Sodium nitrophenolates as a potential tool for the management of grapevine trunk diseases

Fungal trunk diseases represent a major constraint on the production of grapevine and other perennial crops, while effective curative control methods remain limited. This study evaluated the antifungal and defence-modulating effects of the sodium nitrophenolate based product Atonik against selected fungi associated with trunk diseases. In vitro efficacy was tested against ten fungal pathogens, and its effect against Eutypa lata was further evaluated in grapevine under in planta conditions. Atonik inhibited mycelial growth in a pathogen and concentration dependent manner, with the strongest effects at the highest tested concentration observed against Cadophora luteo-olivacea, E. lata, and Phaeoacremonium minimum. In grapevine, E. lata caused a mean lesion length of 48.38 mm, whereas Atonik treatment reduced it to 12.29 mm. Absolute qPCR indicated higher VvSOD transcript abundance in treated plants. RNA-seq analysis identified 168 genes associated with infection and 43 genes associated with treatment. The results suggest that sodium nitrophenolates may reduce wood necrosis caused by E. lata through a combination of direct antifungal activity and modulation of grapevine defence responses.