Chemical Management


Fungicides are pesticides that kill or prevent the growth of fungi and their spores. They can be used to control fungi that damage plants, including rusts, mildews and blights, but they are not without side effects (U.N. May 2019 report on devastating effect of chemicals on crops).

Respect of the microbiology of soil is key component of a healthy growth of cultures as much as preventing soil contamination. Therefore fungicide/pesticides should be apply wisely. Before using chemical products make sure to have followed all the non-chemical management approach to prevent disease.

Fungicides work in a variety of ways, but most of them damage fungal cell membranes or interfere with energy production within fungal cells.

Fungicides for Phytophtora Infestans are classified by their mobility in the plant:

Contact fungicide also called “preventive or protective”: the fungicide remains on the surface where it is applied but does not go deeper; these fungicides have no after-infection activity. Repeated applications are needed to protect new growth of the plant and to replace material that has been washed off by rain or irrigation. The fungicide is applied on the plant as a protective barrier before the pathogen arrives or begins to develop so that it prevents infection from occurring.

Systemic fungicide: the fungicide is absorbed into plant tissue and may offer some after-infection activity. Very few fungicides are truly systemic some are locally systemic (i.e., move into treated leaves and redistribute to some degree within the treated portion of the plant).

Translaminar fungicide: move through the leaf from one side to the other.

Fungicide are also classified through their chemical group.

Field where treatment with fungicide was forgotten by tractor, Harbin, China 2010
Four applications of the wrong fungicide at the wrong time, Luliang, autumn potato, October 2018, Yunnan

The picture below by W.Perez and G.Forbes present an integrated late blight management.

Chemical classification of pepticides against Late Blight. (Forbes&Wilmer, Late Blight manual, CIP collection)

EuroBlight Fungicide Table

EuroBlight evaluate the effectiveness of fungicide products/co-formulations for the control of P. infestans based on the highest rate registered in Europe. These ratings are the opinion of the Fungicides Sub-Group, and are based on field experiments and experience of the products performance when used in commercial conditions.

Go to table


Sponsor XXX

To become a sponsor and have your logo here send e-mail to: