Scientists at the Kazakh Scientific Research Institute for Plant Protection and Quarantine have carried out a survey of fruit crops in 13 regions of Kazakhstan to identify the occurrence and spread of fire blight, the range of affected crops, and the identification of infection reserves. The results showed that the disease was mainly concentrated in the south and southeast of Kazakhstan, in the main fruit growing zone. Symptoms of fire blight were characteristic of two bacterial agents: Pseudomonas syringae and Erwinia amylovora.
"From a study on the seasonal dynamics of the disease for six years, we concluded that the optimal conditions for the multiplication and accumulation of infection were in the spring, during the flowering and growth of young shoots (May-June), when the humidity was above 60% and the temperature was within 16-20°C.
"However, if spring was cold and lasted longer than usual during this period (with temperature below 16°C), despite the high humidity, the disease would not develop," the scientists explained. "The disease stopped with the dry and hot period in July and August but the development of the disease was significantly affected by the microclimate in the gardens. With denser plantings and the compaction of foliage, moisture was retained and condensation formed, which favored the disease."
Bacteriological analyses were performed to isolate and identify the causal agent of fire blight from various fruit and wild cultures of the Rosaceae family, using classical bacteriological and molecular genetic methods.
"Two types of bacteria were isolated from the samples affected by the disease, namely E. amylovora, the causal agent of fire blight, and P. syringae, the causal agent of bacterial necrosis. "Our results on the bacterial identification were confirmed by Swiss scientists from the Agroscope research center based on an immuno-chromatographic test (Agri Strip Bioreba AG) and by Russian scientists at the All-Russian Research Institute of Plant Quarantine, using enzyme-linked immunosorbent assay, FLASH polymerase chain reaction, and polymerase chain reaction in real-time," the scientists concluded.
