Determination of mycoflora of pea (Pisum sativum) seeds and the effects of Rhizobium leguminosorum on fungal pathogens of peas

Mycoflora of pea seeds and the effectiveness of Rhizobium leguminosarum on important seed-borne pathogens were determined. Mycoflora were changed according to seed groups with or without surface sterilization. The most common isolated fungi were Fusarium spp., Alternaria spp., Macrophomina phaseolina, Phytophthora megasperma, Rhizoctonia solani and Sclerotium rolfsii. R. leguminosarum showed antagonistic effect on Fusarium oxysporum and P. megasperma by 66.3 and 62.1%, respectively, in dual culture test in vitro. R. leguminosarum application reduced disease severity of P. megasperma, R. solani, F. oxysporum and S. rolfsii by 52.9, 50, 67.9 and 52%, respectively. Results indicated that R. leguminosarum showed effects on plant pathogenic fungi and could be used as biocontrol agent.Key words: Seed mycoflora, dual culture, Rhizobium leguminosarum, biocontrol pathogenic fungi, disease severity

Growth enhancement and Phytophthora blight (Phytophthora capsici Leonian) control by arbuscular mycorrhizal fungal inoculation in pepper

The effects of selected arbuscular mycorrhizal (AM) fungi, Glomus mosseae, Glomus etunicatum, Glomus fasciculatum and Gigaspora margarita, on growth of pepper seedlings and Phytophthora blight caused by Phytophthora capsici and the role of the phytoalexin, capsidiol were investigated. Root colonization by AM fungi reached between 61.3% and 68.1% in roots of pepper 4 weeks after transplanting. All tested AM fungi increased the shoot height between 23.4% and 31.7% and fresh and dry weights of shoots and roots of plants were enhanced by G. etunicatum, G. fasciculatum and Gigaspora margarita compared to uninoculated plants in pot experiments. G. fasciculatum increased yield significantly by 22% under greenhouse conditions. G. mosseae reduced the disease severity of P. capsici by 91.7%, 43.0% and 57.2% under pot, greenhouse and field conditions, respectively. Compared to the control, the capsidiol level was increased by preinoculation with G. mosseae and in the necrotic stems of P. capsici-inoculated pepper plants. In conclusion, AM fungi, especially G. mosseae enhanced the development of plants and reduced Phytophthora blight of pepper. © 2007 Elsevier Ltd. All rights reserved

The effects of seed treatments with fungicides on stem rot caused by Sclerotium rolfsii sacc., in peanut

The effects and the possibility of using some systemic fungicides as seed treatments with different active ingredients against stem rot caused by Sclerotium rolfsii in peanuts were investigated. The effects of fungicides on mycelial growth of pathogen and seed germination of peanuts In vitro were determined. Severity of disease and yield were determined with pot experiments under controlled conditions as well as field experiments which were conducted for two years. Fungicides decreased the germination disorders caused by some fungal agents (Aspergillus spp., Rhizopus sp., Penicillium spp.) in and/or on the surface of seeds significantly and treatments provided an increase in germination ratio of seeds by 64-96%. Seed treatments decreased the disease severity in pot experiments under controlled conditions and field experiments by 74.3% and 34.2%, respectively. Fungicides having mixture of different active ingredients named tolclofos-methyl 200g/kg + thiram, 200g/kg, carboxin 200g/L + thiram 200g/L, fludioxonil, 100g/L and azoxystrobin 75g/L + fludioxonil 12.5g/L + metalaxyl-M 37.5g/L decreased the disease severity of pathogen in all experiments significantly and it was concluded that seed treatments with these fungicides provided substantial contribution to control of disease

The effects of arbuscular mycorrhizal fungi on yield and stem rot caused by Sclerotium rolfsii Sacc. in peanut

The effects of arbuscular mycorrhizae fungi (AMF) against stem rot disease caused by Sclerotium rolfsii Sacc. in peanut were investigated. The mycorrhizal fungi used were Glomus etunicatum, Glomus mosseae, Glomus clarum, Glomus caledonium, Glomus fasciculatum, Gigaspora margarita. In pot experiments, mycorrhizal fungi decreased infected plant ratio between 17.5 - 84.0%. G. caledonium showed the highest effect by 84.0%. The AMF decreased the disease severity between 37.8 - 64.7%. The effect on disease severity of G. caledonium and G. clarum were 63.3 and 64.7%, respectively. In field trials, the effect on disease locus of mycorrhizal fungi ranged between 30.6 and 47.2%. G. caledonium showed the lowest effect with 30.6% while the other mycorrhizal species had the same effect. G. etunicatum and G. caledonium increased the yield by 24.3%. The results show that AMF fungi could effectively be used against stem rot caused by S. rolfsii. © 2010 Academic Journals

First report of chondrostereum purpureum causing silverleaf disease of apricot (Prunus armeniaca) in Malatya, Turkey

Apricot (Prunus armeniaca) is important in the economy of Turkey. Chondrostereum purpureum causing silvering was observed in apricot growing areas in Malatya, Turkey. The characteristic symptom of the diseased tree was silvering of leaves resulting from fungal toxin. The disease incidence was found to be 2–15% in surveyed areas. The pathogenicity test was undertaken on apricot trees in a nursery, and disease incidence was found to be 22% after inoculation. © 2006 Taylor & Francis Group, LLC

Management of Wheat Stripe Rust and Septoria Leaf Blotch with Cultural Practices and Fungicides Using Disease Prediction

Aim of this study was to control of stripe rust and Septoria leaf blotch diseases in cultivars Panda, Seri-82, Ka"S"/nak and Seyhan 95 with planting rate, nitrogen fertilization and fungicide applications using disease prediction. Climatic data for Cukurova Region in 1995-1999 growth seasons were analyzed in terms of stripe rust and Septoria leaf blotch. Total days that the minimum temperature was less than 4.4 °C and 7 °C, degree days, rainy days and total rain in the periods of February 15-April 15, December-April, and December-February of each year were taken account for prediction of wheat stripe rust and Septoria leaf blotch diseases. It was predicted that when total days that the minimum temperature less than 4.4 °C and 7 °C in December-February were 20 and 50, respectively, while degree days 930, rainy days 32-34, total rain 300-400 mm in addition 10 rainy days would be in March and April, stripe rust and Septoria leaf blotch would be epidemic in that season. Seri-82 was found the most susceptible cultivar to stripe rust with average 4% disease incidence on the first two leaves. However, cultivar Panda was resistant to stripe rust and Septoria leaf blotch with 0.1% and 0.8% disease severity, respectively. Seyhan 95, Seri-82 and Ka"S"/nak were susceptible to Septoria leaf blotch with 9.6%, 7.9% and 7.7% disease severity, respectively. Application of fungicides propiconazole at the dosage of 500 ml/ha or propiconazole (15%)+ difenoconazole (15%) at the dosage of 600 ml/ha in late February-early March reduced stripe rust on Seri-82 at 59% and Septoria leaf blotch on Seri-82, Seyhan 95, and Ka"S"/nak at 38.7%, 38.5% and 28.7%, respectively. One fungicide application improved the yield of Seri-82, Seyhan 95 and Ka"S"/nak by 470-628 kg/ha