Identificación molecular y diversidad genética de las especies de nematodos Globodera rostochiensis y G. pallida en regiones productoras de papa de Guatemala / Molecular identification and genetic diversity of the species of nematodesGlobodera rostochiensisandG. pallidain potato growing regions of Guatemala

En Guatemala, la producción del cultivo de papa se ve afectada por los nematodos Globodera rostochiensis y Globo-dera pallida. La capacidad de ambas especies para formar quistes complica su control y provoca el aumento de sus poblaciones. En Guatemala se reporta la presencia de ambas especies de nematodos por identificación morfológica, sin embargo, no se ha realizado una confirmación molecular. Este es el primer estudio para validar la presencia de ambas especies de nematodos por PCR múltiple y la determinación de la diversidad y estructura genética de las poblaciones utilizando marcadores moleculares. Se realizaron muestreos en cuatro departamentos productores de papa del país. La identificación por PCR se realizó con el cebador común ITS5 y los cebadores PITSr3 específico para G. rostochiensisy PITSp4 para G. pallida. La caracterización molecular se realizó con el marcador AFLP. Se confirmó la presencia de las dos especies de nematodos en los cuatro departamentos. Los índices de diversidad Shannon y heterocigosidad esperada revelaron mayor diversidad genética en G. rostochiensis (H = 0.311, He = 0.301) que en G. pallida (H = 0.035, He = 0.223). Los métodos NJ, DAPC y PCA exhibieron una débil estructura entre las poblaciones de ambas especies de nematodos. Los resultados sugieren un patrón de dispersión desde Quetzaltenango hacia el resto del país, atribuido a la comercialización de semilla contaminada con nematodos. Se sugiere promover programas de socialización sobre los beneficios del uso de semilla certificada, además de constantes monitoreos moleculares para un diagnóstico certero de ambas especies de nematodos.

In Guatemala, potato crop production is affected by the nematodes Globodera rostochiensis and Globodera pallida. The ability of both species to form cysts complicates their control and causes an increase in their populations. In Guatemala, both species of nematodes have been reported by morphological identification; however, molecular confirmation has not been carried out. It is the first study to validate the presence of both nematode species by multiplex PCR and determine the diversity and genetic structure of the populations using molecular markers. Sampling was carried out in four pota-to-producing departments of the country. PCR identification was performed with the common primer ITS5 and the primers PITSr3 specific for G. rostochiensis and PITSp4 for G. pallida. We performed molecular characterization with the AFLP marker. We confirmed the presence of the two nematode species in the four departments. Shannon diversity and expected heterozygosity indices revealed higher genetic diversity in G. rostochiensis (H = 0.311, He = 0.301) than in G. pallida (H = 0.035, He = 0.223). The NJ, DAPC, and PCA methods exhibited weak structure among populations of both nematode species. The results suggest a dispersal pattern from Quetzaltenango to the rest of the country, attributed to the commer-cialization of seed contaminated with nematodes. We suggest promoting socialization programs on the benefits of using certified seeds and constant molecular monitoring for an accurate diagnosis of both species of nematodes.

RNA-seq analysis of the response of plant-pathogenic oomycete Phytophthora parasitica to the fungicide dimethomorph / Análisis RNA-seq de la respuesta del oomiceto fitopatógeno Phytophthora parasitica al fungicida dimetomorf

Phytophthora parasitica is an important oomycete that causes disease in a variety of plants, dimethomorph fungicides being specific for oomycetes. The aim of this study was to use RNA-seq to rapidly discover the mechanism by which dimethomorph acts in the treatment of P. parasitica. We found that the expression of 832 genes changed significantly after the dimethomorph treatment, including 365 up-regulated genes and 467 down-regulated genes. According to the Gene Ontology (GO) enrichment analysis, pathway enrichment and verification test results, the following conclusions are obtained: (i) the treatment of P. parasitica with dimethomorph causes changes in the expression levels of genes associated with the cell wall and cell wall synthesis; (ii) dimethomorph treatment results in reduced permeability of the cell membrane and changes in the expression of certain transport-related proteins; (iii) dimethomorph treatment increased reactive oxygen species and reduced the expression of genes related to the control of oxidative stress.

Phytophthora parasitica es un importante oomiceto que origina enfermedades en una variedad de plantas; el fungicida dimetomorf es específico contra oomicetos. El objetivo de este estudio fue utilizar la tecnología de RNA-seq para descubrir rápidamente el mecanismo por el que el dimetomorf actúa en el tratamiento de P. parasitica. Descubrimos que la expresión de 832 genes se modificaba significativamente tras el tratamiento con dimetomorf, incluyendo 365 genes que son sobrerregulados y 467 genes que son subrregulados. El análisis de enriquecimiento de ontología de genes (GO), análisis de enriquecimiento de las vías y pruebas de verificación permitieron extraer las conclusiones siguientes: 1) el tratamiento de P. parasitica con dimetomorf origina cambios en los niveles de expresión de los genes relacionados con la pared celular y su síntesis; 2) el tratamiento con dimetomorf origina una reducción de la permeabilidad de la membrana celular, así como cambios en la expresión de ciertas proteínas relacionadas con el transporte, y 3) el tratamiento con dimetomorf incrementó las especies reactivas del oxígeno y redujo la expresión de los genes relacionados con el control del estrés oxidativo.

Preference of red mite Tetranychus ludeni Zacher (Acari: Tetranychidae) to sweet potato genotypes / Preferência do ácaro vermelho Tetranychus ludeni Zacher (Acari: Tetranychidae) por genótipos de batata-doce

Abstract Tetranychus ludeni damages the sweet potato. Pest development can vary between plant genotypes. The objective was to identify the preference of Tetranychus ludeni for Ipomoea batatas genotypes, from the germplasm bank at the Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Natural infestations of this mite were observed on 54 sweet potato genotypes in potted, in a greenhouse. Three mite-infested leafs of each genotype were collected and analyzed. The red mite showed different population density rate in genotypes. The BD 29 genotype was found to be highly susceptible, the BD 08, BD 57, BD 17 and Espanhola genotypes were moderately susceptible, and the others forty-nine genotypes showed low susceptibility to the mite.

Resumo Tetranychus ludeni danifica plantas de batata-doce. O desenvolvimento de pragas pode variar entre genótipos de plantas. O objetivo foi identificar a preferência de T. ludeni para genótipos de Ipomoea batatas do banco de germoplasma da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Infestações naturais deste ácaro foram observadas em 54 genótipos de batata doce plantados em vasos e mantidos em estufa. Três folhas infestadas por ácaros, de cada genótipo, foram coletadas e analisadas. Tetranychus ludeni mostrou diferentes taxas de crescimento populacional entres os genótipos. O genótipo BD 29 foi altamente suscetível, os BD 08, BD 57, BD 17 e Espanhola foram moderadamente suscetíveis e os outros 49 genótipos mostraram baixa suscetibilidade ao ácaro.

Potential of endophytic fungi as biocontrol agents of Duponchelia fovealis (Zeller) (Lepidoptera: Crambidae) / Fungos endofíticos para o biocontrole de Duponchelia fovealis (Zeller) (Lepidoptera: Crambidae)

Abstract This study reports the first assessment of endophytic fungi isolated from strawberry leaves and selection of isolates for the control of Duponchelia fovealis, a new pest of strawberries. A total of 400 strawberry leaves of the cultivar 'Albion' were collected in four commercial farms. Leaves were disinfected, cut in fragments, and placed on Petri dishes containing potato dextrose agar media with tetracycline and incubated for 30 days. Following this time, 517 fungal colonies were isolated, and thirteen genera were identified: Cladosporium, Aspergillus, Nigrospora, Fusarium, Trichoderma, Chaetomium, Alternaria, Paecilomyces, Penicillium, Ulocladium, Bipolaris, Diaporthe, and Phoma. Eight isolates belonging to the genera Aspergillus, Diaporthe, Paecilomyces, and Cladosporium were selected for pathogenicity bioassays against third instar larvae of D. fovealis. Isolates of Paecilomyces induced the highest mortality rates.

Resumo Este trabalho apresenta a primeira contribuição no isolamento de fungos endofíticos de folhas de morangueiro e na seleção de isolados para controle de Duponchelia fovealis, uma nova praga do morangueiro. Foram coletadas 400 folhas da cultivar 'Albion' em quatro lavouras comerciais de morangueiro. As folhas foram desinfetadas, cortadas em fragmentos e depositadas em placas de Petri contendo Ágar Batata Dextrose como meio, em conjunto com tetraciclina e incubados durante 30 dias. Um total de 517 colônias fúngicas e treze gêneros foram isolados: Cladosporium, Aspergillus, Nigrospora, Fusarium, Trichoderma, Chaetomium, Alternaria, Paecilomyces, Penicillium, Ulocladium, Bipolaris, Diaporthe e Phoma. Oito isolados pertencentes aos gêneros Aspergillus, Diaporthe, Paecilomyces e Cladosporium foram selecionados para os bioensaios de virulência contra larvas de 3º instar de D. fovealis. Isolados de Paecilomyces causaram as maiores taxas de mortalidade.

Control potential of Meloidogyne javanica and Ditylenchus spp. using fluorescent Pseudomonas and Bacillus spp

ABSTRACT Plant Growth Promoting Rhizobacteria (PGPR) have different mechanisms of action in the development of plants, such as growth promotion, production of phytohormones and antibiotic substances and changes in root exudates. These help to control plant diseases. In order to evaluate the potential of microorganisms in the control of Meloidogyne javanica and Ditylenchus spp., five rhizobacteria isolated from rhizosphere of garlic cultivated in the Curitibanos (SC) region were tested. Hatching chambers were set on Petri dishes, in which were added 10 mL of bacterial suspension and 1 mL of M. javanica eggs suspension, at the rate of 4500, on the filter paper of each chamber. The same procedure was performed with 300 juvenile Ditylenchus spp. The experimental design was completely randomized, with four replications. The evaluations were performed every 72 h for nine days. The antagonized population of nematodes was determined in Peters counting chamber, determining the percentage hatching (for M. javanica) and motility (for Ditylenchus spp). Isolates CBSAL02 and CBSAL05 significantly reduced the hatching of M. javanica eggs (74% and 54.77%, respectively) and the motility of Ditylenchus spp. (55.19% and 53.53%, respectively) in vitro. Isolates were identified as belonging to the genera Pseudomonas (CBSAL05) and Bacillus (CBSAL02).

Plant growth promoting rhizobacteria reduce aphid population and enhance the productivity of bread wheat

Abstract Plant growth promoting rhizobacteria increase plant growth and give protection against insect pests and pathogens. Due to the negative impact of chemical pesticides on environment, alternatives to these chemicals are needed. In this scenario, the biological methods of pest control offer an eco-friendly and an attractive option. In this study, the effect of two plant growth promoting rhizobacterial strains (Bacillus sp. strain 6 and Pseudomonas sp. strain 6K) on aphid population and wheat productivity was evaluated in an aphid susceptible (Pasban-90) and resistant (Inqlab-91) wheat cultivar. The seeds were inoculated with each PGPR strain, separately or the combination of both. The lowest aphid population (2.1 tiller−1), and highest plant height (85.8 cm), number of spikelets per spike (18), grains per spike (44), productive tillers (320 m−2), straw yield (8.6 Mg ha−1), and grain yield (4.8 Mg ha−1) were achieved when seeds were inoculated with Bacillus sp. strain 6 + Pseudomonas sp. strain 6K. The grain yield of both varieties was enhanced by 35.5-38.9% with seed inoculation with both bacterial strains. Thus, the combine use of both PGPR strains viz. Bacillus sp. strain 6 + Pseudomonas sp. strain 6K offers an attractive option to reduce aphid population tied with better wheat productivity.

Enzymatic comparison and mortality of Beauveria bassiana against cabbage caterpillar Pieris brassicae LINN

Abstract Beauveria bassiana, an entomopathogenic fungus, is the alternative biocontrol agent exploited against major economic crop pests. Pieris brassicae L. is an emerging pest of the Brassicaceae family. Therefore, in the present study, fungal isolates of Beauveria bassiana, viz. MTCC 2028, MTCC 4495, MTCC 6291, and NBAII-11, were evaluated for their virulence against third instar larvae of P. brassicae. Among all these fungal isolates, maximum mortality (86.66%) was recorded in B. bassiana MTCC 4495 at higher concentration of spores (109 conidia/ml), and the minimum mortality (30.00%) was recorded in B. bassiana MTCC 6291 at a lower concentration (107 conidia/ml) after ten days of treatment. The extracellular cuticle-degrading enzyme activities of fungal isolates were measured. Variability was observed both in the pattern of enzyme secretion and the level of enzyme activities among various fungal isolates. B. bassiana MTCC 4495 recorded the maximum mean chitinase (0.51 U/ml), protease (1.12 U/ml), and lipase activities (1.36 U/ml). The minimum mean chitinase and protease activities (0.37 and 0.91 U/ml, respectively) were recorded in B. bassiana MTCC 6291. The minimum mean lipase activity (1.04 U/ml) was recorded in B. bassiana NBAII-11. Our studies revealed B. bassiana MTCC 4495 as the most pathogenic isolate against P. brassicae, which also recorded maximum extracellular enzyme activities, suggesting the possible roles of extracellular enzymes in the pathogenicity of B. bassiana against P. brassicae.

Microbial control of the invasive spiraling whitefly on cassava with entomopathogenic fungi

Abstract The entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Isaria fumosorosea were tested for their efficacy in managing the exotic spiraling whitefly Aleurodicus dispersus (Hemiptera, Aleyrodidae) on cassava (Manihot esculenta) during 2 seasons (2011-2012 and 2012-2013). The fungi I. fumosorosea and L. lecanii exhibited promising levels of control (> 70% mortality of the A. dispersus population). The percent mortality increased over time in both seasons. Application of I. fumosorosea was highly pathogenic to A. dispersus in both seasons compared to the other entomopathogenic fungi. Analysis of the percent mortality in both seasons revealed differences in efficacy between 3 and 15 days after treatment. The season also influenced the effects of the fungi on the A. dispersus population. Thus, entomopathogenic fungi have the potential to manage A. dispersus infestation of cassava.

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.

Analysis on the arcelin expression in bruchid pest resistant wild pulses using real time RT-qPCR.

Arcelin, the antimetabolic protein from wild pulses is a known natural insecticidal molecule. Wild pulses with high arcelin content could serve as potential source to increase the levels of insect resistance in cultivated pulse crops. In this study, arcelin (Arl) gene expression was screened in seven stored product insect pest resistant wild pulse varieties using real time RT-qPCR. Arcelin gene specific real time PCR primers were synthesized from arcelin mRNA sequence of the wild pulse variety, Lablab purpureus. The results revealed different levels of arcelin gene expression in the tested varieties. Canavalia virosa registered significantly high content indicating its suitability for utilization of arcelin gene in developing stored product insect pest resistance with other cultivated pulses.

Phenylpropanoid enzymes, phenolic polymers and metabolites as chemical defenses to infection of Pratylenchus coffeae in roots of resistant and susceptible bananas (Musa spp.).

Activity differences of the first (phenylalanine ammonia lyase, PAL) and the last (cinnamyl alcohol dehydrogenase, CAD) enzymes of phenylpropanoid pathway in the roots of resistant (Yangambi Km5 and Anaikomban) and susceptible (Nendran and Robusta) banana cultivars caused by root lesion nematode, Pratylenchus coffeae, were investigated. Also, the accumulation of phenolics and deposition of lignin polymers in cell walls in relation to resistance of the banana cultivars to the nematode were analyzed. Compared to the susceptible cultivars, the resistant cultivars had constitutively significantly higher PAL activity and total soluble and cell wall-bound phenolics than in susceptible cultivars. The resistant cultivars responded strongly to the infection of the nematode by induction of several-time higher PAL and CAD enzymes activities, soluble and wall-bound phenolics and enrichment of lignin polymers in cell wall and these biochemical parameters reached maximum at 7th day postinoculation. In addition, profiles of phenolic acid metabolites in roots of Yangambi Km5 and Nendran were analyzed by HPLC to ascertain the underlying biochemical mechanism of bananas resistance to the nematode. Identification and quantification of soluble and cell wall-bound phenolic acids showed six metabolites and only quantitative, no qualitative, differences occurred between the resistant and susceptible cvs. and between constitutive and induced contents. A very prominent increase of p-coumaric, ferulic and sinapic acids, which are precursors of monolignols of lignin, in resistant cv. was found. These constitutive and induced biochemical alterations are definitely the chemical defenses of resistant cvs. to the nematode infection.

Impact of eucalyptus plantations in different regions of Brazil on the distribution and abundance of defoliating caterpillars

Eucalyptus species are cultivated in homogeneous plantations in Brazil, mainly to supply wood for the cellulose and steel industries, which favors the establishment of insect pests. The objective was to determine the geographical distribution and structure abundance of Lepidoptera defoliators of eucalypt. Primary pest species of eucalypt of the order Lepidoptera were found in all areas sampled and their populations were correlated with the age of the eucalypt plants, rainfall, and monthly average temperature. They presented population peaks between February and July [Tres Marias and Niquelandia] and July to November [Monte Dourado] during periods of lower rainfall. The highest population peaks of these species were recorded when the eucalypt plants were three to six years old. The area of Guanhaes presented better stability and fewer possibilities for the occurrence of eucalyptus Lepidoptera primary pests

Transformation of coffee (Coffea Arabica L. cv. Catimor) with the cry1ac gene by biolistic, without the use of markers / Transformação do café (Coffea arabica L. cv. Catimor) com o gene cry1ac por bombardeamento, sem usar marcadores

The transformation of coffee plantlets with the cry1ac gene of Bacillus thuringiensis was achieved by biolistic using either the whole pUBC plasmid or only the ubi-cry1ac-nos genetic cassette. The cry1ac gene was inserted into coffee plants in order to confer resistance to the leaf miner Leucoptera coffeella, an insect responsible for considerable losses in coffee crops. Bearing in mind that the genetic cassettes used for this study lack reporter genes and/or selection marker genes, the parameters for the transformation procedure by biolistic were previously standardised with a plasmid carrying the gus reporter gene. The presence of the cry1ac gene in young plantlet tissues was determined by PCR, Southern blot and reverse transcription-PCR. Our results show that the obtainment of viable coffee plantlets, transformed by bombardment with the cry1ac gene and without selection markers nor reporter genes, is feasible.

A transformação das plântulas de café com o gene cry1ac de Bacillus thuringiensis foi realizada por biobalística, utilizando todo o pUBC plasmídeo ou só o cassete genético UBI-cry1ac-nos. O gene cry1ac foi inserido no cafeeiro a fim de conferir resistência à folha mineiro Leucoptera coffeella, um inseto responsável por perdas consideráveis nas culturas de café. Tendo em conta que ao plasmídeo e ao cassete genético utilizados para este estudo faltam genes repórteres e/ou de seleção, os parâmetros para o processo de transformação por biobalística foram previamente padronizados com um plasmídeo transportando o gene repórter gus. A presença do gene cry1ac em tecidos de jovens plântulas foi determinada por PCR, Southern blot e transcrição reversa-PCR. Nossos resultados mostram que a obtenção de plântulas de café, transformado por bombardeamento com o gene cry1ac sem genes de seleção genética nem repórteres é viável.

Diversidad de cicadélidos y clastoptéridos (Hemiptera) en tres zonas productoras de café afectadas por Xylella fastidiosa Wells et al. en Costa Rica / Hemipteran diversity (Cicadellidae and Clastopteridae) in three coffee production zones affected by Xylella fastidiosa (Wells et al.) in Costa Rica

Se realizó un estudio durante los años 2002, 2003 y 2004, con el fin de determinar la composición, la abundancia, riqueza, diversidad, equidad, ocurrencia y fluctuación temporal de las especies de saltahojas en tres zonas productoras de café de Costa Rica. Se utilizaron trampas amarillas pegajosas para clasificar y cuantificar el número de saltahojas adultos durante el período de muestreo. Se encontró un total de 82.500 individuos, pertenecientes a 139 especies ubicadas dentro de nueve subfamilias. San Isidro de León Cortés presentó la mayor diversidad entre los sitios estudiados. Veinticinco especies se encontraron frecuentemente en al menos uno de los sitios muestreados, y solamente Coelidiana sp.1, Osbornellus sp.1, Scaphytopius sp.1 y Empoasca sp. se capturaron a lo largo de todo el período de estudio. La fluctuación temporal de los taxa que comprenden los principales vectores de X. fastidiosa Wells et al. mostró diferencias entre las zonas estudiadas.

A survey was conducted during 2002, 2003 and 2004 to determine the leafhopper species composition, abundance, richness, diversity, evenness, occurrence and flight activity among three coffee production zones of Costa Rica. Yellow sticky traps were used to qualify and quantify the number of aerial leafhoppers during the sampling period. A total of 82,500 individuals, belonging to 139 species within nine leafhopper subfamilies, were trapped. San Isidro de León Cortés site presented the highest diversity from the three surveyed sites. Twenty five species were frequently trapped at least in one of the studied zones, and only Coelidiana sp.1, Osbornellus sp.1, Scaphytopius sp.1 and Empoasca sp. were trapped throughout the sampling period. The flight activity of the taxa that contain the main vectors of Xylella fastidiosa Wells et al. showed differences among the sampling zones.

Thrips (Thysanoptera: Thripidae, Phlaeothripidae) damaging peach in Paranapanema, São Paulo State, Brazil / Tripes (Thysanoptera: Thripidae, Phlaeothripidae) danificando pessegueiro Prunus persica (L.) Batsch (Rosaceae) em Paranapanema, SP

Seeking to identify thrips species associated to peach and the injuries they cause, plants of Aurora and Tropic Beauty cultivars were weekly monitored, from May to August of 2005, in Holambra II district, in Paranapanema, SP. Flowers and fruits from six plants per hectare were sampled by the hitting technique. Frankliniella occidentalis (Pergande), F. schultzei (Trybom), F. gardenia (Moulton), F. condei John, F. insularis (Franklin) and Thrips tabaci Lindeman, in Thripidae, and Haplothrips gowdeyi (Franklin), in Phlaeothripidae were identified. F. occidentalis was dominant, comprising 55.7 percent of the total specimens sampled. Slight and severe injuries were registered in fruits.

Objetivando identificar as espécies de tripes associadas ao pessegueiro e as injúrias causadas, pomares das cultivares Aurora e Tropic Beauty foram monitorados semanalmente, de maio a agosto de 2005, no Distrito de Holambra II, em Paranapanema, SP. Flores e frutos de cada seis plantas por hectare foram amostrados pela técnica da batida. Foram identificadas Frankliniella occidentalis (Pergande), F. schultzei (Trybom), F. gardenia (Moulton), F. condei John, F. insularis (Franklin) e Thrips tabaci Lindeman em Thripidae, e, Haplothrips gowdeyi (Franklin) em Phlaeothripidae. F. occidentalis foi dominante compondo 55,7 por cento do total de espécimes amostrado. Injúrias leves e severas foram registradas nos frutos.

Aislamiento de los microorganismos cultivables de la rizosfera de Ornithogalum umbellatum y evaluación del posible efecto biocontrolador en dos patógenos del suelo / Isolating cultured Ornithogalum umbellatum rhizosphere microorganisms and assessment of possible biocontrolling effect on two ground pathogens

Los microorganismos presentes en el suelo ejercen una acción específica cuando se relacionan con una especie vegetal. Ornithogalum umbellatum es una planta silvestre usada en el país como ornamental pero reconocida en otras partes del mundo por los componentes químicos del bulbo y la aplicación de estas sustancias en el tratamiento alternativo de diferentes enfermedades. Esta característica permitió plantear la hipótesis de que la microflora existente en la rizosfera podría tener posibles efectos biocontroladores en fitopatógenos del suelo y a realizar una evaluación del efecto antagónico in vitro con Botrytis cinerea y Sclerotinia sclerotiorum. El estudio se realizó tomando 12 muestras de rizosfera y sembrándolas por duplicado en medios sólidos, agar papa dextrosa, agar Rosa de Bengala (con y sin antibiótico), agar yeast mold y agar Luria Bertani. Se aislaron 8 morfotipos de levaduras, 5 morfotipos de bacterias y 9 morfotipos de mohos; la mayoría de ellos demostraron antagonismo in vitro con los fitopatógenos seleccionados. Este estudio permite concluir que en la rizósfera de la planta Ornithogalum umbellatum se encuentran microorganismos que demostraron antagonismo in vitro y que podrían ser utilizados como biocontroladores de Botrytis cinerea y Sclerotinia sclerotiorum. Además, se observó que algunos de los morfotipos microbianos aislados presentaban un antagonismo muy discreto pero ocasionaban cambios en la estructura y color de las hifas de los hongos fitopatógenos utilizados; posiblemente la concentración influye sobre los mecanismos de biocontrol.

A new concept for insect damage evaluation based on plant physiological variables

The objective of this study was to determine the damage levels caused by Orthezia praelonga Douglas, 1891 and Leucoptera coffeella (Guérin-Mèneville 1842), on rangpur lime and Obatã coffee leaves, respectively. Measurements were based on a new concept for the evaluation of the following plant physiological parameters: photosynthesis, stomatal conductance, leaf temperature and transpiration, and internal concentration of CO2 (by infrared analyzer). A negative correlation between infestation level and photosynthesis was found, where the negative inflexion point of the curve was considered as a reference for damage levels. The control level for O. praelonga is below the 7-13 percent limit for damaged leaf area (40 to 70 scales per leaf), while for L. coffeella it is below the 26-36 percent limit for the same variable. Photosynthesis provided the best correlation for this type of analysis.

O objetivo deste trabalho foi estabelecer, baseado em um novo conceito de avaliação de parâmetros fisiológicos vegetais, o nível de dano causado por Orthezia praelonga Douglas 1891 e por Leucoptera coffeella (Guérin-Mèneville 1842) em folhas de limão cravo e cafeeiro 'Obatã', respectivamente. Foram feitas leituras de trocas gasosas por infravermelho, além da avaliação da condutância estomática, temperatura foliar, transpiração foliar e concentração interna de CO2. Os dados demonstraram uma correlação negativa entre o nível de infestação e a fotossíntese, sendo o ponto de inflexão negativa da curva tomado como referência de nível de dano, onde o nível de controle para O. praelonga encontra-se abaixo do limite de 7 a 13 por cento de área foliar lesionada (40 a 70 cochonilhas por folha), e o de L. coffeella encontra-se abaixo dos valores de 26 a 36 por cento de área foliar lesionada. Dentre os parâmetros avaliados a fotossíntese foi o que demonstrou melhor correlação para este tipo de análise.

Identification of excreted iron superoxide dismutase for the diagnosis of Phtytomonas

An excreted iron superoxide dismutase (FeSODe) of pI 3.6 with a molecular weight of 28-30 kDa was detected in the in vitro culture of Phytomonas isolated from Euphorbia characias (SODeCHA) and from Lycopersicon esculentum (SODeTOM), in Grace's medium without serum. These FeSODe excreted into the medium had immunogenic capacity: the positivity of the anti-SODeCHA serum persisted to a dilution of 1/30,000, and for the anti-SODeTOM to 1/10,000 by Western blot. In addition, cross reaction was detected between the anti-SODe serum of Phytomonas isolated from E. characias against SODeTOM, and the anti-SODe serum from L. esculentum with SODeCHA. This characteristic offers the possibility of its use to diagnose plant trypanosomatids. The validation of the test was confirmed by experimental inoculation of tomato fruits with Phytomonas isolated from L. esculentum. At 7, 10, 15, and 21 days post infection, it was possible to detect the presence of the parasites with the anti-SODe serum of Phytomonas isolated from L. esculentum at a dilution of 1/250. These serological results were confirmed by visualization of the parasites by optical microscopy. The data of this study confirm that the SOD is sufficient to identify a trypanosomatid isolated from plants as belonging to the genus Phytomonas.

Avaliação dos danos de Hyalospila ptychis (Dyar) (Lepidoptera: Phycitidae) em coqueiro / Evaluation of Hyalospila ptychis (Dyar) (Lepidoptera: Phycitidae) damage in coconut palm

O objetivo deste estudo foi avaliar as perdas causadas por lagartas de Hyalospila ptychis (Dyar) em coqueiro da variedade anã-verde (Cocos nucifera L.), no município de Una, BA. Para isso, foram inspecionadas mensalmente, de abril de 1997 a março de 1998, as inflorescências de 100 árvores distribuídas numa área de 15 ha, registrando-se o número de frutos por inflorescência, os frutos atacados por H. ptychis e os perdidos por outras causas. O número de frutos por inflorescência apresentou variação sazonal. As perdas médias causadas pela praga foram da ordem de 2 por cento e a proporção média de frutos que abortaram por causa desconhecida foi de 59,4 por cento. O número de frutos perdidos por outras causas e o número de frutos atacados por H. ptychis acompanharam a variação sazonal do número de frutos por inflorescência. A percentagem de frutos atacados por H. ptychis foi correlacionada significativa e positivamente com a temperatura média mensal.

The aim of this study was to evaluate the losses provoked by the moth Hyalospila ptychis (Dyar) on green-dwarf coconut trees at Una, State of Bahia, Brazil. Inflorescences of 100 trees were inspected monthly, from April 1997 to March 1998, in a 15 ha orchard. The number of coconuts per inflorescence, fruits damaged by H. ptychis, and fruit losses due to other causes, were recorded. The number of nuts per inflorescence followed a seasonal variation. The average losses caused by the pest were around 2 percent of the coconuts and the proportion of losses due to other causes was 59,4 percent. The number of coconuts lost for other causes and attacked by H. ptychis followed the seasonal variation of the number of fruits per inflorescence. The percent of coconuts attacked by H. ptychis was significantly and positively correlated with monthly average temperature.