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.