Detecting the asymptomatic colonization of apple branches by Neonectria ditissima, causing European canker of apple

Abstract European canker is one of the most devastating fungal diseases apple in temperate regions. The causal agent, Neonectria ditissima , infects trees through wounds bark forming cankers that girdle stem and eventually cause tree death. Timely protection challenged by stagnation symptom expression after infections for a long period time. objective this research to use novel TaqMan PCR assay detect quantify N. during asymptomatic colonization wood. Pruning on branches cultivars Elstar Gala were inoculated with wood discs sampled at 2–6, 10–14, 30–34 mm distance from inoculation site 3 hours, 2 weeks, 4 weeks 8 detection quantification pathogen. detected 51% samples. This was more sensitive than culturing method detecting 11% An accumulation DNA up 34 observed without development visible symptoms. To our knowledge first time quantified absence symptoms canker. implications are discussed.