Influence of Nitrogen Fertilization on the Occurrence of Major Phytopathogenic Agents of Alfalfa

Alfalfa crop is considered queen of forage plants, but if we want to get a good production we need to respect all the techniques. Alfalfa is the primary forage crop in Transylvania and is a key element in the county dairy industry. Also we need to know all diseases, pets and prevention techniques. The attack of pathogens can reduce the production with over 40%. In Transylvania, on research period, the most important diseases which produce damage on alfalfa crop was: Alfalfa mosaic virus or Lucerne mosaic virus, Downy mildew of Lucerne - Peronospora aestivalis, Alfalfa powdery mildews - Erysiphe communis Grew. E. medicaginis Dietr., Alfalfa leaf spot - Pseudopeziza medicaginis Sacc., Alfalfa yellow leaf spot - Pseudopeziza josenii Nannf., f.c. Sporonema phacidioides Desm., Alfalfa phomosis - Phoma melaena Mont. et Dur.and in September, on third mow period, was observed Alfalfa rust - Uromyces striatus Schroter. To gain high productions on alfalfa cultures are recommended the following measures: introducing rotation of culture with annual plants especially cereals, choosing optimal seeding densities; to use healthy certified seed callousness sorts; destroying of spontaneous leguminous; monitories and to fight against of vector insects; to harvest (mowing) and destruction of ill plants diminishes otherwise the attack expand.