Comparative spatial analysis of the sooty blotch/flyspeck disease complex, bull’s eye and bitter rots of apples

Abstract

The incidence of sooty blotch ⁄ flyspeck (SBFS) and bitter and bull's eye rots were assessed in a Fuji apple orchard during two seasons. Using a regular sampling design, 252 trees were selected and 20 fruits per tree were sampled at harvest and scored for disease incidence. For bitter and bull's eye rots, additional assessments were made on all symptomless fruit after a 30-day period of storage. Randomness in the spatial pattern was assessed using beta-binomial analysis of incidence data for three sampling scales (one, three or six adjacent trees as sampling units) and using Spatial Analysis by Distance Indices (SADIE) for disease counts for the 3-tree sampling scale. SADIE was also used for testing spatial associations between a pair of diseases, between years for the same disease or between rotted and latently infected fruit. Using a toroidal-shifts procedure, 360 maps of disease counts were created based on the observed data, which were further analysed using SADIE. Most datasets showed an aggregated spatial pattern, which was more consistent for the two fruit rots than SBFS, which showed distinct patterns depending on the year or method of analysis. The two fruit rots were spatially associated in most situations but SBFS and bull's eye rot were dissociated in one season. Results from virtual orchards showed that the patterns observed in the original maps may accurately represent those in similar apple-growing areas. Hypotheses regarding aspects of ecology and epidemiology of pathogens studied and potential efficacy of control measures in the region are discussed.

Latent postharvest pathogens of pome fruit and their management: from single measures to a systems intervention approach

“…Thus, after several months in CA storage symptoms start to appear, when certain physiological or biochemical cues in the host are changed (Coates and Johnson 1997;Lattanzio et al 2001). Examples of fungal pathogens causing postharvest losses are Neofabraea alba (Chen et al 2016;Soto-Alvear et al 2013), Neonectria ditissima (Weber and Dralle 2013), the Colletotrichum acutatum species complex (Spolti et al 2012), Cadophora malorum (Sugar and Spotts 1992), Phytophthora spp., Alternaria spp., and Fusarium spp. (Sever et al 2012).…”

Exploring Spatiotemporal Patterns of Phoma Black Stem in Sunflower

“…Shah et al 2005). Statistical approaches such as Spatial Analysis by Distance IndicEs (SADIE; Perry 1995Perry , 1998 allow considering other processes that may be associated with the progress of plant disease epidemics, such as defoliation (Pethybridge et al 2005), or the occurrence of other diseases (Pethybridge and Turechek 2003;Spolti et al 2012). The measurement of disease gradients allows describing the occurrence and spatial range of secondary infections from a known source of inoculum artificially created (e.g.…”

Fungal pathogens in pome fruit orchards and causal agents of postharvest decay

“…Development and symptom expression takes place during storage. Common pathogens causing such late postharvest losses are able to infect fruits through lenticels, such as the Colletotrichum acutatum species complex (bitter rot) (Spolti et al, 2012), Neofabraea alba , and Neofabraea perennans (Bull's eye rot) (Weber, 2009). Other pathogens infect apple cultivars that have an open blossom end (calyx) into the core and cause dry or wet core rot; mainly Alternaria spp.…”

“…Common pathogens causing such late postharvest losses are Neofabraea alba (syn. Phlyctema vagabunda; lenticel rot disease; often also named bull's eye rot; , Neofabraea perennans (bull's eye rot; Weber, 2009), Neonectria ditissima (nectria rot, blossom-end rot; Weber and Dralle, 2013), Colletotrichum acutatum species complex (bitter rot; Spolti et al, 2012), Phytophthora spp., Alternaria spp., Fusarium spp. , Cadophora malorum (syn.…”

“…Common pathogens causing such late postharvest losses are Neofabraea alba (syn. Phlyctema vagabunda; , Neonectria ditissima , the Colletotrichum acutatum species complex (Spolti et al, 2012), Phytophthora spp., Alternaria spp., Fusarium spp. , Cadophora malorum (syn.…”