EN
In the years 2010-2011 at the Research Institute of Horticulture in Skierniewice the experiments with protection of lettuce against Botrytis cinerea and Bremia lactucae using natural products in open field and under cover were carried out. There were estimated the efficacy of studied products and their influence on marketable yield. In year 2010 in lettuce under cover in spring tillage the best efficacy against downy mildew and grey mould showed product containing Bacillus subtilis in concentration 1.3%. However in lettuce under cover in autumn tillage the best efficacy against B. cinerea and B. lactucae showed conventional product containing azoxystrobin. The product containing tea extract was effective only against downy mildew. In lettuce in open field in years 2010 and 2011, tested natural products showed high efficacy against grey mould and downy mildew. Only Phytium oligandrum showed low efficacy (26%).