Abstract
The growing demand for alternative plant protection products (PPP) that are more environmentally friendly leads to the investigation of novel approaches in agriculture. The use of plant extracts as PPP belongs to one of the most intensively investigated areas. This study aimed to evaluate if the partial substitution of conventional pesticides with selected botanicals (seaweed extract, orange essential oil, thyme essential oil, and a hop extract) will have the same protective effect against Phytophthora infestans as conventional potato treatment. The research was carried out in field conditions in two locations between 2019 and 2021. The impact of treatments on plant health status, relative chlorophyll content, and yield parameters was determined. The protective efficiency of selected natural substances (in concentrations from 0.125 to 1 %) was comparable to that of conventional fungicides. Moreover, their application reduced the use of traditional fungicides by 14-64 %, depending on the locality. In addition, the potato plants treated with the natural substances showed a higher overall and marketable tuber yield.