The behavior of Aphis gossypii and Aphis craccivora (Hemiptera: Aphididae) and of their predator Cycloneda sanguinea (Coleoptera: Coccinellidae) in cotton-cowpea intercropping systems

ABSTRACT The intercropping is an important cultural practice commonly used in pest management. It is based on the principle that increased plant diversity in the agro-ecosystem can lead to reductions of pest populations in the crop. The current study aimed to assess the impact the colored fiber cotton-cowpea intercropped systems on Aphis gossypii and Aphis craccivora and on their predator Cycloneda sanguinea and the losses and the dispersion behavior of these aphids and their predator in these cropping systems. The experiment had a randomized block experimental design with two bioassays and four treatments. The number of apterous and alate aphids (A. gossypii) per cotton plant was 1.46 and 1.73 or 1.97 and 2.19 times highest in the solid cotton system than that found in the cotton-cowpea intercropped systems (S1) and (S2), respectively. On the other hand, the cotton-cowpea intercropped systems (S1 and S2) reduced, respectively, in 43% and 31% the number of apterousA. gossypiiper cotton plant compared to the control. Implementing cotton-cowpea intercropped system in the S1 scheme reduced A. gossypii infestation, favored the multiplication of C. sanguinea, and allowed obtaining heavier open bolls.

Population dynamics of Aphis gossypii Glover and in sole and intercropping systems of cotton and cowpea

ABSTRACT Population dynamics of aphids have been studied in sole and intercropping systems. These studies have required the use of more precise analytical tools in order to better understand patterns in quantitative data. Mathematical models are among the most important tools to explain the dynamics of insect populations. This study investigated the population dynamics of aphids Aphis gossypii and Aphis craccivora over time, using mathematical models composed of a set of differential equations as a helpful analytical tool to understand the population dynamics of aphids in arrangements of cotton and cowpea. The treatments were sole cotton, sole cowpea, and three arrangements of cotton intercropped with cowpea (t1, t2 and t3). The plants were infested with two aphid species and were evaluated at 7, 14, 28, 35, 42, and 49 days after the infestations. Mathematical models were used to fit the population dynamics of two aphid species. There were good fits for aphid dynamics by mathematical model over time. The highest population peak of both species A. gossypii and A. craccivora was found in the sole crops, and the lowest population peak was found in crop system t2. These results are important for integrated management programs of aphids in cotton and cowpea.

Reliable screening technique for evaluation of wild crucifers against mustard aphid Lipaphis erysimi (Kalt.).

Wild crucifers namely Arabidopsis thaliana, Brassica fruticulosa, B. rugosa, B. spinescens, B. tournefortii, Camelina sativa, Capsella bursa-pastoris, Crambe abysinnica, Cronopus didymus, Diplotaxis assurgens, D. gomez-campoi, D. muralis, D. siettiana, D. tenuisiliqua, Enatharocarpus lyratus, Lepidium sativum and Sinapis alba along with five cultivated Brassica species including B. rapa (BSH-1), B. juncea (Rohini), B. napus (GSC-6), B. carinata (DLSC-2) and Eruca sativa (T-27) were screened against mustard aphid Lipaphis erysimi (Kalt.) with a standardized technique under definite level of aphid pressure developed using specially designed cages. Observations have revealed that B. fruticulosa, B. spinescens, Camelina sativa, Crambe abysinnica and Lepidium sativum were resistant to mustard aphid L. erysimi with aphid infestation index (AII) ≤1. Capsella bursa-pastoris was highly susceptible to bean aphid, Aphis fabae during its vegetative stage (with 100% mortality). Other genotypes were found in the range of ‘susceptible’ to ‘highly susceptible’ with AII ranging 3-5.

Natural enemies associated to aphids in peach orchards in Araucária, Paraná, Brazil / Inimigos naturais associados a afídeos em pomares de pessegueiros em Araucária, Estado do Paraná, Brasil

Natural enemies of the Class Insecta are important agents in the balance of aphid populations and an alternative to using insecticides to control these insects. The aim of this study was to identify the species of natural enemies associated with aphids present in peach orchards and observe the efficiency of capturing different sampling methods. The experiment was conducted from July, 2005 to September, 2006 in six peach orchards 'Chimarrita', in Araucária, PR, Brazil. The samples were taken by visual analysis in peach plants and weeds, yellow pan traps, sticky traps and funnels. Predator species were identified: Cryptolaemus montrouzieri, Cycloneda pulchella, Cycloneda sanguinea, Eriopis connexa, Harmonia axyridis, Hippodamia convergens and Scymnus sp. (Coleoptera, Coccinellidae), Allograpta sp., Palpada sp. and Toxomerus sp. (Diptera, Syrphidae) and Chrysoperla sp. (Neuroptera, Chrysopidae) and the parasitoids: Diaretiella rapae, Opius sp. and Praon sp (Braconidae). Examples of Encyrtidae and Eulophidae await identification. Chrysoperla sp. was a less abundant species. There were no statistically significant differences between the different sampling methods tested.

Os inimigos naturais da Classe Insecta são importantes agentes no equilíbrio das populações de afídeos e uma forma alternativa ao uso de inseticidas no controle desses insetos. O objetivo deste estudo foi identificar as espécies de inimigos naturais associados aos afídeos presentes em pomares de pessegueiros, além de verificar a eficiência de captura de diferentes métodos de amostragem. O experimento foi realizado de julho de 2005 a setembro de 2006, em seis pomares de pessegueiros 'Chimarrita' em Araucária-PR, Brasil. As amostragens foram realizadas por meio de: análise visual em plantas de pessegueiros e plantas invasoras; armadilhas amarelas; armadilhas adesivas, e funil. Foram identificados os predadores: Cryptolaemus montrouzieri, Cycloneda pulchella, Cycloneda sanguinea, Eriopis connexa, Harmonia axyridis, Hippodamia convergens, Scymnus sp. (Coleoptera, Coccinellidae), Allograpta sp., Palpada sp., Toxomerus sp. (Diptera, Syrphidae) e Chrysoperla sp. (Neuroptera, Chrysopidae), além dos parasitoides: Diaretiella rapae, Opius sp. e Praon sp. (Braconidae). Exemplares de Encyrtidae e Eulophidae aguardam identificação. Chrysoperla sp. foi a espécie menos abundante. Não foram constatadas diferenças estatísticas significativas entre os diferentes métodos de amostragem testados.

Resistência de cultivares de batata a Myzus persicae (Sulz.)(Hemiptera: Aphididae) / Resistance of potato cultivars to Myzus persicae (Sulz.) (Hemiptera: Aphididae)

Aphids are the most important vectors of viruses infecting potato (Solanum tuberosum). We focused on the response of the aphid vector Myzus persicae (Sulzer) to five commercial potatocultivars: Ágata, Jaette Bintje, Mondial, Monalisa and Santè, by traditional antibiosis and antixenosis tests and by the EPG (Electrical Penetration Graph) technique, as a step forward to the design of effective management practices. Our aim was to identify plant factors involved in resistance of these cultivars against M. persicae, both at the surface and in deeper plant tissues. Results from the antixenosis test confirmed a strong preference of M. persicae for the Mondial cultivar. The antibiosis study indicated a lower population development of the aphid in 'Monalisa' when compared to 'Ágata' and 'Jaette Bintje'. EPG assays indicated that 'Santè' inhibited the initial feeding process of M. persicae, whereas 'Monalisa' showed a physical-type of resistance as demonstrated by a very high number of short probes. The cultivar Mondial showed average values for all EPG variables analyzed. The behavior in 'Jaette Bintje' indicated this cultivar was an ideal host for aphid feeding and reproduction. Together, the EPG data revealed the existence of pre and post-phloematics factors in the cultivars under study, which have important implications on the efficiency of transmission and spread of virus in potato by M. persicae.

Population fluctuation and faunal indices of aphids (Hemiptera, Aphididae) in peach orchards in Araucária, PR / Flutuação populacional e índices faunísticos de afídeos (Hemiptera, Aphididae) em pomares de pessegueiros em Araucária, PR

Aphids are sap-sucking insects that mainly attack shoots and young leaves of peach trees and many other plant species; however, knowledge of the Brazilian aphid fauna is scant. The objective of this study was to identify aphid species collected in peach orchards (Prunus persica Batsch) and to determine their faunal indices for occurrence and dominance. The experiment was conducted from July 2005 to September 2006 in six Chimarrita peach orchards in the municipality of Araucária, PR, Brazil. The survey of aphid species was conducted by visual samplings on peach trees and using Mõericke-type yellow traps containing water. A faunal analysis was made using aphid occurrence and dominance indices. Brachycaudus persicae (Passerini, 1860) was the only aphid species that was found colonizing peach in Araucária/PR. Although most aphids collected were classified as rare, some can be considered potential peach colonizers, such as Myzus persicae (Sulzer, 1776) which was given the status of common or intermediate in some of the orchards studied. The population fluctuation of aphids showed a negative correlation with rainfall and positive correlation with temperature and relative humidity.

Os afídeos são insetos sugadores de seiva que atacam principalmente brotações e folhas novas de pessegueiros e de diversas outras espécies vegetais, porém o conhecimento sobre a afidofauna brasileira é escasso. O objetivo deste trabalho foi identificar as espécies de afídeos coletadas em pomares de pessegueiros (Prunus persica Batsch) e analisar os índices faunísticos de ocorrência e dominância. O experimento foi realizado de julho de 2005 a setembro de 2006 em seis pomares de pessegueiros da cultivar Chimarrita no município de Araucária, PR. O levantamento das espécies de afídeos foi realizado por meio de amostragens visuais em pessegueiros e armadilhas amarelas de água do tipo Mõericke. Brachycaudus persicae (Passerini, 1860) foi a única espécie de afídeo encontrada colonizando pessegueiros em Araucária, PR. Apesar da maioria das espécies de afídeos coletadas serem classificadas como raras, algumas podem ser consideradas colonizadoras potenciais de pessegueiros como Myzus persicae (Sulzer, 1776) que recebeu o status de comum ou intermediária em alguns dos pomares estudados. A flutuação populacional de afídeos apresentou uma correlação negativa com a precipitação pluviométrica e positiva com a temperatura e a umidade relativa do ar.

Danos de Rhopalosiphum padi (L. ) (Hemiptera: Aphididae) no trigo em função da duração e da densidade de infestação / Damage of Rhopalosiphum padi (L. ) (Hemiptera: Aphididae) on wheat plants related to duration time and density of infestation

Aphids are considered relevant pests on wheat either by direct damage through sap sucking or by indirect damage vectoring BYDV (Barley yellow dwarf virus). Rhopalosiphum padi L. has been observed infesting wheat fields with an increasing frequency. The knowledge and the available technology, besides being more related to other aphids species already recognized as pests, they are insufficient to control the specific problem of R. padi. Thus, this work evaluated the effects of feeding duration and infestation densities of R. padi on seedlings of wheat cv. Embrapa 16. Grain yield, yield components and the extent of symptoms were recorded. The experiment was carried out in the field under a completely randomized split-plot experimental design with four replications. The main plot was feeding duration (two and seven days) and the sub-plots were infestation densities (zero, two and 10 aphids per plant). Independent on feeding duration, 10 aphids per plant resulted in significant yield losses, reduction of number of heads and tillers per plant. Canopy dry matter was also reduced. Infestations of two and 10 aphids per plant resulted in continuous yellowing of wheat plants from tillering to the end of flowering stage. When aphids fed for seven days on wheat, more yellowing symptoms were observed at the flower stage in comparison with two days feeding.

Os pulgões associados ao trigo são considerados pragas relevantes por causarem danos diretos, ao se alimentarem da seiva do floema, ou indiretos, ao atuarem como vetores do BYDV (Barley yellow dwarf virus). Rhopalosiphum padi L. tem infestado lavouras com freqüência crescente. O conhecimento e a tecnologia disponíveis, além de estarem mais relacionados a outras espécies de pulgões já reconhecidas como pragas, são insuficientes para controlar o problema específico de R. padi. O objetivo do experimento foi avaliar o efeito da duração e da densidade de infestação de R. padi na fase de plântula, na manifestação de sintomas de danos, na produção de grãos e seus componentes e em outras características agronômicas em trigo. O experimento foi conduzido no campo, com a cultivar Embrapa 16, em blocos ao acaso com quatro repetições, em parcelas subdivididas, avaliando-se duas durações (dois e sete dias) e três densidades de infestação (zero, dois e 10 pulgões por planta), sete dias após a emergência das plantas. A densidade de 10 pulgões por plântula de trigo, independente da duração (dois ou sete dias), reduz a produção de grãos, o número de espigas, o número de afilhos e a massa seca da parte aérea das plantas. Dois e 10 pulgões por plântula provocam amarelecimento de folhas crescente, que se manifesta no afilhamento, no pré-espigamento e no final do estádio de floração das plantas. Sete dias de infestação provoca a manifestação, na fase de floração das plantas em grau de amarelecimento maior que dois dias de infestação.

Efeitos da adubação nitrogenada em algodoeiro sobre a biologia de Aphis gossypii Glover (Hemiptera: Aphididae) / Effects of nitrogen fertilization in cotton crop on Aphis gossypii Glover (Hemiptera: Aphididae) biology

O pulgão Aphis gossypii Glover é uma das pragas do algodoeiro e suas relações com o hospedeiro são dependentes da quantidade de nitrogênio disponível para a planta. A biologia do A. gossypii, em função do regime de adubação nitrogenada no algodoeiro, foi estudada em condições de casa-de-vegetação, em Dourados, MS. Para isto foi utilizado o delineamento experimental inteiramente casualizado com nove repetições, com os tratamentos arranjados em fatorial (2 x 4 x 2) + 1, com duas fontes de adubo nitrogenado, quatro doses de nitrogênio (50, 100, 150 e 200 kg ha-1), duas épocas de aplicação do nitrogênio em cobertura e um tratamento adicional sem a adição do nitrogênio. Foram avaliadas as durações dos estádios ninfais e da fase ninfal, os períodos pré-reprodutivo, reprodutivo e pós-reprodutivo, a longevidade, o ciclo biológico e a fecundidade dos pulgões. Concluiu-se que apenas as doses de nitrogênio influenciaram a biologia do pulgão-do-algodoeiro, independente da fonte e época de aplicação, favorecendo seu desenvolvimento e fecundidade.

The cotton aphid, Aphis gossypii Glove, is one of the pests of cotton crop and its relation with the host seem to depend on the amount of nitrogen available to the plant. The biology of A. gossypii using different cotton nitrogen fertility regimes was studied under greenhouse conditions, in Dourados, MS. A completely randomized design with nine replications in a factorial scheme (2x4x2)+1 was used. Two nitrogen sources (sulphate of ammonium and urea), four doses of nitrogen (50, 100, 150 and 200 kg ha-1), two different times of nitrogen application and one additional treatment without nitrogen were taken as factors. The nymphal phases, the pre-reproductive, reproductive and pos-reproductive periods, longevity, the life cycle and fecundity of the cotton aphid were evaluated. The doses of nitrogen influenced the cotton aphid biology in both sources and times of application, favoring its development and fecundity.

Analysis of the genetic diversity in Metopolophium dirhodum (Walker) (Hemiptera, Aphididae) by RAPD markers

The emergence of host-races within aphids may constitute an obstacle to pest management by means of plant resistance. There are examples of host-races within cereals aphids, but their occurrence in Rose Grain Aphid, Metopolophium dirhodum (Walker, 1849), has not been reported yet. In this work, RAPD markers were used to assess effects of the hosts and geographic distance on the genetic diversity of M. dirhodum lineages. Twenty-three clones were collected on oats and wheat in twelve localitites of southern Brazil. From twenty-seven primers tested, only four primers showed polymorphisms. Fourteen different genotypes were revealed by cluster analysis. Five genotypes were collected only on wheat; seven only on oats and two were collected in both hosts. Genetic and geographical distances among all clonal lineages were not correlated. Analysis of molecular variance showed that some molecular markers are not randomly distributed among clonal lineages collected on oats and on wheat. These results suggest the existence of host-races within M. dirhodum, which should be further investigated using a combination of ecological and genetic data.

A emergência de raças hospedeiro-especialistas em afídeos pode constituir um obstáculo ao manejo de pragas por meio de plantas resistentes. Existem exemplos de raças hospedeiro-especialistas em afídeos de cereais, embora a ocorrência de raça hospedeiro-especialista no pulgão-verde-pálido-do-trigo Metopolophium dirhodum (Walker, 1849) (Hemiptera, Aphididae) não tenha sido relatada ainda. Marcadores RAPD foram utilizados para avaliar os efeitos da distância geográfica e do hospedeiro sobre a diversidade genética de linhas clonais de M. dirhodum. Vinte e três clones foram coletados em aveia e trigo em doze localidades do sul do Brasil. De vinte e sete iniciadores usados para a análise, apenas quatro iniciadores mostraram polimorfismos. A análise de agrupamento por similaridade genética revelou haver quatorze genótipos, cinco dos quais coletados exclusivamente em trigo, sete exclusivamente em aveia e dois em ambos hospedeiros. Não houve correlação entre as similaridades genéticas e a distância geográfica. A análise da variância molecular demonstrou que alguns marcadores RAPD não se distribuem aleatoriamente entre as linhagens clonais coletadas em aveia e em trigo. Estes resultados sugerem a existência de raças hospedeiro-especialistas em M. dirhodum no Brasil, hipótese esta que deve ser investigada combinando-se dados ecológicos e genéticos.

Aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) and their associations related to biological control in Brazil

This study evaluated the parasitoid-aphid-plant associations in Brazil with the objective of developing a useful research database for further studies of aphid parasitoid ecology and aphid management. The original material was obtained from collections made in Paraná, Rio Grande do Sul, Minas Gerais, and São Paulo states. The published information on the Aphidiinae in Brazil is revised. The general features of the target parasitoid fauna of Central and South America is summarized and promising biological control programs of some aphid species in Brazil is discussed.

Este trabalho avaliou as interações parasitóides-pulgão-planta no Brasil, com o objetivo de desenvolver um banco útil de dados para estudos subseqüentes em ecologia de parasitóides de afídeos e manejo de pulgões. O material original foi obtido de coletas nos estados do Paraná, Rio Grande do Sul, Minas Gerais e São Paulo, sendo revisadas as informações sobre Aphidiinae publicadas no Brasil. Foram também sumarizadas as caracteristicas gerais da fauna de parasitóides das Américas Central e do Sul e discutidos os programas potenciais de controle biológico de algumas espécies de pulgões no Brasil.

Modeling egg distribution of Tinocallis kahawaluokalani (Kirkaldy) (Hemiptera: Aphididae) on Lagerstroemia indica L. (Lythraceae)

This is the first record of winter eggs of the holocyclic monoeceous crapemyrtle aphid Tinocallis kahawaluokalani (Kirkaldy) on Lagerstroemia indica L., in Brazil. The shiny black eggs were observed since early autumn, laid on small folds and crevices of the branches. In order to evaluate and model the egg abundance and distribution, four branches from the cardinal points of 10 plants of two age groups, 5-10 and 20-30 years-old, were collected randomly and cut in eight segments of 10 cm and the number of eggs was registered, in the winter 2001. The eggs were laid mainly on the middle portion of the branch, from 40 cm to 60 cm from the apex on the older trees (54 percent) and on 30 cm to 60 cm on younger ones (58 percent). The data fit in a longitudinal regression model that expresses the tendency of the egg distribution on the branches. The number of eggs was greater on the 20-30 year-old plants (61 percent) than on younger ones (39 percent). The average number (± CI 95 percent) of eggs was 70.5 ± 9.3 and 47.4 ± 12.5, respectively, for the older and younger tree groups. There was no correlation between egg distribution and the cardinal positions of the branches.

Este é o primeiro registro da ocorrência de ovos de inverno do afídeo holocíclico monoécio Tinocallis kahawaluokalani (Kirkaldy) em Lagerstroemia indica L., no Brasil. Os ovos, pretos brilhantes, foram observados a partir do início do outono, depositados nas dobras da casca e gemas dos ramos. Com o objetivo de avaliar a abundância e distribuição dos ovos, bem como modelar esse evento, quatro ramos dos pontos cardeais de 10 plantas de dois grupos etários, 5-10 e 20-30 anos de idade, foram coletados ao acaso e cortados em oito segmentos de 10 cm, registrando-se o número de ovos, no inverno de 2001. Os ovos estavam depositados principalmente na porção mediana dos ramos, entre 40 cm e 60 cm do ápice nas árvores mais velhas (54 por cento) e entre 30 cm e 60 cm nas jovens (58 por cento). Os dados ajustaram-se a um modelo de regressão longitudinal que expressa a tendência da distribuição dos ovos nos ramos. O número de ovos foi maior nas plantas mais velhas (61 por cento) que nas jovens (39 por cento), e o número médio de ovos (± IC 95 por cento) foi 70,5 ± 9,3 e 47,4 ± 12,5, respectivamente nos dois grupos etários. Não houve correlação entre a distribuição dos ovos e a posição dos ramos nos pontos cardeais.

Efeitos do ácido silícico e do acibenzolar-S-methyl sobre Schizaphis graminum (Rondani) (Hemiptera: Aphididae) em plantas de trigo / Effects of silicon acid and of acibenzolar-S-methyl on Schizaphis graminum (Rondani) (Hemiptera: Aphididae) in wheat plants

Neste trabalho, o objetivo foi avaliar os efeitos do ácido silícico e do acibenzolar-S-methyl (ASM) sobre a biologia e o comportamento do pulgão-verde em plantas de trigo. O experimento constituiu-se em um fatorial 4 (sem silício, silício via foliar, silício via solo e silício via solo + foliar) x 2 (com e sem acibenzolar-S-methyl), em delineamento inteiramente ao acaso. Um teste de preferência com chance de escolha foi montado em delineamento em blocos casualizados, com dez repetições. A concentração de ácido silícico foi 1 por cento e de ASM, 0,5 por cento. Para a avaliação dos tratamentos foram realizados testes de preferência com chance de escolha (contagem de pulgões adultos em secções foliares de plantas de trigo), avaliação da biologia (duração dos períodos pré-reprodutivo, reprodutivo e pós-reprodutivo, mortalidade no período pré-reprodutivo, número de ninfas produzidas, longevidade e taxa de crescimento populacional) e colonização dos pulgões (número de pulgões adultos e ninfas). No teste de preferência com chance de escolha, as plantas tratadas com ASM não foram preferidas pelos pulgões. A aplicação de silício ou ASM reduziu o número de ninfas produzidas, a taxa de crescimento populacional, o período pós-reprodutivo e a longevidade do pulgão-verde. Na colonização o número de pulgões foi reduzido pela aplicação de ASM ou silício. A aplicação de ácido silícico, principalmente via solo, ou de ASM, é promissora para uso no manejo integrado do pulgão-verde em trigo.

The objective of this work was to evaluate the effects of silicon acid and acibenzolar-S-methyl (ASM) on biology and behavior of the aphid (greenbug) in wheat plants. The experiment involved a 4 factorial (no silicon, silicon on leaf, silicon in the soil and silicon in the soil + on leaf), x 2 (with and without acibenzolar-S-methyl), in a completely randomized design. A preference test with chance of choice was set in blocks randomized, with 10 replications. Silicon acid was used at 1 percent and ASM at 0.5 percent. The treatments were evaluated by means of preference tests with chance of choice (adult aphids in leaf sections of wheat plants were counted), biological studies (length of pre-reproductive, reproductive and post-reproductive periods, mortality rate during the pre-productive period, number of nymphs, longevity and population growth rate were determined) and colonization of aphids (number of adult aphids and nymphs were determined). In the preference test, plants that received ASM were not chosen by the aphids. The application of the silicon or ASM reduced significantly the number of nymphs, the population growth rate, the post-reproductive period and the longevity of the greenbug. A significant reduction of the number of aphids was observed during aphids colonization when ASM or silicon were applied. The addition of silicon acid, mostly in the soil, or of ASM is promising as a control method in the integrated management of aphid in wheat.

Custo adaptativo associado à resistência de Aphis gossypii Glover (Hemiptera: Aphididae) ao inseticida carbosulfam / Fitness cost associated with carbosulfan resistance in Aphis gossypii Glover (Hemiptera: Aphididae)

Com o objetivo de prover subsídios a um programa de manejo de resistência de Aphis gossypii Glover ao carbosulfam, foram avaliados os possíveis custos adaptativos associados a essa resistência em condições laboratoriais. Para tanto, avaliou-se a estabilidade da resistência ao carbosulfam em populações de A. gossypii com diferentes freqüências iniciais de resistência e compararam-se parâmetros biológicos das linhagens suscetível e resistente ao inseticida. A estabilidade da resistência foi avaliada a partir de populações com freqüências iniciais de 20, 50 e 80 por cento de pulgões resistentes ao carbosulfam. A suscetibilidade ao carbosulfam foi estimada mensalmente durante seis meses, utilizando-se de concentração diagnóstica de 32 ppm. A biologia das linhagens suscetível e resistente foi avaliada em plantas de algodão mantidas em condições climáticas controladas. A resistência ao carbosulfam foi instável, ou seja, a suscetibilidade ao inseticida aumentou significativamente em diferentes populações de A. gossypii na ausência de pressão seletiva. Comparações de parâmetros biológicos entre as linhagens suscetível e resistente ao carbosulfam mostraram que há custo adaptativo associado à resistência. A linhagem resistente apresentou menor fecundidade, menor período reprodutivo e menor longevidade do que a linhagem suscetível. A taxa líquida de reprodução (Ro) de 14,04 e 43,18 vezes e razão finita de aumento (lambda) de 1,25 e 1,30 fêmeas/fêmea/dia para as linhagens resistente e suscetível respectivamente. Portanto, a instabilidade da resistência de A. gossypii ao carbosulfam pode ser explorada em programas de manejo da resistência.

Consumption of Cinara spp. (Hemiptera, Aphididae) by Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae)

Adults and larvae of coccinellids were observed feeding on populations of the giant conifer aphids Cinara spp. on Pinus spp., in Southern Brazil. The objective of this research is to evaluate the consumption capacity of Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae) on these aphid species, in order to obtain information for biological control programs. Ten larvae of each predator species were fed with aphids of small size (nymphs of 1st and 2nd instars), and 10 with aphids of medium size (nymphs of 3rd and 4th instars), maintained under 15°C, 20°C and 25°C, 12 h photophase and 70 ± 10 percent relative humidity. The aphids were counted every 24 hours, replacing those that were consumed. The total consumption of Cinara by the larvae of C. sanguinea was not statistically different at the three temperatures: 325.5; 322.2 and 324.8 of small aphids and 121.3; 140.4 and 109.9 of medium ones, respectively at 15°C, 20°C and 25°C. The consumption by H. convergens was higher than by C. sanguinea and increased noticeably with temperature: 444 aphids at 15°C; 491.3 at 20°C and 513.3 at 25°C, considering the small aphids, and 187.1; 205.1 and 216.6 of medium aphids at the three temperatures. The small aphids weigh about half as much as medium ones and were preferred by all larval instars probably because they are easier to manipulate than the large ones. Both predators, especially the 4th instar larvae, showed high consumption capacity on the Cinara nymphs at all temperatures and can be regarded as promising biological control agents.

A guide to the winged aphids (Homoptera) of Costa Rica / Guía de los áfidos alados (Homoptera) de Costa Rica

This guide is a compilation of limited morphological and biological information on the winged morphs of 60 species of aphids that have been collected in Costa Rica. It should not be viewed as a definitive taxonomic treatise on the aphids of Costa Rica, rather it is a tool that can be used to assist in research on the biology, host plant relationships, taxonomy, and virus transmission capabilities of aphids. Each species is covered in an identical manner. Morphological and biological information is provided in both Spanish and English as well as photographs of slide mounted specimens. Keys are provided to help the user in identifying the species. Most of the specimens examined were taken in traps associated with epidemiological studies. Limited field collecting has generated host records and these have been added to a list of the aphids of Central America that was compiled by Pamela Anderson and appended in the guide with her permission. The authors hope that this book will be useful to entomologists in Costa Rica and Central America.

Esta guía es una recopilación de información morfológica y biológica limitada de las formas aladasde 60 especies de áfidos que han sido recolectadas en Costa Rica. No debe ser tomada como un tratado taxónomicodefinitivo de los áfidos de Costa Rica, sino más bien, como una herramienta que puede ser usada paraayudar en la investigación de la biología, de las relaciones planta hospedera, de la taxonomía y de la capacidadde transmisión de virus de los áfidos. Cada especie fue cubierta en forma idéntica. La información morfológicay biológica se presenta tanto en español como en inglés, así como fotografías de los especímenes montados enláminas de vidrio. También se presentan claves para ayudar al usuario en la identificación de las especies. Lamayoría de los especímenes examinados fueron tomados de trampas relacionadas con estudios epidemiológicos.Limitadas recolectas en campo han generado registros de hospederas. Estos registros han sido agregados a lalista de los áfidos de Centroamérica recopilada por Pamela Anderson, la cual aparece con su permiso, como unapéndice en esta guía. Los autores esperan que este libro pueda ser de gran utilidad para los entomólogos enCosta Rica y América Central.

Fecundidade e longevidade de Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) em diferentes temperaturas e cultivares comerciais de crisântemo (Dendranthema grandiflora Tzvelev) / Fecundity and longevity of Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) at different temperatures and commercial chrysanthemum cultivars (Dendranthema grandiflora Tzvelev)

Fecundity and longevity of Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) at different temperatures and commercial chrysanthemum cultivars (Dendranthema grandiflora Tzvelev). The aphid A. gossypii is one of the main pests in a number of crops both under field and protected conditions. The objective of the present study was to evaluate the fecundity and longevity of A. gossypii under different temperatures and commercial chrysanthemum cultivars (Yellow Snowdon, White Reagan and Dark Splendid Reagan) with different trichomes densities (11.3; 16.6 and 21.6 trichome/mm² of the leaf, respectively) The trials were carried out in climatic chambers, at four temperatures (15, 20, 25 and 30 ±1 ºC), 70 ± 10 percent RH and photophase 10h. The reproductive period significantly decreased with increase of temperature in the three cultivars. In Yellow Snowdon cultivar average duration of the reproductive period was 14.3 days at 25 ºC. The maximum fecundity was obtained at the temperature of 25 ºC with 3,1; 2,8 and 3,6 nymphs/female/day in the Yellow Snowdon, White Reagan and Dark S. Reagan cultivars, respectively. The total fecundity was reduced by extreme temperatures (15 and 30 ºC), and was obtained at 25 ºC with 35,9 nymphs/female. Females maintained in Yellow Snowdon cultivar significantly showed superiority (30,7 nymphs/female) in total fecundity in relation to White Reagan (22,1 nymphs/female) and Dark S. Reagan (22,9 nymphs/female). The Yellow Snowdon cultivar (with a lower trichome density) had a significant influence in daily and total capacity of nymphs production, showing a higher fecundity of A. gossypii females. The aphid's longevity was affected by cultivars and temperature, and this longevity decreased whit increase of temperature. The results showed that there was an interaction between the temperature and host plant on reproductive parameters of A. gossypii

Plantas hospederas de Aphis gossypii (Aphididae), vector de virus del melón Cucumis melo (Cucurbitaceae) en Costa Rica / Host plants of Aphis gossypii (Aphididae), vector of virus of Cucumis melo melon (Cucurbitaceae) in Costa Rica

Plant species associated with commercial melon crops and surrounding areas were examined to identity the natural host plants of Aphis gossypii Glover. The study was conducted in two farms located in different melon production areas and plant life zones of Costa Rica. Plant species diversity, percent coverage and distribution over time were recorded during one year. Differences between locations were observed. A total of 86 plant species (49 families) and 72 plant species (40 families) were identified associated to the crop in farms A and B, respectively. In both farms a total of 24 species plants (16 families) were colonized by A. gossypii and 16 (10 families) are new reports of host plant species for this aphid. The new reports are: Justicia comata, Tetramerium nervosum, Alternanthera pubiflora, Cassia massoni, C. reticulata, Cleome viscosa, C. spinosa, Croton argenteus, Caperonia palustris, Chamaesyce gyssopilopia, Phyllantus amarus, Sida decumbens, Ludwigia erecta, Passiflora foetida, Guazuma ulmifolia and Corchorus orinocensis.