Testing resistance of rootstock materials for managing Armillaria root disease in peach orchards of Mexico

Abstract

Armillaria mexicana and/or A. mellea cause Armillaria root disease that results in mortality of peach (Prunus persica) trees in orchards of the Mexican sub-tropics. Resistance/susceptibility reactions to A. mexicana and A. mellea were evaluated for three Prunus rootstocks under greenhouse and field conditions. For greenhouse tests, independent inoculations of A. mexicana and A. mellea were conducted on 14 trees for each of three rootstocks: P. persica × P. davidiana ‘Nemaguard’, P. persica landrace ‘Criollos of La Goleta’ genotypes, and P. salicina Japanese plum ‘Mondragon’, with four non-inoculated trees serving as controls for each rootstock. For greenhouse inoculations with A. mexicana, ‘Criollos of La Goleta’ and ‘Nemaguard’ rootstocks showed the highest incidence of infected roots (21.6% and 24.6%, respectively). In contrast, ‘Mondragon’ showed the lowest (2.5%) incidence of infected roots. Although ‘Criollos of La Goleta’ produced the highest root dry weights, root volumes, and plant dry weights, its root systems contained abundant mycelial infections. Under greenhouse conditions, an overall lower (17.5%) incidence of root infection was observed after inoculations with A. mellea. Inoculations with A. mexicana were performed in a commercial orchard that was naturally infested with A. mexicana using 21 plants of ‘Mondragon’ (cuttingderived), ‘Criollos of La Goleta’, and P. mume ‘Japanese apricot’. The lowest susceptibility to A. mexicana was exhibited by ‘Mondragon’ rootstock. Management of Armillaria root disease in peach orchards of Mexico depends on identifying A. mexicana-resistant rootstock, such as ‘Mondragon’ (Elías-Román et al. 2019).

Citation

Elías-Roman, Ruben Damian; Calderon-Zavala, Guillermo; Guzman-Mendoza, Rafael; Vallejo, Moises; Klopfenstein, Ned B.; Mora-Aguilera, J. Antonio. 2020. Testing resistance of rootstock materials for managing Armillaria root disease in peach orchards of Mexico. In: Reynolds, G. J.; Wilhelmi, N. P.; Palacios, P., compilers. Proceeding of the 66th Western International Forest Disease Work Conference; 3-7 June 2019; Estes Park, CO, USA. WIFDWC: www.wifdwc.org. p. 135-140.