Rui Sales Júnior

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

Controle biológico de Monosporascus cannonballus com Chaetomium

Melon collapse caused by Monosporascus cannonballus is one of the main diseases that affect this cucurbit. The objective of this research was to study the biological control of M. cannonballus by Chaetomium. Infested substrates with 0.5, 1, 2, 4 and 8 x 105 CFU g-1 were introduced in plates where seeds of melon type Piel de Sapo cv. PS 1430 were sowed in seeding trays after two weeks of incubation. The seedlings were transplanted to pots with a similar substrate, infested additionally with 2.5 x 104 CFU of Chaetomium per gram and 20 CFU of M. cannonballus per gram of substrate. Three controls were considered: one infested with Chaetomium alone, another with M. cannonballus and one without any treatment. The experimental design was completely randomized with five replicates. General disease index and control percentage were evaluated forty-five days after transplant. The General disease index varied according to the increased Chaetomium concentration. The results demonstrated that 4 and 8 x 105 CFU of Chaetomium g-1 were equivalent to 0.9 and 0.6, respectively. The statistical analysis showed that 4 and 8 x 105 CFU g-1 of Chaetomium concentration were the most efficient treatments, with control percentage higher than 55 %, indicating the potential of Chaetomium to control M. cannonballus.

Qualidade do melão exportado pelo porto de Natal-RN

Brazil was studied. The post quality harvest from the melon exported from the Natal-RN port, the qualitative characteristics unfavorable to the market 2,303 fruits were analyzed from September to December of 2002 .Sampling was done according to control norms of Delegacia da Agricultura e do Abastecimento - DFA/SSV. The work was developed in the Natal port, on unit of Vigiagro/SSV/MA. The study in systematic form, using a special form “Card of Quality Control of the Melon Exported” was determined. The contents of solid solubles and pulp firmness. The yellow type were 50.33% from the fruits of the total, 19.06% of the Orange Flesh, 9.90% of the Piel de Sapo , 11.60% of the Galia , 7.03% of the Cantaloupe and 2.52% of the Charentais type. Only the melon Yellow type presented content average of solids soluble accepted for export. The Piel de Sapo melons presented the less firmness of pulp.

Qualidade do melão exportado pelo porto de Natal

We evaluated the post harvest quality of melons exported through the port of Natal, identifying the unfavorable characteristics for the market that could be prejudicial to the exportation. A total of 2.218 fruits was analyzed from September to Dezember 2001. Sampling procedures were done following norms of the Delegacia da Agricultura e do Abastecimento. The work was carried out in the port of Natal. Solid soluble content and fruit firmness were the parameters used to evaluate fruit quality. Nearly 62.58% of the fruits were of the Yellow type; 15.1% Orange Flesh type; 9.29% Piel de Sapo (Frog Skin) type; 5.77% Galia type; 5.09% Cantaloupe type and 2.17% were of the Charentais type. Only the Yellow type melon presented more than 50% of its fruits with soluble solid content superior to 10o Brix, and the Frog Skin was the only type with low index for pulp firmness.

Quantificação de ascósporos de Monosporascus cannonballus em solos não cultivados de Caatinga e em áreas de cultivo de melão do Rio Grande do Norte e Ceará

The fungus Monosporascus cannonballus is an important melon root pathogen in the Northeast of Brazil, where it causes a disease called collapse. As information on population levels of M. cannonballus ascospores in Brazilian soils does not exist, this study aimed to compare ascospore density between soil samples of 15 non-cultivated areas of the Caatinga and 15 soil samples of melon producing areas in the States of Rio Grande do Norte and Ceara. Ascospores of M. cannonballus were detected in all soil samples analyzed. The density of the ascospores varied from 0.18 to 18.30 ascospores.g-1 of soil in non-cultivated Caatinga soil. Ascospore density in areas cultivated with melon varied from 0.50 to 26.04 ascospores.g-1 of soil. There was no significant statistical difference (P=0.05) in the ascospore average density between cultivated and non-cultivated soil. Among the cultivated areas, the ascospore average density was significantly higher in the areas with a history of collapse caused by M. cannonballus when compared with areas without a disease history. There is evidence that M. cannonballus was not introduced in Brazil by propagation material, but is possibly a natural inhabitant of non-cultivated soils of Caatinga.

Comportamento de cultivares de meloeiro e melancia inoculados com Acremonium cucurbitacearum e Monosporascus cannonballus

Vine decline or collapse on cucurbits is a syndrome that can be caused by several phytopathogenic agents and is frequently associated with the attack of several of them. Acremonium cucurbitacearum and Monosporascus cannonballus are two of the main fungal pathogens associated with this syndrome. The pathogenicity of these fungi was evaluated for 19 muskmelon (Cucumis melo) and two watermelon (Citrullus lanatus) cultivars usually cultivated in Brazil. All cultivars tested were highly susceptible to these pathogens except for the combination watermelon-M. cannonballus. The importance of continuing the study with other cultivars using the methodology described is discussed.

Reaction of melon genotypes to Rhizoctonia solani

O cultivo intensivo de melao (Cucumis melo L.) no Nordeste brasileiro tem favorecido a ocorrencia de doencas radiculares como a rizoctoniose, causada pelo fungo Rhizoctonia solani. Visando selecionar genotipos com potencial de utilizacao nos programas de melhoramento e/ou no manejo integrado da doenca, foram avaliados 20 genotipos de melao, em relacao a dois isolados do patogeno (RS-9 e RS-10). As sementes foram plantadas em solo infestado com o patogeno pela incorporacao de 50 mg de substrato (graos de arroz) colonizado kg-1 de solo. A avaliacao dos genotipos foi realizada apos 15 dias, com o auxilio de escala de notas de 0 a 4, para agrupamento de cada genotipo em cinco classes e calculo do indice de severidade da doenca. Nenhum dos genotipos apresentou reacao de imunidade a R. solani, independentemente do isolado. Os indices de severidade da doenca variaram de 6,2 a 85,4% e de 7,8 a 85,2% para os isolados RS-9 e RS-10, respectivamente. Quando considerados os dois isolados do patogeno simultaneamente, os genotipos Sancho, AF-1805, Athenas, AF-682, Torreon e Galileo comportaram-se como altamente resistentes. Os genotipos Sancho e AF-1805 apresentaram os menores indices de severidade da rizoctoniose em relacao a RS-9 e, o genotipo Gold Pride, em relacao a RS-10. Esses genotipos diferiram significativamente dos demais, considerando cada isolado do patogeno individualmente e, portanto, constituem fontes promissoras de resistencia a R. Solani, devendo ser preferidos para plantio em areas infestadas pelo patogeno.

Estabilidade fenotípica de híbridos de melão amarelo avaliados no Pólo Agrícola Mossoró-Assu

The objective of this work was to estimate the participation of single and complex components of interaction as well as to identify cultivars with high phenotypic adaptability and stability. Twelve hybrids of yellow melon were evaluated in four sites of Rio Grande do Norte in 2000, 2001, 2002 coming to twelve environments. The experiments were carried out in a randomized complete block design with three replications. The experimental plot was constituted by two 5 m long rows. Yield and total soluble solids contents were evaluated. For the partition of the hybrids by environments interaction in single and complex part, the method of Cruz and Castoldi was used. In order to indentify hybrids with high phenotypic adaptability and stability, the Toler method was utilized. Great variation among environments and hybrids as well as interaction were observed between these two factors. The complex part is responsible for most of the environment hybrids interaction. Hybrids AMR-04 and AMR-12, comprising higher means to yield and total soluble solids content, are responsive to the improved environment.

Produtividade e qualidade de frutos de melão pele-de-sapo em duas densidades de plantio

There are doubts whether the planting density used for Yellow melon allows harvesting Piel del Sapo fruits that meet the standards of foreign markets. Two experiments were carried out to evaluate Piel de Sapo hybrids in two planting densities, 10 and 15 thousand plants ha-1. Hybrids Sancho, PS 07, and Tendency were evaluated in the first experiment, while hybrids PS RDR, PS 10, PS 15, PS 21, and PS 32 were evaluated in the second experiment. The experimental design used was blocks at random, with four replications. Treatments were arranged in split-plot, with planting densities assigned to plots and hybrids to sub-plots. Sub-plots had 16 and 24 plants in the useful area in the first and the second experiments, respectively. There was no significant interaction between planting densities and hybrids in none of the assessed traits. Fruit yield and total number were significantly higher in the planting density of 15,000 plants ha-1, with mean values of 38.95 t ha-1 and 23.05 thousand fruits ha-1, respectively, in comparison to 10,000 plants ha-1. Pulp firmness and total content of soluble solids were not influenced by planting density. There were significant differences among hybrids for fruit total number, yield, pulp firmness and total content of soluble solids. In the first experiment, hybrids Sancho and Tendency had the best performance, with fruit yields of respectively 31.3 and 32.9 t ha-1, with average weight over than 3.0 kg, pulp firmness of 28 and 27 N, respectively, and soluble solids contents of 9.33 and 12.03%, therefore above the market limit. In the second experiment, hybrids PS 15 and PS 32 outstood, with yields of 36.6 and 41.3 t ha-1, respectively, fruit weight of 3.10 and 3.02 kg, pulp firmness of 27 and 28 N, respectively, and soluble solids contents of 12.03 and 9.96%. Worth mentioning that hybrid PS 32 produced significantly more fruits (25.2 thousand fruits ha-1) as compared to hybrid PS 15 (19.7 thousand fruits ha-1).

Análisis de Distintos Tipos de Azúcares en el Método de Extracción de Ascosporas de Monosporascus cannonballus en Suelo

The objective of this work was to test different kinds of sugar for the extraction of ascospores of M. cannonballus. The ascospores of this ascomycete involved in melon (Cucumis melo) collapse can be recovered from soil by a physical method using a gradient of sucrose (50% concentration). The use of commercial sucrose represents a high cost per sample. This is the reason for research into a cheaper substitute sugar. In this work, we compared dextrose, commercial cane sugar and dessert sugar. Average ascospores/g of soil recovered with all these sugars were not statistically different, using the Tukey Test (P=0.05). The use of commercial cane sugar is recommended for its efficacy and low cost in every sample (R