Results Regarding the Re-emergence of Early Blight (Alternaria spp.) and Risk Management in Potato Growing Areas

Early blight caused by Alternaria spp. is a problem in many potato and tomato growing areas. Since some years, more and more countries report an increasing occurrence of early blight in the fields. Attacks of early blight was not see in potato fields from Barsa country, Romania, in the last years. But 2019 was an year with reemergence of early blight attack to different potato varieties. Application of fungicides is commonly used to effectively control the disease, although they are undesirable due to environmental consequences. Use of resistant cultivars would be the most optimal solution, but there are no cultivars with high level of resistance available on the market. Potato trials were carried out between 2019-2020 to the NIRDPSB Brasov on chernozeum soil with a randomised complete block design and four replicates with five Romanian varieties: Brasovia, Cezarina, Asinaria, Sevastia and Castrum. At the time of the disease, observations were made regarding the level of the attack. The determinations were performed on the lower, middle and upper level of the foliage of the tested plants (10 plants x 2 rows x 4 repetitions). Area under the disease progress curve (AUDPC) was calculated based on visual assessment of foliar disease during the growing season each year. AUDPC ranged from 3143 to 170.5 in 2019 and from 1681.6 to 54 in 2020, respectively. The obtained productions varied between 27.17 t/ha (Castrum variety) and 43.03 t/ha (Cezarina variety) in 2019 and between 37.06 t/ha (Castrum variety) and 61.12 t/ha (Sevastia variety) in 2020.