Methyl jasmonate does improve postharvest conservation of 'Golden' papaya fruit / Metil jasmonato contribui para a conservação de mamão 'Golden'

ABSTRACT: Methyl jasmonate (MeJA) is recognized as a plant hormone that induces several biochemical changes related to improving fruit quality, but it is evident that the effect of MeJA during postharvest is very variable upon concentration, plant species, and even cultivars. The objective of this research was to relate the application of this regulator at low concentration (10 µmol L-1 for 24 h) to changes in postharvest physiology, on the incidence of anthracnose and quality of 'Golden' papaya fruit during storage at 24 ± 1°C. From the seventh day of storage, anthracnose incidence was reduced by more than 50% with MeJA treatment. The lesion area after infection was also reduced. Although, MeJA reduced fruit acidity, the ascorbic acid and soluble solids content were not altered during storage with the hormonal treatment. The skin color and pulp firmness showed slight retention. The reduction in ethylene production was accompanied by a reduction of respiration in treated fruits. MeJa increased CAT activity only in the skin whereas SOD activity was not induced by MeJA in both skin and pulp. Although, the increase of CAT from the third day of storage may have contributed to the reduction of lipid peroxidation in the skin, the MDA reduction in the pulp cannot be explained only by CAT activity. In summary, the application of MeJA in 'Golden' papaya reduced the incidence and severity of anthracnose, decreased respiration, ethylene production and lipid peroxidation. It is concluded that the application of MeJA at a low concentration (10 µmol L-1) may contribute to anthracnose control in ´Golden`papaya and slows the ripening of fruits.

RESUMO: O metil jasmonato (MeJA) é reconhecido como um hormônio vegetal que induz várias alterações bioquímicas relacionadas à qualidade dos frutos, mas é evidente que o efeito do MeJA durante a pós-colheita é muito variável quanto à concentração, espécies de plantas e até mesmo cultivares. O objetivo deste trabalho foi relacionar a aplicação deste regulador em baixa concentração (10 µmol L-1 por 24 h) às mudanças na fisiologia pós-colheita, na incidência de antracnose e na qualidade do mamão 'Golden' durante o armazenamento a 24 ± 1 ° C. A partir do sétimo dia de armazenamento, a incidência de antracnose foi reduzida em mais de 50% com o tratamento com MeJA. Incidência da doença também foi reduzida. Embora o MeJA tenha reduzido a acidez dos frutos, os teores de ácido ascórbico e sólidos solúveis não foram alterados durante o armazenamento com o tratamento hormonal. A cor da casca e a firmeza da polpa apresentaram ligeira retenção. A redução na produção de etileno foi acompanhada pela redução da respiração nos frutos tratados. MeJa aumentou a atividade da CAT apenas na casca, enquanto a atividade da SOD não foi induzida por MeJA na casca e na polpa. Embora o aumento da CAT a partir do terceiro dia de armazenamento possa ter contribuído para a redução da peroxidação lipídica na casca, a redução do MDA na polpa não pode ser explicada apenas pela atividade da CAT. Em resumo, a aplicação de MeJA em mamão 'Golden' reduziu a incidência e severidade da antracnose, diminuiu a respiração, a produção de etileno e a peroxidação lipídica. Conclui-se que a aplicação de MeJA em baixa concentração (10 µmol L-1) pode contribuir para o controle da antracnose em mamão ´Golden` e retardar o amadurecimento dos frutos.

Methyl jasmonate does improve postharvest conservation of 'Golden' papaya fruit / Metil jasmonato contribui para a conservação de mamão 'Golden'

Methyl jasmonate (MeJA) is recognized as a plant hormone that induces several biochemical changes related to improving fruit quality, but it is evident that the effect of MeJA during postharvest is very variable upon concentration, plant species, and even cultivars. The objective of this research was to relate the application of this regulator at low concentration (10 µmol L-1 for 24 h) to changes in postharvest physiology, on the incidence of anthracnose and quality of 'Golden' papaya fruit during storage at 24 ± 1°C. From the seventh day of storage, anthracnose incidence was reduced by more than 50% with MeJA treatment. The lesion area after infection was also reduced. Although, MeJA reduced fruit acidity, the ascorbic acid and soluble solids content were not altered during storage with the hormonal treatment. The skin color and pulp firmness showed slight retention. The reduction in ethylene production was accompanied by a reduction of respiration in treated fruits. MeJa increased CAT activity only in the skin whereas SOD activity was not induced by MeJA in both skin and pulp. Although, the increase of CAT from the third day of storage may have contributed to the reduction of lipid peroxidation in the skin, the MDA reduction in the pulp cannot be explained only by CAT activity. In summary, the application of MeJA in 'Golden' papaya reduced the incidence and severity of anthracnose, decreased respiration, ethylene production and lipid peroxidation. It is concluded that the application of MeJA at a low concentration (10 µmol L-1) may contribute to anthracnose control in ´Golden`papaya and slows the ripening of fruits.

O metil jasmonato (MeJA) é reconhecido como um hormônio vegetal que induz várias alterações bioquímicas relacionadas à qualidade dos frutos, mas é evidente que o efeito do MeJA durante a pós-colheita é muito variável quanto à concentração, espécies de plantas e até mesmo cultivares. O objetivo deste trabalho foi relacionar a aplicação deste regulador em baixa concentração (10 µmol L-1 por 24 h) às mudanças na fisiologia pós-colheita, na incidência de antracnose e na qualidade do mamão 'Golden' durante o armazenamento a 24 ± 1 ° C. A partir do sétimo dia de armazenamento, a incidência de antracnose foi reduzida em mais de 50% com o tratamento com MeJA. Incidência da doença também foi reduzida. Embora o MeJA tenha reduzido a acidez dos frutos, os teores de ácido ascórbico e sólidos solúveis não foram alterados durante o armazenamento com o tratamento hormonal. A cor da casca e a firmeza da polpa apresentaram ligeira retenção. A redução na produção de etileno foi acompanhada pela redução da respiração nos frutos tratados. MeJa aumentou a atividade da CAT apenas na casca, enquanto a atividade da SOD não foi induzida por MeJA na casca e na polpa. Embora o aumento da CAT a partir do terceiro dia de armazenamento possa ter contribuído para a redução da peroxidação lipídica na casca, a redução do MDA na polpa não pode ser explicada apenas pela atividade da CAT. Em resumo, a aplicação de MeJA em mamão 'Golden' reduziu a incidência e severidade da antracnose, diminuiu a respiração, a produção de etileno e a peroxidação lipídica. Conclui-se que a aplicação de MeJA em baixa concentração (10 µmol L-1) pode contribuir para o controle da antracnose em mamão ´Golden` e retardar o amadurecimento dos frutos.

Eco-friendly fungicide based on chitosan and pecan nut oil: development and evaluation in anthracnose control

Industrial processing of pecan nuts results in edible oil ­ with fractions of fatty acids, polyphenols and phytosterols - that may be used for managing phytopathogens. Besides, chitosan may interfere with pathogen development directly and/or activate mechanisms of defense in plant tissues. This study aimed at developing a novel, natural and eco-friendly fungicide based on pecan nut oil immobilized in chitosan and at evaluating its activity against Colletotrichum gloeosporioides, an agent of anthracnose in guava trees and other fruit trees. Changes in the immobilized material exhibited at bands were identified by infrared spectroscopy. Additionally, micrographs by scanning electron microscopy (SEM) showed efficient changes in the immobilized material, by comparison with the polymer chitosan. Decreases in Colletotrichum gloeosporioides sporulation in vitro were 37% in the case of pecan nut oil immobilized in chitosan (IO) and 39% in the case of non-immobilized pecan nut oil (NIO). These results are positive because this fungus produces a large number of spores which may disseminate and survive on surfaces of plant tissues infected by anthracnose. Immobilization of pecan oil in chitosan showed benefits in the synthesis of a novel, stable and eco-friendly material which may be applied to guava trees to control anthracnose.(AU)

Presence of pink sugarcane mealybug (Hemiptera: Pseudococcidae) increases probability of red rot on sugarcane

Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) is globally disseminated on sugarcane plants. In Brazil, this species has been occurred in the same region as the occurrence of the fungal pathogen causing red rot, Colletotrichum falcatum Went, 1893 (Glomerellales). The objective of this study was to evaluate the hypothesis that this pseudococcid could act as a facilitator of the penetration of the phytopathogen C. falcatum. Species of this mealybug were reared at laboratory to infest sugarcane plants during the experiment. A total of 320 sugarcane plants were utilized for this study, 160 of CTC4 and 160 of RB86 7515 cultivars (cv.), each group subdivided into four treatments: (1) infested with mealybugs; (2) infected with fungal conidia; (3) infested with mealybugs and infected with fungal conidia; and (4) control. Biometrics of the plants, disease symptoms, Total Reducing Sugars (TRS) and Reducing Sugar (RS) were evaluated. To both cv., there was no difference in the height and diameter of the plants in all treatments; and only in "mealybug + fungus", significant difference on the lengths of the disease lesions inside the plants was found to each cv. as well as the levels of TRS and RS. The presence of the pseudococcid increased the incidence of the disease in both cv., although RB86 7515 was more susceptible to red rot than CTC4.(AU)

Diagrammatic scale for assessment of anthracnose severity in feijoa fruit / Escala diagramática para avaliação da severidade de Antracnose em frutos de feijoa

A diagrammatic scale of anthracnose in feijoa fruit was elaborated and validated in order to standardize disease severity assessments. The proposed scale showed six disease severity levels: 2, 10, 20, 40, 70 and 100% of the injured fruit surface. The scale took into account the minimum and maximum limits of disease severity observed in the field and the intermediate values followed logarithmic increments according to the Weber-Fechner stimulus-response law. Eight inexperienced raters validated the scale by quantifying the disease severity (using/not using the scale) of 50 feijoas with anthracnose symptoms. In conclusion, the scale improved the assessment of anthracnose in feijoa. Eight genotypes from different crosses were tolerant to anthracnose.(AU)

Com o objetivo de padronizar avaliações da severidade da antracnose em frutos de feijoa elaborou-se e validou-se uma escala diagramática com os seguintes níveis de severidade: 2, 10, 20, 40, 70 e 100% de área superficial do fruto com lesão. A escala considerou os limites de severidade mínima e máxima da doença observados em campo e os níveis intermediários seguiram incrementos logarítmicos, obedecendo-se a Lei do estímulo de Weber-Fechner. A severidade foi estimada, por oito avaliadores sem experiência, em 50 frutos sem e com o auxílio da escala proposta. Em conclusão, a escala melhorou a avaliação da antracnose na feijoa. Oito genótipos de diferentes cruzamentos foram tolerantes à antracnose.(AU)

Silicon alters early development of bean seedlings from seeds infected by Anthracnose / Silício altera desenvolvimento inicial de plântulas de feijão oriundas de sementes infectadas por Antracnose

The present study aimed to evaluate the effect of seed coating with Si in response to infection in a cultivar susceptible and resistant to Colletotrichum lindemuthianum, on the physiological and health potential of seeds and seedlings, during the initial development of bean culture. The experiment was carried out in a completely randomizeddesign, in a 2 × 2 × 2 factorial scheme, with four replications, where the factors were: cultivar (BRS Esplendor and IPR Tuiuiú), silicate application (with and without Agrosilício® coating) and inoculation (seeds inoculated or not with C. lindemuthianum). In the evaluation of the initial development of the culture, the following variables were measured: germination, first count of the germination test, emergence, emergence speed index (IVE), total seedling length, shoot and root length, total dry mass, aerial part dry matter, root dry matter and aerial part dry matter at 15 days after sowing (DAS). The incidence of C. lindemuthianumin beans was determined by the paper roll method. Covering the seeds with Si reduces the incidence and severity of C. lindemuthianumand provides greater growth of bean seedlings. The effect of responses potentiated by Si is more expressive in the cultivar of greater susceptibility.

O presente trabalho teve por objetivo, avaliar o efeito do recobrimento de sementes com Si em resposta à infecção em uma cultivar suscetível e resistente ao Colletotrichumlindemuthianum, sobre o potencial fisiológico e sanitário de sementes e plântulas, durante o desenvolvimento inicial da cultura do feijão. O experimento foi realizado em delineamento inteiramente casualizado, em esquema fatorial 2 × 2 × 2, com quatro repetições, onde os fatores foram: cultivar (BRS Esplendor e a IPR Tuiuiú), aplicação de silicato (com e sem recobrimento com Agrosilício®) e inoculação (sementes inoculadas ou não com C. lindemuthianum). Na avaliação do desenvolvimento inicial da cultura foram mensuradas as seguintes variáveis: germinação, primeira contagem do teste de germinação, emergência, índice da velocidade de emergência (IVE), comprimento total da plântula, comprimento de parte aérea e de raiz, massa seca total, massa seca de parte aérea, massa seca de raiz e massa seca de parte aérea aos 15 dias após semeadura (DAS). A incidência de C. lindemuthianumem feijão foi determinada pelo método do rolo de papel. O recobrimento das sementes com Si diminui a incidência e a severidade de C. lindemuthianume proporciona maior crescimento das plântulas de feijão. O efeito de respostas potencializadas pelo Si tem maior expressividade na cultivar de maior suscetibilidade.

Silicon alters early development of bean seedlings from seeds infected by Anthracnose / Silício altera desenvolvimento inicial de plântulas de feijão oriundas de sementes infectadas por Antracnose

The present study aimed to evaluate the effect of seed coating with Si in response to infection in a cultivar susceptible and resistant to Colletotrichum lindemuthianum, on the physiological and health potential of seeds and seedlings, during the initial development of bean culture. The experiment was carried out in a completely randomizeddesign, in a 2 × 2 × 2 factorial scheme, with four replications, where the factors were: cultivar (BRS Esplendor and IPR Tuiuiú), silicate application (with and without Agrosilício® coating) and inoculation (seeds inoculated or not with C. lindemuthianum). In the evaluation of the initial development of the culture, the following variables were measured: germination, first count of the germination test, emergence, emergence speed index (IVE), total seedling length, shoot and root length, total dry mass, aerial part dry matter, root dry matter and aerial part dry matter at 15 days after sowing (DAS). The incidence of C. lindemuthianumin beans was determined by the paper roll method. Covering the seeds with Si reduces the incidence and severity of C. lindemuthianumand provides greater growth of bean seedlings. The effect of responses potentiated by Si is more expressive in the cultivar of greater susceptibility.(AU)

O presente trabalho teve por objetivo, avaliar o efeito do recobrimento de sementes com Si em resposta à infecção em uma cultivar suscetível e resistente ao Colletotrichumlindemuthianum, sobre o potencial fisiológico e sanitário de sementes e plântulas, durante o desenvolvimento inicial da cultura do feijão. O experimento foi realizado em delineamento inteiramente casualizado, em esquema fatorial 2 × 2 × 2, com quatro repetições, onde os fatores foram: cultivar (BRS Esplendor e a IPR Tuiuiú), aplicação de silicato (com e sem recobrimento com Agrosilício®) e inoculação (sementes inoculadas ou não com C. lindemuthianum). Na avaliação do desenvolvimento inicial da cultura foram mensuradas as seguintes variáveis: germinação, primeira contagem do teste de germinação, emergência, índice da velocidade de emergência (IVE), comprimento total da plântula, comprimento de parte aérea e de raiz, massa seca total, massa seca de parte aérea, massa seca de raiz e massa seca de parte aérea aos 15 dias após semeadura (DAS). A incidência de C. lindemuthianumem feijão foi determinada pelo método do rolo de papel. O recobrimento das sementes com Si diminui a incidência e a severidade de C. lindemuthianume proporciona maior crescimento das plântulas de feijão. O efeito de respostas potencializadas pelo Si tem maior expressividade na cultivar de maior suscetibilidade.(AU)

Colletotrichum nymphaeae var. entomophilum var. nov. a natural enemy of the citrus scale insect, Praelongorthezia praelonga (Hemiptera: Ortheziidae)

The citrus scale insect Praelongorthezia praelonga (Douglas), a major pest of citrus and other economically important crops, has only two commonly documented natural enemies: an entomopathogenic strain of the fungus Colletotrichum nymphaeae (Pass.) Aa and several parasitoids. The entomopathogenic strain of C. nymphaeae, formerly recognized under the synonym C. gloeosporioides f. sp. ortheziidae, is under development for commercial application as a biological control agent in citrus in Brazil-the top exporter of citrus globally. The synonomy of C. gloeosporioides f. sp. ortheziidae with C. nymphaeae remains based on limited DNA sequence data and without morphological study. To qualify for future approval as a biological control agent by federal agencies in Brazil and the European Union, the circumscription of a microorganism must be explicit and without ambiguities. Herein, through morphological study and phylogenetic analysis of five DNA regions we clarify the circumscription and affinity of entomopathogenic C. nymphaeae and describe it as a new variety.

Colletotrichum nymphaeae var. entomophilum var. nov. a natural enemy of the citrus scale insect, Praelongorthezia praelonga (Hemiptera: Ortheziidae)

The citrus scale insect Praelongorthezia praelonga (Douglas), a major pest of citrus and other economically important crops, has only two commonly documented natural enemies: an entomopathogenic strain of the fungus Colletotrichum nymphaeae (Pass.) Aa and several parasitoids. The entomopathogenic strain of C. nymphaeae, formerly recognized under the synonym C. gloeosporioides f. sp. ortheziidae, is under development for commercial application as a biological control agent in citrus in Brazil-the top exporter of citrus globally. The synonomy of C. gloeosporioides f. sp. ortheziidae with C. nymphaeae remains based on limited DNA sequence data and without morphological study. To qualify for future approval as a biological control agent by federal agencies in Brazil and the European Union, the circumscription of a microorganism must be explicit and without ambiguities. Herein, through morphological study and phylogenetic analysis of five DNA regions we clarify the circumscription and affinity of entomopathogenic C. nymphaeae and describe it as a new variety.(AU)

Yield, seasonality and plant health care of banana 'BRS Conquista' covered with different coloured polyethylene bags / Rendimento, sazonalidade e fitossanidade dos frutos de bananeira'BRS Conquista' ensacados com polietileno de diferentes colorações

Bananas are the world's most popular fruit. Nonetheless, a great part of the production is lost, mainly for insect and disease incidences. Thus, cover developing banana bunches is a promising physical protection method that will improve the visual quality of the fruits, especially the rapidly growing consumer demand for healthy fruits. In fact, bags serve as protective barrier, allowing the production of free fruit damage; consequently, lowering production costs by cutting crop losses, as well as avoiding chemical materials. There is a wide variety of bag types and colours, but also, there is a scarce literature on their efficiency. This study hence aimed to evaluate the influence of coloured polyethylene bags on yield, seasonality and plant health of the 'BRS Conquista' bananas in subtropical high-altitude growing conditions. Treatments therefore consisted of using white, black, red and blue polyethylene bags, besides control (uncovered). Then, bags were randomly distributed in five blocks, four plants per plot. After bunch harvest, the following evaluation were proceeded: agronomic yield, the interval between bunches cover and harvest, injuries caused by thrips and the incidence of anthracnose. Results indicated that banana bunch coverings did not interfere in bunch yield. Nevertheless, white and black bags reduced the interval between bunch covers and harvest, that is, 114 and 115 days, respectively. Furthermore, white and red bags reduced the damage caused by thrips in fruits; while white, red and blue bags decreased the anthracnose incidence. This study therefore recommends the use of white polyethylene bags to cover banana bunches of the cultivar BRS Conquista, since this bag colour showed highly efficiency in controlling thrips and anthracnose incidence, besides reducing the interval between bunch cover andharvest.

Bananas são as frutas mais populares do mundo, porém a incidência de insetos e de doenças provoca muitas perdas de frutos. Neste sentido, o ensacamento dos cachos torna-se uma técnica promissora, sobretudo diante da crescente exigência dos consumidores por frutos de qualidade e seguros do ponto de vista alimentar. Os sacos funcionam como barreira de proteção, permitindo a produção de frutos livres de danos, com consequente redução de perdas e dos custos com aplicações de produtos químicos. Contudo, existe uma grande variedade de tipos e cores de sacos no mercado, mas não há relatos sobre a interferência destes parâmetros sobre a eficiência do ensacamento. Portanto, este estudo objetivou avaliara influência do uso de sacolas de polietileno, com diferentes cores, sobre o rendimento, sazonalidade e fitossanidade dos cachos da banana 'BRS Conquista' cultivada em região subtropical de alta altitude. Os tratamentos consistiram na utilização de sacos de polietileno branco, preto, vermelho e azul, além do controle (sem ensacamento). Estes sacos foram distribuídos aleatoriamente em cinco blocos e quatro plantas por parcela. Após a colheita dos cachos, avaliou-se o rendimento agronômico, o intervalo entre a emissão do cacho e a colheita e a presença de danos de tripes, além do avanço da incidência de antracnose até a maturação dos frutos. A partir dos resultados, verifica-se que o ensacamento não interferiu no rendimento dos cachos. Porém, a utilização de sacos brancos (114 dias) e pretos (115dias) reduziram o intervalo entre o ensacamento e a colheita. Os sacos brancos e vermelhos reduziram os danos provocados pelos tripes nas frutas; enquanto sacos brancos, vermelhos e azuis diminuíram a incidência de antracnose. Portanto, recomenda-se o uso de sacos de polietileno branco para coberturas de cachos de banana 'BRS Conquista', devido à maior eficiência no controle de tripes e antracnose; além de diminuir o intervalo de tempo entre a emissão do cacho e a colheita.

Stalk rots are associated with the early maturity of hybrid corn / Podridões de colmo estão associadas à precocidade de híbridos de milho

Stalk rots of corn are responsible for significant decreases in grain yield. The aim of this study was to examine the relationship between the incidence of stalk rots and the maturity cycle of six corn hybrids. The experiment was conducted in the field, where 70,000 seeds ha-1 of the commercial hybrids P32R22 YHR and AG9045 VT PRO (super early) and P30F53 Hx, DKB250 VT PRO2, AS1656 VT PRO2, and AG8025 VT PRO (early) were sown in October in the 2012/2013 and 2013/2014 crop years. A randomized block design with four replications was applied, and five linear meters were evaluated in each plot. The incidence of stalk rot was determined by the presence of discoloration and lower stalk resistance. Ears from healthy and infected plants were separately screened to determine the percentage loss. Losses caused by stalk rot due to the severity of the disease may vary depending on the hybrid, even if their maturity cycles have similar characteristics. The fungi detected in the stalks were Stenocarpella sp., Colletotrichum graminicola, Fusarium graminearum, and F. verticillioides. All of the hybrids in the study exhibited symptoms of stalk rot as they showed no resistance, but different degrees of susceptibility were observed among the tested materials. The hybrid AG8025 VT PRO demonstrated the least susceptibility to stalk rots. The super early hybrids P32R22 YHR and AG9045

As podridões de colmo do milho são responsáveis por significativas reduções em rendimento de grãos. O objetivo deste estudo foi avaliar a relação existente entre a incidência de podridões de colmo e o ciclo de seis híbridos de milho. O experimento foi conduzido a campo, semeados no mês de outubro nas safras 2012/2013 e 2013/2014 utilizando-se 70.000 sementes ha-1 dos híbridos comerciais P32R22 YHR e AG9045 VT PRO (superprecoces) e P30F53 Hx, DKB250 VT PRO2, AS1656 VT PRO2 e AG8025 VT PRO (precoces). O delineamento utilizado foi de blocos casualizados com quatro repetições avaliando-se, em cada parcela cinco metros lineares. A incidência de podridões foi determinada pela presença de descoloração e menor resistência do colmo. Espigas provenientes de plantas sadias e doentes foram trilhadas separadamente para determinação do dano percentual. Danos ocasionados por podridões de colmo, em função da severidade da doença podem ser variáveis em função dos híbridos, mesmo com características semelhantes de ciclo. Os fungos detectados nos colmos foram Stenocarpella sp., Colletotrichum graminicola, Fusarium graminearum e F. verticillioides. Todos os híbridos avaliados expressaram sintomas de podridão de colmo demonstrando não haver resistência, mas sim, apenas diferentes graus de suscetibilidade entre os materiais testados. O híbrido AG8025 VT PRO demonstrou ser o menos suscetível

Stalk rots are associated with the early maturity of hybrid corn / Podridões de colmo estão associadas à precocidade de híbridos de milho

Stalk rots of corn are responsible for significant decreases in grain yield. The aim of this study was to examine the relationship between the incidence of stalk rots and the maturity cycle of six corn hybrids. The experiment was conducted in the field, where 70,000 seeds ha-1 of the commercial hybrids P32R22 YHR and AG9045 VT PRO (super early) and P30F53 Hx, DKB250 VT PRO2, AS1656 VT PRO2, and AG8025 VT PRO (early) were sown in October in the 2012/2013 and 2013/2014 crop years. A randomized block design with four replications was applied, and five linear meters were evaluated in each plot. The incidence of stalk rot was determined by the presence of discoloration and lower stalk resistance. Ears from healthy and infected plants were separately screened to determine the percentage loss. Losses caused by stalk rot due to the severity of the disease may vary depending on the hybrid, even if their maturity cycles have similar characteristics. The fungi detected in the stalks were Stenocarpella sp., Colletotrichum graminicola, Fusarium graminearum, and F. verticillioides. All of the hybrids in the study exhibited symptoms of stalk rot as they showed no resistance, but different degrees of susceptibility were observed among the tested materials. The hybrid AG8025 VT PRO demonstrated the least susceptibility to stalk rots. The super early hybrids P32R22 YHR and AG9045(AU)

As podridões de colmo do milho são responsáveis por significativas reduções em rendimento de grãos. O objetivo deste estudo foi avaliar a relação existente entre a incidência de podridões de colmo e o ciclo de seis híbridos de milho. O experimento foi conduzido a campo, semeados no mês de outubro nas safras 2012/2013 e 2013/2014 utilizando-se 70.000 sementes ha-1 dos híbridos comerciais P32R22 YHR e AG9045 VT PRO (superprecoces) e P30F53 Hx, DKB250 VT PRO2, AS1656 VT PRO2 e AG8025 VT PRO (precoces). O delineamento utilizado foi de blocos casualizados com quatro repetições avaliando-se, em cada parcela cinco metros lineares. A incidência de podridões foi determinada pela presença de descoloração e menor resistência do colmo. Espigas provenientes de plantas sadias e doentes foram trilhadas separadamente para determinação do dano percentual. Danos ocasionados por podridões de colmo, em função da severidade da doença podem ser variáveis em função dos híbridos, mesmo com características semelhantes de ciclo. Os fungos detectados nos colmos foram Stenocarpella sp., Colletotrichum graminicola, Fusarium graminearum e F. verticillioides. Todos os híbridos avaliados expressaram sintomas de podridão de colmo demonstrando não haver resistência, mas sim, apenas diferentes graus de suscetibilidade entre os materiais testados. O híbrido AG8025 VT PRO demonstrou ser o menos suscetível(AU)

Yield, seasonality and plant health care of banana 'BRS Conquista' covered with different coloured polyethylene bags / Rendimento, sazonalidade e fitossanidade dos frutos de bananeira'BRS Conquista' ensacados com polietileno de diferentes colorações

Bananas are the world's most popular fruit. Nonetheless, a great part of the production is lost, mainly for insect and disease incidences. Thus, cover developing banana bunches is a promising physical protection method that will improve the visual quality of the fruits, especially the rapidly growing consumer demand for healthy fruits. In fact, bags serve as protective barrier, allowing the production of free fruit damage; consequently, lowering production costs by cutting crop losses, as well as avoiding chemical materials. There is a wide variety of bag types and colours, but also, there is a scarce literature on their efficiency. This study hence aimed to evaluate the influence of coloured polyethylene bags on yield, seasonality and plant health of the 'BRS Conquista' bananas in subtropical high-altitude growing conditions. Treatments therefore consisted of using white, black, red and blue polyethylene bags, besides control (uncovered). Then, bags were randomly distributed in five blocks, four plants per plot. After bunch harvest, the following evaluation were proceeded: agronomic yield, the interval between bunches cover and harvest, injuries caused by thrips and the incidence of anthracnose. Results indicated that banana bunch coverings did not interfere in bunch yield. Nevertheless, white and black bags reduced the interval between bunch covers and harvest, that is, 114 and 115 days, respectively. Furthermore, white and red bags reduced the damage caused by thrips in fruits; while white, red and blue bags decreased the anthracnose incidence. This study therefore recommends the use of white polyethylene bags to cover banana bunches of the cultivar BRS Conquista, since this bag colour showed highly efficiency in controlling thrips and anthracnose incidence, besides reducing the interval between bunch cover andharvest.(AU)

Bananas são as frutas mais populares do mundo, porém a incidência de insetos e de doenças provoca muitas perdas de frutos. Neste sentido, o ensacamento dos cachos torna-se uma técnica promissora, sobretudo diante da crescente exigência dos consumidores por frutos de qualidade e seguros do ponto de vista alimentar. Os sacos funcionam como barreira de proteção, permitindo a produção de frutos livres de danos, com consequente redução de perdas e dos custos com aplicações de produtos químicos. Contudo, existe uma grande variedade de tipos e cores de sacos no mercado, mas não há relatos sobre a interferência destes parâmetros sobre a eficiência do ensacamento. Portanto, este estudo objetivou avaliara influência do uso de sacolas de polietileno, com diferentes cores, sobre o rendimento, sazonalidade e fitossanidade dos cachos da banana 'BRS Conquista' cultivada em região subtropical de alta altitude. Os tratamentos consistiram na utilização de sacos de polietileno branco, preto, vermelho e azul, além do controle (sem ensacamento). Estes sacos foram distribuídos aleatoriamente em cinco blocos e quatro plantas por parcela. Após a colheita dos cachos, avaliou-se o rendimento agronômico, o intervalo entre a emissão do cacho e a colheita e a presença de danos de tripes, além do avanço da incidência de antracnose até a maturação dos frutos. A partir dos resultados, verifica-se que o ensacamento não interferiu no rendimento dos cachos. Porém, a utilização de sacos brancos (114 dias) e pretos (115dias) reduziram o intervalo entre o ensacamento e a colheita. Os sacos brancos e vermelhos reduziram os danos provocados pelos tripes nas frutas; enquanto sacos brancos, vermelhos e azuis diminuíram a incidência de antracnose. Portanto, recomenda-se o uso de sacos de polietileno branco para coberturas de cachos de banana 'BRS Conquista', devido à maior eficiência no controle de tripes e antracnose; além de diminuir o intervalo de tempo entre a emissão do cacho e a colheita.(AU)

A diagramatic scale to quantify severity of antracnose in Rubus glaucus Benth / Uma escala diagramática para quantificar a severidade da antracnose em Rubus glaucus Benth

Rubus glaucus Benth, commonly referred to as mora de Castilla, is affected by Colletotrichum acutatum, as it induces anthracnose in many of the plant organs. Generally, it affects the fruits during the post-harvest phase and damages them, causing economic losses due to the poor crop quality. At present, no standardized methods are available for this pathosystem that can be used to characterize quantitatively the epidemic and to permit the prediction and comparison of the disease management techniques. In this research, we proposed a logarithmic diagrammatic scale of the severity of anthracnose induced by C. acutatum in the fruits of the thornless variety of R. glaucus Benth. This scale is constructed on the adjustment of the Weber-Fechner law and includes six classes, viz., 0%, 1-6%, 7-25%, 26-50%, 51-75%, 76-100%. The scale was validated using 14 evaluators, which entailed measuring the affected fruits with and without utilizing the scale; this improved the precision, accuracy and reproducibility of the calculations whenever the scale was used. We concluded that the scale proposed can be used to assess the severity of anthracnose induced by the fungus in the R. glaucus Benth fruits.(AU)

Mora de Castilla (Rubus glaucus Benth) é afetado por Colletotrichum acutatum, causando antracnose em órgãos diferentes da planta. Nos frutos geralmente é em pós-colheita, causando danos que geram perdas econômicas relacionadas com a qualidade das culturas. Ainda não existem para esse patossistema métodos padronizados para caracterizar quantitativamente a epidemia e que pode prever e comparar os métodos de manejo da doença. Por esta razão, neste trabalho foi criada uma escala logarítmica diagramática da severidade da antracnose causada pelo fungo C. acutatum em frutos de R. glaucus Benth com base na lei de Weber-Fechnere composto por 6 niveis: 0%, 1-6%, 7-25%, 26-50%, 51-75% e 76-100%. A escala foi validada por 14 evaluadores, fazendo medições de frutos afetados com e sem o uso da escala, que mostrou melhor precisão, exatitude e reproducibilidade nas avaliações em que o uso da escala foi feito. Isto permite concluir que a escala proposta pode ser usada na estimação da severidade da antracnose causada em frutos de R. glaucus Benth.(AU)

Association mapping in common bean revealed regions associated with Anthracnose and Angular Leaf Spot resistance

Despite important biotic stresses to common bean, Anthracnose (ANT) and Angular Leaf Spot (ALS) can cause losses of up to 80 % and occur in more than 60 countries around the world. Genetic resistance is the most sustainable strategy to manage these diseases. Thus, we aimed to (1) identify new SNP markers associated with ALS and ANT resistance loci in elite common bean lines, and (2) provide a functional characterization of the DNA sequences containing the identified SNP markers. We evaluated 60 inbred lines, under field conditions, which represent the elite germplasm developed by the Embrapa common bean breeding program across 22 years, in terms of severity of the ALS and ANT. The lines were genotyped with 5,398 SNPs. Then, a Mixed Linear Model was run to determine the SNP-trait associations. We observed two-significant marker-trait associations reacting to ANT, both located on chromosome Pv-02. These markers explained 25 % of the phenotypic variation. For ALS, only one significant marker-trait association was observed, which is located in chromosome Pv-10 and explained 19 % of the phenotypic variation. These markers, along with others already used, will be useful to add or keep ANT and ALS resistance loci identified in this work in the new carioca and black seeded cultivars.

Association mapping in common bean revealed regions associated with Anthracnose and Angular Leaf Spot resistance

Despite important biotic stresses to common bean, Anthracnose (ANT) and Angular Leaf Spot (ALS) can cause losses of up to 80 % and occur in more than 60 countries around the world. Genetic resistance is the most sustainable strategy to manage these diseases. Thus, we aimed to (1) identify new SNP markers associated with ALS and ANT resistance loci in elite common bean lines, and (2) provide a functional characterization of the DNA sequences containing the identified SNP markers. We evaluated 60 inbred lines, under field conditions, which represent the elite germplasm developed by the Embrapa common bean breeding program across 22 years, in terms of severity of the ALS and ANT. The lines were genotyped with 5,398 SNPs. Then, a Mixed Linear Model was run to determine the SNP-trait associations. We observed two-significant marker-trait associations reacting to ANT, both located on chromosome Pv-02. These markers explained 25 % of the phenotypic variation. For ALS, only one significant marker-trait association was observed, which is located in chromosome Pv-10 and explained 19 % of the phenotypic variation. These markers, along with others already used, will be useful to add or keep ANT and ALS resistance loci identified in this work in the new carioca and black seeded cultivars.(AU)

Screening of endophytic fungi stored in a culture collection for taxol production

Abstract In this work, four isolates of endophytic fungi (Alternaria alternata, Colletotrichum gloesporioides, Glomerella cingulata and Nigrospora sphaerica), deposited in the culture collection University Recife Mycologia (URM) at the Universidade Federal de Pernambuco, were characterized for the genes ITS 1 and 4 (region 5.8 S) and evaluated for taxol production.

Screening of endophytic fungi stored in a culture collection for taxol production

In this work, four isolates of endophytic fungi (Alternaria alternata, Colletotrichum gloesporioides, Glomerella cingulata and Nigrospora sphaerica), deposited in the culture collection ‘University Recife Mycologia (URM) at the Universidade Federal de Pernambuco, were characterized for the genes ITS 1 and 4 (region 5.8 S) and evaluated for taxol production.(AU)

Temporal progress and spatial patterns of quiescent diseases in guava influenced by sanitation practices

Postharvest diseases are a major problem in guava crops as the symptoms normally appear during fruit ripening. This study aimed to detect and characterize the temporal dynamics and spatial patterns of the most important guava diseases in orchards with and without removal of crop residues as a sanitation practice. The experiment was conducted in an orchard of Pedro Sato guavas, over two consecutive seasons, and data were collected from the flowering to the fruit ripening stage. In immature guavas treated with paraquat and ethrel, Colletotrichum spp. was detected from the 5th day of incubation. Anthracnose was detected in flowers at incidences higher than 50 % and black spot in fruit larger than 5.5 cm in length. The monomolecular and the exponential models provided the best fit to anthracnose and black spot incidence progress curve data, respectively. Both diseases showed a predominantly random spatial pattern in the orchard. The removal of crop residues reduced the rate of disease progress in at least one season, and was effective in reducing the areas under the quiescent disease progress curves (AUDPC) of anthracnose. Anthracnose incidence increased from 57 to 96 % and black spot from 1 to 48 %, respectively, at fruit maturation levels 1 and 3. A negative correlation was found between disease incidence and the color of the fruit skin (°h). Fruit harvested during the later maturation stages showed higher incidence of the diseases. Due to the wide distribution and early infection of quiescent diseases, starting at flowering, preventive management should consider disease monitoring and removal of crop residues.

Temporal progress and spatial patterns of quiescent diseases in guava influenced by sanitation practices

Postharvest diseases are a major problem in guava crops as the symptoms normally appear during fruit ripening. This study aimed to detect and characterize the temporal dynamics and spatial patterns of the most important guava diseases in orchards with and without removal of crop residues as a sanitation practice. The experiment was conducted in an orchard of Pedro Sato guavas, over two consecutive seasons, and data were collected from the flowering to the fruit ripening stage. In immature guavas treated with paraquat and ethrel, Colletotrichum spp. was detected from the 5th day of incubation. Anthracnose was detected in flowers at incidences higher than 50 % and black spot in fruit larger than 5.5 cm in length. The monomolecular and the exponential models provided the best fit to anthracnose and black spot incidence progress curve data, respectively. Both diseases showed a predominantly random spatial pattern in the orchard. The removal of crop residues reduced the rate of disease progress in at least one season, and was effective in reducing the areas under the quiescent disease progress curves (AUDPC) of anthracnose. Anthracnose incidence increased from 57 to 96 % and black spot from 1 to 48 %, respectively, at fruit maturation levels 1 and 3. A negative correlation was found between disease incidence and the color of the fruit skin (°h). Fruit harvested during the later maturation stages showed higher incidence of the diseases. Due to the wide distribution and early infection of quiescent diseases, starting at flowering, preventive management should consider disease monitoring and removal of crop residues.(AU)