Major diseases of Cumbu are:-
1. Cumbu Downy Mildew: Sclerospora graminicola
- Symptoms often vary as a result of systemic infection.
- Leaf symptoms begin as chlorosis at the base and successively higher leaves show progressively greater chlorosis.
- Infected chlorotic leaf areas can support abundant white asexual sporulation on the lower leaf surface.
- Severely infected plants are generally stunted and do not produce panicles.
- Green ear symptoms result from transformation of floral parts into leafy structures.
- Grow downy mildew resistant varieties CO7, WCC 75, CO(Cu)9, TNAU-Cumbu Hybrid-CO9
- Transplanting reduces disease incidence. At the time of planting infected seedlings should be removed.
- In the direct sown crop, infested plants should be removed up to 45 days of sowing as and when the symptoms are noticed.
- Spray any one of the fungicides Metalaxyl + Mancozeb @500 g or Mancozeb 1000g/ha.
2. Ergot: Claviceps fusiformis
- Cream to pink mucilaginous droplets of “honeydew” ooze out of infected florets on pearl millet panicles.
- Within 10 to 15 days, the droplets dry and harden, and dark brown to black sclerotia develop in place of seeds on the panicle.
- Sclerotia are larger than seed and irregularly shaped, and generally get mixed with the grain during threshing
- Conditions favoring the disease are relative humidity greater than 80%, and 20 to 30 0C temperatures during flowering.
- Spray any one of the fungicides like Carbendazim 500g or Mancozeb 1000g /ha when 5 – 10% flowers have opened and again at 50% flowering stage.
3. Cumbu Rust: Puccinia substriata
- Small reddish-brown to reddish orange, round to elliptical uredinia develop mainly on foliage.
- As severity of infection increases, leaf tissue will wilt and become necrotic from the leaf apex to base.
- In infection sites developing late in the season, uredinia are replaced by telia which are black, elliptical, and subepidermal.
- Sowing during December – May result in less incidence.
- Adopt control measures when there is rust incidence in the early stages as spread of infection to top leaves results in poor grain filling.
- Spray any one of the following fungicides when the initial symptoms of the diseases are noticed. Wettable sulphur 2500g / ha Mancozeb 1000g/ha
- Repeat application 10 days after if necessary.
4. Cumbu Head Mold: Various fungi
- Pink, white, brown or grey fungal growth on grain. Apparently asymptomatic seed may be contaminated.
- Many pathogens cause grain molds.
- Grain molds on pearl millet tend to be more severe with humid conditions during grain fill and if grain harvest is delayed
- Several fungi cause grain molds, and these differ by the region of cultivation, crop management, environmental conditions prior to harvest, and storage conditions.
- Spray mancozeb 1kg/ha or Captan 1kg +Aureofungisol 100g/ha if intermittent rainfall occurs during earhead emergence, a week later and during milky stage.
5. Bipolaris Leaf Spot: Bipolaris setariae
- Foliar symptoms vary, as brown flecks, fine linear streaks, small oval spots, large irregular oval, oblong, or almost rectangular spots measuring 1-10 x 0.5-3 mm.
- Large fusiform lesions are sometimes produced.
- Lesions may expand and coalesce.
- Lesions may be solid dark brown but usually become tan or greyish brown with a more or less distinct dark brown border.
6. Cercospora Leaf Spot:Cercospora penniseti
- Foliar lesions are typically oval, 1-8 x 0.8-2.5 mm, with dark brown margins and pale tan to grey or white centers, dotted with rows of black conidiophore tufts. Lesions can form on stems.
7. Curvularia Leaf Spot-Curvularia penniseti
- Small yellow-brown spots on leaves expand to oblong lesions. Center of lesions change to brown and margins remain yellow. Lesions are more common on leaf margins.
- Leaf spots can be managed by spray Mancozeb 1kg/ha
- TamilNadu Agritech Portal