Romero M. Moura

Meloidogyne mayaguensis on Psidium guajava in Rio Grande do Norte

ABSTRACT Meloidogyne mayaguensis on Psidium guajava in Rio Grande doNorte This paper reports the occurrence of Meloidogynemayaguensis on Psidium guajava cv. Paluma in the State of RioGrande do Norte, Brazil. O Laboratorio de Agricultura Irrigada da Escola Superiorde Agricultura de Mossoro – ESAM, Rio Grande do Norte,recebeu, em junho de 2003, amostras de solo de rizosfera degoiabeira ( Psidium guajava L.) cv. Paluma e sistemas radicularesdeficientes constituidos por poucas raizes, finas e necrosadas,coletadas em pomar com aproximadamente 500 plantas, comsete anos de idade, situado no municipio de Touros–RN.Segundo o proprietario, as plantas doentes expressavamsintomas de amarelecimento e declinio, e distribuiam-se emreboleiras.Para diagnostico, amostras foram encaminhadas aoLaboratorio de Fitonematologia da Universidade Federal Ruralde Pernambuco; das quais aliquotas de solo de 300 cm 3 foramdestinadas ao processamento por flotacao centrifuga, segundoJenkins (1964) (Plant Disease Reporter, v.48, p.692, 1964), e 10g de raizes para trituracao em liquidificador, por 20 s, associadaa flotacao centrifuga. Nas amostras de solo e de raiz foramdetectadas 440 e 11.380 formas juvenis do segundo estadio,respectivamente, de

Severidade da podridão-verde em inhames e especialização fisiológica em Penicillium sclerotigenum

ABSTRACTSeverity of green rot in yellow and water yams and the physiological specialization of Penicillium sclerotigenum The degree of green rot severity was evaluated in two yam species, D. alata and D. cayennensis . The causal agentof this disease is the fungus Penicillium sclerotigenum, a highly virulent pathogen on D. cayennensis in the producingareas all over the world. In addition, by cross inoculation, an investigation was conducted on the occurrence of physiologicaladaptations of the fungus relative to its pathogenicity on these species of yams. To complement this study the mycelialgrowth of P. sclerotigenum was evaluated on three culture media, two based on extracts of the yam species examined andthe other one on potato ( Solanum tuberosum ). Dextrose and agar were added to all cultures. The results showed thatgreen rot was less severe on D. alata than on D. cayennensis . No physiological adaptation in relation to the pathogenicityof P. sclerotigenum to both yam species was found. Potato-dextrose-agar and

Efeito de terbufos em soqueira sobre fitonematóides ectoparasitos de cana-de-açúcar

Due to the usually high population levels of ectoparasitic nematodes associated with sugarcane (Saccharum spp.) Northeastern Brazil, the effect of the systemic nematicide Terbufos (Counter 50G) was studied, on first ratoon, in soil naturally infested with Helicotylenchus dihystera, Criconemella ornata and Paratrichodorus minor. The experimental design consisted of completely randomized blocks with treatments factorially arranged in 2x3x5 (two harvest periods x three nematicide doses x five sugarcane varieties), with five replicates. Nematicide doses consisted of 3 kg a.i./ha, applied at planting and immediately after first cutting, 4 kg a.i./ha, applied at planting and control, 0 kg a.i./ha, distributed into 2.0 m x 2.0 m microplots. Evaluations based on nematode population densities were carried out on five varieties, CB45-3, RB813804, SP78-4764, SP79-1011 e SP 70-1143, at plant and first ratoon harvest. There was no interaction among nematicide, variety and harvest time. Results showed nematicide doses and sugarcane varieties did not affect significantly nematode population levels. However, in contrast to H. dihystera, population densities of C. ornata and P. minor were significantly lower at ratoon than plant harvest.

Sobrevivência de Rotylenchulus reniformis em solo naturalmente infestado submetido a diferentes períodos de armazenamento

The reniform nematode (Rotylenchulus spp.) survives to dissecation better than most plant parasite nematodes, being recorded that R. reniformis survived after 29 months with no host. The aim of this research was to investigate the survival fo R. reniformis in the absence of host, in a naturally infested soil, submitted to different periods of storage, under laboratory conditions. At 45, 90, 135 and 180 days after storage, five soil samples were placed in pots and melon (Cucumis melo) cv. Amarelo Ouro were grown for 80 days under greenhouse conditions. Juveniles, males and imature females in the soil, adult females in root system and total of nematodes (soil+root) were recorded per experimental unit. Linear, logarithmic and quadratic models were tested to describe each variable in relation to storage time. Quadratic models fitted better the variation of all variables except for females in the root system for which the variation did not fit any of the models tested. Nematode populations tended to decrease after 90 days of storage. After 180-days storing soil and subsequently growth of melon in the soil stored, nematode population density at harvest was equivalent to 83.41% of population level at begin of storage.

Pratylenchus brachyurus on Cucumis melo in Brazil

This is the first report in Brazil on the lesion nematode Pratylenchus brachyurus on melon (Cucumis melo) plants in naturally infested soil in Acu-Mossoro belt, Rio Grande do Norte. Morphometric data of the nematode population are presented.

Efeitos do uso de Crotalaria juncea e carbofuran em fitonematóides ectoparasitos de cana-de-açúcar

A study was done on the effects of Crotalaria juncea and carbofuran on ectoparasite nematodes of sugarcane (Saccharum sp.) planted in soil naturally infested by Helicotylenchus dihystera, Criconemella ornata, Paratrichodorus minor, and Trichodorus sp. The stydy compared the use of C. juncea for one year, with incorporation, with one application of the systemic nematicide carbofuran at time of planting sugarcane var. SP79-1011. Evaluations were based upon soil nematode population densities throughout the first year of cropping. The nematode populations showed low number of specimens, being slighly influenced by the crotalaria incorporation and carbofuran application. Nematode population level remained low, during plant development, with low increment, in general, after 90 days of planting. The behavior of the C. ornata population in function of the time in plots treated with crotalaria or carbofuran was described by the equations Y = 100,56524 + 0,01504X - 0,00003032X2 (R2 = 0,5605**) or Y = 10 0,62059 + 0,01394X - 0,00002786X2 (R2 = 0,6416**), respectively. On sugarcane treated with carbofuran the increase of Trichodorus sp. population followed the quadractic model Y = 13,16667 - 0,10904X + 0,00065711X2 (R2 = 0,6916**).

Incidência de Pratylenchus coffeae causando severa nematose em cafeeiro no nordeste

Pratylenchus coffeae (Zimmerman) Filipjev & Shuurmans-Stekhoven é responsável por perdas em muitas culturas nas regiões tropicais (Luc et al. Plant Parasitic Nematodes in Tropical and Subtropical Agriculture. Wallingford. CAB International. 1990). No Brasil, o primeiro assinalamento desse patógeno foi feito por Monteiro & Lordello. (Rev. Agricultura 49:169. 1974). Ao longo dos anos, esse endoparasito migrador não se revelou de alta virulência em cafeeiro (Coffea arabica L.). No Nordeste, P. coffeae foi primeiramente assinalado em inhame (Dioscorea cayennensis Lam. var. rotundata Poir.) (Moura & Monteiro. Fitopatol. Bras. 20:256. 1995) e mais tarde em gravioleira (Annona muricata L.) causando perdas elevadas. Ambas, atualmente, são epidêmicas. Por terem origem comum, as duas populações do nematóide têm sido diagnosticadas como população inhame (Moura et al. Nematol. Bras. 23:62-68. 1999). O objetivo deste trabalho foi relatar P. coffeae causando pratilencose severa em cafeeiro em Barra da Guabiraba, Pernambuco. Tratava-se de um pomar contendo 1.500 plantas de 1,5 ano de idade, instalado numa antiga área de produção de inhame desativada pelas altas incidências de casca preta, causada por P. coffeae. Plantas atacadas apresentavam extenso escurecimento do córtex radicular e muitas lesões na região do colo, que atingiam até 10 cm para cima, ao longo do caule (Figura 1A,B). Plantas atacadas morriam após amarelecimento intenso e queda das folhas, o que ocorreu em aproximadamente 70% do plantio. Estudos morfológicos comparativos do patógeno revelaram tratar-se de população semelhante à do inhame e da gravioleira. Em média, foram encontrados 1.630 espécimes, por 20 g de raízes. O presente assinalamento ressalta a importância da aplicação imediata de técnicas de exclusão, impostas por rigorosa legislação, para dificultar a disseminação desse patógeno na Zona da Mata do Nordeste, onde se encontram culturas suscetíveis de alto valor econômico. Pratylenchus coffeae no Nordeste deve ser classificado como Praga Quarentenária 2.

Relembrando Anton de Bary e sua obra fitopatológica

Heinrich Anton de Bary is considered to be the father of Plant Pathology and modern Mycology. This great scientist was born in Germany in 1831. Although he graduated in Medicine, he devoted his entire life to Botany, more specifically to the study of fungi, algae and mixomyctes; he also made contributions to the area of bacteriology. His publications were numerous and diversified but his masterpiece contribution to Plant Pathology and Mycology were his studies of potato blight and cereal rust. He died at age 58.

Estudos sobre aplicações conjuntas de herbicidas e nematicidas sistêmicos na eficácia dos nematicidas em cana-de-açúcar

Com o objetivo de avaliar uma possivel influencia da aplicacao conjunta de nematicidas sistemicos e herbicidas sobre a eficacia dos nematicidas, no controle de Meloidogyne spp. e Pratylenchus zeae em cana-de-acucar (hibrido de Saccharum spp.) no Nordeste, instalaram-se dois experimentos, um irrigado e outro nao irrigado, ambos em canaviais nordestinos, ha muito cultivados e comprovadamente infestados por fitonematoides. A variedade utilizada foi SP79-1011, os nematicidas aldicarb e terbufos e os herbicidas diuron, ametrina, oxyfluorfen e pendimetalin, aplicados no plantio, nas doses recomendadas comercialmente. As avaliacoes fundamentaram-se nos niveis populacionais dos nematoides observados em tres diferentes momentos, e nos fatores de reproducao. Avaliaram-se tambem o desenvolvimento das plantas, a produtividade agricola e dois parâmetros tecnologicos. Os resultados demonstraram que nao houve efeito dos herbicidas na eficacia dos nematicidas, nem foram significativas as diferencas em relacao a produtividade, exceto na area irrigada, para perfilhamento nos tratamentos com herbicidas, e numero de colmos e perfilhos, nos tratamentos com nematicidas em relacao a testemunha. Os nematicidas e herbicidas nao afetaram os niveis de Pol e PCC do caldo, nao interferindo, portanto, na produtividade industrial. Houve interacao estatistica entre nematicida e herbicida para P. zeae na rizosfera, na area irrigada, com a menor populacao do parasito encontrada na combinacao aldicarb + pendimetalin.

Patogenicidade de Penicillium sclerotigenum a Diferentes Frutas e Hortaliças em Pós-Colheita

ABSTRACTPost-harvest pathogenicity of Penicillium sclerotigenum to fruits and vegetables. The aim of this investigation was to study the pathogenicity of the fungus Penicillium sclerotigenum, the causal agent of the green-rot of yams (Dioscorea spp.) on different fruits and vegetables. A highly virulent isolate of the fungus was wound-inoculated on selected fruits and vegetables. A disease index ranging from 1 to 3 was adopted in order to rank disease susceptible. The results pointed out apple, pear and banana as highly susceptible; potato, beet, eggplant and taro as relatively susceptible and charlotte, carrot, papaya, zuchinni, sweet-potato and cassava as resistant to infection. These results indicated the need of special care when packaging and storage areas are utilized for both yams and other products susceptible to infection by P. sclerotigenum, particularly bananas, apples and pears. So far, P. sclerotigenum has been reported only on yams and these new finding also indicate that, besides yams losses, storage losses of apple, pear and banana may also occur. Penicillium sclerotigenum ability to infect these other products may represent an additional source of patulin in under storage conditions. This mycotoxin has well demonstrated mutagenic, carcinogenic and teratogenic effects on animal and apple and pear are known to be good substrates for patulin production.