Efficacy of fungicides for the control of early blight caused by Alternaria solani and Alternaria alternata. Updated 4 December 2020. Responsible authors: Bert Evenhuis (WUR), Peter Hartvig (AU), Hans Hausladen (TUM)
The EuroBlight Table to rate the efficacy of crop protection products has changed. The protocol for the EuroBlight trials was evaluated in the Alternaria sub-group meeting in Munich. Changes were proposed for the assessments and consequently the ratings. This was discussed in the EuroBlight meeting in York. The outcome was that a few adaptations were to be made to the protocol and rating calculations:
In York it was agreed that the strategies programs and their efficacy ratings were to be removed from the early blight fungicide table
In the efficacy ratings trials, the early blight test fungicides should be applied only until the percentage of early blight reaches 10 to 15% in the EB-untreated control.
Weekly disease assessments should continue until desiccation but only those made up to 4 weeks after the last application of the test fungicides will be included in the calculation of ratings.
A field experiment can be used for calculating a rating if the early blight disease severity in the untreated control will be at least 10-15% at the last disease assessment.
1: Ratings for early blight control are based on results from EuroBlight field trials during 2015-2019, and only compounds included in these trials are rated for Alternaria. The scale for Alternaria is a 0-5 scale (see technical report to be uploaded soon). 2: The ratings are intended as a guide only and will be amended in future if new information becomes available. 3: Alternaria solani isolates that are less sensitive to QoI-fungicides have been isolated from potato plants in Europe. Therefore resistance management strategies should be implemented (see FRAC web site for details). Rating will be lower where strains with reduced fungicide sensitivity are present.
Disclaimer: Whilst every effort has been made to ensure that the information is accurate, no liability can be accepted for any error or omission in the content of the table or for any loss, damage or other accident arising from the use of the fungicides listed herein. Omission of a fungicide does not necessarily mean that it is not approved for use within one or more EU countries. The ratings are based on the label recommendation for a particular product. Where the disease pressure is low, intervals between spray applications may be extended and, in some countries, fungicide applications are made in response to nationally issued spray warnings and/or Decision Support Systems. It is essential therefore to follow the instructions given on the approved label of a particular early blight fungicide appropriate to the country of use before handling, storing or using any early blight fungicide or other crop protection product.