During August 2005, wilted cucumber (Cucumis sativus cv. Tasty Green) plants were observed in a commercial greenhouse with a closed hydroponic system in the state of Mexico. Disease incidence was 50%. Diseased plants were detected 15 days after transplanting, when plants were overwatered. Yield was severely reduced when disease affected mature plants. Wilted plants showed basal stem lesions and root rot. Phytophthora capsici was consistently isolated from diseased tissue on corn meal agar (CMA) with tartaric acid. Oomycete identification was based on sporangial and gametangial characteristics (2). Sporangia produced on blocks of CMA at 25°C were spherical, broadly ellipsoid or obovoid with one papillae, and deciduous with a long pedicel (1). The isolates were heterothallic, and oogonia with amphigynous antheridia were observed in pairings with an A1 isolate of P. capsici, therefore, the isolates were determined to be an A2. Pathogenicity tests were conducted on 2-month-old cucumber seedlings under controlled conditions (25°C). Inoculation was performed by placing small pieces of agar with mycelium of 5- to 7-day-old cultures on the stem base and wrapping with Parafilm. Control plants were inoculated with CMA agar. No symptoms were observed on the control. Plants inoculated with the P. capsici isolated from the diseased cucumbers showed a basal stem lesion, followed by wilting and death 7 to 14 days after inoculation. The isolate was also pathogenic on tomato and eggplant that were grown at the same time in the commercial greenhouse sharing the nutrient solution. P. capsici sporangia were observed on the roots of both hosts. To our knowledge, this is the first report of P. capsici affecting cucumber in a hydroponics system in Mexico. References: (1) M. Aragaki and J. Y. Uchida. Mycologia 93:137, 2001. (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul MN, 1996.

lisianthus (Eustoma grandiflorum [Raf.] Shinn) es una especie ornamental que ha cobrado relevancia internacional en la última década. No obstante, a pesar de ser originaria de México, en el país no se ha detonado su cultivo, el cual podría representar una alternativa para consolidar la floricultura nacional. Con el objetivo de contribuir al conocimiento del lisianthus, en esta revisión se presentan aspectos relacionados con su origen, clasificación y descripción botánica, importancia económica e investigación destacada que se realiza en esta especie.

The effects of three fertilization methods (FM) using the Peters Professional® 30N-10P-10K water soluble fertilizer were analyzed: fertilization in irrigation water (FIW), foliar fertilization (FF), and their combination (FIW + FF), as well as two substrate particle sizes (SuPS): larger particle size (LPS) and smaller particle size (SPS), on the growth and macronutrient status of Laelia anceps subsp. anceps (Orchidaceae). A 3 × 2 factorial experiment was established. Aerial and root growth, dry weight and concentration of macronutrients N, P, K, Ca, and Mg in leaves, pseudobulbs, and roots were all evaluated. The interaction of the study factors resulted in a greater number of leaves, while by simple effects, greater leaf area, number of pseudobulbs, root volume, and dry matter of leaves and roots were obtained, when FIW and LPS were used. With FF, greater growth in root volume was observed. There were no differences in the concentration of N in the growth organs analyzed, but due to the interaction of factors, a higher concentration of P, K, Mg, and S was observed in roots, mainly with FIW + FF and SPS; although for P, there was a higher concentration in FIW and LPS. In the case of SPS, the concentrations of K and S were higher in leaves, and in pseudobulbs P, K, Ca, Mg, and S were higher. The results showed that there are positive effects on plant growth when FIW and LPS are used, while higher concentrations of nutrients in leaves, pseudobulbs and mainly in roots are observed when using SPS.

<p>No se ha reportado la presencia de ambos tipos de compatibilidad de especies de Phytophthora en plantas hospedantes sembradas en una misma maceta en viveros comerciales de México. En 2015, se colectaron aislados de <em>Phytophthora</em> en viveros comerciales en la Ciudad de México y en el estado de Morelos. Se detectaron los tipos de compatibilidad A1 y A2 de <em>Phytophthora capsici</em> y <em>P. drechsleri</em> en plantas marchitas de <em>Capsicum annuum</em> (tallos) y <em>Petunia x hybrida</em> (rizósfera), respectivamente. Los aislados de <em>Phytophthora</em> coinoculados <em>in planta</em> formaron oosporas en condiciones de invernadero. <em>Phytophthora</em> fue re-aislada de plantas inoculadas e identificada mediante herramientas morfológicas y moleculares. Los tipos de compatibilidad A1 y A2 de <em>Phytophthora capsici</em> y <em>P. drechsleri</em> se presentan simultáneamente en plantas de invernadero, lo cual sugiere que están ocurriendo recombinación sexual y variación genética. Los tipos de compatibilidad A1 y A2 de <em>Phytophthora capsici</em> y <em>Phytophtora dechsleri</em> fueron detectados por primera vez en <em>Capsicum annuum</em> y <em>Petunia x hybrida</em> respectivamente, en viveros mexicanos.</p>

Objective: To induce in vitro flowering of vanilla (Vanilla planifolia) with different plant growth regulators (PGRs) using the double-layer technique. Design/methodology/approach: A layer of semi-solid Knudson C (KC) medium, added with 40 g L-1 sucrose, 15% coconut water (CW; v/v) and 7 g L-1 agar, was placed in 100 mL flasks. A liquid layer of the same composition without agar was placed on top. It was supplemented with different doses (mg L-1) of PGRs: 6-benzyladenine (BA) (7), thidiazuron (TDZ) (6), paclobutrazol (PBZ) (0.5) and gibberellic acid (AG3) (2). Plus two controls, C1: no PGRs + no CW; C2: no PGRs + CW. Vanilla shoots of 2 cm in length and with at least one axillary shoot were placed. They were incubated at a temperature of 26±2 °C day and 18 °C darkness, with light intensity of 55 µmol m-2 s-1 during 13 weeks. The number of shoots, leaves and roots was evaluated, as well as the length of shoots and fresh weight. Floral differentiation was evaluated at the tenth week by conventional microtechnique. Results: The number shoots and leaves and shoot length were significantly higher in C2. The number of roots increased with PBZ 0.5 mgL-1. C1 and C2 promoted higher fresh weight. Floral differentiation was observed with AG3 2 and PBZ 0.5 mg L-1 treatments. Limitations on study/implications: Further evaluation of other PGR doses and environmental conditions is required to achieve full floral differentiation of vanilla. Findings/conclusions: CW increased vegetative growth. AG3 and PBZ showed early floral differentiation in Vanilla planifolia, which is the first report of this phenomenon for the species.