Developing Novel Management Options for Pear Fire Blight and Apple Bitter Rot with Characterization of Apple European Canker in Virginia

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Virginia Tech


In the realm of tree fruit cultivation, the management of various diseases affecting pome fruits like apples and pears is crucial for sustaining production. This study amalgamates findings from three distinct disease investigations to propose an integrated approach to their management. Firstly, in pursuit of mitigating shoot blight severity caused by Erwinia amylovora and preventing fire blight cankers on pear trees, a two-year evaluation was conducted. The study assessed the efficacy of preventive treatments, including foliar spray and trunk injection applications of Giant Knotweed Extract (RSE) alongside antibiotics. Results highlighted the effectiveness of RSE in controlling both shoot blight severity and canker incidence, offering a sustainable alternative to antibiotics. Secondly, in addressing the bitter rot of apples caused by Colletotrichum spp., eighteen fungicide treatments were evaluated over two years, focusing on newer fungicide options to mitigate fungicide resistance development. Fungicides such as Omega, Aprovia, Ferbam, Captan, Ziram, and Cabrio were proven reliable management tools, complementing the existing effective fungicides that growers heavily depend on. Lastly, the emergence of European canker (Neonectria ditissima) on cider apple cultivars was investigated. Molecular analysis confirmed the presence of N. ditissima as the causal agent, posing a significant threat to cider apple production. Koch's postulates were fulfilled through various tests, proving the pathogenicity of N. ditissima. Further research avenues, including genome sequencing were conducted to enhance understanding and control of a devastating pathogen like N. ditissima. Integrating findings from these studies proposes a comprehensive management strategy incorporating preventive spray programs, alternative fungicides, and pathogen identification to combat these diseases effectively, ensuring sustainable production of apples and pears in orchards. This holistic approach offers growers a multifaceted toolkit to manage diseases effectively, safeguarding apple and pear orchards' productivity and economic viability.



Erwinia amylovora, pear fire blight, Regalia, Colletotrichum spp., apple bitter rot, biorational, QoI Neonectria ditissima, European canker, cider apple cultivars