SUSCEPTIBILITY OF PEAR CULTIVARS TO FIRE BLIGHT IN HUNGARY

Experiments for evaluation of susceptibility of pear cultivars to fire blight were conducted under controlled greenhouse conditions because of current quarantine regulations in Hungary.
The 22 tested cultivars included those approved by the state and other recently selected promising European and Japanese cultivars.
The aim of our work was to determine the host response (susceptibility/resistance) of pear cultivars based on the development of disease severity of shoots, flower parts and fruits after inoculation.
Suspensions of two Hungarian Erwinia amylovora strains (isolated from pear grown in different regions) were used in mixed inoculum (5 x 10⁸ cfu/ml). Disease rating was calculated and cultivars were grouped into four categories, low susceptibility, moderate susceptibility, susceptible and very susceptible.
Division of cultivars into susceptibility categories did not coincide completely with disease response of plant organs.
In some cultivars the flowers became heavily infected, while the shoots or fruits showed moderate symptoms.
We came to the conclusion that symptoms of flowers – among the flower parts mainly the browning of the receptacle – and shoots determined more exactly the degree of susceptibility of cultivars.
We observed that most of the cultivars examined were susceptible or very susceptible.
The promising ‘Harrow Delight’, ‘Kieffer’ (based on shoots and flowers), and ‘Hosui’ (shoots and fruits) were found to display low susceptibility.

X International Workshop on Fire Blight

K. Honty, M. Göndör, M. Toth, K Kasa, M. Hevesi

flower susceptibility, shoot susceptibility, Erwinia amylovora, artificial inoculation

https://doi.org/10.17660/ActaHortic.2006.704.93