Fire blight detection and control in Poland

Fire blight has disseminated in the last years into new regions, mainly to western, southwestern and central parts of Poland. So far, the disease was not found in the east. Fifteen diagnostic laboratories of Plant Protection Stations were organised for the detection and identification of pathogen using classical and ELISA methods. Recently, a PCR-based method of Erwinia amylovora detection utilising rDNA-specific primers designed in Belgium and a special DNA purification method using Genomic DNA Prep Plus columns was developed and is used in two laboratories. Detailed studies revealed that pathogen overwintered only in about one forth of necrosis/cankers developed in previous season on young apple shoots or older pear branches. In some cases only PCR-based method detected Erwinia amylovora at the distance of 5 or 15 cm from necrosis/canker margin. Two surveys of host plants per season made by orchard owners and supervised by plant protection inspectors are obligatory. In more endangered areas such inspections must be performed at least 4 times in a season. Besides copper-based preparations recommended for infected areas, the registration of streptomycin is also seriously considered. The efficacy of chemical preparations determined on pear fruitlets was in reverse relation to the concentration of bacteria in inoculum. In case of a lower disease intensity the infected part of plant with additional 30-50 cm of apparently healthy tissue is removed. For wound protection the white emulsion paint with 1% copper preparation and 12% Pomonit R10 (NAA) is recommended. Heavily infected plants must be destroyed. However, a much more restricted procedure is applied for nurseries and nuclear stock plantations. Special attention is paid to the protection of zones surrounding these plantations. The details are presented.