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Number of results: 5
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Abstract

The shipment of cut flowers from Colombia and Ecuador to the United States, the biggest importer of this product in the world, has doubled in the last 20 years. One of the main constraints in cut roses production is the gray mold disease caused by the fungus Botrytis cinerea, which can destroy the flowers, in the crop, during storage and/or shipping. Since the resistance of the fungus to conventional fungicides has been increasing, as well as the health effects in rose growers, alternative approaches for controlling the disease are needed. The effect of UV-C light on the gray mold development in cut roses was studied. Irradiation with 2,160; 1,080 and 540 J ⋅ m–2 UV-C, every 24 h for 5 days in a humid chamber, did not harm the roses. Instead, as seen by image analysis, a highly significant reduction of the area of the lesions by the disease and of the fungus germination was obtained at 1,080 J ⋅ m–2. The addition of a 4-h dark period to the irradiation did not improve the effect of UV-C on the disease. The results of this work potentiate the use of UV-C light in the agro-industry as a low-cost and non-invasive alternative method to control diseases. They also reflect the application of optical approaches as image analysis in the evaluation of important agricultural features.

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Authors and Affiliations

Katherine Vega
Samuel Ochoa
Luis F. Patiño
Jorge A. Herrera-Ramírez
Jorge A. Gómez
Jairo C. Quijano
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Abstract

Saprol 190 EC (triforine) and Rubigan 12 EC (fenarimol) diluted in 6 types of water were applied against rose rust Phragmidium mucronatum Cooke. No adjuvants were added to the emulsion except when the spray mix was made using water from Poznań prepared in 2 variants: with an addition of Citowett AL and without it. Independently on the plant protection product type, efficacy of fungicides diluted in well water from Szczepankowo, Kościan or Śmigiel was better than when they were diluted in water after reversed osmosis. However, no type of water exerted any significant effect on efficacy of the investigated fungicides independently on the year of studies, although, in 1999, a better biological activity was shown by Rubigan 12 EC diluted in water from Kościan and Poznań than when they were diluted in water after reversed osmosis. The fungicides were most effective after addition of Citowett AL, however, a visible effect of this adjuvant showing increased rose protection against rose rust was found only in 1998.

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Authors and Affiliations

Henryk Ratajkiewicz
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Abstract

Interest in growing roses in Poland is related to the production of cut flowers as ornamentals and of petals and hips for cosmetics or food products. However, recently there has been an increasing number of reports of pest damage on rose plantations. In the case of fruits the damage has been attributed to flies (Rhagoletis alternata) or moths (Cydia tenebrosana), while nematodes have been implicated for growth reduction even on plantations grown under soil-less conditions. Field trials and laboratory experiments to test the possibility of controlling R. alternata larvae or pupae with entomopathogenic fungi and nematodes resulted in a lack of parasitism. On the other hand, the use of Bacillus thuringiensis subsp. kurstaki or Cydia pomonella granulovirus effectively controlled C. tenebrosana. Meloidogyne incognita infestation of roses growing on rock wool substrate was drastically reduced by Arthrobothrys oligospora or abamectin. Factors such as the method of product application or pest susceptibility to the used microbial-based products accounted for the observed differences in efficacy.

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Authors and Affiliations

Eligio Malusá
Malgorzata Tartanus
Grażyna Soika
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Abstract

J.L. Hindmarsh, R.M. Rose introduced the concept of neuronal burst. In this paper, synchronization is investigated for the construction of a model of neuronal burst using backstepping control with recursive feedback. Synchronization for a model of neuronal bursting system is established using Lyapunov stability theory. The backstepping scheme is a recursive procedure that links the choice of a Lyapunov function with the design of a controller. The backstepping control method is effective and convenient to synchronize identical systems. Numerical simulations are furnished to illustrate and validate the synchronization result derived in this paper.

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Authors and Affiliations

Suresh Rasappan
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Abstract

We determined the level of flavonoids, citric acid and ascorbic acid in hips of rose species from the Caninae section occurring in Poland. We performed phytochemical analyses of 75 samples representing 11 species: Rosaagrestis Savi, R. canina L., R. dumalis Bechst., R. glauca Pourret, R. inodora Fries, R. jundzillii Besser, R. rubiginosa L., R. sherardii Davies, R. tomentosa Sm., R. villosa L. and R. zalana Wiesb. Flavonoid content was determined spectrophotometrically, and organic acid concentrations by HPLC. The content of the studied compounds varied greatly. Interspecific differences in the amount of flavonoids and ascorbic acid were highly significant. The most common species, Rosa canina, showed low average content of vitamin C (0.51 g/100 g of dry matter) and flavonoids (41 mg/100 g DM) and high content of citric acid (3.48 g/100 g DM). Ascorbic acid was highest in R. villosa hips (avg. 2.25 g/100 g DM), flavonoids were highest in R. rubiginosa (72 mg/100 g DM), and citric acid was highest in R. tomentosa (4.34 g/100 g DM). Flavonoid level correlated negatively with the amount of citric acid (r=-0.47, p<0.001). Cluster analysis of rose species based on the content of the investigated compounds confirmed the validity of the division of sect. Caninae into three subsections: Rubiginosae, Vestitae and Rubrifoliae. The phytochemical variation of these roses reflects their probable phylogenetic relationships as determined from morphology.

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Authors and Affiliations

Artur Adamczak
Waldemar Buchwald
Jerzy Zieliński
Sebastian Mielcarek

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