Erwinia amylovora is a very dangerous plant pathogen bacterium that produces the disease named fire blight. Due to its gravity was mentioned in the category of the phytosanitary quarantine in the Annex II from H.G. 563/2007. The pathogen has entered on the territory of Romania in the ’90 and slightly was expanded in all the fruit tree cultivation areas. In the last years there was noticed an increase of the frequency and intensity in apple, pear and quince. Erwinia amylovora represents a risk for the fruit tree sector, mainly in pear and apple but also in nurseries. The topic approached in this study is present-day and is looking to bring support for the fruit tree farmers from Banat’s area because they are confronting often with problems that are regarding the pathogens control from the apple orchards and mainly the control of the fire blight that is almost impossible to control, mostly in the years with hot and humid weather. The main objective of the research was the monitoring of six apple varieties from a fruit tree farm from Banat, where the bacterium Erwinia amylovora is present for several years. There was monitored the response of these varieties to the attack of the bacterium during two years. The studied apple varieties monitored were Florina, Granny Smith, Generos, Mutsu, Idared and Golden Spur. The mentioned varieties have different resistance to the attack of fire blight. The obtained results following this research show that there is a relative great variability in the response of the varieties to the attack of the pathogen, this aspect being confirmed by other researches too. The age of the trees is very important. There was noticed that the younger trees have better resistance to the attack than the older ones. The most attacked varieties from the research were Idared, Mutsu and Golden Spur. The varieties Granny Smith, Florina and Generos were manifested as medium resistant (MR). The lowest attack intensity was registered in the variety Granny Smith (between 1% and 2% attacked shoots). The genetic resistance of the varieties from this research is supported by the obtained results, being very important in the management of the infections produced by Erwinia amylovora.

Erwinia amylovora, fire blight, varieties, genetic resistance, apple, intensity.

biology

Presentation: poster