ADVERTISEMENTS:
The following points highlight the five major diseases of barnyard millet with its management. The diseases are: 1. Head Smut 2. Grain Smut 3. Kernel Smut 4. Leaf Spot or Blight 5. Leaf Blast.
Barnyard Millet: Disease # 1. Head Smut:
Head smut of barnyard millet is known to be caused by Ustilago crusgalli. It also infects E. colonum in Karnataka and Tamil Nadu. The disease has been reported from India and United States. In India, it has been reported from Madhya Pradesh and Uttarakhand. According to Kulkarni (1922) when seeds are mixed with spores and sown, about 90 per cent of the plants become infected.
The infected inflorescence is deformed and destroyed. In addition, the smut also produces gall-like swellings on the stem, the nodes of young shoots and in the axils of the older leaves. Sometimes, twisted, deformed clusters of leafy shoots with aborted ears may also develop.
ADVERTISEMENTS:
The gall-like swellings are covered by a hairy rough membrane of host tissue and may be up to 12 mm in diameter. The pathogen infects only ovaries. The affected ovary is transformed into hairy, grey sac, round but does not increase in size than the normal grain.
The disease is externally seed borne and occurs late in the crop season when the crop is about to mature. During this time, the temperature ranges with in 20 to 25°C.
Management of Head Smut:
Since, the disease is seed-borne; it can be easily controlled by seed treatment with Carbendazim or Thiram at the rate 2 g/kg seed before sowing. The variety PRJ 1 is reported to be resistant to this disease. Rouging of infected plants from the field is also helpful in reducing the spread of disease.
Barnyard Millet: Disease # 2. Grain Smut:
ADVERTISEMENTS:
Grain smut disease is prevalent in Eastern Europe and in many states of India such as Uttar Pradesh, Bihar, Uttarakhand, Karnataka and Maharashtra. In nature, smut incidence has been found to range from 0-75% on different species of barnyard.
The disease is ovariculous but only few grains in an ear are affected. The affected seeds enlarge two to three times of their normal size and their surface becomes hairy. The disease appears at the time of grain formation when the temperature ranges from 20 to 25°C.
Management of Grain Smut:
ADVERTISEMENTS:
Pall and Nema (1978) reported that seed treatment with Ceresan dry, Dithane M 45, MBC, and Thiram controlled the disease. Pre-sowing treatment with either Carbendazim or Thiram at the rate 2 g/kg seed is also recommended.
Barnyard Millet: Disease # 3. Kernel Smut:
Ustilago paradoxa causing the kernel smut, was first recorded in Italy. In India, it has been reported from Bihar, Maharashtra, and Tamil Nadu.
Only few grains in ear are infected. They are scattered and the affected grains appear as greenish swollen bodies. The sori are 1.5-4 to 1-2 mm in size and up to 25 infected grains may occur in a panicle.
Management of Kernel Smut:
Since, the disease is seed-borne; it can be controlled by seed treatment with systemic fungicides.
Barnyard Millet: Disease # 4. Leaf Spot or Blight:
ADVERTISEMENTS:
Leaf spot or blight caused by Helminthosporium crusgalli, was first reported in 1923 by Drechsler from the USA. The disease is also reported from Japan China and India.
The disease appears as isolated, dark brown, scattered and spindle shaped spots, measuring 0.5 to 3.0 mm x 0.25 to 1.5 mm, on flag leaves. Afterwards, several such spots coalesce and cover the entire leaf, which becomes grey and dried up.
The spots are dark brown to grey in colour and are surrounded by yellow halo. Just after the appearance of the lesions, dark points are visible in the centre. Under humid conditions fungal growth is visible on these spots. In severe form the leaves show brightening. Similar spots can also be seen on the leaf sheath. The disease is most common under humid conditions.
Management of Leaf Spot or Blight:
ADVERTISEMENTS:
Since, the primary infection comes from the seed-borne inoculum; seeds treatment with systemic fungicides before sowing helps in disease control. Spraying of copper fungicides at the rate 0.3% helps in reducing the disease intensity.
Barnyard Millet: Disease # 5. Leaf Blast:
Leaf blast is caused by the fungal pathogen Magnaporthe grisea (anamorph: Pyricularia grisea). The symptoms in form of spindle to circular shaped spots and of different sizes appear on the young seedlings in the field. In the beginning the isolated spots have yellowish margin and grayish centre.
Later, the centres become ash coloured. Under humid conditions, an olive-grey overgrowth of fungus having conidiophores and conidia develops at the centre of the spots. At the later stage of infection the spots enlarge and coalesce.
Temperature range of 25-30°C, humidity of 90 per cent and above, cloudy days with intermittent rainfall, are favourable for the development and rapid spread of disease.
ADVERTISEMENTS:
Management of Leaf Blast:
Seed treatment with Thiram, Mancozeb or Carbendazim at the rate 2 g/kg seed 24 hours before sowing is effective. Sowing early in the season, replacing 25% N with either FYM or compost reduces the blast severity.
