Downy mildew (Plasmopara halstedii) of sunflower
2006
Masirevic, S.(Naucni institut za ratarstvo i povrtarstvo, Novi Sad (Serbia)) | Jasnic, S.(Poljoprivredni fakultet, Novi Sad (Serbia))
Downy mildew is a most harmful sunflower disease in Serbia. In years favourable for disease development, up to 50% of plants may be infected, the yield of systematically infected plants being reduced by about 50%. After the introduction of domestic hybrids resistant to the causal agent, the disease occurs sporadically and causes limiting damage. The causal agent of the disease is the fungal species Plasmopara halstedii (syn.: P. helianthi). Symptoms of the disease are two fold: systemic infection and local infection. Systemic infection occurs on roots, seedlings and young plants. Local infection occurs on mature plants, as secondary infection. Typical symptoms of the disease occur on the reverse side of the leaf. Those are the mycelium, conidiophores and conidia which form a thick white layer. The systematically infected plants have a retarded growth rate. They form small heads which are frequently sterile.
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