Pests of Sorghum and their Management by agrifunda


Hi friends. Welcome to the agrifunda . Today post on ‘Pests of Sorghum and their Management’. Sorghum is one of the major cereal crops in India. The successful cultivation of sorghum crop is aided by many factors. One such factor is insect pest. So far more than 150 pest species have been reported on this crop. Of which, few of them are causing serious damage or economic damage. Like shoot fly, stem borer, shoot bug, arid bug, arid mite, and defoliators like army worm and fall army worm.


Pests of Sorghum and their Management by agrifunda



Pests of Sorghum and their Management:

Let us understand these pests in detail. Except fall army worm. It will be covered under mites. We will start with sorghum shoot fly. Scientific name is Atherigona soccata, belongs to family Muscidae of the order Diptera. It prefers to attack up to 4th week old crop or less than one month old crop. Thereby it affects the establishment of the crop. Late sowing in kharif and early sowing in winter increases its incidence. Coming to adult identification. Adult fly looks like housefly, but smaller than housefly, with 6 dark spots on the dorsal abdomen region of the female. While in male only 4 dark spots are present.

Life-cycle:

Then coming to life-cycle. It has 4 life stages. One is egg, maggot, pupa and adult. Here adult female lays finger shaped or cylindrical eggs on lower surface of the leaf, particularly 2nd to 5th youngest leaves. Maggot is yellowish in color and apodous. Pupa, it pupates in the central shoot, sometimes in the soil. It takes 17 to 22 days to complete a single generation. Then coming to nature of damage. Maggot is the damaging stage. It enters into the central shoot causing death of the central shoot, commonly called dead heart. If you pull the dead heart, it comes out very easily. Sometimes dead heart leads to production of side shoots or tillers.

Then coming to ETL. 10% dead heart. Management as a preventive measures. Go for early sowing, that is before June 15th to escape from the incidence of this pest. If sowing is delayed, then go for higher seed rate. So here use 2 kg extra seed. Seeds to maintain optimum population. Then other preventive measures are, go for synchronized sowing. Use resistant varieties. Few resistant varieties are available. Again they are location specific. If resistant varieties are not available then go for seed treatment with imidacloprid @ of 3gm per kg seeds.
Then as a curative measure, destroy the affected plant parts or plants, within 15 days after sowing. Then other curative measures are set up fish meal traps @ 5 traps per acre for mass trapping of adult flies. As a last option you can spray insecticide like imidacloprid @ of 3ml per liter of water, at 12 to 14 days after sowing.




Stem borer:


Then another major pest on sorghum is stem borer. That is Chilo partellus, belongs to family Crambidae of the order Lepidoptera. It occurs on sorghum crop after one month and causes 25 to 30% yield loss. In addition to sorghum it attacks other cereals, even commercial crops like sugarcane. Adult is straw colored moth with a series of black spots present on the apical region of front wing. Then coming to life- cycle. It has 4 stages. Egg, larva, pupa and adult. So here adult female lays eggs on leaves in groups. Eggs are flat, scale like and they are overlapping each other. Then larva is yellowish brown in color with a dark head and prothoracic shield. Pupation occurs inside the stem. It takes 30 to 40 days to complete single generation.

Nature of damage:


Then coming to nature of damage. Larva is the damaging stage. It bores into the stem and feeds on internal content of the stem, thereby it affects the supply of nutrients to the growing points, causing death of the central shoot. Commonly called dead heart. If you pull the dead heart, it comes out very easily. In addition to dead heart you can see the series of pinholes on the leaf. Coming to ETL. 10% dead heart.

Management:



Management, as a monitoring set up the light traps @ one trap per acre. Then as a preventive measure, destroy the stubbles immediately after harvest of the crop. This is to kill the pupa. Then go for crop rotation with non-cereals to break the life cycle of the pest. Then go for intercropping with cowpea. So pest will take more time to establish on the crop. Then as curative measures, collection and destruction of affected plant parts, especially dead hearts along with larvae and pupae. Spray NSKE @ 5% or commercial neem product containing Azadirachtin @ of 2ml per liter of water. As a last option you can go for oral application of Carbofuran @ 7.5 kg per hectare or you can go for foliar application of newer insecticide molecules like Chlorantraniliprole @ of 0.2ml per liter of water.

Army worm:

Then another major pest on sorghum is army worm that is Mythimna separata. It belongs to family Noctuidae of the order Lepidoptera. It is a major defoliator on sorghum crop. In addition to sorghum it also attacks other cereals. Usually it causes 33% leaf damage. Adult is medium sized moth usually straw colored. An adult female lays eggs in groups on leaves. These eggs are covered by brownish hairs. Then larva. Early instars are dark green in color. Later turns to greenish brown. Larvae are nocturnal in habit. During daytime they hide in the central leaf whorl or in the plant debris. Or sometimes under the stone or clots etc. Pupation occurs in the soil.

Nature of damage:


Then coming to nature of damage. Larvae is the damaging stage. Larvae feeds on leaf from margin, leaving only midrib and stalk of the plant. Resulted in defoliation of the plant. So here you can see the defoliated plants. Management. As a monitoring install the light traps @ one trap per acre. Then as a preventive measures go for deep summer ploughing to expose the pupa to the hot sunlight or to the insectivorous birds. Keep the field clean and also the surrounding plants. Because larvae take shelter in the plant debris.
Then curative measures. Go for collection and destruction of egg masses newed larva, since they are in group. Then spray fungal pathogen like Metarhizium rileyi @ 2 to 5g per liter of water. As a last option you can spray synthetic pyrethroid like lamda-cyhalothrin @ 0.5 ml per liter of water. If spraying is difficult you can go for application of poison bait @ 50 kg per hectare.


Shoot bug:


Then another major pest on sorghum is shoot bug. That is the Perigrinus maidis. It belongs to family Delphacidae of the order Hemiptera. It is one of the major sucking pest on sorghum, especially on rabi sorghum in southern India. In addition to sorghum it also attacks other cereals. Adult is small active, pale brown with translucent wings. So here adult female insert eggs into the tissues of the leaf. Nymphs and adults are the damaging stage. They suck the sap from the central leaf whorls, sometimes on the leaf sheath of the tender plants. Resulted in yellowing of leaves and stunted growth of the plant. Under severe infestation plants dry up.
Indirectly it acts as a vector in transmission of maize dwarf mosaic virus, and freckled yellows. The pest can be easily diagnosed in the field. Presence of ant activities in the central leaf whorls. Management. As a preventive measures, go for seed treatment with Imidacloprid @ 2g per kg seeds. Then as a curative measures. Spray fungal pathogen like Lecanicillium lecanii @ 2 to 5g per liter of water. Or spray NSKE @ 5% or Azadirachtin @ 2ml per liter of water. As a last option you can spray any one of the insecticides at recommended dose.
Then ear head midges, that is the Contarinia sorghicola. It belongs to family Cecidomyiidae of the order Diptera. It is one of the major ear head pest on sorghum. In addition to sorghum it also attacks other Graminaeceous plants. Adult looks like mosquito with long legs. Abdomen is orange or orange-yellow in color. So here adult female insert eggs into the floret. And hatching maggots feeds on ovary inside the floret, causing chaffy grains or blighted grains. If you press the blighted grains, you can see the pinkish fluid comes out from the grains. That indicates the presence of the pest.



Then ETL. 5 blighted grains per ear head or 5 midges per ear head. As a management, as a preventive measures go for synchronized sowing. As a curative measures, spray Melathion 50EC @ 2ml per liter of water, when the crop is at ear head formation stage.

Ear head bug:


Then another major pest on sorghum is ear head bug. That is the Calocoris angustatus, belongs to family Miridae of the order Hemiptera. It is another ear head pest on sorghum, especially in southern India. It prefers to attack compact ear head varieties, than open type of varieties. It attacks at the milky stage of the crop. So here adult is delicate with long legs, usually pale green in color. Nymphs and adults are the damaging stage. They suck the juice at the milky stage of the crop leading to chaffy grains and grains are shriveled. Even affected ear head appears uneven.
ETL, 10 bugs per ear head. Management. As a preventive measure go for synchronized sowing. As a curative measure, dust Melathion 5% d @ 8 to 10 kg per acre, when the crop is at the milky stage.

Thank You.

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