Comparative study of some Romanian and foreign apple cultivars response to natural infections with Erwinia amylovora (Burrill.)

Abstract

The bacterium Erwinia amylovora is one of the most important pathogens of apples, causing significant damage. During the experimental years, 2021 and 2022, both the temperature and humidity in summer months, were favourable for the occurrence of fire blight in areas with a temperate climate. The absence of major genes for resistance to fire blight makes it difficult to improve apple cultivars in terms of this characteristic. Therefore, studies regarding the behaviour of apple cultivars, in certain environmental conditions, have kept their relevance. The behaviour of the cultivars studied was compared with that of ‘Auriu de Bistrița’, previously known to be susceptible to fire blight. Ten of the twelve cultivars performed well in 2021 and 2022 The results showed that ‘Jonaprim’ was not affected by Erwinia amylovora while other Romanian or foreign cultivars were sporadically affected. ‘Auriu de Bistrița’ presented a higher frequency of specific symptoms, than all the other cultivars.

Keywords

• bacterial disease
• fire blight
• temperate climate
• necrotic shoots