İsmail Erper

First Report of Root Rot of Bean and Soybean Caused by Rhizoctonia zeae in Turkey

To determine the species of Rhizoctonia on bean and soybean plants grown in Samsun (Turkey), field surveys were performed at 104 locations during 2001 and 2002. Rhizoctonia spp. were obtained from isolations from the necrotic lesions on the hypocotyl and rhizosphere soils. Species were identified according to Ogoshi (3) on the basis of hyphal and colony morphology and anastomosis reaction with known tester isolates (provided by M. Hyakumachi, Gifu University, Japan). Fifty Rhizoctonia spp. isolates obtained from these locations were identified as Rhizoctonia zeae (teleomorph Waitea circinata var. zeae). Nine of the 27 bean isolates and 8 of the 23 soybean isolates were recovered from plant tissues. These isolates had optimum temperature (32°C) for growth. Colonies were orange when young, becoming salmon colored with age. Sclerotia formed both on the agar surface or submerged in the medium. Superficial sclerotia were more uniform and nearly spherical, mostly 0.2 to 0.5 mm in diameter, and they were first orange and then turned brown. Pathogenicity was tested with three R. zeae isolates grown on sterile oat seeds at 25°C for 10 days. Bean and soybean seedlings grown in 1-liter plastic pots containing sterile potting mix (field soil/composted manure/sand 2:2:1 [v/v]) at true-leaf stage were inoculated by placing five infested oat seeds adjacent to the roots. Sterile oat seeds were used for controls. After 3 to 4 weeks of incubation at 17 to 25°C in a glasshouse, roots of the plants were cleaned with tap water and evaluated for disease severity. Four replicate pots were used for each isolate/plant combination. All isolates produced superficial brown lesions on roots and hypocotyls similar to those observed on plants used for isolations and root growth declined. R. zeae was reisolated from the lesions on all bean and soybean plants used for the pathogenicity test. While R. zeae was previously reported from Johnsongrass roots (1) and corn kernels (2), to our knowledge, this is the first report of R. zeae isolated from bean and soybean plants and rhizosphere soils in Turkey. References: (1) E. Demirci, and C. Eken. Plant Dis. 83:200, 1999. (2) E. Demirci and S. Kordali. Plant Dis. 83:879, 1999. (3) A. Ogoshi. Rev. Plant. Prot. Res. 8:93, 1975.

Inactivation effect of electron beam irradiation on fungal load of naturally contaminated maize seeds

BACKGROUND This work focuses on the effect of accelerated electrons (0.1-6.2 kGy) on naturally attached fungi on maize seeds. The fungal viability and corresponding inactivation kinetics were determined. The inactivation and radiosensitivity of the most abundant species in the contaminant fungi detected on maize seeds (Aspergillus spp., Penicillium spp. and Fusarium spp.) are discussed. RESULTS Fungal contamination of maize seeds decreased significantly with increasing irradiation dose. The survival curve of total fungi determined by the blotter test showed a sigmoidal pattern that can be attributed to the mixture of fungal subpopulations with different radiation sensitivities. This behaviour could be modelled well (R²  = 0.995) with a modified Gompertz equation. The predicted values for shoulder length and inactivation rate were 0.63 ± 0.10 kGy and 0.44 ± 0.04 kGy⁻¹ respectively. The sensitivity of the most common fungi to electron beam treatment followed the order Penicillium spp. > Fusarium spp. > Aspergillus spp., with total inactivation at irradiation doses of 1.7, 2.5 and 4.8 kGy respectively. CONCLUSION The effect of electron beam treatment against fungi on naturally contaminated maize seeds depended on irradiation dose, allowing the control of maize fungal load.

Identification and pathogenicity of Rhizoctonia species isolated from bean and soybean plants in Samsun, Turkey

A total of 434 isolates of Rhizoctonia belonging to 10 anastomosis groups were obtained from the roots and rhizosphere soils of bean and soybean plants grown in Samsun, Turkey. AG-4 was found to be the most common group on bean and soybean plants and AG-5, AG-6, binucleate AG-A, AG-B and R. zeae were other groups isolated from the both plant species. AG-1, AG-7 and AG-K from bean and AG-E from soybean were other groups obtained in the study. The pathogenicity tests on bean and soybean seedlings showed that the highest disease severities were caused by AG-4 isolates, whereas AG-1 and AG-6 isolates were moderately pathogenic. Binucleate Rhizoctonia AG-B isolates were also moderately pathogenic, while other binucleate Rhizoctonia were found to be weakly pathogenic. Rhizoctonia zeae isolates caused moderate disease symptoms on bean, but soybean plants were slightly affected by this group of isolates. This is the first reported observation of R. solani AG-6 and AG-7 and binucleate Rhizoctonia AG-B on bean, and R. solani AG-5 and AG-6 and binucleate Rhizoctonia AG-A, AG-B and AG-E on soybean, in Turkey.

First report of Cylindrocarpon liriodendri on kiwifruit in Turkey.

During a routine survey of diseases of kiwifruit (Actinidia chinensis Planch.) cv. Hayward conducted in autumn of 2009 in Ardeşen, Rize Province (eastern Black Sea Region, Turkey), symptoms of a new disease were observed in five locations. Affected trees showed leaf wilting that frequently led to the death of the trees. Symptoms at ground level included necrotic lesions on woody tissues of both the rootstock and roots. Small pieces from necrotic wood and root tissues were surface disinfested and plated onto potato dextrose agar (PDA) medium amended with 0.5 g liter-1 of streptomycin sulfate and incubated for 7 days at 25°C in the dark. Isolates were transferred to PDA and presumptively identified as a Cylindrocarpon sp. by morphology and conidial characteristics. The isolates were transferred to PDA and Spezieller Nährstoffarmer Agar (SNA) and then incubated at 25°C for 10 days with a 12-h photoperiod. On PDA, the isolates developed floccose to felted mycelium, which varied in color from brown-yellow to sepia. On SNA, all isolates produced microconidia measuring 6.25 to 15 (9.6) × 2.5 to 5 (3.02) μm and macroconidia of one-septate measuring 7.5 to 20 (13.3) × 2.5 to 5 (3.8) μm, two-septate measuring 12.5 to 25 (20.7) × 3.25 to 5 (4.58) μm, and three-septate measuring 16.3 to 30 (11.04) × 3.75 to 5 (4.82) μm. Chlamydospores 7.5 to 11.3 (9.78) μm were intercalary or terminal in the mycelium, single or occasionally in chains. Identity of these isolates was determined by a multiplex PCR system using a set of three pairs of specific primers (Mac1/MaPa2, Lir1/Lir2, and Pau1/MaPa2) (1), which generated a product size of 253 bp, which is characteristic of Cylindrocarpon liriodendri J.D. MacDonald and E.E. Butler, in agreement with morphological features (2). Additionally, the internal transcribed spacers regions (ITS1 and ITS4) of rDNA were obtained for isolates 10K-TR1 and 10K-TR2 and deposited in GenBank (Accession Nos. HQ113122 and HQ113123). These sequences showed high similarity (98%) with the sequence of C. liriodendri (GenBank Accession No. DQ718166). A pathogenicity test was conducted using isolate 10K-TR1 and repeated twice. Six 8-month-old callused and rooted cuttings of kiwifruit cv. Hayward were surface disinfested for 1 min in a 1.5% sodium hypochlorite solution, washed twice with sterile distilled water (SDW), and inoculated by dipping their roots for 30 min in a spore suspension of the fungus (1 × 106 conidia ml-1) obtained from 30-day-old colonies grown on PDA. Six control cuttings were dipped in SDW. Two weeks later, cuttings were drench inoculated with 50 ml of the designated spore suspension to guarantee root infection and controls were drenched again with SDW. Plants were maintained in a greenhouse with a temperature range of 25 to 30°C. Four months after inoculation, the inoculated plants developed wilting and root symptoms similar to those observed in natural infections and C. liriodendri was reisolated, completing successfully Kochs postulates. No symptoms were observed on the control plants. To our knowledge, this is the first report of C. liriodendri on kiwifruit trees in Turkey. References: (1) S. Alaniz et al. Plant Dis. 93:821, 2009. (2) F. Halleen et al. Stud. Mycol. 55:227, 2006.

Root rot disease incidence and severity on some legume species grown in Samsun and the fungi isolated from roots and soils

Abstract Root rot disease is very common in the bean, soybean, faba bean and pea plants growing areas in Samsun province. Disease incidence and severity were detected the highest at 93.8% and 55.4% in the bean growing area, and the lowest at 64.0% and 24.3% in the faba bean growing area respectively. In this study, a total of 2714 fungal isolates were obtained from some legume plants and soil samples. The most common fungi isolated from root and soil samples were Fusarium spp., multinucleate Rhizoctonia (MNR), binucleate Rhizoctonia (BNR) and Pythium spp. respectively. Fusarium spp. were isolated at high rates from all the examined areas. MN Rhizoctonia and BN Rhizoctonia were isolated both from inner and coastal areas of the province, whereas Pythium spp. were isolated in costal areas, except for the Vezirköprü district which is situated in the inner area. When looking at the interactions among pathogens causing root rot, it was found the great majority of the samples (30.4%) isolated both Fusarium spp. and MNR-BNR group fungi, whereas Fusarium spp. and Pythium spp. were isolated together from 10.9% of the samples and MNR-BNR and Pythium spp. from only 1.5% of the samples.

New hosts for Phyllactinia guttata in the Black Sea Region of Turkey

Abstract Fungi belonging to the family Erysiphaceae (Ascomycota) are obligate biotrophs causing powdery mildew disease on various host plants. Most of the species in this family are ectoparasitic while the genus Phyllactinia is known to be partly endoparasitic. Phyllactinia guttata is one of the most important powdery mildews among Phyllactinia species causing disease on deciduous trees. In this study, P. guttata was detected on 11 woody plant species belonging to 8 families of Actinidiaceae, Betulaceae, Cornaceae, Fagaceae, Moraceae, Rhamnaceae, Rosaceae and Ulmaceae in 5 provinces in the Black Sea Region of Turkey. This is the first report of P. guttata on Actinidia deliciosa, Alnus glutinosa var. barbata, A. glutinosa var. glutinosa, Cornus mas, Cydonia oblonga and Fagus orientalis in the Black Sea Region of Turkey.

First report of Botrytis cinerea on golden berry

Botrytis cinerea infection of golden berry was reported for the first time from Turkey. The pathogen caused grey mould disease. The disease was widely observed in a golden berry orchard in Samsun province (Eastern Black Sea region), Turkey. The fungus was identified as B. cinerea based on morphological characteristics and sequence analysis.

rDNA-ITS DIVERSITY OF Waitea circinata var. zeae (anamorph: Rhizoctonia zeae)

In this study, we analysed a collection of Waitea circinata comprising 20 isolates (17 var. zeae; one var. circinata and two var. oryzae) from different localities and hosts with macroscopic anastomosis tests, PCR-RFLP and phylogenetic analysis of the 18S-28S rDNAITS region. Macroscopic anastomosis was not useful for the identification of W. circinata isolates because all isolates, even those of the same variety, gave tuft reactions indicating unrelatedness. However, varieties of W. circinata showed unique RFLP patterns with HhaI, MseI and TaqI enzymes, suggesting that this molecular method may be suitable for quick identification. 18S-28S rDNA-ITS phylogeny revealed two main monophyletic groups within W. circinata var. zeae isolates. The first main monophyletic group appeared global as it contained isolates from Asia, the Americas and Europe, and the second main monophyletic group was only comprised of isolates from the Americas. Because the genetic diversity of W. circinata var. zeae isolates from the Americas was higher than that from other continents, it may have originated there and later it may have disseminated from Far East to Eastern Europe.

Evaluation of some entomopathogenic fungi against the fall webworm (Hyphantria cunea Durry, Lepidoptera: Arctidae)

Fall webworm ( Hyphantria cunea Durry, Lepidoptera: Arctidae) is an important pest infecting about 600 hosts. It is harmful especially in hazelnut orchards in the Black Sea Region and is becoming epidemic occasionally. It may cause damage in mulberry, cherry, apple, poplar, and willow beside hazelnut in the region. Due to having a polyphagous feeding behavior and a high reproduction power; fall webworm can spread rapidly and make difficult to manage. In the region, currently, mostly chemical control is applied against this pest. Due to adverse effects of the chemical control to the environment and to living organisms, it is inevitable to develop other alternative control methods for this pest. In this study, the effects of some entomopathogenic fungi isolates obtained from Palomena prasina which is another pest in hazelnut production areas, on H. cunea in laboratory conditions. Overall, 1x10 8 conidia mL -1 of concentration obtained from 2 isolates of Simplicillium lamellicola (TR-01 and TR-02) and 4 isolates of Lecanicillium muscarium (TR-04, TR-05, TR-07 and TR-08) was used against 3 rd period larva of the H. cunea. The experiment was conducted with four replications, 10 larvae individuals in each. Mortality of H. cunea were reported daily, over 12 days. At the end of 12 th day, among the isolates of entomopathogenic fungi, the TR-05 isolate of the L. muscarium ranked the highest mortality by 93.9% rate. Effect of the other isolates of L. muscarium varied between 72.7% and 90.9%. The TR-01 isolate of the S. lamellicola showed effect of 57.6%, and the TR-02 isolate showed effect of 78.8% mortality. Effects of all the isolates used in the study were differed from the control (P<0.05). Based on LT 50 and LT 90 values, the most effective isolate was identified as TR-04 (5.64/day and 9.38/day, respectively). It can be concluded that, the isolates of L. muscarium was found quite effective and it could be a promising agent for controlling this pest in the field in the future.

Inhibitory Influence of Organic and Inorganic Sodium Salts and Synthetic Fungicides Against Bean Root Rot Pathogens

The efficacy of 20 organic and inorganic sodium salts, and two synthetic fungicides against eight bean root rot pathogens—Fusarium equiseti, F. proliferatum, F. semitectum, F. solani f. sp. phaseoli, F. verticillioides, Rhizoctonia solani AG4–HG I, Macrophomina phaseolina and Sclerotium rolfsii—were evaluated in this study. Accordingly to preliminary in vitro tests, only captan, benzoate and metabisulfite (2 %) were able to completely inhibit mycelial growth of all eight fungi. Moreover, no significant differences were observed among the inhibitory effect of these three compounds and EDTA (P ≤ 0.05). With few exceptions, the ED50 values indicated captan to have a greater effect against fungi than benzoate, EDTA and metabisulfite. However, captan, benzoate and EDTA all had MIC values that varied greatly from that of metabisulfite. Whereas captan, benzoate and EDTA showed fungitoxic activity against all fungi tested at concentrations greater than 0.1 %, metabisulfite showed fungitoxic activity against all fungi tested at concentrations of 0.025–0.25 %. Soil bioassays showed 0.25 % metabisulfite to completely inhibit mycelial growth of F. proliferatum, F. semitectum, R. solani AG–4 HG I, M. phaseolina and S. rolfsii, but not F. equiseti, F. solani f. sp. phaseoli and F. verticillioides. Higher concentrations of captan and benzoate were required to achieve total inhibition in soil bioassays when compared to metabisulfite, whereas EDTA was not able to completely inhibit growth of any of the fungi tested, even at the highest concentration. Moreover, the application of 1.0–2.0 % EDTA was found to be phytotoxic to bean seeds in terms of both seed germination and root elongation, whereas 0.1–0.75 % captan, 0.1–0.75 % benzoate and 0.1 % metabisulfite did not exhibit any phytotoxicity in terms of germination; 0.5 % captan, 0.1 % benzoate and 0.1 % metabisulfite did, however, have a negative effect on root elongation.The results of pH studies also demonstrated all eight fungi tested to be capable of growth in both acidic and basic environments, although the growth of some species was inhibited at the lowest value tested (pH 2), and the growth of all species was totally inhibited at the highest value tested (pH 12).ZusammenfassungDie Wirksamkeit von 20 organischen und anorganischen Natriumsalzen und zwei synthetischen Fungiziden gegen acht Wurzelfäuleerreger bei Bohnen – Fusarium equiseti, F. proliferatum, F. semitectum, F. solani f. sp. phaseoli, F. verticillioides, Rhizoctonia solani AG4–HG I, Macrophomina phaseolina und Sclerotium rolfsii – wurde in dieser Studie beurteilt. Vorläufigen In-vitro-Tests zufolge konnten nur Captan, Benzoat und Metabisulfit (2 %) das Myzelwachstum aller acht Pilze vollständig hemmen. Außerdem wurden keine signifikanten Unterschiede zwischen der hemmenden Wirkung dieser drei Verbindungen und von EDTA festgestellt (P ≤ 0,05). Mit wenigen Ausnahmen deuteten die ED50-Werte darauf hin, dass Captan eine stärkere Wirkung gegen Pilze hat als Benzoat, EDTA und Metabisulfit. Captan, Benzoat und EDTA wichen aber stark in ihren MHK-Werten von Metabisulfit ab. Während Captan, Benzoat und EDTA bei Konzentrationen über 0,1 % eine fungitoxische Wirkung gegen alle getesteten Pilze zeigten, zeigte Metabisulfit bei Konzentrationen zwischen 0,025 und 0,25 % eine fungitoxische Wirkung gegen alle getesteten Pilze. Boden-Bioassays ergaben, dass 0,25 % Metabisulfit das Myzelwachstum von F. proliferatum, F. semitectum, R. solani AG–4 HG I, M. phaseolina und S. rolfsii vollständig hemmt, nicht aber das von F. equiseti, F. solani f. sp. phaseoli und F. verticillioides. Höhere Konzentrationen als bei Metabisulfit waren von Captan und Benzoat erforderlich, um in Boden-Bioassays eine vollständige Hemmung zu erreichen, wohingegen EDTA das Wachstum keines der getesteten Pilze vollständig hemmen konnte, auch nicht in der höchsten Konzentration. Außerdem wurde der Einsatz von 0,1–2,0 % EDTA als phytotoxische für Bohnensaat erkannt, was die Saatkeimung und das Längenwachstum der Wurzeln betrifft, wohingegen 0,1 − 0,75 % Captan, 0,1 − 0,75 % Benzoat und 0,1 % Metabisulfit keine phytotoxische Wirkung auf die Keimung aufwiesen. 0,5 % Captan, 0,1 % Benzoat und 0,1 % Metabisulfit hatten allerdings negative Auswirkungen auf das Längenwachstum der Wurzeln.Die Ergebnisse von pH-Studien zeigten auch, dass alle acht getesteten Pilze sowohl in saurem als auch in basischem Milieu wachsen können, obwohl das Wachstum mancher Spezies beim geringsten getesteten pH-Wert (2) und das Wachstum aller Spezies beim höchsten getesteten pH-Wert (12) gehemmt wurde.