Pest of Maize and their Management by agrifunda


Hi friends. Welcome to the agrifunda today post on ‘Pests of Maize and their Management’. Maize is another major cereal crop grown in India. The crop is prone to attack by a number of insect as well as non-insect pests. So far more than 130 pest species have been recorded on maize. Of which some of them are causing serious damage or economic damage to the crop. Some of the major insect pests are serious pests recorded on maize includes shoot flies, stem borers, stem bug, cob worm and defoliators like army worm and fall army worm.



 Pest of Maize and their Management by agrifunda


Pest of Maize and their Management

Let us understand the cob army worm and the fall army worm in detail. Remaining pests are already dealt under sorghum. So we will start with cob worm. Scientific name is Helicoverpa armigera.  It belongs to family Noctuidae of the order Lepidoptera. It is polyphagous. It has more than 200 host plants, includes field as well as horticultural crops. Then coming to adult identification. Adult is a medium sized moth. Forewings are pale brown to yellowish brown in color. Wings, V-shaped speck. And hind wings are dull white in color with dark border


life cycle :

Then coming to life cycle. It has 4 life stages. Egg, larval, pupal and adult stage. So here adult female lays eggs singly on the silk of the crop. So eggs are spherical in shape with longitudinal ridges. Then larva, variously colored or polyphormic in nature. Usually pale white, longitudinal stripe or band present on lateral side of the abdomen. Pupation occurs in the soil. It takes 25 -30 days to complete single generation.


 Pest of Maize and their Management by agrifunda


Nature of damage and damage symptoms:


Then coming to nature of damage and damage symptoms. Larva is the damaging stage. It feeds on silk and milky grains at the tip of the cob, thereby yields get reduced. Coming to Management. Handpicking of grown up larva from the plant and destroy them. Spray anyone of the bio-pesticides, either Metarhizium rileyi @ 2-5g per liter of water, or you can spray Ha NPV @ 100 larval equivalent per acre. Spray Ha NPV in the evening hours. Add jaggery to the spray solution. It acts as a further stimulant. If you are spraying NPV in the morning or in the afternoon. Add .1% boric acid, it protects the virus particle from the weevil race. As a last option you can spray newer insecticides molecules like chlorantraniliprole @ 2 ml per liter of water.

Fall army worm:


Then another major pest on maize is fall army worm. That is spodoptera frugiperda. It belongs to the family Noctuidae and of the order Lepidoptera. It is a new invasive pest reported from India. It was first reported on rice from Karnataka in the year 2018. Its native is South America. Probably it has entered India from African countries. It is polyphagous. It has more than 500 host plants. In India it was noticed on sugarcane, paddy, jowar, ragi etc.
Then coming to adult identification character. Adult is medium sized moth. It exhibits sexual dimorphism. In male, forewings are shaded with gray and brown with a triangular bright spot on the apical region of forewings and a circular spot in the center. In female, forewings are uniformly greyish brown to a fine mottling of grey and brown. Hindwings are silvery white in color with a narrow dark border, both in the male as well as in the female.
life cycle.

here adult female usually lays eggs on leaves. Sometimes it lays eggs on the stem or in the central leaf whorls. Eggs are covered by brownish hairs. Usually eggs are golden yellow in color. Then larva. Here larva has white inverted Y shaped line on the head, especially on the frons. Larva also has 4 dark spots on the dorsal region of eighth abdominal segment, which are arranged in square pattern. Pupation occurs in the soil. It takes 24 to 35 days to complete a single generation.

Nature of damage



Then coming to nature of damage. Larva is the damaging stage. Neonate larva feed by scrapping the green tissues. Grown up larva feed large amount of green tissue, causing window pane like damage on the leaves in the early stages. As appearing only as a scratch on the leaf. At later stages you can see the ragged and elongated holes on the leaves, leading to shredded appearance.

Management:


Then management. In India as a fall army worm recorded as a new pest on maize. We do not have any scientific recommendation. But we have adhoc recommendation. Some of the adhoc recommendations are, set up light traps @ 2 traps per acre at the time of sowing for monitoring the pest. As a preventive measure go for deep ploughing before the onset of rains. Then go for area wide sowing in early June. Avoid late sowing in August.


 Pest of Maize and their Management by agrifunda


Then as a curative measures, collection and destruction of egg masses as well as early instars, since they are in group. Then spray fungal pathogen like Metarhizium anisopliae or Metarhizium rileyi @ 2g per liter of water or you can spray commercial product containing Azadirachtin @ 2ml per liter of water. As a last option, you can spray synthetic pyrethroids like lamda-cyhalothrin @ 1ml per liter of water, or you can use newer insecticide molecules like chloranthraniliprole @ 0.4ml per liter of water, or you can use emmamectin benzoate @ 0.5g per liter of water, or you can use spinetoram @ 0.4ml per liter of water. If spraying is difficult, then you can apply poison bait in the evening hours.

Thank You.

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