Effect of spent mushroom compost tea on mycelial growth and yield of button mushroom (Agaricus bisporus).

Preliminary studies suggested that the use of compost tea made from spent mushroom substrate (SMS) may be regarded as a potential method for biologically controlling dry bubble disease in button mushroom. The aim of this study was to assess the effect of SMS compost tea on the host, the button mushroom, to ascertain whether the addition of these water extracts has a toxic effect on Agaricus bisporus mycelium growth and on mushroom yield. In vitro experiments showed that the addition of SMS compost tea to the culture medium inoculated with a mushroom spawn grain did not have an inhibitory effect on A. bisporus mycelial growth. The effect of compost teas on the quantitative production parameters of A. bisporus (yield, unitary weight, biological efficiency and earliness) was tested in a cropping trial, applying the compost teas to the casing in three different drench applications. Quantitative production parameters were not significantly affected by the compost tea treatments although there was a slight delay of 0.8-1.4 days in the harvest time of the first flush. These results suggest that compost teas have no fungitoxic effect on A. bisporus so that they can be considered a suitable biocontrol substance for the control of dry bubble disease.

Reduced sensitivity of the mushroom pathogen Verticillium fungicola to prochloraz-manganese in vitro.

105 isolates of Verticillium fungicola from Spanish mushroom crops collected between 1992 and 1999 were tested in vitro for their sensitivities to prochloraz-manganese. Dose response relationships for inhibition of mycelial growth by the fungicide were assessed in radial growth experiments on fungicide-amended malt extract agar. The ED50 values recorded for all 105 isolates studied ranged between 0.8 ppm in 1992 and 8.8 in 1998, with an average of 2.9. 86% of the isolates tested were more sensitive to prochloraz-manganese and had ED50 values below 5 ppm, while the other 14% were slightly tolerant with ED50 values equal or above 5 ppm. Of those tested from 1999, 60% (21 isolates) grew with 50 ppm and 40% (14) also at 100 ppm, although mycelial growth was inhibited at least by 82 and 87%, respectively. The resistance factor calculated ranged from low fungicide resistance (RF=3.0) in 1992 to moderate resistance (RF=12.6) in 1998. These data confirm that the sensitivity of V. fungicola to the prochloraz-manganese gradually diminishes.

Predictive factors for the suppression of fusarium wilt of tomato in plant growth media.

ABSTRACT Fusarium wilts are economically important diseases for which there are no effective chemical control measures. However, biological control and fertility management are becoming efficient alternatives for controlling this disease. Growth media formulated with composts that are able to suppress Fusarium wilt of tomato provide a control system that integrates both strategies. The aim of this study was to predict Fusarium wilt suppression of growth media using abiotic and biotic variables. Grape marc compost was the most effective medium used to suppress Fusarium wilt. Cork compost was intermediate, and light peat and expanded vermiculite were the most conducive growth media. The growth media evaluated were in a pH range of 6.26 to 7.97. Both composts had high beta-glucosidase activity. When pH and beta-glucosidase activity were taken into account as predictive variables, more than 91% of the variation in severity of Fusarium wilt was explained. This relationship illustrates the effect of nutrient availability and the degree of microbiostasis, two key factors in this pathosystem. Microbial populations involved in suppressiveness were cellulolytic and oligotrophic actinomycetes, fungi, and the ratios cellulolytic actinomycetes/cellulolytic bacteria, oligotrophic bacteria/copiotrophic bacteria, and oligotrophic actinomycetes/oligotrophic bacteria. Based on community level physiological profiles, different community structures were evident among growth media evaluated.

La antiguedad de la sifilis en el Perú

Hagamos una disección de la enfermedad en sus más salientes e importantes atributos con el fin de cerciorarnos de su existencia entre las lenguas, creencias religiosas, costumbres y supersticiones de los antiguos peruanos, y lo que es de mayor interes aún, en las numerosas osamentas y huacos que guardan sus habitaciones y tumbas, así como para ser más claros y proceder con orden en el curso de esta disertación, procurando desde luego conservar la unidad de la sifilis en sus tan múltiples y variadas manifestaciones. Proponiendose las siguientes proposiciones: Sinonimia de la sifilis, causas que predisponen al contagio, accidente primario de la sifilis, las sifilis cutáneas del período secundario, las sifilis gomosas, la sifilis ósea. Luego del estudio se llega a las conclusiones: El estudio social ha podido favorecer la propagación de una enfermedad como la sifilis, sin que en esto el Perú antiguo haya hecho excepción a los demás pueblos de la tierra. En tiempo de los Incas aparecio o recrudeció una epidemia en la que fue lo más saltante la manifestación exantemica, siendo con toda probabilidad la sifilis la que desempeña el papel principal. Entre las dermatosis consideradas como autóctonas del Perú, la sifilis entre frecuentemente en la etiología de ellas, y las mutilaciones observadas en los huacos pueden atribuirse a esta enfermedad. Las lesiones patológicas observadas en craneos provenientes de antiquisimas tumbas y habitaciones de los peruanos, parecen ser debidas a la sifilis.