Powdery Mildew update December 2014

Collecting powdery mildew samples

From March until July 2014 leaf samples have been collected from cereal crops, grasses and other plant species affected by powdery mildews. 504 leaf samples were collected in the Netherlands, Northeast, Central and Western Germany and Southern Sweden. The samples were collected by the BIOCOMES partners Wageningen UR (the Netherlands), Agro Plantarum (Sweden) and Bayer CropScience Biologics GmbH (Germany). From the leaf samples 1.237 cultures of fungal isolates have been obtained. On the picture on the right the number of isolates per location.

The fungal isolates originated from different hosts:

  • Grasses (39%)
  • Wheat (21%)
  • Other cereals (7%)
  • Trees (4%)
  • Herbal plants (29%)

The isolates from grasses, wheat and other cereals were found in pustules of the powdery mildew fungus Blumeria graminis. Isolates from trees and herbal plants originated from other species causing powdery mildew.

Species: searching and testing

All isolates will be screened by Wageningen UR in rapid throughput systems.Selection criteria for this pre-screening are: mass production, safety, cold and drought tolerance and UV-B resistance. At the end of October 2014 495 isolates had been tested and a first set of 91 isolates have been identified by ITS sequences.

The next step consists of risk assessments per identified species. A bioassay for an antagonist efficacy screening is under development and will be used to determine the biological activity. Also the potential of isolates for mass production will be tested. The risk assessments will be performed by BIOCOMES partner GAB Consulting GmbH in Germany.

Read more about our activities on powdery mildew


Jürgen Köhl
Jürgen Köhl
Powdery mildew in cereals