Diagnosis of Fusarium spp. causing dry rot disease in stored potatoes in izmir province and investigation of control possibilities

Potato dry rot disease (Fusarium spp.) is one of the most important fungal storage rots on potato tubers after harvesting. The disease can significantly reduce yield, seed quality and marketability of the product. The aim of this study was to identify the Fusarium species that cause dry rot disease in potato storages in Ödemiş and Torbalı districts of İzmir province using morphological and molecular methods. In this context, as a result of surveys carried out in potato warehouses in these districts in 2015-2016; Fusarium species obtained from diseased potato tubers were identified as Fusarium sambucinum, F. oxysporum, F. avenaceum and F. equiseti. F. sambucinum was the most virulent according to the pathogenicity studies. In the molecular diagnosis of F. sambucinum, using spesific primers FSF1 and FSR1, predicted size was obtained 315 bp. To determine the susceptibility to disease, between 13 potato cultivars commonly stored in the region, Russet Burbank was found to be the most sensitive cultivar. There is not any plant protection products licensed against this disease in our country. In vitro tests carried out in disease control studies, fludioxonil 100 g/L, flutolanil 464 g/L, thiophanate methyl %70, imazalil 500 g/L, fludioxonil 50 g/L+sedaxane 40 g/L, fluxapyroxad 300 g/L and tolclophos-methyl %20+thiram %30 were investigated on the mycelial growth of F. sambucinum, a dry rot pathogen in potato. In these in vitro tests; fludioxonil, fludioxonil+sedaxane and imazalil were the most effective fungicides to prevent mycelial growth of the pathogen. In the experiments carried out in the cold storage of potato tubers, in addition to chemicals that are effective against the disease in in vitro tests, efficacy of Bacillus subtilis QST 713 strain % 1,34 (min.1x109 cfu/ml), Pseudomonas fluorescens strain Pf1 %1,5, 1x108 kob/ml min and %42 carboxylic acid were also tested. In vivo tests were conducted with Russet Burbank, Lady Olympia and Granola cultivars and two different methods were used including before and after inoculation. Fludioxonil 50 g/L+sedaxane 40 g/L showed the highest effect with 77.18% on Granola cultivar in the applications before artificial inoculation, while fludioxonil 50 g/L+sedaxane 40 g/L has the highest efficacy with an efficacy value of 63,53% on Granola cultivar using after artificial inoculation.