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TNAU Agritech Portal :: Crop Protection

   
Stem fly: Atherigona orientalis Web worm: Cryptoblabes gnidiella
Stem borer: Chilo partellus Ash weevil: Myllocerus sp
Pink stem borer: Sesamia inferens Leafhopper: Pyrilla perpusilla
Corn worm: Helicoverpa armigera Aphid or Plant lice: Rhopalosiphum maidis
Ear head bug: Calocoris angustatus Shoot bug: Peregrinus maidis
   

Important pests

I. Borer
Stem fly: Atherigona orientalis


Symptoms of damage

  • The maggot feeds on the young growing shoots results in “dead hearts”.

Identification of the pest

  • Adult - Small grey coloured fly.
Adult Nymph, Larva, Pupa and Adult Dead Heart

Management

  • Use seeds pelleted with insecticides (see sorghum)
  • Seed treatment with imidacloprid 70 WS 10 g/kg of seeds
  • 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.
  • Soil application of phorate 10%CG 10 kg/ha at the time of sowing

Apply any one of the following insecticides:

  • Methyl demeton 25 EC 500 ml/ha
  • Carbofuran 3%CG 33.3 kg/ha
  • Dimethoate 30%EC 1155 ml/ha
  • Methyl demeton 25% EC 1000 ml/ha
  • Phorate 10%CG 10 kg/ha

Top 
Stem borer: Chilo partellus

Symptoms of damage

  • Central shoot withers and leading to “dead heart”.
  • Larvae mines the midrib enter the stem and feeds on the internal tissues.
  • Bore holes visible on the stem near the nodes.
  • Young larva crawls and feeds on tender folded leaves causing typical “shot hole” symptom.
  • Affected parts of stem may show internally tunnelling caterpillars

Elongated windows

Bore hole Dead heart

Identification of the pest

  • Larva - Yellowish brown with a brown head 
  • Adult - Moth is medium size, straw coloured
 

 

Larva and Pupa Moth
Management
  • Mix any of the following granular insecticides with sand to make up
    a total quantity of 50 kg and apply in the leaf whorls on the 20th
    day of sowing
  • Phorate 10% CG10 kg/ha
  • Carbaryl 4% G 20 kg/ha.
  •  For stem borer, release egg p[arasitoid Trichogramma chilonis @
    2,50,000 /ha coinciding egg laying period. Three releases at
    weekly interval are desirable. Third release is to be accompanied
    with larval parasitoid Cotesia flavipes @ 5000/ha
  • If granular insecticides are not used, spray any one of the
    following :
  • Carbaryl 50 WP 1 kg/ha on the 20th day of sowing (500 l of spray
    fluid/ha).
  • Dimethoate 30% EC 660 ml/ha

Top 
Pink stem borer: Sesamia inferens
Symptoms of damage
  • Pink larva enters into the stem causing dead heart symptom .

Identification of the pest

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

Management

  • Spray phosaloneb 35%EC at every 20 days interval

Egg

Pupa and Larva

Adult

Top 
II. Earhead feeders
Corn worm/Earworm: Helicoverpa armigera

Symptom of damage

  • Larva feeds on silk and developing grains.

Bore hole on the cob

 

Identification of the pest

  • 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 debris

Adult

  • 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.

Management

  • Set up of light traps
  • Set up sex pheromone traps at 12/ha
  • 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 ear heads

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

Larva in different colour forms

Nymph
Adult

Top 
Ear head bug: Calocoris angustatus

Symptom of damage

  • 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.
  • Orange and pale green nymphs and adults are seen on the ear head.

Identification of the pest

  • 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

Management

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%
  • Azadirachtin 1%

III. Leaf feeders
Web worm: Cryptoblabes gnidiella

Symptom of damage

  • larva first feeds on the lemma of the flowers scraping the chlorphyll
  • later on the milky grains.
  • Webbing of maize cobs and feeding on the flowers and the grains.

Identification of the pest

  • Larva - Long and dark brown. It forms silken webs on cobs
  • Adult - Dark grey forewings

Management

  • Spray monocrotophos

 


Top 
Ash weevil: Myllocerus sp.

Symptom of damage

  • larva feeds on the secondary roots and adults on leaves.

Identification of the pest

  • Adult - Grey coloured weevil.

 

Management

    • Mix any of the following granular insecticides with sand to make up
      a total quantity of 50 kg and apply in the leaf whorls on the 20th
      day of sowing
    • Phorate 10% CG10 kg/ha
    • Carbaryl 4% G 20 kg/ha.
    •  For stem borer, release egg p[arasitoid Trichogramma chilonis @
      2,50,000 /ha coinciding egg laying period. Three releases at
      weekly interval are desirable. Third release is to be accompanied
      with larval parasitoid Cotesia flavipes @ 5000/ha
    • If granular insecticides are not used, spray any one of the
      following :
    • Carbaryl 50 WP 1 kg/ha on the 20th day of sowing (500 l of spray
      fluid/ha).
    • Dimethoate 30% EC 660 ml/ha

Top 
IV. Sap feeders
Leafhopper:  Pyrilla perpusilla

Symptom of damage

  • Leaves become yellow
  • Covered with black sooty mould
  • Top leaves get dried up and lateral buds germinate

Identification of the pest

  • Nymph - Soft, pale brown dorsally and pale orange ventrally
  • Adult - Straw coloured, head pointing forward as a snou

 

Management
  • Avoid excessive use of nitrogenous fertilizers
  • Set up light trap
  •  Detrash: 150 and  210th  DAP
  •  Release lepidopteran parasitoid:
  • Epiricrania melanoleuca @8000 -10,000 cocoon /ha (or) 8 - 10 lacs egg/ha.
  • Spray any one of the following on the 150th and 210th day (1000 l spray fluid)
    • Malathion 50 EC 2000 ml
    • Monocrotophos 36 WSC 2000 ml

Top 
Aphid or Plant lice: Rhopalosiphum maidis

Symptom of damage

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

Identification of the pest

  • Yellow with dark green legs

 

DSC06230.JPG
Aphids Winked Adult Colony of aphids
Nymph Nymph
Management
  • Mix any of the following granular insecticides with sand to make up
    a total quantity of 50 kg and apply in the leaf whorls on the 20th
    day of sowing
  • Phorate 10% CG10 kg/ha
  • Carbaryl 4% G 20 kg/ha.
  •  For stem borer, release egg p[arasitoid Trichogramma chilonis @
    2,50,000 /ha coinciding egg laying period. Three releases at
    weekly interval are desirable. Third release is to be accompanied
    with larval parasitoid Cotesia flavipes @ 5000/ha
  • If granular insecticides are not used, spray any one of the
    following :
  • Carbaryl 50 WP 1 kg/ha on the 20th day of sowing (500 l of spray
    fluid/ha).
  • Dimethoate 30% EC 660 ml/ha

Top 
Shoot bug: Peregrinus maidis

Symptom of damage

  • 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.

Identification of the pest

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

Management

Spray any following insecticides

  • Diazine0.04%
  • Dimethoate (or) 0.02%,
  • Phosphomidon @ 250 ml in 450-500 litres water/ha
Nymph Adult
Top 
Updated on June, 2014

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