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