Marlon Vagner Valentim Martins

Erradicação de escleródios de Sclerotium rolfsii em substratos tratados em coletores solares, em Campos dos Goytacazes-RJ

Although there is a risk of soil being contaminated with plant pathogen inocula its uses in the substrate composition is the most economical and useful practice for fruit propagation in general. In this work, looking for an alternative method besides the methyl bromide fumigation for soil sterilization the efficiency of solar collector devices for substrate disinfestations in the elimination of S. rolfsii sclerotia was evaluated. The assays were realized in three dates: October 6th and 25th and December 13th of 2000. For evaluation of the sclerotia viability the sclerotia recovered from the soil treated in solar collector were sown in culture medium and submitted to the tetrazolium staining test (tetrazolium triphenil-chloride). The tetrazolium coloration was used to confirm if non-germinated sclerotia were really heat inactivated or if there was fungistase induction. In the first assay during a cloudy day, the maximum temperature reached in the substrate was 45oC and the germination of sclerotia was null and accompanied by 100% of bacteria colonization. In the two last dates of evaluation during sunny days the maximum temperatures in the substrate varied from 60 to 80oC and the sclerotia were 100% eradicated with only one day-treatment. The staining test with TTC confirmed that non-germinated sclerotia were heat inactivated by the absence of red color due to the dehydrogenase activity inhibition (enzymatic denaturation). It was concluded that even under sub-optimum conditions for substrate treatment in solar collector devices the long exposition to higher temperatures were enough to cause severe injuries in the pathogen sclerotia which became vulnerable to microbial antagonism. The solar collector devices were efficient for substrate disinfestations and for the control of S. rolfsii in the evaluated conditions.

Caracterização cultural, morfológica e patogênica de Lasiodiplodia theobromae associado a frutíferas tropicais

Lasiodiplodia theobromae is a cosmopolitan, polyphagous and opportunistic fungus with reduced pathogenic specialization, which is capable of infecting plant species in tropical and temperate regions, causing varied symptoms. This study aimed to characterize L. theobromae isolates associated with tropical fruit plants in Northeastern Brazil, considering their cultural, morphological and pathogenic characteristics. The evaluated aspects were mycelial growth, colony coloration, conidium dimension and pathogenicity of the isolates for seedlings of yellow mombin (Spondias mombin L.), cashew (Anacardium occidentale L.), soursop (Annona muricata L.), and Brazil plum (Spondias tuberosa Arruda). Data of morphological and cultural characterization revealed diversity in the pathogen population. High pathogenic variability was also detected, although no pathogenic specificity was found for cashew. Brazil plum showed higher relative resistance to the fungus. The data also demonstrated interaction between morphocultural characteristics and aggressiveness of L. theobromae isolates.

Chemical control of guava rust (Puccinia psidii) in the Northern Region of Rio de Janeiro State, Brazil

Fungicides were evaluated under field conditions for their efficacy in the control of guava rust (Puccinia psidii); five systemic fungicides (azoxystrobin, pyraclostrobin, cyproconazole, tebuconazole, triadimenol) and the protectant mancozeb. In a first trial, the fungicides were applied at two-week intervals intercalated with bi-weekly sprays of copper oxychloride. The initial incidence of rust on flower buds before treatment was 47%. Triadimenol and azoxystrobin were most effective in reducing the incidence of rust on fruit. The minimum rust incidence achieved with triadimenol was 12% compared to 84% in the control treatment (water). The initial level of rust on flower buds was particularly high for the tebuconazole treatment, which may have contributed to the ineffective control by this fungicide in the first trial. In the second trial, copper oxychloride sprays were applied when disease incidence on flower buds was low (7%). Azoxystrobin, tebuconazole, triadimenol and mancozeb treatments were started nine days after a second application of copper oxychloride. The fungicides were then applied at bi-weekly intervals and at the same concentrations as in the first trial. Triadimenol was again most effective in controlling rust, although its effect did not greatly differ from that of tebuconazole. The maximum disease incidence in all fungicide treatments was significantly lower than that observed in the control treatment.

First Report of Erysiphe quercicola Causing Powdery Mildew on Cashew in Brazil

Cashewnut (Anacardium occidentale L.) is a very important crop plant native to northern Brazil. In 2010 and following years, a powdery mildew outbreak was observed in over 60% of cashew growing areas in coastal and highland fields in Ceará and Piauí states, which account for over 70% of Brazilian cashewnut production. Disease symptoms commonly appeared as white to gray powder on young shoots, inflorescences, young fruits, and leaves, reducing fruit onset and severely damaging apple and kernels. Highest level of infection was observed by the time of flowering and fruiting plant stages, which occurs from June to September in those particular states. Today, powdery mildew is the main pathological constraint of cashew production in Brazil, as it affects mature trees, nursery stocks, and new plantings. Although there is great variability within cashew genotypes, most growing varieties are susceptible. From 2012 until 2014, field surveys were conducted to collect samples from different environments and host genotypes. Severely infected flushing leaves of BRS 189 cashew clone were collected in Pacajus county, Ceará State, and introduced into the Laboratory of Plant Pathology, Embrapa, for further studies. Due to conspicuous differences between these and commonly known symptoms from early described powdery mildew (Noack 1898), morphological and sequence data molecular studies were then conducted in order to determine the causal fungus. Conidiophores were erect with cylindrical foot cells, average size 100.2 μm. Chasmothecia were absent. Primary conidia were ellipsoid, with a rounded apex and truncate base. Mature conidia were mainly dolioform and formed singly (no catenescent), measuring 26.9 to 31.7 μm long × 14.3 to 20.4 μm wide (avg. 29.9 × 14.8 μm), with length/width ratio of 1.8 on average. The internal transcribed spacer (ITS) region, including 5.8S and partial 28S from genomic DNA extracted, was amplified with ITS1F (5′-TCCGTAGGTGAACCTGCGG-3′) and P3 (5′-GCCGCTTCACTCGCCGTTAC-3′) primers. The amplicon was sequenced by external service (Macrogen, Seoul, South Korea). BLASTn analysis of the ITS sequence (661 pb) Quick Links

Incidência e controle químico da ferrugem da goiabeira em diferentes épocas de poda na região norte do Espírito Santo

No norte do Estado do Espirito Santo, vem sendo observada a ocorrencia crescente da ferrugem ( Puccinia psidii G. Winter) nos pomares de goiabeira, ocasionando a queda de frutos novos e o declinio na producao. Este trabalho teve como objetivo avaliar tratamentos com fungicidas no controle da ferrugem em goiabeiras ‘Paluma’ podadas em diferentes epocas do ano. Foram realizados tres experimentos, em delineamento em blocos ao acaso, com diferentes epocas de poda de frutificacao (janeiro; maio e outubro) e quatro tratamentos fungicidas (I- testemunha ‐ aplicacao de agua, II- oxicloreto de cobre, III- tebuconazole e IV - tebuconazole + oxicloreto de cobre). Observou-se que, quando a poda foi realizada em janeiro, houve as maiores incidencias maxima e final da doenca, acarretando menor numero de frutos por planta. Dentre os fungicidas testados, tebuconazole isolado ou em mistura com oxicloreto de cobre foram os mais eficientes em controlar a doenca nas tres epocas de poda, inclusive na epoca de maior incidencia da doenca. Quatro pulverizacoes com tebuconazole, isolado ou em mistura com o oxicloreto de cobre, foram suficientes para minimizar os danos causados pela ferrugem da goiabeira. Palavras-chave: Psidium guajava L., Puccinia psidii G. Winter, poda de frutificacao, fungicidas.

First Report of Lasiodiplodia brasiliense Causing Postharvest Fruit Rot of Custard Apple (Annona squamosa) in Brazil

Custard apple is a perennial tropical plant cultivated in Brazil for it fresh consumed fruit, which is commercially sold all over the country. Custard apple is a climacteric fruit so it is harvested and commercialized at an early maturation stage; therefore it must be incubated for a few days to ensure ripening and consumption. Although it can be found in the market throughout the year, its production peaks during May to July in Northeast Brazil. In June 2016, in Aracoiaba County, Ceara State, Brazil, a fungal fruit rot was observed on approximately 20% of fruits within stored containers for wholesale market. Rotten fruits were taken to the Laboratory of Plant Pathology, Embrapa to isolate the causal agent. Externally, symptoms were darkening of the grooves, beginning in the peduncle. The lesions expanded rapidly, reaching the entire fruit within two to three days. Internally, there was discoloration of the pulp, invading the whole fruit. Upon complete infection, which takes approximately ten days, the wh...

Alternativas a fungicidas sintéticos no controle da antracnose da banana

Dentre as doencas de pos-colheita em banana, a antracnose (Colletotrichum musae), destaca-se entre os mais importantes fatores limitantes da producao no mundo. Com objetivo de controlar esse patogeno, avaliou-se a atividade fungitoxica dos extratos e oleos essenciais de Lippia sidoides Cham., Caryophillus aromaticus L. e Eucalyptus citriodora Hook.; dos antagonistas Trichoderma sp., levedura IA8, e um isolado de Bacillus subtilis; dos indutores de resistencia Acibenzolar-S-Metil, fosfito e acido salicilico e dos produtos anti-microbianos, hipoclorito de sodio, dioxido de cloro e sorbato de potassio, atraves de ensaios in vitro e in vivo. Os testes in vitro os tratamentos foram incorporados em meio de cultura BDA + tetraciclina (50 µg.mL-1), nas concentracoes de 5, 10, 15, 20, 25, 30 % (p/v) de cada extrato bruto; 0, 25, 50 e 100 µL de cada oleo; 0,05 g, 0,3 g e 300 µL dos indutores Acibenzolar-S-Metil, acido salicilico e fosfito repectivamente, 0,1 g, 25 mL e 100 µL dos anti-microbianos, sorbato de potassio, hipoclorito de sodio e dioxido de cloro, respectivamente. A atividade antagonica foi determinada pelo metodo de culturas pareadas para Trichoderma sp. e pelo metodo do funil para a levedura IA8, ambos cultivados em placas de Petri contendo meio BDA. B. subtilis (ja formulado) foi testado na proporcao de 100 µL/100 mL de BDA. Placas contendo apenas meio BDA ou o fungicida carbendazim (10 µL/100 mL), foram usadas para efeitos comparativos. Todos os tratamentos foram distribuidos em delineamento inteiramente casualizado com cinco repeticoes cada, incubadas a 28 ± 2o C e fotoperiodo de 12 h durante sete dias. As medias foram comparadas pelo teste de Tukey a 5 % de probabilidade. Nos testes in vivo foram usadas bananas “Prata” com dois orificios cada, onde foram depositados 20 µL de cada tratamento utilizado in vitro (extratos e oleos essenciais, antagonistas, produtos sanitizantes e indutores de resistencia). Doze horas apos incubacao, as bananas foram inoculadas com 20 µL da suspensao de esporos de C. musae (2,7x104 conidios/mL) e distribuidos em bandejas plasticas (5 bananas/bandeja/tratamento) em delineamento inteiramente casualizado, cada orificio representando uma repeticao. Os dados foram submetidos a analise de variância e as medias comparadas pelo teste de Tukey a 5 % de probabilidade. Os resultados in vitro observou-se que os extratos e oleos essenciais de L. sidoides e C. aromaticus, em todas as concentracoes testadas, assim como o acido salicilico e o hipoclorito de sodio foram tao efetivos quanto o controle quimico, em inibir o crescimento do patogeno em 100 %. O fosfito e os antagonistas Trichoderma sp. e B. subtilis tambem exerceram excelente atividade fungitoxica com reducoes de 91,8; 84,0 e 74,0 % respectivamente. Nos testes in vivo apenas Trichoderma sp e hipoclorito de sodio apresentaram reducoes significativas (acima de 50 %) no desenvolvimento de lesoes nas bananas.

Uso da desfolha para indução da brotação de atemoleiras 'Gefner'

aBstract- The use of cultural practices that allows production scheduling of atemoyas trees is for exploration of this crop. The shoot defoliation induces budbreak of atemoyas in certain weather conditions, with other cultural techniques, may control the production times. Thus, the aim of this study was to evaluate different defoliation treatments on budbreak induction of atemoyas trees growing at tropical conditions. The experiment was conducted in a commercial orchard located in Limoeiro do Norte/CE, Brazil, using five years old atemoya trees ‘Gefner’, grafted on sugar apple rootstock. Thereabout ten days after harvest was held pruning production and then applied the treatments: 1) control (without defoliation); 2) hand defoliation, 3) urea 150 g L -1 ; 4) urea 150 g L + mineral oil 24 mL L -1 ; 5) urea 150 g L + copper sulfate 10 g L -1 ; 6) copper sulfate 10 g L -1 + mineral oil 24 mL L -1 ; 7) urea 150 g L + mineral oil 24 mL L -1 + copper sulfate 10 g L -1 ; and 8) ethephon 2.4 mL L. All chemical treatments tested induced defoliation and budbreak of ‘Gefner’ atemoya trees, especially foliar applications of ethephon 2.4 mL L

Progresso do oídio em função da fenologia do cajueiro

Embrapa Agroindústria Tropical, Rua Dra. Sara Mesquita, 2270, 60110-511, Fortaleza, CE, Brasil. Instituto Federal de Educação, Ciência e Tecnologia do Ceará IFCE, 62042-030, Sobral, CE, Brasil. Universidade Federal do Ceará UFC, 60455-900, Fortaleza, CE, Brasil. Autor para correspondência: Marlon Vagner Valentim Martins (marlon.valentim@embrapa.br) Data de chegada: 06/10/2016. Aceito para publicação em: 26/09/2017. 10.1590/0100-5405/170270

Ocorrência de Phytophthora nicotianae em Lilium speciosum no Brasil

383 A Serra da Ibiapaba, no Estado do Ceará, tem se destacado na produção de flores, sendo essa atividade uma importante oportunidade na geração de renda para as famílias envolvidas. Plantas de lírio doente, da espécie Lilium speciosum Thunb., variedade Constanta, foram enviadas ao Laboratório de Fitopatologia da Embrapa Agroindústria Tropical, Fortaleza-CE, apresentando murcha, amarelecimento das folhas, necrose em bulbo e lesão encharcada acima do colo das plantas. Amostras de tecidos doentes do caule das plantas foram utilizadas para identificar o agente causal através de isolamento em meio de cultura ágar-ágar (AA). As placas de petri foram incubadas em temperatura de 28 ± 1 C por três dias para o crescimento do fitopatógeno. Após esse período, a cultura axênica foi transferida para o meio cenoura-ágar (CA) para a caracterização morfológica realizada no Phytolab, do Centro de Pesquisas do Cacau/Ceplac, Ilhéus-BA. O agente causal apresentou crescimento micelial branco e esporângios predominantemente não caducos, papilados, com forma variando de ovoide a alongado ou elipsoide, com média de comprimento 41,9 ± 0,9 μm e de largura 32,6 ± 0,7 μm, com relação comprimento/largura de 1,3:1 (média de 50 esporângios avaliados em caldo de cenoura), com abertura do poro apical das papilas medindo 6,6 ± 0,2 μm (Figura 1A); clamidósporos terminais e intercalares presentes e formados isoladamente com 23,7 ± 0,9 μm de diâmetro (Figura 1B). Oósporos não foram observados em cultura tanto em CA quanto em caldo de cenoura. O isolado formou culturas petaloides em cenoura-ágar e cresceu a 35 C, embora com redução de Ocorrência de Phytophthora nicotianae em Lilium speciosum no Brasil