RESUMO
The common bean (Phaseolus vulgaris L.) is an important leguminous crop providing low-cost protein in developing countries worldwide. Insect pests are the main threats to common bean production, and this article focuses on the soybean looper (SL) Chrysodeixis includens (Walker, 1858) (Lepidoptera: Noctuidae), which feeds on leaves and pods. The recurrent use of synthetic chemicals may lead to pest resistance. Genetically resistant plants may diminish their use. Thus, the objective was to study common bean genotypes' resistance toward SL. The plants were grown in greenhouse conditions. The biology, fertility life table, oviposition preference and free-choice feeding preference were analyzed. Phenol and flavonoid content were assessed in leaves using a biology assay. Uirapuru genotype negatively affected C. includens biology and reproduction. Tangará genotype favored these parameters. Genotypes Quero-Quero, Nhambu, Corujinha, Andorinha, ANFC 9, Siriri, BRS Radiante and Verdão were more attractive for third-instar larvae. Negative correlations between phenolic and flavonoid compounds with survival rate (from egg to adult) rate were found. Common bean genotypes with dark leaves are less preferred for oviposition.
RESUMO
The broad mite (BM) Polyphagotarsonemus latus is a pest of great prominence for several crops, including the common bean (Phaseolus vulgaris). The objective of this study was to select resistant genotypes and to determine chemicals associated with resistance. In the first experiment, BM incidence was assessed for 36 genotypes in a greenhouse study. A group of 10 genotypes was selected according to the development of BM populations. Mite populations and phytometric and biochemical variables were then determined to study eventual differential genotypic responses to mite infestation. Lower numbers of mite mobile forms (larvae + adults) were found on Verdão, Negrão and Carioca Original genotypes. The magnitude of differences reached 5.4 times more BM in the IAC Alvorada than the Verdão genotype. Plant yields were reduced for the genotypes TAA Bola Cheia, IPR Sabiá, IPR Uirapuru, IAC Alvorada and Carioca Original when plants were infested with BM. The yields for LP 13833, BRS Esteio, Negrão 11, Verdão and MD 1133 were similar between infested and non-infested genotypes, indicating tolerance. Verdão and Negrão 11, besides the tolerance, exhibited low offspring development, indicating antibiosis and/or antixenosis. Higher phenolic compound levels were found in the Verdão genotype. Increased contents of catalase and peroxidase were detected for Negrão 11 genotype when infested with BM. This work allowed the detection of common bean genotypes that express resistance and tolerance to BM. These genotypes can be used in places with a history of BM infestation, or used in breeding programs to incorporate these characteristics in other genotypes.
RESUMO
ABSTRACT: The infestation of coffee leaf miner and its predation by wasps were assessed in commercial organic coffee plantings shaded with leucaena or intercropped with pigeon pea. Plantings in northern Paraná were assessed every two weeks from June 2011 to December 2012. The percent of infested leaves, number of mines per leaf and the percent of predation by wasps (indicated by lacerations) were determined. Fewer coffee leaf miners and fewer mines per leaf were found in pigeon pea intercropped plantings (28.4% and 0.3, respectively) than in shaded plantings with leucaena (48.1% and 0.8, respectively). More predation by wasps was found in the shaded (27.2%) than in the intercropped (13.2%) plantings. Suggestions for new studies are presented along with suggestions for managing the leaf miner in coffee plantings.
RESUMO: A infestação de bicho-mineiro e a sua predação por vespas foram avaliadas em lavouras comerciais de café orgânico sombreadas com leucena ou consorciadas com feijão guandu. As lavouras situadas na região Norte do Paraná foram avaliadas a cada duas semanas de junho de 2011 a dezembro de 2012. Determinou-se o percentual de folhas infestadas, o número de minas por folha e a porcentagem de predação por vespas (indicada pela laceração das minas). Menor infestação do Bicho-mineiro e o menor número de minas por folha foi verificada na lavoura consorciada com feijão guandu (28,4% e 0,3; respectivamente) em relação a lavoura sombreada com leucina (48,1% e 0,8; respectivamente). Maior predação por vespas foi verificada na lavoura sombreada (27,2%) em relação a lavoura consorciada (13,18%). Sugestões de novas pesquisas e para o manejo do bicho-mineiro em lavouras de café são apresentadas.
RESUMO
Paecilomyces lilacinus é um fungo de solo, parasita facultativo de ovos de nematóides, que pode crescer rapidamente "in vitro". Este trabalho teve como objetivo avaliar o crescimento micelial de P. lilacinus em diferentes temperaturas e selecionar os melhores isolados quanto à capacidade de parasitar ovos de Meloidogyne paranaensis. Foram avaliados isolados de P. lilacinus, obtidos de solos coletados na região de Londrina, PR. Para o isolamento empregou-se a técnica de diluição seriada dos solos e plaqueamento em meio de cultura semi-seletivo. A determinação do crescimento micelial e do parasitismo "in vitro" dos isolados sobre M. paranaensis foi realizada em placas de Petri contendo meio BDA. Os isolados foram incubados em B.O.D. a temperaturas de 20°C, 22,5°C, 25°C, 27,5°C e 30°C. A avaliação do crescimento foi interrompida quando em um dos tratamentos a colônia do fungo atingiu a borda da placa de Petri e a determinação do parasitismo foi realizada depois de oito dias de incubação, calculando-se a porcentagem de ovos parasitados. O crescimento micelial dos isolados de P. lilacinus teve grande dependência da temperatura de incubação a que foram submetidos, sendo mais rápido à temperatura de 22,5°C. Os isolados de P. lilacinus revelaram habilidade para infectar os ovos de M. paranaensis em meio BDA, principalmente na temperatura de 25°C.
Paecilomyces lilacinus is a soil fungus, facultative parasite of nematode eggs, which develops quickly "in vitro". The mycelial growth of P. lilacinus isolates was evaluated at different temperatures and the best isolates, regarding the capacity to parasite Meloidogyne paranaensis eggs, were chosen. P. lilacinus soil isolates from Londrina, Parana state, were evaluated. Isolation was done using serial dilution of the soils and plating it in semi-selective agar medium. The determination of mycelial growth and "in vitro" parasitism of these isolates was done using Petri plates containing potato-dextrose-agar (PDA), placed in chamber at 20°C, 22.5°C, 25°C, 27.5°C or 30°C. The evaluation started when in one of the treatments of the fungus colonies reached the edge of the Petri plate. Parasitism was determined after 8 days of incubation, calculating the percentage of parasited eggs. The mycelial growth of P. lilacinus isolates was greatly dependent on the temperature. The fastest growth occurred at 22.5°C. The isolates of P. lilacinus were able to infect M. paranaensis eggs in PDA medium, mostly at 25°C.
