Yield maximization from high yielding varieties can be attributed through effective insect-pest management as outlined hereunder:
1. Stemfly (Atherigona Orientalis):
Nature of Damage:
The maggot feeds on the young growing shoots results in ‘dead hearts’.
Control:
Use seeds pelleted with insecticides. Seed treatment with imidacloprid 70 WS 10 g/kg of seeds. Plough soon after harvest, remove and destroy the stubbles. Spray Endosulfan 35 EC 500 ml/ha or Methyl demeton 25 EC 500 ml/ha or Dimethoate 30 EC 500 ml/ha or Neem seed kernel extract 5 percent.
2. Stem Borer (Chilo Partellus):
Nature of Damage:
Stem borer is a serious pest of maize. It attacks immediately after germination. It causes “dead hearts” in young plants. Larvae mines the midrib enter the stem and feeds on the internal tissues. Young larva crawls and feeds on tender folded leaves causing typical “shot hole” symptom. Affected parts of stem may show internally tunnelling caterpillars.
Control:
Sow the cowpea as an intercrop (Maize + cowpea at 4:1). Set up light trap till midnight to attract and kill the stem borer moths. Collect the stubbles after harvest and burn to destroy diapausing borers. Mix phorate 10G 8 kg, carbofuran 3G @17 kg or endosulfan 4D @10 kg with sand (total quantity of 50 kg). Spraying of endosulfan 35 EC @ 750 ml or carbaryl 50 WP @1 kg dissolved in 500 lit. Water/ha.
3. Pink Stem Borer (Sesamia Inferens):
Nature of Damage:
Pink larva enters into the stem causing dead heart symptom.
Control:
Spray endosulfan 35 EC @ 1 lit/ha at every 20 days interval
4. Corn Worm/Earworm (Helicoverpa Armigera):
Nature of Damage:
Larva feeds on silk and developing grains.
Control:
Set up of light traps .Set up sex pheromone traps at 12/ha. Apply carbaryl 10 D 25 kg/ha or Malathion 5 D 25 kg/ha or Phosalone 4 D 25 kg/ha on 3rd and 18th day after panicle emergence.
5. Web Worm (Cryptoblabes Gnidiella):
Nature 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.
Control:
Spray monocrotophos (or) endosulfan.
6. Ash Weevil (Myllocerus sp.):
Nature of Damage:
Larva feeds on the secondary roots and adults on leaves.
Control:
Spray quinalphos 25 EC @1 lit/ha or carbaryl 50 WP @1 kg (500 l of spray fluid/ha).
7. Leaf Hopper (Pyrilla Perpusilla):
Nature of Damage:
Leaves become yellow, covered with black sooty mould. Top leaves get dried up and lateral buds germinate.
Control:
Avoid excessive use of nitrogenous fertilizers. Set up light trap. Detrash at 150 and 210th DAP. Release lepidopteran parasitoid – Epiricrania melanoleuca @8000 – 10,000 cocoon /ha (or) 8 – 10 lacs egg/ha. Spray malathion 50 EC 2000 ml or endosulfan 35 EC 2000 ml or monocrotophos 36 WSC 2000 ml on the 150th and 210th day with 1000 liters of water.
8. Aphid or Plant Lice (Rhopalosiphum Maidis):
Nature of Damage:
Yellowing of leaves, colonies of aphids found in central leaf whorl.
Control:
Spraying the base of attacked plants with a contact (or) systemic insecticide.
9. Shoot Bug (Peregrinus Maidis):
Nature 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.
Control:
Spray diazine 0.04% or dimethoate (or) 0.02% or phosphomidon @ 250 ml in 450-500 litres water/ha.
10. Ear Head Bug (Calocoris Angustatus):
Nature 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.
Control:
Apply Carbaryl 10 D @25 kg/ha or Malathion 5 D @25 kg/ha or Phosalone 4 D @25 kg/ha or Azadirachtin 1% on 3rd and 18th day after panicle emergence.