Inoculation methods, aggressiveness of isolates and resistance of peach palm progenies to Phytophthora palmivora

ABSTRACT Stem base rot (SBR) caused by Phytophthora palmivora is the main disease affecting peach palm in the nursery and in the field. This study aimed to: a) determine the most appropriate method for P. palmivora inoculation in peach palm; b) assess the aggressiveness of P. palmivora isolates; c) evaluate the resistance of peach palm progenies to P. palmivora. Experiments were carried out at “Embrapa Florestas” from March 2011 to March 2012. A descriptive rating scale was developed to assess SBR severity in peach palm. The disease severity was evaluated 7, 14, 21 and 28 days after inoculation. The conclusions were: a) injection at the stem base was the most effective method for P. palmivora inoculation; b) SA-5, SA-9, SA-10, SA-11, SA-14, SA-15, SA-16, SA-30 and SA-31 were the most aggressive P. palmivora isolates; and c) peach palm progenies T2, T4, T7, T9 and T15 showed resistance to P. palmivora.