Studies on the generative reproduction of grapevine powdery mildew (<i>Uncinula necator</i> BERK.)

Authors

  • H. J. Diehl
  • Catherine Heintz

DOI:

https://doi.org/10.5073/vitis.1987.26.114-122

Keywords:

oidium, sexuality, growth, irradiation, temperature, water, resistance, variety of vine, morphology

Abstract

Morphology and factors influencing the development of Uncinula necator fruit bodies were studied.
The resistance levels of hostplants and the amount of cleistothecia on their leaves were significantly correlated under field conditions.
The number of cleistothecia was about 80 % lower on greenhouse plants than on field-grown vines with similar susceptibility.
An UV irradiation (2 h) did not induce the opening of the cleistothecia after cold storage, neither did light or darkness. A longer UV treatment (5 h), however, decreased the percentage of open cleistothecia.
Liquid water was essential for the opening process. An atmosphere with a 100 % relative humidity was not sufficient.
The fruit bodies opened readily at +22 °C, but not at +5 °C and below.
Cleistothecia contained up to 6 asci with an average content of 6 ascospores. About 50 % of the ascospores had still their full vitality after 6-weeks cold storage.

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Published

2015-12-16

Issue

Vol. 26 No. 2 (1987): VITIS

Section

Article

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