Articles
RISK ASSESSMENT OF FIRE BLIGHT IN HUNGARY BASED ON BILLING’S FORECAST SYSTEM
Although Hungary is free from E. amylovora infection, the above mentioned fact, the importation of propagation material of pome fruits from countries where the disease is present, and the great number of susceptible varieties cultivated in our country make necessary the regular survey of the commercial orchards and nurseries for disease.
The goal of the investigation is to determine the sites of production and phenological stages of host plants, where and when disease occurrence is most probably the case of accidental introduction of the pathogen, and to educate the plant protection specialists and growers to carry out the survey in their own orchards in the future.
For risk assessment, Billing’s forecast system was chosen.
At this moment, 12 orchards of about 40 varieties of apple, pear and quince, in the four most endangered regions, are involved in the investigation.
Collected data are evaluated in the Bacteriological Laboratory of Plant Health Organization.
Based on the date of 1993–94 years, the following conclusions could be made:
- no Erwinia amylovora infection was found;
- in nearly all inspected orchards, at the time of flowering of pome fruits, daily mean temperatures were low, with wide daily temperature ranges and with minimum, frequently below threshold, which was not optimal for disease development at this phenological stage;
- in the latest years, beginning from the end of May until the end of September, weather was very hot and extremely dry, not optimal for disease development;
- in spite of these facts, there were some short periods, when the weather and other environmental conditions were favourable for infection and disease development, especially at the time of intensive shoot (extension) growth.
Based on three years of trial results, it can be concluded that in all inspected orchards there were periods, when all factors influencing E. amylovora infection were optimal for disease outbreak.
The fact that Hundary is still free from fire blight infection is partly due to the strict phytosanitary regulations.