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A total of 132 Rhizoctonia isolates were recovered from red cabbage plants with root rot and wirestem symptoms in the province of Samsun (Turkey) between 2018 and 2019. Based on the sequence analysis of the internal transcribed spacer (ITS) region located between the 18S and 28S ribosomal RNA genes and including nuclear staining, these 124 isolates were assigned to multinucleate Rhizoctonia solani, and eight were binucleate Rhizoctonia. The most prevalent anastomosis group (AG) was AG 4 (84%), which was subdivided into AG 4 HG-I (81%) and AG 4 HG-III (3%), followed by AG 5 (10%) and AG-A (6%), respectively. The unweighted pair group method phylogenetic tree resulting from the data of 68 isolates with the inter-PBS amplification DNA profiling method based on interspersed retrotransposon element sequences confirmed the differentiation of AGs with a higher resolution. In the greenhouse experiment with representative isolates (n = 24) from AGs on red cabbage (cv. Rondale), the disease severity index was between 3.33 and 4.0 for multinucleate AG isolates and ranged from 2.5 to 3.17 for AG-A isolates. In the pathogenicity assay of six red cabbage cultivars, one isolate for each AG was tested using a similar method, and all cultivars were susceptible to AG 4 HG-I and AG 4 HG-III isolates. Redriver and Remale were moderately susceptible, while Rescue, Travero, Integro, and Rondale were susceptible to the AG 5 isolate. The results indicate that the most prevalent and aggressive AGs of Rhizoctonia are devastating pathogens to red cabbage, which means that rotation with nonhost-crops for these AGs may be the most effective control strategy. This is the first comprehensive study of Rhizoctonia isolates in red cabbage using a molecular approach to assess genetic diversity using iPBS-amplified DNA profiling.

During the period of June to October in 2018, a widespread decline was observed on kiwifruit vines in the vineyards located in the Altınordu, Fatsa, and Perşembe districts of Ordu province in Turkey. 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%), Globisporangium sylvaticum (14.3%), Globisporangium 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 gene and the mitochondrial cytochrome c oxidase subunit II gene. The optimum growth temperature and the optimum pH values of the five 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 Globisporangium sylvaticum isolates caused severe root and collar rot resulting in seedling death, while Globisporangium heterothallicum and Globisporangium intermedium isolates had relatively lower virulence. All Globisporangium spp. and Phytopythium vexans isolates significantly decreased plant growth parameters (plant height, shoot and root dry weights, and root length); however, Pythium dissotocum caused very mild symptoms and did not affect these parameters of growth. To our knowledge, this is the first study reporting Globisporangium sylvaticum, Globisporangium heterothallicum, and Globisporangium intermedium causing root and collar rot on kiwifruit not only in Turkey but also in the world.

Control of grey mould of kiwifruit caused by Botrytis cinerea has been accomplished by postharvest application of synthetic fungicides. However, the development of resistant fungal strains and increasing public concern over food safety and the environment are driving a search for alternative disease control strategies. In the present study, the inhibitory effect of carbonate and bicarbonate salts of ammonium, potassium and sodium against B. cinerea were investigated in both in vitro and in vivo experiments. Ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate completely inhibited the mycelial growth of B. cinerea at 10, 25, 25, 50, 50 and 75 mM, respectively. With the exceptions of few, carbonate and bicarbonate salts totaly halted spore germination at lower concentrations than that of the mycelial growth of fungus. Complete inhibitory activity of ammonium carbonate exhibited spore germination at 10 mM, whereas same concentration of sodium carbonate reduced spore germination of fungus by 98.75%; however, the difference between this and the effects of first salt was not statistically significant (P<0.05). The lowest minimum inhibition concentration (MIC) and EC50 values were also recorded in ammonium carbonate treatment. In vivo, however, with the exception of 100 mM ammonium carbonate, five other carbonate and bicarbonate salts significantly reduced the incidence of grey mould on kiwifruits (cv. Hayward). Moreover, potassium bicarbonate was detected to be the most effective salt for in vivo control of disease, and the difference between the effects of the lowest and highest concentrations of the salt was not statistically significant (P<0.05). Results from this study may provide an important basis for further study on the uses of carbonate and bicarbonate salts in the control of grey mould in kiwifruit at wider semi-commercial conditions.