First report of rust disease caused by Puccinia Porri on Egyptian leek in Egypt and its control by bergamot essential oil

Puccinia porri (previously known as Puccinia allii) is one of the most important rust fungi that cause rust disease on garlic, onions, leek and chives. It usually appears as bright orange spots on infected plants. Typical symptoms of the rust disease on Egyptian leek were observed in Nubaria, El-Behera, Egypt, in March and April 2021. This is the first report on observing symptoms of rust disease caused by P. porri on Egyptian leek in Egypt. The aim of this research was to investigate antifungal properties of bergamot (Citrus bergamia L.) essential oil against Puccinia porri in vitro and under greenhouse experiments. The impact of various bergamot oil concentrations (100, 250, 500, 750 and 1000 µl/L) on the germination of urediniospores of the causing fungus was investigated in laboratory conditions. The results showed that bergamot oil reduced the percentage of urediniospores germination at all concentrations; however, high concentrations were more effective than low concentrations. Furthermore, treatment with 1000 µl/L of bergamot oil reduced spore germination by 88.65%. Bergamot oil used as a foliar treatment in greenhouses considerably decreased the kurrat rust disease’s severity. This study suggests applying bergamot oil to kurrat plants at a concentration of 1000 µl/L to protect against rust disease. Overall, this study showed that bergamot oil is a promising eco-friendly and safe fungicide that can be used for controlling kurrat rust disease.