Crop: Sorghum

Scientific name: Sorghum Bicolor

Order: Cyperales

Family: Poaceae

Local names: Mtama (Swahili)

Important pests of sorghum

I. Borer

II. Earhead feeders

III. Sap feeders

Symptom of damage

• The maggot bores inside the stem and cuts the growing point.
• Central shoots dried and produce “dead heart” symptom.
• The infested plant produces side tillers.

Identification of the pest

• Egg - white, cylindrical, distal somewhat flattened
• Adult - Whitish grey fly

Management

• ETL: 1 egg/plant in 10% of plants in the first two weeks of sowing or 10% dead hearts
• Take up early sowing of sorghum immediately after the receipt of South West or North East monsoon to minimise the shoot fly incidence.
• Use seeds pelleted with insecticides
• Seed treatment with imidacloprid 70 WS @ 10 g/kg of seeds
• In case of direct seeding, use increased seed rate upto 12.5 kg/per hectare and remove the shoot fly damaged seedlings at the time of thinning or raise nursery and transplant only healthy seedlings.
• Plough soon after harvest, remove and destroy the stubbles.
• Set up the TNAU low cost fish meal trap @ 12/ha till the crop is 30 days old.

Spray one of the following for an area of 120 m2 nursery :

• Methyl demeton 25 EC 12 ml/ha
• Dimethoate 30 EC 12 ml/ha

In main field for direct sown crop spray any one of the following

• Methyl demeton 25 EC 500 ml/ha
• Dimethoate 30 EC 500 ml/ha
• Neem Seed Kernel extract 5%
• Soil application of phorate 10 G 18 kg/ha or carbofuran @ 33.3 kg /ha at the time of sowing

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Symptoms of damage

• Withering and drying of central shoot -“ dead heart”
• Red mining in the midrib
• Bore holes visible on the stem near the nodes.
• Tender folded leaves have parallel “ shot hole ”
• Affected parts of stem may show internally tunneling of caterpillars

• Egg - Scale-like flat oval eggs in batches on the under surface of leaves near the midribs.
• Larva - Yellowish brown with a brown head and prothoracic shield.
• Adult - Moth is medium size, straw coloured.

• ETL: 10% damage
• Sowing the lab lab / cowpea as an intercrop to minimise stemborer damage (Sorghum: Lab lab /cowpea 4:1).
• Set up of light traps till mid night to monitor, attract and kill adults of stem borer, grain midge and earhead caterpillars
• Mix any one of the following insecticides with sand to make up a total quantity of 50 kg/ha and apply in the leaf whorls :
• Phorate 10 G 8 kg/ha
• Carbofuran 3 G 17 kg/ha
• Spray any one of the following insecticides : Carbaryl 50 WP 1.00 kg/ha (500 l spray fluid/ ha).

• Central shoots dried and produce the dead hearts.

• Egg - Bead like laid in rows within the leaf sheath
• Larva - Pinkish brown with dark head
• Adult - Straw coloured moth with white wing

• Earheads are partially eaten with chalky appearance.
• Feacal pellets are visible within the ear heads.

• Eggs - Spherical in shape and creamy white in colour, laid singly
• Larva - Shows colour variation from greenish to brown.
• It has dark brown grey lines on the body with lateral white lines
• Pupa - Brown in colour, occurs in soil, leaf, pod and crop debri

• Light pale brownish yellow stout moth.
• Forewings are olive green to pale brown with a dark brown circular spot in the centre.
• Hind wings are pale smoky white with a broad blackish outer margin.

• ETL: 2 / earhead
• Set up of light traps till mid night to monitor, attract and kill adults of stem borer, grain midge and earhead caterpillars.
• Set up sex pheromone traps at 12/ha to attract male moths of Helicoverpa armigera from flowering to grain hardening. Two applications of NPV at 10 days interval at 1.5 X1012 POB along with crude sugar 2.5 kg + cotton seed kernel powder 250 g on the earheads is effective in reducing the larval population of Helicoverpa .

Apply any one of the following on 3rd and 18th day after panicle emergence

• Plants become unhealthy stunted and yellow.
• The leaves wither from top downwards.
• Panicle formation is inhibited and the plants die if attack is severe.
• Honeydew secreted by the bug causes growth of sooty mould on leaves.
• The midribs of the leaves turn red due to egg-laying and may dry up subsequently.

• Egg - Laid inside the leaf tissue and covered with a white waxy substance.
• A dult - Yellowish brown to dark brown with translucent wings.

• Spray with 0.04% diazine (or) dimethoate 0.02%
• Application of phosphomidon @ 250 ml in 450-500 litres water/ha.

• Nymphs and adult suck the juice from within the grains when they are in the milky stage.
• Grains shrink and turn black in colour and ill filled (or) chaffy.
• Presence of large number of nymphs and adults are seen on the ear head.

• Egg - Blue cigar shaped , laid under the glumes or into the middle of the florets
• Nymphs - Slender, green in colour
• Adults - Male is green in colour. Female is green with a brown margin

• ETL: 10 / earhead
• Apply any one of the following on 3rd and 18th day after panicle emergence :
• Carbaryl 10 D 25 kg/ha
• Malathion 5 D 25 kg/ha
• Neem seed kernel extract 5%
• Spray twice with Malathion 50 EC 500 ml/ha. in 500 lit of water at 10% heading and 9days after.

• Pollen shedding due to egg laying
• White pupal cases protruding out from the grains
• Chaffy grains with holes

• Adult - Fly is small, fragile with a bright orange abdomen and a pair of transparent wings.

• Sett up of light traps till mid night to monitor, attract and kill adults of stem borer, grain midge and earhead caterpillars.
• Apply any one of the following on 3rd and 18th day after panicle emergence :
• Carbaryl 10 D 25 kg/ha
• Malathion 5 D 25 kg/ha
• Phosalone 4 D 25 kg/ha
• Neem seed kernel extract 5% (or) Spray malathion 50 EC @ 1600 ml/ha or phosalone 1150 ml/ha
• The sowing of sorghum should be completed in as short a time as possible to avoid continuous flowering which favours grain midge and earhead bug multiplication in an area.

• Yellowing of leaves
• Colonies of aphids found in central leaf whorl.

• Yellow with dark green legs

• Spraying the base of attacked plants with a contact (or) systemic insecticide controls the aphid.