THE DAMPING OFF OF TOBACCO AND ITS CONTROL IN PUERTO RICO

Resumen en inglé

MANGO WITHER-TIP (Colletotrichum gloeosporioides Penz.)

Resumen en inglé

THE ANTHRACNOSES OF CITRUS FRUITS, MANGO AND AVOCADO

(1) Colletotrichum glocosporioides Penz. appears to be the cause of the anthracnose diseases of mango, orange, grapefruit, lemon, avocado, and sometimes of lime. (2) Lime wither-tip may be caused by either G. gloeosporioides or Glocosporium limetticolum Clausen. (3) Collelotrichum gloeosporioides Penz. frequently causes spotting of lime blossoms and the wither-tip. It is also the cause of the spots on lime thorns. The latter is demonstrated by cultures L 9- L, 13, inclusive, which behaved like other G. gloeosporioides cultures and very distinct from cultures of G. limetticolum. (4) Glocosporium limetticolum Clausen is the cause of wither-tip· ancl leaf spot of limes. (5) G. limetticolum appears to be the only cause of fruit canker or fruit spot of limes. (6) Under artificial conditions the various cultures of G. gloeosporioides and G. limetticolum exhibit distinct cultural characteristics. (7) Cultures from the avocado differ somewhat from cultures obtained from other hosts in cultural characteristics. The difference may not furnish enough evidence for their separation into a new species. (8) There are such differences between most cultures from the lime and all cultures from the other hosts that Clausen's (5) separation of the former into a distinct species appears to be justified. (9) The four most salient growth characters in which cultures of C. gloeosporioides varied from cultures of G. limetticolum or such cultures among themselves are: (a) size, number, and arrangement of acervuli; (b) color of acervuli and substratum; (c) character of aerial mycelium; (d) size of colonies. (10) C. gloeosporioides can resist slightly more acid or alkaline concentrations than G. limetticolum. (11) Setae are occasionally present in C. gloeosporioides and absent in G. limetticolum. (12) Variation in spore size is induced by the culture medium. (13) There is great morphological similarity between G. limetticolum and C. gloeosporioides. (14) Environment induces variation in form and shape of spores. (15) The character of conidia appears to be rather uncertain for distinguishing between Gloeosporium limetticolum gloeosporioides

THE DAMPING-OFF OF TOBACCO AND ITS CONTROL IN PUERTO RICO

1. Damping-off of tobacco is a very severe disease in Pu erto Rico. 2. The disease is caused by Pythium debaryanum and Phytophthora Parasitica var. nicotianae. 3. The agents of transportation of the fungus are water currents, laborers, animals, burrowing insects, etc. 4. Leaves are infected by zoospores of Phy. Parasitica var. nicotianae but apparently not by those of P. debaryanum. 5. Environmental conditions are important factors influencing the spread and severity of the disease. The disease seems to be equally severe during all seasons provided the proper moisture relations are maintained. Organic manures seem to influence favorably the incidence of the disease. The disease is severe on thickly-sowed beds. 6. Control of damping-dff of tobacco is today one of the most serious problems with Puerto Rico tobacco growers. 7. When the disease appears in small areas only, it may be checked by drenching these with a 1-30 formaldehyde solution. 8. Soil disinfestation by means of steam or with formaldehyde does not seem to be practicable under Puerto Rican conditions. 9. Phy. Parasitica var. nicotianae is probably slightly less susceptible to the sterilizing action of formaldehyde than P. debaryanum. 10. Mercury compounds have been found injurious to tobacco seedlings, and ineffectiYe against the clamping-off pathogenes. 11. In preliminary trials two applications of Corona Copper carbonate of four grams per square foot, before seed sowing, and at the same rate a week after germination, were fairly effective. Two applications of copper carbonate in the field did not give effective control probably due to the heavy rains and to overcrowding of the seedlings. Two late applications of copper carbonate on heavily infected beds were unsuccessful. Two 4-gram applications of copper carbonate resulted in good control of the damping-off of tomato, pepper, and eggplant. 12. Copper stereate, in two applications of 4 grams each, seemed to control P. debaryanum but did not have any effect on Phy. Parasitica var. nicotianae. 13. Bayer dust and Uspulun were injurious when applied to the foliage and proved to be ineffective in the control of the disease. 14. Copper sulfate solutions (4 and 5 pounds to 50 gallons) applied at the rate of 1/2 gallon per square foot before sowing the seed were ineffective. 15. Effectiveness of copper fluosilicate is doubtful. 16. Acetic acid does not control the disease under conditions of high infection. 17. Two applications of 4-4-50 and 5-5-50 Bordeaux mixture at the rate of 1/2 gallon per square foot, one before sowing the seed and the other a week after germination, were effective in controlling damping-off. The treatment was not very successful when applied to beds in the field in which the disease had made its appearance. 18. Injury to seedlings resulted when copper carbonate was applied to a tobacco seed-bed on the site of an old bed. It was proved by experiment that the injury was not clue to dryness. Soil reaction appears to have little to do as a direct cause of the injurious action. No injurious action of formaldehyde or acetic acid was found under similar conditions. Charcoal was not effective in preventing injury from the copper compounds. Recovery from injury resulted in one case when a sodium nitrate solution was applied. It is suggested that the injurious action is connected with nitrification which would be hindered by the lasting effect of the copper treatments. 19. Continuous cultivation of infested soils for periods of six to twelve months does not eradicate the disease

Cobertura do solo proporcionada pelo cultivo consorciado de milho com leguminosas e espécies espontâneas.

Os consórcios entre leguminosas e gramíneas são bastante comuns, proporcionando grande preservação do solo e maiores retornos econômicos ao agricultor. As espécies vegetais que emergem espontaneamente na lavoura, conhecidas pelo seu efeito prejudicial, são fundamentais para a melhoria da cobertura do solo, colaborando para a manutenção da camada superficial do solo e de seus nutrientes. No intuito de estudar a cobertura proporcionada ao solo por sistemas de cultivo, avaliou-se a cobertura proporcionada na consorciação de milho + espontâneas com feijão de porco, feijão bravo do ceará, mucuna preta, lablab e guandu. Na implantação dos tratamentos, incorporaram-se as espécies espontâneas e leguminosas do experimento anterior, semeando-se o milho e as leguminosas aos 64 dias. O milho foi colhido aos 120 dias, e as leguminosas aos 144 dias. O consórcio milho + espontâneas + mucuna-preta foi o que acumulou mais matéria seca e nutrientes. A mucuna preta e o feijão-de-porco foram as leguminosas que apresentaram as maiores coberturas do solo. Todos os componentes do consórcio exerceram efeitos de cobertura, contribuindo no acúmulo de matéria seca e na reciclagem de nutrientes, e assim, na sustentabilidade do sistema

Las deformidades vertebrales a través de las artes plásticas

Si la medicina constituye el primero y más poderoso medio de intervención del hombre con respecto a su vulnerable naturaleza, el arte es también el primero y más poderoso instrumento que el hombre ha podido encontrar para expresar su propia condición. Con los años el hombre ha evolucionado, y con él la medicina y el arte. El arte trabaja sobre el mismo motivo que la medicina: el hombre. De ahí el extraordinario valor, desde el punto de vista ontológico, de muchas obras de arte, que jamás habrían sido realizadas si la enfermedad y el ejercicio del arte médico no les hubiera creado el tema; ya no tiene sentido la separación entre ciencias del espíritu y ciencias de la naturaleza para el mejor entendimiento del ser humano, porque lo correcto es considerar que los conocimientos médico-científicos y artístico-plásticos se unen en el hombre

Relación entre la orientación del cotilo y los cambios radiológicos evolutivos tras prótesis total de cadera tipo Charnley-Müller

Los autores realizan un estudio retrospectivo de 87 cotilos cementados, para averiguar si la posición del implante determina alteraciones radiológicas alrededor de este cotilo en la evolución de la prótesis total de cadera. Se valoraron una serie de parámetros radiológicos: protusión acetabular del cotilo, osteoporosis regional periacetabular, presencia de imágenes quísticas alrededor del acetábulo, presencia de esclerosis subcondral, calcificaciones yuxtacotiloideas y migración vertical del cotilo. Estos parámetros se relacionaron con los ángulos de inclinación y anteversión del cotilo. En los resultados obtenidos, destaca la relación estadísticamente significativa entre la posición del cotilo con la presencia de protusión acetabular, imágenes quísticas y osteoporosis regional y esclerosis subcondral periacetabulares. La posición «idónea» para este cotilo cementado parece ser de 35° a 45° el ángulo de inclinación y de 15° el ángulo de anteversiónEighty-seven cemented total hip prothesis were retrospectively reviewed in order to ascertain whether the position of the acetabular implant induces radiographic changes around the cup during follow-up. Several radiographic parameters were evaluated: acetabular protrusión of the cup, periacetabular local osteoporosis, cystic images, subchondral sclerosis, presence of calcifications around the cup and vertical displacement of the cup. These findings were correlated with the inclination and anteversion angles of the cup. A statistically significant correlation was found between the position of the cup the following parameters: degree of acetabular protrusion, presence of cystic images, local osteoporosis and periacetabular subchondral sclerosis. The ideal position of the cemented cup results to be of 35-45° inclination angle and 15° anteversion angle