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  • Author: Halina Kurzawińska x
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Małgorzata Nadziakiewicz, Halina Kurzawińska, Stanisław Mazur and Dorota Tekielska

Abstract

Symptoms of discoloration and necrosis of the leaves/needles and shoots of plants are an increasingly common phenomenon in nurseries. They necessitate the withdrawal of the affected plants from sale, which has significant economic consequences. In 2010-2011, observations were conducted of the health of shrubs in nurseries of the Małopolska province. Disease symptoms were mostly found in juniper (Juniperus horizontalis ‘Wiltonii’), rose (ground-cover rose ‘Star Profusion’), yew (Taxus × media ‘Hillii’) and highbush blueberry (Vaccinium corymbosum ‘Patriot’). These species were selected for further study. The affected shrubs represented more than 46% of the population of a given species. Fragments of the diseased organs: the leaves or needles, the base of the shoots, and the roots, were collected from the borderline between healthy and diseased tissue, and used to isolate and identify the microorganisms colonizing the diseased parts. The affected organs were found to be inhabited to the largest extent by the fungus Alternaria alternata (Fr.) Keissl., which accounted for 19.7 to 47.5% of the isolates from the tested species of shrubs. There were also large populations of fungi of the genera: Botrytis (up to 9.82%), Cladosporium (up to 5.66%), Colletotrichum (up to 5.13%), Fusarium (up to 18.38%), Mortierella (up to 7.26%), Pestalotia (up to 5.36%), Rhizoctonia (up to 5.36%), Sclerotinia (up to 6.99%), and Trichoderma (up to 17.09%). The fungus A. alternata, being by far the dominant pathogen, was tested for its pathogenicity for the shoots of the chosen species of shrubs. The test was conducted for 14 days in a chamber with parameters so programmed that they reflected the natural conditions at the height of the growing season. The fungus A. alternata exhibited pathogenicity for all of the tested species of shrubs. Necrosis developed on all the inoculated fragments of shoots. The surface area of necrotic lesions was larger on the shoots of juniper and blueberry.

Open access

Halina Kurzawińska and Mazur Stanisław

Abstract

The effect of tuber dressing and plant spraying with Polyversum (B.A.S. Pythium oligandrum) and Biochikol 020 PC (B.A.S. chitosan) bio-preparations on the infestation of potatoe tubers by Streptomyces spp. was studied during the 2005-2007 years. The Vitavax 2000 FS (B.A.S. karboxin and thiuram) was used as a standard fungicide.

The results received from field experiments indicate that, during all years of study these preparations significantly reduced tubers infestation by Streptomyces spp. The Polyversum bio-preparation, which was applied to tuber dressing and sprayed on plants four times during vegetation period, showed the best protective effect against Streptomyces spp.

Open access

Halina Kurzawińska and Stanisław Mazur

Abstract

The studies were carried out both in in vitro and in vivo conditions. The field experiment was conducted during the years 2005-2007 at the Experimental Station in Mydlniki, owned by the Department of Plant Protection at the University of Agriculture in Krakow. The aim of these studies was to determine the effect of tuber dressing and plant spraying with Polyversum (B.A.S. Pythium oligandrum) and Biochikol 020 PC (B.A.S. chitosan) bio-preparations on the top leaves and tubers of ‘Ibis’ potatoes infested by Phytophthora infestans. The chemical preparation Vitavax 2000 FS (B.A.S. karboxin and thiuram) was used. The in vitro evaluation of Polyversum and Biochikol 020 PC bio-preparations on the P. infestans mycelium linear growth was investigated. The above-mentioned preparations were applied at three different concentrations. The experiment was carried out using the Kowalik and Krechniak method (1961). Based on the results it was found that the preparations under examination significantly inhibited top leaf and tuber infestation by Phytophthora infestans. Moreover, according to the results obtained from in vitro tests, a significant effect from the Vitavax 2000 FS and Polyversum preparations and from the highest concentration (2%) of Biochikol 020 PC preparation on the percentage inhibition of P. infestans mycelium linear growth was observed (in comparison to the control).

Open access

Halina Kurzawińska and Stanisław Mazur

Abstract

The effect of tuber dressing and plant spraying with Biochikol 020 PC (B.A.S. chitosan) and with Polyversum bio-preparation (B.A.S. Pythium oligandrum) on the infestation of stored tubers by Helminthosporium solani was studied. Vitavax 2000 FS (B.A.S. karboxin and thiuram) was used as a standard fungicide. The effect of these preparations applied at three different concentrations on H. solani mycelium linear growth was investigated under in vitro conditions according to the Kowalik and Krechniak method (1961). The application of all tested preparations during potato vegetation resulted in both lower (in comparison to the control) mean infestation degree and lower percent of tubers infected by this pathogen. Results showed that all preparations inhibited H. solani mycelium linear growth.