Present status of Acidovorax citrulli- causing Bacterial Fruit Blotch of watermelon fruits in North Macedonia

Acidovorax citrulli is the causal agent of Bacterial Fruit Blotch (BFB) of cucurbit plants. So far, A. citrulli has been added to the EPPO A1 List version 2023-09.
Despite the economic importance of the disease, little is known about the basic aspects of A. citrulli pathogenesis. In the late spring months of 2020 to 2022, the appearance of fruit blotch symptoms on fully ripened watermelon crops, attributed to A. citrulli was documented. In our research, we conducted a comprehensive analysis utilizing various methods including observation of fruit symptoms, pathogenicity assessment on young watermelon fruit and seedlings, as well as biochemical tests, ELISA test, and Real-time PCR analyses, all compared with positive controls. As a result of this thorough examination done for the first time, we have conclusively identified the pathogen responsible for the observed symptoms as A. citrulli, the causal agent of BFB in watermelon fruits.