Poda del duraznero Prunus persica (L.) Batsch, dinámica de las enfermedades y calidad de cosecha

La provincia de Pamplona por sus condiciones ambientales ha crecido en cultivos de duraznero, marcando un renglón económico muy importante para muchas familias. El objetivo de esta investigación fue evaluar la influencia de diferentes momentos de poda del duraznero Prunus persica (L.) Batsch sobre la dinámica estacional de las principales enfermedades y la calidad de la cosecha en el municipio de Cácota. Para lograrlo, se tomaron parcelas con tres momentos de poda del cultivar Gran Jarillo, evaluándose el porcentaje de incidencia, severidad y el Área Bajo la Curva de Progreso de la Enfermedad (ABCPE) de las principales enfermedades del follaje y de los frutos. Los lotes se evaluaron por un periodo de 11 meses, teniendo en cuenta las condiciones ambientales de la finca. Al finalizar el ciclo productivo, se valoró la calidad de la cosecha a través de pruebas físicas como evaluación de apariencia, diámetros, peso de pulpa y semilla, firmeza y pruebas químicas como °Brix, pH y Acidez Total Titulable de los frutos. Para cada variable se realizó un análisis estadístico de comparación de medias para muestras no relacionadas según la prueba de Z (p<0,05), además al igual que para la evaluación de las enfermedades se utilizó el paquete estadístico SPSS 23. El resultado de la dinámica estacional de las enfermedades mostró que Taphrina deformans afecta principalmente las hojas y Sphaerotheca pannosa los frutos. Respecto a la calidad de la cosecha, para el momento de poda de enero las variables estudiadas presentaron los valores y características más ideales.

Features of phytosanitary condition of rose cultivars of miniature garden group of the collection of the Nikitsky Botanical Gardens

The objective of the research is the identification of dominant species of phytophagans and the determination of species composition of causative agents of phytopathogenic diseases of garden group of miniature rose cultivars. Methods of research . Species composition of pests was studied by visual inspection of generative and vegetative organs 1 time in 7-10 days. Samples of affections were analyzed under a binocular microscope in the laboratory. The frequency of pests’ occurrence was determined on a 3-point scale. The assessment of garden roses infestation with fungal diseases was carried out on a natural infectious background on a 5-point scale. Results and discussions. The study was performed on 49 cultivars, of which 46 were introduced species, 3 cultivars were of breeding of the Nikitsky Gardens. As a result of the research, three species of phytophagans belonging to three orders of the class Insecta - Homoptera , Lepidoptera Acarina were revealed. Green rose aphid (Macrosiphum rosae L.), rose moth (Archips rosana L.), twospotted spider mite (Tetranychus urticae Koch) were most commonly observed during the growing season. In 2016, the focus of reproduction of an invasive species - cattony cushion scale (Icerya purchasi Maskell) was found for the first time on the cultivar of the miniature group Rouletii. The species composition of pathogens of phytopathogenic diseases was identified, the most harmful of which are: powdery mildew (Sphaerotheca pannosa (Wallr)). Lev.), black spot (Marsonina rosae (Lib.) Died, rust (Phragmidium tuberculosis J.). Conclusion. The cultivars that are resistant to fungal diseases mainly dominated in the garden group of miniature roses. For the stable expression of this feature, it is necessary to create optimal conditions for cultivation: the use of preventive sprays with biological preparations or low-risk pesticides and compliance with the regime of agricultural activities. On the base of complex cultivar study, cultivar evaluation and phytosanitary evaluation of roses of the miniature garden group of the Nikitsky Botanical Gardens’ collection, an assortment for flower decoration was developed, including 46 cultivars for group planting, which can be recommended for landscaping parks, squares, streets in the populated areas of the Crimea.

Variedades mejoradas de durazno (Prunus pérsica L.)

En México, las variedades de durazno (Prunus pérsica L.) que se tienen de alta productividad, son de alto requerimiento de frío, y los que registran menor requerimiento de frío, tienen bajos niveles de producción y calidad, son poco precoces, y presentan frutos con alto potencial de oxidación, además de bajo contenido de sólidos solubles, baja firmeza y forma inadecuada de fruto (con punta y sutura pronunciadas). Los tipos criollos de durazno que se cultivan, presentan alta susceptibilidad a la cenicilla (Sphaerotheca pannosa Wall y Lev.), y se registran ataque en hojas y ramas tiernas. Las hojas infectadas pueden llegar a cubrirse con un micelio blanco y harinoso, además, de rizarse y atrofiarse, mientras que en el fruto, se presentan manchas circulares y blancas, observándose una necrosis y agrietamiento de la epidermis.

Chitosan in the control of rose powdery mildew and downy mildew

Microcrystalline chitosan at concentrations from 0.025% to 0.2% was evaluated in the control of Sphaerotheca pannosa var. rosae and Peronospora sparsa. Shrubs were sprayed with chitosan 4 times at weekly intervals. Depending on the concentration used, chitosan reduced development of powdery mildew from 43.5% to 77% and its effectiveness was similar to triforine at concentration 0.03% (standard). Observations of rose leaves under light microscopic, which had been done 24 h after spraying showed, that chitosan caused strong hyphae deformation which almost completely collapse. Cell walls of the pathogen were sunken, corrugated and longitudinally cracked. When applied against P. sparsa effectiveness of the compound at concentration 0.0625% was similar like oxadixil at dose 0.016% (standard) and ranged from 55% to 74%. Efficacy of chitosan decreased with increasing of its concentration.

Evaluation of bupirimate against rose powdery mildew

Bupirimate 25% Emulsifiable concentrate (EC) was evaluated for efficacy on Sphaerotheca pannosa, the causal agent of rose powdery mildew in vivo. In this experiment Bupirimate 25% EC 6 ml/L and 4 ml/L effectively reduced the powdery mildew infection over rest of the treatments and improved the flower yield. Moreover, application of Bupirimate 25% EC at the doses of 2, 4 and 6 ml/L and even at higher dose 8 ml/L did not show any phyto-toxic symptoms on rose plant. Thus, Bupirimate 25% EC may be considered as compared to other fungicides.