Control of foliar fungal disease in carrots with plant extracts

Carrot diseases caused by Alternaria species remain among the most important reasons for yield and quality losses. Over the last several decades, chemical treatment has been a potent approach toward disease control, and chemical fungicides added further possibilities. Considering the European Commission’s strategy and commitments to reduce the use of pesticides by 2030, chemical fungicides replacement or plant protection supplementation with natural compounds would decrease problems of pathogen resistance and contamination of the environment. The antifungal effect of plant extracts on various fungal pathogens suppression in vitro has been demonstrated in previous studies. This study aimed to investigate plant extracts’ influence on reducing Alternaria spp. caused diseases spread in field conditions. Additionally, yield changes were evaluated. Field trials were conducted at the experimental fields of the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry, in 2021 and 2022. Experimental treatments were: thyme essential oil, clove extract, and clove mixed with laurel extract. The control without essential oil and extract treatment was used for results comparison. Applied essential oil and extracts suppressed disease spread in the carrot field. A higher yield was obtained in all treatments compared with the untreated carrots. The most significant results were with a mixture of clove and laurel extracts. The obtained research results would potentially provide more knowledge about alternative and sustainable plant protection measures and their integration into traditional plant protection schemes.