Update of the EuroBlight fungicide efficacy tables

EuroBlight, the European network of scientists and other specialists working on potato early and late blight, has updated its fungicide efficacy tables for the control of late blight and early blight ahead of the 2018 field season.
 

Early blight
 

Recently the first fungicide decimal ratings for the control of early blight, calculated from the results of dedicated experiments with a standard protocol and therefore entirely objective, were published in the early blight table. The six experiments were conducted in Denmark (Bent Nielsen), Germany (Hans Hausladen) and the Netherlands (Bert Evenhuis & Huub Schepers) in 2015 and 2016. These new ratings replaced the previous ones that were partially subjective.
 

Late blight          
 

EuroBlight fungicide efficacy table
 

Ratings for the control of potato late blight and tuber blight are based on unbiased EuroBlight trials carried out over multiple years and at multiple locations in Europe. Ratings for all other characteristics are based upon the expert knowledge of EuroBlight members.
 

Multiple years and locations
 

To evaluate the effectiveness of fungicides, harmonized protocols were used. The ratings of fungicides for late blight control for the EuroBlight table were calculated after field experiments have been carried out over at least two years in three European countries. Each year from 2006 to 2017, at least three foliar blight experiments were carried out in Denmark (Bent Nielsen), Germany (Hans Hausladen), the Netherlands (Bert Evenhuis & Huub Schepers) and the United Kingdom (Ruairidh Bain). In total, 37 field experiments were set up to compare the fungicides’ effectiveness against foliar late blight. Foliar protection resulting from the application of a fungicide in a standard 7-day spray schedule (which did not necessarily correspond with the label recommendations) was measured. Protection against disease originates from the protectant and/or curative properties of the active ingredients. In addition, during the rapid growth phase of the crop, protection of new growth can also contribute to the effectiveness of the fungicide for foliar blight control. Dose rates used were the highest preventative doses registered in Europe. The results of the trials were used to evaluate the effectiveness of fungicides to control potato late blight. Details can be found in the EuroBlight report on the EuroBlight website:
 

Fungicide evaluation to rate efficacy to control leaf late blight for the EuroBlight table
 

Ratings
 

The ratings of the other characteristics were decided by the EuroBlight experts (independent scientists) using available data (provided by the crop protection industry or already in the possession of the EuroBlight fungicide experts). The characteristics rated this way were:
 

• Protection of new growth: the ratings for the protection of new growth indicate the protection of new foliage due to the systemic or translaminar movement or the redistribution of a contact fungicide. New growth consists of the growth and development of leaves present at the time of the last fungicide application and/or newly formed leaflets and leaves that were not present.

• Protection of stems: effective control of stem infection by either direct contact or via locally systemic activity.

• Mode of action:

Protectant: spores killed before or upon germination/penetration. The fungicide has to be present on/in the leaf/stem surface before spore germination/penetration occurs

Curative: the fungicide is active against P. infestans during the immediate post-infection period but before symptoms become visible

Anti-sporulant: P. infestans lesions are affected by the fungicide decreasing sporangiophore formation and/or decreasing the viability of the sporangia formed.
• Rainfastness: a fungicide is considered rainfast after application if it has adequately dried or has been absorbed by plant tissues so that it will still be effective after rainfall or irrigation.     

• Mobility in the plant: contact, translaminar or systemic.

• Year of introduction: the year the fungicide was introduced in Europe.
 

The EuroBlight late blight and early blight fungicide rating tables are widely accepted as the standard within Europe and beyond by independent scientists and fungicide producers. The ratings are invaluable for consultants and decision support users in controlling these two very important diseases of  potato  in Europe.