Sunflower diseases

Major and important disease in Sunflower

1. DISEASES OF SUNFLOWER - Helianthus annuus Presented by, k.vignesh , P h. D – I ST YEAR, Department of plant pathology, Annamalai university.

2. Alternaria blight - Alternaria helianthi Rust - Puccinia helianthi Head rot - Rhizopus nigricans Charcoal rot / Root rot – Macrophomina phaseolina Downy mildew - Plasmopara halstedii Cercospora leaf spot - Cercospora helianthicola Septoria leaf spot - Septoria helianthi Verticillium wilt - Verticillium dahliae Powdery mildew - Erysiphe cichoracearum Southern blight - Sclerotium rolfsii Sclerotinia wilt/ stem rot - Sclerotinia sclerotiorum

3. ALTERNARIA BLIGHT- Alternaria helianthi

4. symptoms : Leaf spot lesions on the leaves are dark brown with pale margin and yellow halo ,as first smaller in size ,then up to 2-3 cm in diameter ,usually irregulary circular in shape . Plants at flowering and seed filling stages more susceptible than young plants MODE OF SURVIVAL,SPREAD AND EPIDEMIOLOGY : Fungus survives on plant residue , spread by wind borne conidia ,low temperature and high RH , Rainfall shortly after planting favours disease development . MANAGEMENT : Remove and destroy the infected plant materials Early sowing ( june sowing) Seed treatment with Thiram or Carbendazim at 2g/Kg of Seed Spary Mancozeb @ 1Kg/ha Grow resistant genotypes like EC 126184, 132846,132847 and TNAU suf 5 SYMPTOMS :

5. RUST – Puccinia helianthi

6. Symptoms : Small,reddish brown pustules covered with rusty appear on the lower surface of bottom leaves In severe infection , numerous pustules appear on leaves leading to yellowing and drying of leaves . The black coloured telia are also seen among uredia on the lower surface Pycnidial and aecial stages occur on volunteer plants . MODE OF SPREAD : The disease spreads through wind borne uredospores SURVIVAL: The pathogen is an Autocious rust and survives in the volunteer Sunflower plants and infected plant debris. EPIDEMIOLOGY: Rainy weather & cool winter encourage the disease development MANAGEMENT : Remove the volunteer sunflower plants Field sanitation Spray Mancozeb @ 1Kg/ha Grow resistant Genotypes EC 32361, 82819,MSFH3,9,12 and BSH 1

7. Charcoal rot – Macrophomina phaseolina

8. Symptoms : Affected seedlings Show brown or ashy black discolouration at the collar region . The infected plants show drooping of leaves and death occurs in patches The bark of the lower stem and roots shred and associated with a large number of sclerotia MODE OF SPREAD : Primary infection takes place from the inoculum in soil and secondary infection takes place through air borne spores SURVIVAL: The pathogen survives as sclerotia in soil,irrigation water and implements EPIDEMIOLOGY: Dry weather favour for the disease development MANAGEMENT : Seed Treatment with Thiram or captan or T.viride @4g/kg of seed Soil drench with Carbendazim @0.1%

9. Head rot - Rhizopus nigricans

10. Symptoms The disease occurs on head ( capitulum ) at heading stage and during grain formation. The affected heads show water-soaked lesion on the lower surface which later turns brown. The infection spreads from head to the stalk. In advanced cases the head becomes soft and pulpy with putrification of tissues. The insects and larvae feed on the developing seeds pave the way for the entry of the fungus. Viability of seeds is highly reduced. MODE OF SPREAD : Disease spread by wind-borne sporangiospores . SURVIVAL: Survives in the infected plant debris EPIDEMIOLOGY: Prolonged Rain at flowering stage encourage the disease MANAGEMENT : Seed treatment with captan or thiram at 4g/kg of the seed Spray the head with Mancozeb @ 1kg/ha

11. Verticillium wilt Necrosis Downy mildew

12. Powdry mildew Septoria leaf spot

13. Presented by K.VIGNESH ,M.Sc(Ag),DCA,DABM,DOLG., THANK YOU …