Spatio-temporal patterns of pre-harvest brown rot epidemics within individual peach tree canopies

Abstract

Tree canopies are architecturally complex and pose several challenges for measuring and characterizing spatial patterns of disease. Recently developed methods for fine-scale canopy mapping and three-dimensional spatial pattern analysis were applied in a 3-year study to characterize spatio-temporal development of pre-harvest brown rot of peach, caused by Monilinia fructicola, in 13 trees of different maturity classes. We observed a negative correlation between an index of disease aggregation and disease incidence in the same tree (r = −0.653, P < 0.0001), showing that trees with higher brown rot incidence had lower aggregation of affected fruit in their canopies. Significant (P ≤ 0.05) within-canopy aggregation among symptomatic fruit was most pronounced for early-maturing cultivars and/or early in the epidemic. This is consistent with the notion of a greater importance of localized, withintree sources of inoculum at the beginning of the epidemic. Four of five trees having >10 blossom blight symptoms per tree showed a significant positive spatial association of pre-harvest fruit rot to blossom blight within the same canopy. Spatial association analyses further revealed one of two outcomes for the association of new fruit rot symptoms with previous fruit rot symptoms in the same tree, whereby the relationship was either not significant or exhibited a significant negative association. In the latter scenario, the newly diseased fruit were farther apart from previously symptomatic fruit than expected by random chance. This unexpected result could have been due to uneven fruit ripening in different sectors of the canopy, which could have affected the timing of symptom development and thus led to negative spatial associations among symptoms developing over time in a tree.

Frequency of brown rot fungi on blossoms and fruit in stone fruit orchards in Greece

“…It is well established that brown rot incidence on blighted blossoms is directly correlated with the subsequent disease stages leading to twig or fruit blight and to fruit rots (Stensvand et al ., ; Everhart et al ., ; Holb et al ., ). Therefore, the observed predominance of M. laxa on blighted blossoms of all four hosts in the current study suggested that it would be the predominant species on the decayed fruit.…”

Fruit Decay to Diseases: Can Induced Resistance and Priming Help?

“…They have proven effective in securing that fruit reach storage and distribution in the cleanest possible conditions. Similarly, disease monitoring pre-harvest represents another strategy that provides guidance for specific treatments later on during post-harvest [41]. In addition, the use of biocontrol is a robust and effective method that serves to protect both the plant during growth and the fruit post-harvest [42].…”

Spatial Patterns of Host-Pathogen Complex: A Geostatistical Insight

“…In plant pathology K-S test have been utilized by Lescure et al, (1992), Lin et al, (2004), Camarero et al, (2005) Freita-Nunes and Rocha (2007), Carneiro (2009) and Everhart et al, (2011). Everhart et al, (2012) used this for spatio-temporal patterns of pre-harvest brown rot epidemics within individual peach tree canopies. This approach also used for host-pathogen like Prunus persica-Monilinia fructicola, Prunus cerasus-Monilinia laxa and Triticum aestivum "WPB926-Rhizoctonia oryzae.…”

“…Kelly and Meentemeyer (2002) used this as a supportive tool for study the landscape dynamics of the spread of sudden oak death (Lithocarpus densiflorus-Phytophthora ramorum) in California. For Citrus black spot-Guignardia citricarpa and Prunus persica-Monilinia fructicola this procedure was utilized by Sposito et al, (2008) and Everhart et al, (2012), respectively. Gent et al, (2007) used this technique to determine the probability of classifying mean disease incidence for Humulus lupulus-Podosphaera macularis.…”