experimentos foram conduzidos em câmaras climáticas a 22; 25 e 28±1ºC, 70±10 por cento de UR e fotofase de 12 horas. O delineamento experimental foi inteiramente casualizado com três tratamentos (temperaturas), com 40 repetições. Verificou-se redução no tempo de vida das larvas nos três ínstares, das fases de pré-pupa e pupa em função do aumento da temperatura. As maiores viabilidades foram obtidas a 22ºC. Para larvas de primeiro ínstar não houve diferença significativa no consumo médio diário nas três temperaturas. Para larvas de segundo e terceiro ínstares houve maior consumo diário de pulgões na maior temperatura. O número médio total de afídeos consumido por larvas de primeiro e segundo ínstares não diferiu em função do aumento da temperatura. Para larvas de terceiro ínstar o maior consumo total foi observado a 22ºC, e o menor a 25ºC. Na menor temperatura observou-se maior consumo médio total na fase larval.

Some biological aspects and the predatory capacity at three temperatures of larvae of Ceraeochrysa cubana (Hagen) fed third and fourth instar nymphs of Aphis gossypii Glover were evaluated. The experiments were conducted in climatic chambers at 22; 25 and 28±1ºC, 70±10 percent of RH and 12-hour photophase. The experimental design was completely randomized with three treatments (temperatures) and 40 replicates. A reduction in the median life time of the larvae in the three instars of the stages of pre-pupa and pupa was found as related with the increase of temperature. The highest survivals were obtained at 22ºC. For larvae of first instar, there were no significant differences in the daily average consumption of aphids at the three temperatures. For second and third instar larvae, there was higher consumption of aphids at the highest temperature. The total average number of aphids consumed by first and second instar larvae did not differ as related with the increase of temperature. For third instar larvae, the greatest total consumption was observed at 22ºC, and the lowest consumption at 25ºC. The lowest temperature enabled the highest total average consumption of the larval stage.

Eficiência de Chrysoperla externa (Hagen, 1861)(Neuroptera: Chrysopidae) no controle de Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) em pimentão (Capsicum annum L.) / Efficiency of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) in the Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) population reduction in sweet pepper (Capsicum annum L.)

Avaliou-se a eficiência de larvas de primeiro ínstar de Chrysoperla externa no controle Myzus persicae em pimentão, em experimentos realizados em câmara e sala climatizadas a 25 ± 1ºC, UR de 70 ± 10 por cento e fotofase de 12 horas. Larvas de C. externa recém-eclodidas foram liberadas em discos foliares, contendo 5; 10 ou 20 ninfas do afídeo, acondicionados em placas de Petri. Em um segundo experimento, larvas do predador foram liberadas nas proporções 1:5, 1:10 e 1:20, em plantas inoculadas com 60; 100 e 140 ninfas do pulgão. O potencial predatório de C. externa nos discos foliares foi influenciado pela densidade inicial do pulgão. A eficiência do predador nas densidades de 5; 10 e 20 pulgões foi de 100 por cento; 96,7 por cento e 79,3 por cento, respectivamente. A eficiência das larvas em eliminar as populações do pulgão nas plantas de pimentão variou em função do tempo. Na proporção 1:5, a eliminação das ninfas ocorreu entre um e dois dias após a liberação do predador, enquanto nas proporções 1:10 e 1:20 o período de quatro dias não foi suficiente para que os pulgões fossem eliminados. As larvas de C. externa quando liberadas nas três proporções promoveram reduções na população de M. persicae, se comparada à testemunha. No entanto, nas proporções 1:5 e 1:10 o predador se mostrou mais eficiente.

The efficiency of Chrysoperla externa first instar larvae in the control of Myzus persicae in sweet pepper was evaluated in experiments conducted in climatic chamber and room at 25 ± 1ºC, 70 ± 10 percent RH and 12h photophase. C. externa newly emerged larvae were released in sweet pepper foliar discs containing 5; 10 or 20 aphid nymphs, putted in Petri dishes. In a second experiment, predator larvae were released in 1:5, 1:10 and 1:20 proportions in sweet pepper plants inoculated with 60; 100 and 140 aphids nymphs. The C. externa predatory potential in the foliar discs was affected by aphid initial density. The predator efficiency in 5; 10 and 20 aphid densities was 100 percent; 96,7 percent and 79,3 percent, respectively. The larvae efficiency in eliminating aphids populations in sweet pepper plants range as a result of the time. In 1:5 proportion the nymphs elimination occurred between one and two days after the predator release, while in 1:10 and 1:20 proportions four days were not sufficient to the aphids elimination. C. externa larvae released in the three proportions promoted reductions in M. persicae population when compared to the control. The proportions 1:5 and 1:10 the predator was more efficient.

Aspectos da predação entre larvas de Chrysoperla externa (Hagen, 1861) e Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae) em laboratório / Predation among Chrysoperla externa (Hagen, 1861) and Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae) larvae under laboratory conditions

Objetivou-se no presente trabalho estudar aspectos da predação entre larvas de Chrysoperla externa e Ceraeochrysa cubana, sob condições de laboratório, verificando a sobrevivência desses predadores nos diferentes ínstares, quando mantidos nas proporções de 1:1, 2:2 e 3:3. De modo geral, C. externa apresentou maior sobrevivência, independente do ínstar e da proporção de adensamento entre indivíduos. Ao contrário, C. cubana foi fortemente afetada pela interação com C. externa, tendo sua capacidade de sobrevivência reduzida com o aumento da proporção de adensamento e com o desenvolvimento larval. No final da fase larval, verificou-se uma taxa de sobrevivência próxima a 96, 90 e 95 por cento, e 56, 23 e 9 por cento para C. externa e C. cubana nas proporções de 1:1, 2:2 e 3:3 indivíduos, respectivamente.

This work aimed to study aspects of predation among Chrysoperla externa and Ceraeochrysa cubana larvae under laboratory conditions. The survival of those predators in different larval stages was studied, maintaining the larvae grouped in proportions of 1:1, 2:2 and 3:3 individuals. C. externa presented higher survival rates, independently of larval ínstar and density proportion among individuals. On the other hand, C. cubana was strongly affected by interaction with C. externa, and had its survival capacity reduced with the increase of grouping proportion and larval development. At the end of larval phase, a survival rate around 96, 90, and 95 and 56, 23 and 9 percent for C. externa and C. cubana in proportions of 1:1, 2:2 and 3:3 individuals, respectively, was verified.

Biologia e não-preferência para oviposição por Bemisia tabaci (Gennadius) biótipo B (Hemiptera: Aleyrodidae) em cultivares de algodoeiro / Biology and non-preference for oviposition by Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) on cotton cultivars

Os objetivos deste trabalho foram avaliar alguns aspectos biológicos das fases de ovo e de ninfa de Bemisia tabaci (Gennadius) biótipo B e avaliar a não-preferência para oviposição em testes com e sem chance de escolha e sua correlação com o número e tipo de tricomas nas cultivares de algodoeiro (BRS Ipê, BRS 186-Precoce 3, BRS Acala, BRS Verde, BRS 200-Marrom, BRS Cedro, BRS Ita 90-2 e BRS Aroeira). Os experimentos foram realizados em câmaras climatizadas (28 ± 2°C, 70 ± 10 por cento UR e fotofase de 14h), e em casa-de-vegetação. A viabilidade dos ovos não foi afetada pelas cultivares de algodoeiro, porém, a sobrevivência no período de ovo a adulto foi influenciada pelo hospedeiro. Não houve efeito das cultivares na duração da fase de ovo, do segundo, terceiro e quarto ínstares nem no período de ovo a adulto. As ninfas que se desenvolveram na cultivar BRS Ipê tiveram o primeiro ínstar alongado, diferentemente daquelas desenvolvidas nas demais cultivares. As cultivares BRS Aroeira, BRS Verde e BRS Ita 90-2 apresentaram baixo número de ovos nos testes com e sem chance de escolha, indicando um possível mecanismo de resistência, mas não foi possível estabelecer uma correlação entre a densidade de tricomas e a não-preferência para oviposição.

The purposes of this work were to evaluate some biological aspects of Bemisia tabaci (Gennadius) biotype B at egg and nymphal stages and to evaluate the non-preference for oviposition and its correlation with the number and type of trichomes on the cotton cultivars BRS Ipê, BRS 186-Precoce 3, BRS Acala, BRS Verde, BRS-200 Marrom, BRS Cedro, BRS Ita 90-2 and BRS Aroeira. The experiments were conducted in climatic chambers at 28 ± 2°C, 70 percent RH and photophase of 14h, and in greenhouse. Egg fertility was not affected by the cotton cultivars but survival in egg-adult period was influenced by the host plant. There was no influence of cultivars neither on the duration of egg stage, nymphs at 2nd, 3rd and 4th instars nor on the duration from egg to adult, but nymphs reared on the cultivar BRS Ipê had their 1st instar extended. Low number of eggs was detected on the cultivars BRS Aroeira, BRS Verde and BRS Ita 90-2 in both experiments with and without oviposition choice, indicating a possible mechanism of resistance, but no correlation could be established between trichome densisty and oviposition non-preference.

Acúmulo e exportação de nutrientes em beterraba / Accumulation and exportation of nutrients in beet crop

O objetivo do presente trabalho foi determinar o acúmulo e exportação de nutrientes pela cultura da beterraba em condições de altas temperaturas e luminosidade. O delineamento experimental utilizado foi em blocos casualizados completos com quatro repetições, sendo os tratamentos constituídos pelas épocas de coleta de plantas (20, 30, 40, 50 e 60 dias após semeadura). Em cada coleta foram utilizadas quatro plantas por repetição. O máximo acúmulo de massa seca ocorreu aos 60 DAS, sendo de 21,35 g/planta. A maior demanda de nutriente aconteceu no período de 50 a 60 DAS para N e Mg, 30 a 50 DAS para P, 30 a 40 para K e 40 a 50 DAS para Ca. A ordem decrescente dos nutrientes acumulados pela beterraba foi: N, K, Mg, Ca e P. As quantidades totais de N, P, K, Ca e Mg exportadas pelas raízes foram respectivamente de 88,0; 6,1; 93,2; 12,1 e 16,8 kg/ha.

The objective of this research was to determine on field condition the accumulation and exportation of nutrients by beet crop in conditions of high temperatures and radiations intensity. The experimental design was fully randomized blocks, with four replications. The treatments consisted of the sampling times (20, 30, 40, 50 and 60 days after sowing (DAS). The maximum accumulation of dry mass occurred at 60 DAS, being of 21.35 g/plant. The period of higher demand for N and Mg occurred from 50 to 60 DAS, 30 the 50 DAT for P, 30 the 40 for K and 40 the 50 for Ca. The decreasing order of nutrient accumulation by the beet crop was: N, K, Mg, Ca and P. The roots exported 88.0 kg/ha of N; 6.1 kg/ha of P; 93.1 kg/ha of K; 12.1 kg/ha of Ca and 16.8 kg/ha of Mg.

Suitability of leguminous cover crop pollens as food source for the green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae)

Diversification of crops with species that provide suitable pollen for predators may reduce pest population on crops by enhancing predator effectiveness. In this paper we evaluated the suitability of leguminous cover crop pollens to the predatory green lacewing Chrysoperla externa (Hagen). The predator is commonly found in coffee agroecosystems and the plant species tested were pigeon pea and sunn hemp, which are used in organic coffee systems. Newly emerged females and males of C. externa were reared on diets containing pollen of pigeon pea, sunn hemp, or castor bean, used as a control. The reproductive success of C. externa was evaluated when females fed the pollen species and when honey was added to the diets, to verify the predator need for an extra carbohydrate source. Similar intrinsic growth rates were found for females fed on pigeon pea pollen and on sunn hemp pollen but these rates increased significantly when honey was added to the diets. Females fed with pigeon pea pollen plus honey and with sunn hemp pollen plus honey had higher intrinsic growth rates than those fed with castor bean pollen plus honey. Females fed on castor bean pollen only or on honey only, did not oviposit. Leguminous pollen species were equally suitable for C. externa especially when they were complemented with honey. The results suggest that to successfully enhance predator effectiveness, organic coffee plantation should be diversified with plant providing pollen in combination with plant providing nectar.

A diversificação das culturas com plantas que forneçam pólen nutricionalmente adequado para predadores pode reduzir a população de pragas pelo aumento da efetividade dos predadores. Neste trabalho, avaliou-se a viabilidade nutricional de polens de leguminosas utilizadas como adubação verde, para o crisopídeo Chrysoperla externa (Hagen), comumente encontrado em agroecossistemas cafeeiros. Os adubos verdes testados foram guandu e crotalária, leguminosas utilizadas em sistemas orgânicos de café. Adultos de C. externa recém-emergidos foram criados em dietas contendo pólen de guandu, de crotalária e de mamona (controle). O sucesso reprodutivo de C. externa foi avaliado nas dietas de pólen e quando mel foi adicionado ao pólen, para se verificar a necessidade do predador por fonte extra de carboidratos. A taxa de crescimento populacional do predador foi semelhante nas dietas de pólen de guandu e de crotalária. No entanto, a taxa aumentou significativamente quando mel foi adicionado às dietas. Fêmeas alimentadas com pólen de guandu e mel e com pólen de crotalária e mel tiveram crescimento superior ao das alimentadas com pólen de mamona e mel. Fêmeas alimentadas somente com pólen de mamona ou somente com mel não ovipositaram. Os polens de guandu e de crotalária foram igualmente adequados para C. externa, especialmente quando foram complementados com mel. Os resultados sugerem que para aumentar a efetividade dos predadores, os sistemas orgânicos de café deveriam ser diversificados com plantas que forneçam pólen em combinação com plantas que forneçam néctar.