ISHS Acta Horticulturae 704: X International Workshop on Fireblight
DEVELOPMENT OF ECO-FRIENDLY STRATEGIES FOR THE CONTROL OF FIRE BLIGHT IN HUNGARY |
| Authors: | M. Hevesi, K. Al-Arabi, M. Göndör, J. Papp, K. Honty, K. Kasa, M. Toth |
| Keywords: | Photorhabdus, Xenorhabdus, biological control, Erwinia amylovora, Pantoea agglomerans, plant oils, breeding for resistance |
| Abstract:
Complex research projects have been initiated in 1999 at the Department of Pomology (Corvinus University of Budapest) for development of different eco-friendly solutions for integrated control, as well as to find genetic sources of resistance for breading of apple and pear. During this research program we have isolated and characterized an antagonistic bacterium Pantoea agglomerans (HIP 32) bio group G1 that strongly inhibited the growth of Erwinia amylovora in vitro. It was also effective in vivo in disease reduction on leaves of different apple cultivars (40-50%), pear, quince and cotoneaster leaves, flowers, and fruits. On each host, pre-treatment (applying the antagonist 24 hour before the inoculation with E. amylovora) was generally more effective than treatment after inoculation of the pathogen. Epiphytic fitness of HIP 32 was confirmed under Hungarian climatic conditions on apple foliage in the summer period (from May to August). Several Photorhabdus sp. and Xenorhabdus sp. – symbiotic bacteria of insect pathogenic nematodes – had a strong bactericidal activity against E. amylovora in vitro. Out of thirty plant oils examined, nine showed exceptional inhibition, especially oils encoded as “MF”, “VB” and “FK”. A bactericide effect also was confirmed for other phytopathogenic Pseudomonas and Xanthomonas species. Behavior towards fire blight of Hungarian apple and pear cultivars was determined by assessment of disease symptoms. Among 20 apple cultivars we found that ‘Szemes alma’, ‘Pónyik alma’ and ‘Sikulai’ belong to the resistant category. Pear cultivars examined included those approved by the state and other recently promising European and Japanese ones. Most of the pear cultivars were susceptible or very susceptible to fire blight, only the cultivars ‘Kieffer’, ‘Harrow Delight’ and ‘Hosui’ were found to display low susceptibility. Effective control of fire blight is possible with the aid of complex disease management programs. | |
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