Characterization of root rot disease of kiwifruit in the Black Sea region of Turkey

Forty-two kiwifruit orchards from Rize and Samsun provinces (Black Sea region, Turkey) exhibiting symptoms of root rot disease were examined between 2009 and 2010. Twenty-four fungal isolates recovered from affected roots were included in this study. Morphological characteristics of all isolates were recorded on potato dextrose agar, malt extract agar and Spezieller Nährstoffarmer agar. The effect of temperature on radial colony growth was also evaluated at 5, 10, 15, 20, 25, 30, and 35 °C. Histone H3 gene (HIS) was amplified with primers CYLH3F and CYLH3R and the amplified fragments were sequenced. The HIS phylogeny grouped all the isolates into six well-supported clades which were in agreement with phenotypical characteristics. Isolates were identified as “Cylindrocarpon” pauciseptatum, Cylindrocladiella parva, Ilyonectria liriodendri, I. torresensis, I. robusta and I. europaea, I. liriodendri being the most frequent species. All of them are reported for the first time on kiwifruit in Turkey, with the exception of I. liriodendri. Pathogenicity tests with selected isolates showed that 10 out of 11 isolates tested were able to induce typical root rot disease symptoms, affecting plant development and leading to the death of some plants. This study shows the high diversity of root rot pathogens found in kiwifruit trees in the Black Sea region of Turkey, being the first step towards a better understanding and management of the disease in local conditions.     

The utility of Trichoderma spp. isolates to control of Xylosandrus germanus Blandford (Coleoptera: Curculionidae: Scolytinae)

Journal of Plant Diseases and Protection - The invasive ambrosia beetle, Xylosandrus germanus Blandford (Coleoptera: Curculionidae: Scolytinae), is a serious pest of hazelnut in Turkey, which is...     

First report of dry rot of potato caused by Fusarium sambucinum in Kyrgyzstan

Journal of Plant Diseases and Protection - In October 2020, the presence of an intense Fusarium dry rot disease was detected during a survey of potato tubers in the production storage facilities in...     

Evaluation of Inhibitory Effect of Some Bicarbonate Salts and Fungicides Against Hazelnut Powdery Mildew

Hazelnut (Corylus avellana L.) which is intensively grown in the Black Sea region is the most important agricultural product of Turkey. Hazelnut production and quality are negatively affected by several diseases and pests. Powdery mildew is nowadays one of the most common diseases in almost whole hazelnut producing areas. The disease is caused by two different species, Phyllactinia guttata (Wallr. et Lev.) Fr. and Erysiphe corylacearum U. Braun & S. Takam. For the last 4 years, E. corylacearum, a newly invasive fungus in Turkey, has been caused significant economic losses. In the present study, the efficacy of ammonium, potassium and sodium bicarbonates, and two fungicides were evaluated in field trials against powdery mildew on hazelnuts in Samsun in 2016. The application rates of compounds used in the experiment were as follows: ammonium, potassium and sodium bicarbonates (Sigma-Aldrich, Seelze, Germany) at 1.5, 3, 4.5 and 6% (w/v); Collis® SC (100?g/l Kresoxim methyl +200?g/l Boscalid, BASF, Spain) at 30?ml/100?l and Sulflow® 80 WG (Sulphur 800?g/l, Agrofarm, Turkey) at 400?g/100?l. Of the compounds tested, except for fungicides, sodium was found to be the most effective in controlling the powdery mildew on hazelnuts, followed by potassium and ammonium, respectively. Among those three, ammonium bicarbonate was ineffective against fruit infections of the disease. There was also no significant difference between inhibitory effects of 6% sodium bicarbonate, Collis and Sulflow against the disease (P < 0.05). In addition, bicarbonate salts was phytotoxic to hazelnut leaves at concentrations greater than 1.5%. The results indicate that sodium or potassium bicarbonate solutions seems to be a useful biocompatible fungicide for controlling the powdery mildew on hazelnuts.