Fire Blight Management: Physiological Assessment of Cultural Control By Pruning in Pear Orchards

Abstract

The aim of this work was to evaluate the photosynthetic performance of Pear trees (cv. ‘Rocha’) infected with Erwinia amylovora, three months after suffering a pruning of infected branches (P-trees) compared with asymptomatic trees (C-trees) of the same orchard. Three months after pruning, P-trees looked healthy and were negative for the presence of E. amylovora. In September of 2018, fully expanded leaves of both P- and C- trees were sampled and analysed for photosynthetic parameters related to chlorophyll a fluorescence and gas exchange, alongside with pigments, total soluble sugars, starch, and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents. No significant differences were found in chlorophyll and carotenoids levels, but anthocyanins significantly decreased in P-trees. Also, despite the maximum quantum yield (Fv/Fm) significantly decreased in P-trees, the effective quantum yield of the PSII was maintained, paralleled with no changes in gas exchange parameters (PN, gs, Ci, E, iWUE, PN/gs), nor in RuBisCO relative content. Finally, the maintenance of the levels of total soluble sugars and starch also supports that the photosynthetic performance of P-trees, three months after pruning, reached values similar to those of the C-trees, contributing to the normal development and ripening of the fruit. Data support that pruning represents a reliable control measure against this quarantine pathogen. This work is the first evaluation of pruning in fire blight management regarding carbon metabolism in P. communis trees.

Organic orchard floor management in peach: effects on arthropods and associated fruit injury in the Intermountain West

“…The orchard floor is vital for successful fruit production since its management impacts tree health and crop performance. Maintaining a healthy orchard floor can reduce pathogen infection (Mendes et al 2021), impact nutrient availability (Culumber et al 2019, Mia et al 2020a), lower pest arthropod abundance (Mills 2013, Michalko and Košulič 2020), and influence tree-weed competition for limited resources (Parker et al 1993, Belding et al 2004), such as water. In the Intermountain West, water quantity and quality are major concerns for producers; certain organic management strategies can help mitigate crop water demand (Prichard et al 1990, Novara et al 2021).…”

Exploring Antimicrobial Peptides Efficacy against Fire Blight (Erwinia amylovora)

“…To date, the main challenge of fire blight is due to the lack of effective phytosanitary measures to stop its spread and prevent enormous losses in pome fruit production [ 4 ]. Current methods are mainly based on preventive measures and applications of antibiotics, namely streptomycin and oxytetracycline [ 5 ]. However, the dramatic increase in antibiotic resistance has led many regions (e.g., the European Union) to ban their use [ 6 ].…”

Evaluation of Three Antimicrobial Peptides Mixtures to Control the Phytopathogen Responsible for Fire Blight Disease

“…Current control measures are mainly based on preventive action against fire blight (cultural control, such as, pruning of early-stage infected trees for example), and/or copperbased phytosanitary compounds and antibiotic applications (chemical control), which is prohibited in the European Union with a few exceptions, due to the dramatic rise of antibiotic resistance [7][8][9][10][11]. Alternative sustainable control methods of E. amylovora have been explored extensively in the last few years, such as, the use of antagonistic bacteria [12], bacteriophages [13], essential oils [14], and antimicrobial peptides (AMPs) [15][16][17].…”