Introduction. Citrus trees in Brazil are often attacked by the blackfly, Aleurocanthus woglumi Ashby. The induction of resistance to control this pest is required to maintain the sanitary and ...nutritional quality of the crop. The aim of this study was to evaluate the potential of silicon in the form of potassium silicate (K2SiO3) to modify the activity of enzymes involved in the defence of Citrus reticulata and to find any correlation between the activity of these enzymes and the development of A. woglumi. Materials and methods. The study was conducted in a greenhouse using seedlings of C. reticulate cv. ‘Dancy’ in the following one-application treatments: T1: Infestation with A. woglumi and no K2SiO3 (control, “C”); T2: No A. woglumi and no K2SiO3 (absolute control “AC”); T3: 17 g L-1K2SiO +A. woglumi, T4: 35 g L-1K2SiO +A. woglumi; T5: 52 g L-1 K2SiO +A. woglumi; and T6: 70 g L-1K2SiO +A. woglumi. To perform the enzymatic analyses, one leaf was removed separately from each mandarin seedling after 10, 30, 50, 70, and 90 days of continuous feeding of A. woglumi. The activity of peroxidase, polyphenol oxidase and phenylalanine ammonia-lyase was assessed. Results and discussion. The correlation between peroxidase activity and A. woglumi development was positive. The peroxidase and polyphenol activities indicated strong induction of plant defences against A. woglumi. The increase in peroxidase and polyphenoloxidase activity revealed the induction of synthesis of compounds for plant defence against A. woglumi, but this effect depended on the time of A. woglumi feeding and on the concentration of silicon. Conclusion. Silicon was shown to be an elicitor that potentiates the defence mechanisms of C. reticulata to A. woglumi.
Introduction. Les agrumes au Brésil sont fréquemment attaqués par des aleurodes (Aleurocanthus woglumi Ashby). L’induction de résistance pour lutter contre ce ravageur est nécessaire pour maintenir la qualité sanitaire et nutritionnelle de la récolte. Le but de cette étude était d’évaluer le potentiel du silicium sous la forme de silicate de potassium (K2SiO3) dans la modification de l’activité des enzymes impliquées dans la réaction de défense du mandarinier (Citrus reticulata), et aussi de trouver une corrélation entre l’activité de ces enzymes et le développement des aleurodes. Matériel et méthodes. L’étude a été menée en serre en utilisant des plants de mandarinier cv. Dancy. Les traitements suivants ont été appliqués : T1 : infestation par A. woglumi et pas de K2SiO3 (contrôle, “C”; T2 : pas d’A. woglumi et pas de K2SiO3 (contrôle absolu “AC”); T3 : 17 g L-1 K2SiO +A. woglumi, T4 : 35 g L-1 K2SiO +A. woglumi; T5 : 52 g L-1 K2SiO +A. woglumi; et T6 : 70 g L-1 K2SiO +A. woglumi. Pour effectuer les analyses enzymatiques, une feuille de mandarinier a été prélevée séparément de chaque plante après 10, 30, 50, 70 et 90 jours d’alimentation continue en aleurodes des agrumes. L’activité de la peroxydase, de la polyphénol oxydase et de la phénylalanine ammonia-lyase (PAL) a été évaluée. Résultats et discussion. La corrélation entre l’activité de la peroxydase et le développement d’A. woglumi s’est montrée positive. L’activité de la peroxydase et celle de la polyphénol oxydase ont indiqué une forte induction des défenses de la plante contre A. woglumi. L’augmentation de l’activité polyphénol oxydase et peroxydase a révélé l’induction de la synthèse de composés actifs dans la défense des plantes contre A. woglumi, mais cet effet dépendait de la durée ’alimentation des aleurodes et de la concentration en silicium. Conclusion. L’étude a montré que le silicium pouvait jouer le rôle d’éliciteur en stimulant des mécanismes de défense de C. reticulata contre A. woglumi.
The objective of this research was to assess the potential of abiotic compounds as defense response enhancers in maize using enzymatic quantification and their efficiency in reduction of damages ...caused by 'S. frugiperda'. The experiment was laid out in a randomized complete block design with six treatments and five replications. The treatments were: T1: positive control (distilled water + infestation); T2: negative control (without product application, uninfested); T3: biofertilizer; T4: acibenzolar-S-methyl (ASM); T5: potassium silicate; T6: potassium silicate + ASM. The treatments were applied in V6 stage of maize plants. After five days, the plants were artificially infested with 2nd instar caterpillars of 'S. frugiperda'. Damage assessments were carried out at 4, 8, 16 and 22 days after infestation using a scale of notes. To evaluate the enzymatic activity, one leaf of each plant was removed at 2, 4, 8, 16 and 22 days after infestation. The largest peroxidase activities were observed at two DAI (days after infestation) using the potassium silicate + ASM (2,344.12 UAE.mg-1 of proteina.min-1) treatment, while the larger polyphenol oxidase activity peaks were observed after treatment with ASM at 22 DAI. The application of potassium silicate + ASM in corn plants can promote peroxidase activity. The polyphenol oxidase activity was increased after application of ASM, whereas the presence of the pest (on positive control) could potentially increase the activity of phenylalanine ammonia-lyase. The applications of ASM alone and potassium silicate + ASM contributed to reduction of the foliar damage level caused by 'S. frugiperda' in corn plants.
Aleurocanthus woglumi is present in Paraiba state since 2009, causing a lot of damage to the citrus production in the State. There is a lack of knowledge about the bioecology of this Aleyrodidae ...member under the climatic conditions of ParaÃba State. Thus, in order to know the population density of the pest and study the interference of climatic factors upon these insects, yellow sticky traps were installed evenly distributed in the orchard in the agroecological citrus property in Areia city, in Paraiba state. There were two distinct population peaks of the pest, one in September 2011 and another in April 2012. The lowest densities of the pest were recorded between October and December 2011, a period in which there was no new budding. The population monitoring of A. woglumi in Paraiba state has allowed knowing the time in which the insect occurs in the orchard and the variations in the number of individuals throughout time.
This study evaluated the development and reproduction of Ceraeochrysa cubana when fed the citrus blackfly Aleurocanthus woglumi. The study was carried out at the Laboratory of Entomology, Department ...of Plant and Environmental Sciences, Federal University of Paraíba – Areia/PB. It used a completely randomized design. The study was conducted in climate chambers, regulated to 26 ± 2°C and a relative humidity of 70 ± 10% with a 12 h photoperiod. The treatments were as follows: eggs, nymphs of only the 1st, 2nd, 3rd, or 4th instars, and nymphs of multiple instars (1st, 2nd, 3rd, and 4th instars) of A. woglumi, with eggs of Sitotroga cerealella as a control. The 1st instar of C. cubana lasted 5.8 to 10.7 days, the 2nd instar lasted 6.0 to 13.3 days, and the 3rd instar lasted 8.2 to 18.5 days. The larvae of C. cubana did not survive when the food provided was only the eggs of A. woglumi, since the predator could not eat them. C. cubana, when provided nymphs of multiple instars (1st, 2nd, 3rd, and 4th instars) of the citrus blackfly, had a shorter pre-pupal period and lower longevity than when consuming the eggs of S. cerealella, but the sex ratio and oviposition period were not affected. However, changes occurred in the pre-oviposition period, the total number of eggs, and the number of viable eggs.
: A mosca negra dos citros, Aleurocanthus woglumi Asbhy, causa danos diretos e indiretos à cultura do citros, sendo seu hospedeiro preferencial. Em busca de alternativas de controle para a mosca ...negra dos citros a pesquisa objetivou avaliar o efeito ovicida de diferentes óleos vegetais sobre A. woglumi. O trabalho foi desenvolvido no laboratório de Entomologia da UFPB- Areia em condições controladas de umidade, temperatura e luminosidade (B.O.D). Utilizou-se o delineamento inteiramente casualizado em parcela subdividida com fatorial 5x4 na parcela (cinco óleos vegetais e quatro doses). As subparcelas foram o tempo de avaliação após a aplicação dos óleos (primeiro, quinto, décimo e décimo quinto). Os tratamentos foram os seguintes óleos vegetais comerciais: eucalipto (Eucalyptus globulus Labil.), alho (Allium sativum L.), gergelim (Sesamum indicum L.), mamona (Ricinus communis L.) e cravo (Dianthus caryophyllus L.), nas seguintes dosagens: 0 (testemunha - água destilada), 2, 4 e 6%. Na analise estatística os dados foram submetidos a regressão logística binomial, utilizando o procedimento LOGISTIC do software SAS 9.3 (2011). Houve efeito significativo para interação entre os dias de avaliação quanto à média de ninfas eclodidas para o primeiro, quinto, décimo e décimo quinto dia. Os óleos comerciais de eucalipto (E. globulus), alho (A. sativum), mamona (R. communis) são uma alternativa promissora no controle de A. woglumi.
O processo de colheita mecanizada constitui-se em uma etapa importante do processo produtivo do amendoim, em que as operações envolvem práticas realizadas em duas etapas: arranquio e recolhimento. ...Durante estas etapas ocorrem perdas quantitativas e qualitativas que devem ser mensuradas para que possam ser diminuídas para não ocasionarem quedas na produção. O objetivo foi verificar a qualidade sanitária de sementes de Arachis hypogaea L., cultivar Runner IAC 886, em função das velocidades de arranquio e recolhimento. O experimento foi conduzido na área da Fazenda de Ensino, Pesquisa e Produção e no Laboratório de Fitopatologia da Faculdade de Ciências Agrárias e Veterinárias - FCAV/UNESP, Campus de Jaboticabal. Foram utilizadas duas velocidades de arranquio (4,3 e 5,0 km h-1) e três de recolhimento (3,5; 4,6 e 6,2 km h-1). A sanidade foi realizada com base em metodologia descrita por ITO et al. (1992). A avaliação foi feita sob microscópio, observando-se as estruturas dos patógenos. Os dados foram submetidos ao teste de Shapiro-Wilk, foi utilizado o delineamento inteiramente casualizado em esquema fatorial 2x3(duas velocidades de arranquio x três velocidades de recolhimento), os dados obtidos foram submetidos à análise de variância pelo teste F, e as médias comparadas por meio do teste de Tukey a 5%, utilizando-se o programa estatístico computacional SAS (SAS, 2004). Foram encontrados os seguintes fungos nas sementes de amendoim: Penicillium sp., Fusarium sp., Aspergillus flavus, Aspergillus ochraceus, Aspergillus niger, Cladosporium sp., Epicocum sp., Phoma sp., Rhizopus sp., e a bactéria Rhizoctonia solani.
Black rot of pineapple caused by the fungus Chalara paradoxa is considered an aggressive and difficult disease to control. The use of natural products has been studied with the goal to incorporate ...them into integrated pest management and reduce the use of agrochemicals. Plant extracts have shown satisfactory results in controlling postharvest diseases by providing fungitoxic action and inducing plant resistance. The aim of this study was to evaluate C. paradoxa severity by the application of plant extract of Mormodica charantia, determinate effect of the plant extract on post-harvest quality, and induction of enzymes linked to host resistance induction. The following treatments were studied: plant extract of bitter melon at concentrations of 10, 100, 500 and 1000 ppm, the commercial products acibenzolar-S–Methyl and fungicide (thiabendazole) in the dosages recommended by the manufacturers, and distilled water as the control, with five replications and two plants per plot. The extract of M. charantia reduced the severity of black rot caused by C. paradoxa, compared to the control treatment, showing similar efficacy to the treatments with commercial inductor Acibenzolar-S-methyl and the fungicide. The enzymatic analysis showed increase of the peroxidase by the use of the bitter melon extract along the evaluation period. The enzymes polyphenol oxidase and phenylalanine ammonia lyase showed greater activity by treatment with M. charantia extract at 500 ppm. It was observed that the plant extract did not affect most of the variables analyzed related to postharvest quality of treated fruits. The use of the extract reduced the fruit weight loss, being a positive aspect under the studied conditions.
The objective of this research was to assess the potential of abiotic compounds as defense response enhancers in maize using enzymatic quantification and their efficiency in reduction of damages ...caused by 'S. frugiperda'. The experiment was laid out in a randomized complete block design with six treatments and five replications. The treatments were: T1: positive control (distilled water + infestation); T2: negative control (without product application, uninfested); T3: biofertilizer; T4: acibenzolar-S-methyl (ASM); T5: potassium silicate; T6: potassium silicate + ASM. The treatments were applied in V6 stage of maize plants. After five days, the plants were artificially infested with 2nd instar caterpillars of 'S. frugiperda'. Damage assessments were carried out at 4, 8, 16 and 22 days after infestation using a scale of notes. To evaluate the enzymatic activity, one leaf of each plant was removed at 2, 4, 8, 16 and 22 days after infestation. The largest peroxidase activities were observed at two DAI (days after infestation) using the potassium silicate + ASM (2,344.12 UAE.mg-1 of proteina.min-1) treatment, while the larger polyphenol oxidase activity peaks were observed after treatment with ASM at 22 DAI. The application of potassium silicate + ASM in corn plants can promote peroxidase activity. The polyphenol oxidase activity was increased after application of ASM, whereas the presence of the pest (on positive control) could potentially increase the activity of phenylalanine ammonia-lyase. The applications of ASM alone and potassium silicate + ASM contributed to reduction of the foliar damage level caused by 'S. frugiperda' in corn plants.
A mosca-negra-dos-citros, Aleurocanthus woglumi, apresenta elevada capacidade de dispersão e adaptação a diversas condições climáticas, além de grande potencial reprodutivo. O presente trabalho teve ...como objetivo avaliar a flutuação populacional e caracterizar o padrão de dependência espacial de A. woglumi em um pomar de lima- ácida Tahiti (Citrus latifolia, Tanaka), no município de São José de Ribamar, Estado do Maranhão. Um sistema de posicionamento global (GPS) e um sistema de informação geográfica (SIG) foram usados para localizar os pontos das amostras, caracterizar o padrão de distribuição, calcular a área de agregação e elaborar mapas de distribuição dos adultos de mosca-negra-dos-citros dentro do pomar. O número médio total de moscas negras foi maior durante a estação chuvosa e observaram-se correlações significativas entre as variáveis precipitação pluvial, umidade relativa do ar e número total de adultos. A distribuição espacial A. woglumi no pomar é agregada, ajustando-se os variogramas calculados ao modelo esférico nas estações seca e chuvosa. Os insetos mostraram uma área de agregação média de 162.092 m² na estação chuvosa e de 9.615 m² na estação seca. Para se obter uma estimativa confiável de populações de mosca-negra-dos-citros, pelo menos uma armadilha deve ser usada a cada 17 hectares na estação chuvosa e uma armadilha por hectare na estação seca.
Aleurocanthus woglumi Ashby conhecida popularmente como mosca-negra-dos-citros é considerada praga quarentenária A2 no Brasil e ocasiona prejuízo em diversas frutíferas, principalmente em citros ...(laranja, limão e tangerina). Poucas são as pesquisas relacionadas aos seus aspectos biológicos nas condições ambientais brasileiras. Nesse sentido, o objetivo da pesquisa foi verificar a preferência de oviposição e a duração do ciclo de vida de A. woglumi em diferentes hospedeiros. A pesquisa foi conduzida em casa de vegetação, durante o período de março de 2009 a março de 2010. Foram realizados testes de preferência sem chance de escolha em seis hospedeiros, simultaneamente, em períodos de 48 e 72 horas, além da biologia comparada em mangueira e laranjeira. Foram observados nos testes que A. woglumi apresenta preferência por ovipositar nas espécies cítricas (limoeiro, laranjeira e tangerineira), mantendo um padrão de não preferência em cajueiro e goiabeira. Os hospedeiros laranjeira e mangueira não interferiram no ciclo biológico da praga.
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