Open AccessPathogenicity and Control of Phacidium lacerum, an Emerging Pome Fruit Pathogen in Washington State
Author(s) -
İbrahim Kutay Öztürk,
Achour Amiri
Publication year - 2020
Publication title -
plant disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.663
H-Index - 108
eISSN - 1943-7692
pISSN - 0191-2917
DOI - 10.1094/pdis-04-20-0793-re
Subject(s) - preharvest , biology , fungicide , pyrimethanil , fludioxonil , postharvest , horticulture , malus , cultivar , orchard , botrytis cinerea , botany
Phacidium lacerum (anamorph Ceuthospora pinastri) is a recently reported quarantine fungal pathogen responsible for postharvest rot in apples and pears. Very little is known about its pathogenicity, epidemiology, and best management practices. We screened pathogenicity of P. lacerum on twigs from seven and fruit from nine major commercial apple cultivars. Among the nine cultivars tested, detached fruit of Honeycrisp and Gala cultivars were the most susceptible, whereas WA38 (Cosmic Crisp) was the least susceptible (P < 0.05). Effective concentrations to inhibit 50% growth (EC 50 ) were determined in 41 baseline P. lacerum isolates. The mean EC 50 values for four postharvest fungicides, i.e., fludioxonil (FDL), difenoconazole (DIF), thiabendazole (TBZ), and pyrimethanil (PYRI) were 0.16, 0.38, 0.54, and 0.72 µg/ml, respectively. The mean EC 50 values for four preharvest fungicides, i.e., pyraclostrobin (PYRA), fluxapyroxad (FLUX), boscalid (BOSC), and fluopyram (FLUP) were 0.96, 12.64, 16.54, and 44.46 µg/ml, respectively. In situ efficacy trials were conducted on detached Gala apples treated preventively and curatively with the aforementioned fungicides. After 6 months of storage at 1°C, FDL and DIF provided full control followed by TBZ and PYRI, whereas the other preharvest fungicides provided fair or low efficacies. Findings of this study shed light on pathogenicity of this emerging pathogen and provide necessary knowledge for effective management of Phacidium rot.