RESUMO
Brown rot is the most important disease of peaches in Brazil. The objective of this study was to compare the brown rot monocyclic components from Monilinia fructicola and M. laxa isolates from Brazil on peaches, due to the detection of M. laxa in the São Paulo production area. Conidia germination and pathogen sporulation were assessed in vitro under a temperature range of 5-35oC and wetness duration of 6-48h. Incubation and latent periods, disease incidence, disease severity and pathogen reproduction on peach fruit were evaluated under 10, 15, 20, 25 and 30oC and wetness duration of 6, 12 and 24h. Six of seven parameters of a generalised beta function fitted to conidia germination of M. fructicola and M. laxa were similar. Only the shape parameter was higher for M. fructicola indicating that the range of temperatures and wetness periods favourable for germination is wider for M. laxa than for M. fructicola. The optimum temperature for brown rot development caused by M. fructicola was 24.5oC and for. Monilinia laxa was 19.8oC. At 10oC M. laxa lesions produced more conidia than M. fructicola, and the opposite occurred at 30oC. The estimated maximum temperature for lesion development was also higher for M. fructicola than for M. laxa. M. fructicola is favored by warmer weather than M. laxa and the presence and impact of this specie in Brazil must be investigated especially in the South states.
Podridão parda é a doença mais importante de pêssegos no Brasil. O objetivo deste estudo foi comparar os componentes monocíclicos da podridão parda de isolados brasileiros de M. fructicola e M. laxa, devido à detecção de M. laxa em uma área de produção de São Paulo. A germinação de conídios e esporulação do patógeno foram avaliadas in vitro sob uma faixa de temperatura de 5-35oC e duração do molhamento de 6-48h. Os períodos de incubação e de latência, a incidência da doença, a severidade da doença e a reprodução do patógeno em frutos de pêssego foram avaliados em 10, 15, 20, 25 e 30ºC e duração de molhamento de 6, 12 e 24h. Seis dos sete parâmetros de uma função beta generalizada para germinação de conídios de M. fructicola e M. laxa foram semelhantes. Apenas o parâmetro de forma foi mais alto para M. fructicola indicando que a gama de temperaturas e períodos de molhamento favoráveis para germinação é maior para M. laxa do que para M. fructicola. A temperatura ideal para o desenvolvimento de podridão parda causada por M. fructicola foi 24,5oC e para Monilinia laxa foi 19,8oC. A 10oC lesões de M. laxa produziram mais conídios que as de M. fructicola, e o inverso ocorreu a 30oC. A temperatura máxima estimada para o desenvolvimento de lesões também foi maior para M. fructicola do que para M. laxa. M. fructicola é favorecido por um clima mais quente do que M. laxa e a presença e impacto deste patógeno no Brazil deve ser acompanhado em especial no estados do sul do país.
Assuntos
Controle de Pragas , Fungos/patogenicidade , Prunus persica/parasitologia , Epidemiologia , Prunus/parasitologia , TemperaturaRESUMO
Brown rot is the most important disease of peaches in Brazil. The objective of this study was to compare the brown rot monocyclic components from Monilinia fructicola and M. laxa isolates from Brazil on peaches, due to the detection of M. laxa in the São Paulo production area. Conidia germination and pathogen sporulation were assessed in vitro under a temperature range of 5-35oC and wetness duration of 6-48h. Incubation and latent periods, disease incidence, disease severity and pathogen reproduction on peach fruit were evaluated under 10, 15, 20, 25 and 30oC and wetness duration of 6, 12 and 24h. Six of seven parameters of a generalised beta function fitted to conidia germination of M. fructicola and M. laxa were similar. Only the shape parameter was higher for M. fructicola indicating that the range of temperatures and wetness periods favourable for germination is wider for M. laxa than for M. fructicola. The optimum temperature for brown rot development caused by M. fructicola was 24.5oC and for. Monilinia laxa was 19.8oC. At 10oC M. laxa lesions produced more conidia than M. fructicola, and the opposite occurred at 30oC. The estimated maximum temperature for lesion development was also higher for M. fructicola than for M. laxa. M. fructicola is favored by warmer weather than M. laxa and the presence and impact of this specie in Brazil must be investigated especially in the South states.(AU)
Podridão parda é a doença mais importante de pêssegos no Brasil. O objetivo deste estudo foi comparar os componentes monocíclicos da podridão parda de isolados brasileiros de M. fructicola e M. laxa, devido à detecção de M. laxa em uma área de produção de São Paulo. A germinação de conídios e esporulação do patógeno foram avaliadas in vitro sob uma faixa de temperatura de 5-35oC e duração do molhamento de 6-48h. Os períodos de incubação e de latência, a incidência da doença, a severidade da doença e a reprodução do patógeno em frutos de pêssego foram avaliados em 10, 15, 20, 25 e 30ºC e duração de molhamento de 6, 12 e 24h. Seis dos sete parâmetros de uma função beta generalizada para germinação de conídios de M. fructicola e M. laxa foram semelhantes. Apenas o parâmetro de forma foi mais alto para M. fructicola indicando que a gama de temperaturas e períodos de molhamento favoráveis para germinação é maior para M. laxa do que para M. fructicola. A temperatura ideal para o desenvolvimento de podridão parda causada por M. fructicola foi 24,5oC e para Monilinia laxa foi 19,8oC. A 10oC lesões de M. laxa produziram mais conídios que as de M. fructicola, e o inverso ocorreu a 30oC. A temperatura máxima estimada para o desenvolvimento de lesões também foi maior para M. fructicola do que para M. laxa. M. fructicola é favorecido por um clima mais quente do que M. laxa e a presença e impacto deste patógeno no Brazil deve ser acompanhado em especial no estados do sul do país.(AU)
Assuntos
Prunus persica/parasitologia , Controle de Pragas , Fungos/patogenicidade , Epidemiologia , Prunus/parasitologia , TemperaturaRESUMO
Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a major pest in temperate fruit trees, such as peach and apple. Entomopathogenic nematodes (EPNs) are regarded as viable for pest management control due to their efficiency against tortricid in these trees. The objective of this study was to evaluate the effectiveness of native EPNs from Rio Grande do Sul state against pre-pupae of G. molesta under laboratory and field conditions. In the laboratory, pre-pupae of G. molesta were placed in corrugated cardboard sheets inside glass tubes and exposed to 17 different EPNs strains at concentrations of 6, 12, 24, 48 and 60 IJs/cm(2) and maintained at 25 °C, 70 ± 10% RH and photophase of 16 h. Insect mortality was recorded 72 h after inoculation of EPNs. Steinernema rarum RS69 and Heterorhabditis bacteriophora RS33 were the most virulent strains and selected for field application (LC95 of 70.5 and 53.8 IJs/cm(2), respectively). Both strains were highly efficient under field conditions when applied in aqueous suspension directed to larvae on peach tree trunk, causing mortality of 94 and 97.0%, respectively.
Assuntos
Mariposas/parasitologia , Mariposas/patogenicidade , Controle Biológico de Vetores , Doenças das Plantas/prevenção & controle , Prunus/parasitologia , Rabditídios/patogenicidade , Animais , Brasil , Larva/parasitologia , Larva/patogenicidade , Controle Biológico de Vetores/métodos , Controle Biológico de Vetores/normas , Doenças das Plantas/parasitologia , Distribuição Aleatória , VirulênciaRESUMO
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.
Assuntos
Animais , Afídeos/fisiologia , Controle Biológico de Vetores , Comportamento Predatório/fisiologia , Prunus/parasitologia , Brasil , Densidade Demográfica , Comportamento Predatório/classificação , Estações do AnoRESUMO
BACKGROUND: Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans have invested considerable effort to stay ahead of resistance phenotypes that repeatedly develop in insects. Aphids are a group of insects that have become global pests in agriculture and frequently exhibit insecticide resistance. The green peach aphid, Myzus persicae, has developed resistance to at least seventy different synthetic compounds, and different insecticide resistance mechanisms have been reported worldwide. METHODOLOGY/PRINCIPAL FINDINGS: To further characterize this resistance, we analyzed genome-wide transcriptional responses in three genotypes of M. persicae, each exhibiting different resistance mechanisms, in response to an anti-cholinesterase insecticide. The sensitive genotype (exhibiting no resistance mechanism) responded to the insecticide by up-regulating 183 genes primarily ones related to energy metabolism, detoxifying enzymes, proteins of extracellular transport, peptidases and cuticular proteins. The second genotype (resistant through a kdr sodium channel mutation), up-regulated 17 genes coding for detoxifying enzymes, peptidase and cuticular proteins. Finally, a multiply resistant genotype (carrying kdr and a modified acetylcholinesterase), up-regulated only 7 genes, appears not to require induced insecticide detoxification, and instead down-regulated many genes. CONCLUSIONS/SIGNIFICANCE: This study suggests strongly that insecticide resistance in M. persicae is more complex that has been described, with the participation of a broad array of resistance mechanisms. The sensitive genotype exhibited the highest transcriptional plasticity, accounting for the wide range of potential adaptations to insecticides that this species can evolve. In contrast, the multiply resistant genotype exhibited a low transcriptional plasticity, even for the expression of genes encoding enzymes involved in insecticide detoxification. Our results emphasize the value of microarray studies to search for regulated genes in insects, but also highlights the many ways those different genotypes can assemble resistant phenotypes depending on the environmental pressure.
Assuntos
Afídeos/genética , Genoma de Inseto/genética , Resistência a Inseticidas/genética , Transcriptoma , Animais , Afídeos/crescimento & desenvolvimento , Carbamatos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Genótipo , Humanos , Proteínas de Insetos/genética , Inseticidas/farmacologia , Análise de Sequência com Séries de Oligonucleotídeos , Prunus/parasitologia , Pirimidinas/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests worldwide. Uses over 400 plant species and has evolved different insecticides resistance mechanisms. As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems. METHODOLOGY/PRINCIPAL FINDINGS: In this work we (i) evaluated whether insecticide resistance mutations (IRM) in M. persicae can give an advantage in terms of reproductive fitness when aphids face two hosts, pepper (Capsicum annuum) a suitable host and radish (Raphanus sativus) the unfavorable host and (ii) examined the transcriptional expression of six genes that are known to be up-regulated in response to insecticides. Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)). Susceptible genotypes (not carrying insensitivity mutations) had a higher r(m) on pepper, and the transcriptional levels of five genes increased on radish. The r(m) relationship was reversed on the unfavorable host; genotypes with multiple IRM exhibited higher r(m), without altering the transcriptional levels of the studied genes. Genotypes with one IRM kept a similar r(m) on both hosts, but they increased the transcriptional levels of two genes. CONCLUSIONS/SIGNIFICANCE: Although we have studied only nine genotypes, overall our results are in agreement with the general idea that allelochemical detoxification systems could constitute a pre-adaptation for the development of insecticide resistance. Genotypes carrying IRM exhibited a higher r(m) than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.
Assuntos
Afídeos/genética , Regulação da Expressão Gênica/genética , Resistência a Inseticidas/genética , Mutação , Adaptação Fisiológica/genética , Animais , Afídeos/fisiologia , Capsicum/parasitologia , Carbamatos/farmacologia , Carboxilesterase/genética , Catepsina B/genética , Sistema Enzimático do Citocromo P-450/genética , Evolução Molecular , Regulação da Expressão Gênica/efeitos dos fármacos , Genótipo , Glutationa Transferase/genética , Proteínas de Choque Térmico HSP70/genética , Especificidade de Hospedeiro/genética , Humanos , Proteínas de Insetos/genética , Inseticidas/farmacologia , Isoenzimas/genética , Prunus/parasitologia , Pirimidinas/farmacologia , Raphanus/parasitologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para Cima/efeitos dos fármacosRESUMO
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.
Assuntos
Afídeos/fisiologia , Controle Biológico de Vetores , Comportamento Predatório/fisiologia , Prunus/parasitologia , Animais , Brasil , Densidade Demográfica , Comportamento Predatório/classificação , Estações do AnoRESUMO
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 Möericke-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.
Assuntos
Afídeos/fisiologia , Prunus/parasitologia , Animais , Afídeos/classificação , Brasil , Interações Hospedeiro-Parasita , Umidade , Densidade Demográfica , Dinâmica Populacional , Chuva , Estações do Ano , TemperaturaRESUMO
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.
Assuntos
Animais , Afídeos/fisiologia , Prunus/parasitologia , Afídeos/classificação , Brasil , Interações Hospedeiro-Parasita , Umidade , Densidade Demográfica , Dinâmica Populacional , Chuva , Estações do Ano , TemperaturaRESUMO
This work was carried out in orchards of guava progenies, and loquat and peach cultivars, in Monte Alegre do Sul, SP, Brazil, in 2002 and 2003. Guavas and loquats were bagged and unbagged bi-weekly and weekly, respectively, for assessment of the infestation period. Peach was only bagged weekly. The assays started when the fruits were at the beginning of development, but still green. Ripe fruits were taken to the laboratory and placed individually into plastic cups. McPhail plastic traps containing torula yeast were hung from January 2002 to January 2004 to assess the fruit fly population in each orchard, but only the Ceratitis capitata population is here discussed. Five tephritid species were reared from the fruits: Anastrepha bistrigata Bezzi, A. fraterculus (Wiedemann), A. obliqua (Macquart), A. sororcula Zucchi, and C. capitata, in addition to six lonchaeid species: Neosilba certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. zadolicha McAlpine and Steyskal, Neosilba sp. 4, and Neosilba sp. 10 (both species are in the process of being described by P. C. Strikis), as well as some unidentified Neosilba species. Ten parasitoid species were obtained from fruit fly puparia, of which five were braconids: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, and Utetes anastrephae (Viereck), and five figitids: Aganaspis pelleranoi (Brèthes), Dicerataspis grenadensis Ashmead, Lopheucoila anastrephae (Rhower), Leptopilina boulardi (Barbotin, Carlton and Kelner-Pillaut), and Trybliographa infuscata Diaz, Gallardo and Uchôa. Ceratitis capitata showed a seasonal behavior with population density peaking at the second semester of each year. Anastrepha and Neosilba species remained in the orchards throughout both years.