Grape downy mildew in India <p>I. Foliar, floral and fruit infections</p>
DOI:
https://doi.org/10.5073/vitis.1976.15.113-120Abstract
The incidence and intensity of downy mildew on "Anab-e-Shahi" grapevine were recorded on leaves of six ages as indicated by colours. Red and green with orange leaves did not show symptoms of the disease. The rate of disease development was highest in agathia-green and viridian-green leaves. The time taken for reaching grade 3 from grade 2 was shorter than the time taken for development to grade 2 from grade 1. The incubation periods were 18 and 14 days in red and green with orange leaves, respectively. But in older leaves it was only 10 days. In leaves of all colours the stomatal pore was broader than the width of the germ tube of the pathogen. Upon artificial inoculation inflorescences as weil as clusters with mustard seed-sized (2.00 mm) and pea-sized (6.5 mm) berries became infected whereas older bunches with neem-sized (12.5 mm) and mature berries were not infected. Complete shed of infected flowers and mustard seed-sized berries and a drop of 53.1 per cent of pea-sized berries were noticed.
Der falsche Rebenmehltau in Indien
I. Befall von Blättern, Blüten und Beeren
Bei der Rebensorte Anab-e-Shahi wurden Auftreten und Intensität des Befalls durch Plasmopara viticola an sechs durch ihre Färbung gekennzeichneten Blattstadien verfolgt. Rote und grün-orange gefärbte Blätter zeigten keine Krankheitssymptome. Agathia- und chromgrüne Blätter erkrankten am häufigsten. Der Übergang von Parasitierungsgrad 1 nach 2 dauerte länger als von 2 nach 3 (1 = bis zu 25%, 2 = 26-50%, 3 = über 50% der Blattfläche von Myzel bedeckt). Bei den roten und grün-orange gefärbten Blättern betrug die Inkubationszeit 18 bzw. 14 Tage, bei älteren Blättern dagegen nur noch 10 Tage. Die Weite der Spaltöffnungen war bei allen Blattstadien größer als der Durchmesser des Sporenkeimschlauches. Nach künstlicher Infektion wurden sowohl Infloreszenzen wie Trauben mit 2,0 mm und 6,5 mm großen Beeren befallen, während ältere Trauben mit 12,5 mm großen sowie mit reifen Beeren nicht erkrankten. Infizierte Blüten verrieselten vollständig; bei einer Größe von 2,0 mm fielen 53,1% der Beeren ab.
Downloads
Published
Issue
Section
License
The content of VITIS is published under a Creative Commons Attribution 4.0 license. Any user is free to share and adapt (remix, transform, build upon) the content as long as the original publication is attributed (authors, title, year, journal, issue, pages) and any changes to the original are clearly labeled. We do not prohibit or charge a fee for reuse of published content. The use of general descriptive names, trade names, trademarks, and so forth in any publication herein, even if not specifically indicated, does not imply that these names are not protected by the relevant laws and regulations. The submitting author agrees to these terms on behalf of all co-authors when submitting a manuscript. Please be aware that this license cannot be revoked. All authors retain the copyright on their work and are able to enter into separate, additional contractual arrangements.