Effect of Hot Water Treatments on Eradication of «Phaeomoniella chlamydospora» and «Phaeoacremonium inflatipes» from Dmant Grapevine Wood

Abstract

Hot water treatments were applied to eradicate Phaeoacremonium inflatipes and Phaeomoniella chlamydospora from dormant grapevine wood. A thirty-minute hot water treatment at 51°C did not eliminate these pathogens from dormant wood cuttings. Cuttings first inoculated with Pa. chlamydospora or Pm. inflatipes or both fungi, and then subjected to a hot water treatment were either incubated in crispers, or planted for six to eight weeks. Vascular discoloration was scored followed by isolation from the cuttings onto potato dextrose agar amended with 0.1 g l-1 tetracycline (PDA-tet). Isolations confirmed the presence of the pathogens in the inoculated, hot-water treated cuttings as well as in the inoculated, untreated control cuttings. This finding, along with earlier research on the direct effect of hot water on the mycelium of these species, leads to the conclusion that hot water treatments are ineffective in eliminating vine decline pathogens from dormant wood.