Studies on management of white root rot of apple caused by Dematophora necatrix

White root rot caused by Dematophora necatrix is an important disease in the nurseries as well as orchards of apple. Fifteen fungicides including 4 contact, 10 systemic and 1 combination product were evaluated against the mycelial growth of D. necatrix through poisoned food technique. Selected fungicides were tested for management of white root rot disease using seedling dip and drenching under pot and field conditions for 3 consecutive years. The result of the poisoned food technique revealed that propineb, mancozeb, carbendazim, propiconazole and tricyclazole completely inhibited the mycelial growth of D. necatrix. In seedling dip treatment, only two fungicides viz., carbendazim and propiconazole were effective against D. necatrix, while all infected plants treated with these fungicides survived. However, drenching with propineb, carbendazim and propiconazole were found to be effective in managing the white root rot of apple. Since carbendazim has been proposed to be banned by the Government of India and based on the cost-effectiveness of fungicides, propiconazole followed by propineb can be a cheaper and most effective alternative for the management of the white root rot of apple. Hence for eradication of D. necatrix from infected nursery plants dip treatment for 30 min with propiconazole [1 mL per liter (L) of water] can be recommended to the farmers. Also, for the treatment of white root rot infected trees, soil drenching with propiconazole (1 mL per L of water) and propineb (3 g per L of water) can be recommended. © 2022, Indian Phytopathological Society.