Browsing by Author "Erper, İsmail"

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Antifungal effect of boron compounds against Neoscytalidium dimiatum
(2023) Yildirim, Elif; Türkkan, Muharrem; Yiğit, Abdurrahman; Derviş, Sibel; Özer, Göksel; Erper, İsmail
Neoscytalidium dimidiatum has been recently identified as the agent responsible for canker, dieback, shoot blight, and root rot on different hosts in Türkiye. In this study, we evaluated the inhibitory effect of boric acid (H3BO3), three borates [disodium octaborate tetrahydrate (Na2B8O13.4H2O), disodium tetraborate decahydrate (Na2B4O7.10H2O) and disodium tetraborate (Na2B4O7)] on the mycelial growth, germ tube elongation and conidial germination of N. dimidiatum. The antifungal effects of the boron compounds were investigated at 0.125, 0.25, 0.5, 1.0 and 2.0% (w/v) concentrations. The differences observed between the inhibitory effects of boron compounds on the parameters were found to be significantly important at P < 0.05. The 0.5% concentration of disodium tetraborate decahydrate and disodium octaborate tetrahydrate completely inhibited the fungus, whereas other salts did not. Disodium tetraborate decahydrate and disodium octaborate tetrahydrate completely inhibited three parameters at 0.5% and higher concentrations. However, boric acid and disodium tetraborate were able to completely inhibit investigated factors of N. dimidiatum at 2.0% and 1.0% concentration, respectively. Disodium tetraborate and boric acid at 0.5% concentration decreased germ tube elongation and conidia germination of the fungus by 94.97%-63.57%, 59.33%-51.26%, respectively. The effectiveness of the 0.5% concentration on conidial germination was also similar in both salts at P < 0.05. However, disodium tetraborate inhibited germ tube elongation more effectively than boric acid. The minimum inhibition concentration (MIC) values of the four boron compounds also varied between 0.5% and 2.0% concentrations. The boron compounds in this study could be potential agents to manage N. dimidiatum.
Characterization and pathogenicity of Pythium-like species associated with root and collar rot of kiwifruit in Turkey
(In Plant Disease, 2021) Türkkan, Muharrem; Özer, Göksel; Karaca, Gürsel; Erper, İsmail; Derviş, Sibel
During the period of June to October in 2018, a widespread decline was observed on kiwifruit vines in the vineyards located in Altınordu, Fatsa, and Perşembe districts of Ordu province. The symptoms were associated with reddish-brown rots expanding from the root to the collar with sparse off-color foliage. Based on the percentage of the total infected samples across 18 vineyards, the most common oomycete species were Globisporangium intermedium (37.1%), Phytopythium vexans (34.3%), G. sylvaticum (14.3%), G. heterothallicum (11.4%), and Pythium dissotocum (2.9%). The morphological identification of isolates was confirmed based on partial DNA sequences containing the nuclear rDNA internal transcribed spacer region (rDNA ITS) and the mitochondrial cytochrome c oxidase subunit II (coxII) gene. The optimum growth temperature and the optimum pH of 5 species ranged from 22.98 to 28.25°C and 5.67 to 8.51, respectively. Pathogenicity tests on the seedlings of kiwifruit cv. Hayward revealed significant differences in virulence among isolates. Phytopythium vexans and G. sylvaticum isolates caused severe root and collar rot resulting in seedling death, while G. heterothallicum and G. intermedium isolates had relatively lower virulence. All Globisporangium spp. and P. vexans isolates significantly decreased plant growth parameters (plant height, shoot and root dry weights and root length); however, P. dissotocum caused very mild symptoms and did not affect these parameters of growth. To our knowledge, this is the first study reporting G. sylvaticum, G. heterothallicum, and G. intermedium causing root and collar rot on kiwifruit not only in Turkey but also in the world.
Evaluation of inhibitory effect some bicarbonate carbonate salts against Neoscytalidium dimiatum
(2023) Yildirim, Elif; Türkkan, Muharrem; Özer, Göksel; Derviş, Sibel; Erper, İsmail
Neoscytalidium dimidiatum, a member of the Botryosphaeriaceae family, has emerged as a significant pathogen causing canker and blight diseases in various fruit trees, field crops, park and forest trees, and other hosts. Neoscytalidium dimidiatum is the only recognized species within the genus, with the other two previously recognized species, N. novaehollandiae and N. orchidacearum. There is no suggested chemical control method against Neoscytalidium. In this study, we evaluated the inhibitory effect of some salts on the mycelial growth, germ tube elongation and conidial germination of the N. dimidiatum isolate phylogenetically clustered with the isolates previously recognized as N. novaehollandiae. The antifungal effects of the salts were determined at 0.125, 0.25, 0.5, 1.0 and 2.0% (w/v) concentrations of salts in vitro conditions. Statistically, differences were observed between the inhibitory effects of six salts on the parameters at P ≤ 0.05. The 0.25% and higher concentrations of the ammonium bicarbonate and ammonium carbonate salts completely inhibited mycelial growth, germ tube elongation and conidial germination. Potassium and sodium bicarbonate salts in the highest concentration (2.0%) were able to decrease the mycelial growth, germ tube elongation and conidial germination with the rates of 95.58%-95.58%, 95.05%-95.76% and 77.44%-82.91%, respectively. In addition, potassium and sodium carbonate were able to completely inhibit investigated factors of the pathogen at 2.0% and 1.0% concentrations, respectively. The minimum inhibition concentration values of the ammonium bicarbonate, potassium carbonate and sodium carbonate varied between 0.25% and 2.0%. The minimum fungicidal concentration values of the ammonium carbonate and bicarbonate also ranged between 0.25% and 1.0%. As a result, this study showed that salts of carbonate and bicarbonate could be recommended to manage diseases caused by N. dimidiatum.