| Sign of Attack/ Symptom |
Control |
| Insect-pests |
|
| Maize borer : Caterpillars intially feed on young leaves in the whorl which show shot hole symptoms and borne into central shoots and stem. They feed on the tissues of the stem and cause dead hearts. Attacked plants gradually dry and wither. The damage is more serious on young plants. In older plants, larvae sometimes bore into cobs and eat the ripening grains. |
1. Adopt clean cultivation by removing weeds, ploughing and removing alternate hosts.
2. Use high seed rate to compensate for early attack.Uproot and destroy those pants showing shot holes or borer injury.
3. Apply in soil 2 g phorate (Thimet 10 G)/M row before sowing sprinkle the granules over the central whorl especially of those plants showing shot holes.
4. At harvest, cut the plants as near the ground as possible. Collect the stubbles and burn them. Caution :Do not use insecticides on maize fodder. |
| Hairy caterpillars and grasshoppers : Both insects feed on foliage and soft stems of young maize plants. Hairy caterpillars initially feed gregariously and are noticeable. |
1. Collect and destroy the congregating caterpillars.
2. Dust Folidol 2% @ 20-25 kg/ha |
| Cutworms, black beetles and white grubs : These insects remain hidden in soil and cause heavy damage to seedlings immediately after germination mixed with 25 kg sand per ha at sowing time. |
1. Use of well decomposed FYM
2. Use high seed rate
3. Apply 2 L Chloropyriphos 20 EC |
| Blister beetle :Adults feed voraciously at the tasselling stage. |
Spray 1250 ml endosulfan (Thiodan/ Endocel 35 EC) or 625 ml methyl parathion (Metacid 50 EC) in 625 L water/ha at the tasselling stage. |
Diseases
|
| Bacterial stalk rot : The disease generally appears at the time of flowering. One or a few basal internodes above the soil line become tan to dark brown, water soaked and soft. The stems easily break at the point of attack. Alcoholic smell in the affected plant is a diagnostic feature of the disease. |
1.Apply judicious doses of nitrogen and potassic fertilizers. Avoid heavy nitrogen fertilization.
2. Field should be properly drained off excess water.
3. Drench maize field with bleaching powder (3%) @ 16.5 kg/ha or Klorocin granules @ 15 kg/ha (one application only) a week before tasselling or initial appearance of disease. Give two more drenches at weekly intervals in case of bleaching powder application.
4. Grow resistant variety in low and mid hills. |
| Leaf blight : Blight generally appears when the crop is about 30-40 days old, appearing first on flower leaves and progressing upwards. Lesions due to turcicum leaf blight are long, eliptical, greyish green or tan reaching upto 15 cm length whereas those of maydis leaf blight are tan coloured with parallel sides ranging from 1-2 cm in length. The disease affect leaf sheaths, earhusks, shanks, ears and cobs also. In severe cases, drying up of leaves and premature death of the plants also occurs. |
1. Early sowing preferably before 10 th June results in less
2. Apply recommended dose of nitrogenous fertilizers.
3. Spray the crop with Indofil Z-78 or Indofil M-45 (1.5 kg in 750 L water/ha) when disease is first observed. Repeat at 10-day interval in case of seed crop, sweet corn or pop corn. |
| Brown spot : Brown stripe :Lesions develop on leaves as narrow, chlorotic or yellowish stripes, 3-7 mm wide with well defined by the veins. Strips later become reddish to purple in colour. Whitish downy growth on the early morning is diagnostic feature of diease. |
Spray the crop with Indofil M-45 (1.5 kg in 750 L water/ha) at bi-weekly interval starting as soon as the disease is noticed. |
| Head smut : The symptoms are observed at the time of tasselling and ear formation which are completely or partially transformed into black powdery mass. |
1. Treat seed with vitavax/Bavistin @ 2.5 g/kg before sowing.
2. Rogue out the infected plants
3. Follow a rotation of 4-5 years in infested fields. |
| Seed rot and seedling blight : Infected seeds when sown especially in cold wet soil may result in killing of embryos before germination or in the killing of the seedlings before or after emergence. Seedling blight may occur due to soft rot of the stem tissue and water soaking near the ground level. |
1. Sow healthy seed of recommended varieties by eliminating seed lots showing streaking or pericarp injury.
2. Treat seed with Thiram @ 2.5 g/kg seed.
3. Avoid sowing in cold wet soil |
| Leaf and sheath banded blight : This disease appears at pre-tasselling stage on 40-50 days old plants in the form of 1-2 cm straw coloured bands. From distance, symptoms look like as cast-off snake skin. On the stalk, disease starts from soil leavel and the lesions develop on leaf sheath upto 4-5 internodes.Later on, dark brown coloured sclerotia of the fungus develop on these lesions. Silk fibers darken at the end and caked up and turned into hardened structure. Sometimes grains fails to develop. Crown portion of the grain becomes lusterless. Kernels turn light in weight and chaffy. All plant parts except root and tassels are infected. |
1. Infected plants should be uprooted and brunt. While uprooting plants, care should be taken that the sclerotia of the fungus do not fall in the field.
2. Grow moderately resistant varieties like Early Composite and Parvati.
3. The recommended row to row and plant to plant distance should be strictly followed in order to avoid contact of diseased leaves with healthy leaves.
4. When the crop is 40-45 days old the disease sheaths and leaves should be removed from infected plants and burnt.
5. Spray Indofil M-45 (0.2%) as soon as the disease appears. Repeat the spray after 10 days depending upon the stage of crop and disease severity. |
| Seed rot and seedling blight : Late wilt : Sudden wilting of leaves at tasselling with the leaves turning dull green. Lower stalk portions become dry, shrunken and hollow. The stalk when split shows discoloration of the split tissue. The disease is severe in sandy or clay soil. |
1. Apply recommended dose of potassic fertilizer at sowing at sowing time in drought prone areas.
2. Irrigate the crop at flowering stage
|
| Seed rot and seedling blight : Brown spot : Symptoms appear on leaf blades, leaf sheaths and stalks; lesions concentrated towards the leaf base small, yellowish which later turn brown. Stalk also get infected at the nodes baneath the sheaths. Severe infection leads to stalk breakage. |
Practice crop rotation and sanitation. |