Susceptibility of Peach Cultivars to Rusty Spot and Characterization of Susceptibility Groups

Abstract

<jats:p>A field study was conducted during the 2007 and 2008 growing seasons to determine and compare the susceptibility of 33 peach (<jats:italic>Prunus persica</jats:italic> L. Batsch) cultivars and advanced selections to rusty spot caused by <jats:italic>Podosphaera leucotricha</jats:italic>. During each season, the progression of peach rusty spot was monitored on three cultivars of varying susceptibility to determine when the epidemics had terminated. At that time, disease incidence and severity were estimated as percent infected fruit and number of lesions per fruit, respectively, for all cultivars in the study. Observations were recorded on fruit sampled from four replicate trees of each cultivar located in experimental plantings at the Rutgers Agricultural Research and Extension Center, Bridgeton, NJ. No fungicide sprays were applied to the trees during the study. Overall disease incidence values, estimated by averaging data from both years, varied widely across cultivars, ranging from 5% to 68% fruit infected. The three most susceptible cultivars were Autumnglo, Jerseyqueen, and Bounty, whereas the three least susceptible cultivars were Gloria, Harrow Beauty, and Sugar May. Results of Tukey-Kramer mean separation groupings and relative susceptibility rankings across both years were used to place cultivars into five disease susceptibility categories. The most susceptible cultivars were characterized as having yellow flesh with normal melting flesh texture and acidity, whereas less susceptible cultivars tended to have white-fleshed stony-hard subacid fruit. Among eight quantitative fruit characteristics examined for association with disease levels, ripening date, fruit weight at pit hardening, and fruit pubescence were found to be positively correlated with rusty spot development. Finally, the relationship between disease incidence and lesion density within the 0 to 0.5 incidence range, based on data from all cultivars in the study, agreed closely with former models derived from only a single cultivar.</jats:p>

Assessment of Responses of Peach Cultivars to Postharvest Pathogen Botrytis Cinerea and its Mitigation using Plant Essential Oils

“…According to previous studies, peach cultivars can be infected by various mold species, such as P. expansum, which causes blue mold rot, A. flavus and A. niger, which produce aflatoxins and cause black rot, and P. pannosa var. persicae, which causes powdery mildew (Pascal et al, 2010;Korba et al, 2013;Lalancette et al, 2014). Each of these mold species may have different preferences and distributions among peach cultivars and may interact with each other in complex ways (Pascal et al, 2010).…”

“…The study also did not consider the environmental factors that may influence the development and spread of mold in peach cultivars. Factors such as temperature, humidity, rainfall, irrigation, pruning, fertilization, and pesticide application may affect the susceptibility or resistance of peach cultivars to mold (Carrera et al, 2005;Byrne, 2010;Pascal et al, 2010;Lalancette et al, 2014;Szymajda and Zurawicz, 2016;Oh et al, 2017). For example, high humidity and low temperature may favor the growth of B. cinerea and P. expansum, while high temperature and low humidity may favor the growth of A. flavus and A. niger (Pascal et al, 2010).…”