What Are the Best Practices to Control Stem Borer in Maize?
Maize (corn) is an important food and fodder crop grown widely across India. It is known for its good yield potential and adaptability to different climates. However, one of the most serious pests that affects maize is the stem borer. This pest causes severe damage to the crop and can lead to significant yield loss if not managed properly. Knowing how to identify and control the stem borer is very important for every maize farmer.
1. Understanding Stem Borer and Its Damage
The maize stem borer, also known as Chilo partellus, is a common pest in most maize-growing regions. The adult moth lays eggs on the underside of maize leaves. When the larvae hatch, they first feed on the leaves and then bore into the stem. Once inside, they eat the internal tissues, making the plant weak and hollow from within.
Symptoms of stem borer attack include:
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Holes in leaves forming a “shot-hole” pattern.
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Drying of the central leaf whorl (known as “dead heart”).
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Weak stems that break easily due to tunneling.
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Poor grain filling and reduced cob size in later stages.
If the attack is severe, yield losses can range from 20% to 80%, depending on the crop stage and pest population.
2. Factors Favoring Stem Borer Attack
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Continuous maize cultivation without crop rotation.
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Early sowing during warm and humid conditions.
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Poor field sanitation, where previous crop residues are left in the field.
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Dense crop stand with poor aeration.
Understanding these conditions helps farmers take preventive steps before the pest population increases.
3. Best Practices to Control Stem Borer in Maize
a) Cultural Control
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Timely Sowing: Sow maize at the recommended time for your region. Early or late sowing increases pest risk.
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Crop Rotation: Avoid planting maize continuously in the same field. Rotate with legumes like soybean, black gram, or groundnut to break the pest cycle.
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Field Sanitation: Remove and burn infested stubbles and crop residues after harvest to destroy the pest larvae and pupae hiding inside stems.
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Proper Spacing: Maintain adequate plant spacing for good air circulation and to reduce humidity around plants.
b) Mechanical and Physical Control
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Light Traps: Use light traps in the field during evening hours to attract and kill adult moths.
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Hand Picking: In small plots, infested plants or dead hearts can be removed and destroyed early to prevent pest spread.
c) Biological Control
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Release Trichogramma chilonis cards (egg parasitoids) in the field at regular intervals, starting 20–25 days after sowing. These tiny beneficial insects destroy the eggs of the stem borer before they hatch.
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Encourage natural enemies like spiders, ladybird beetles, and earwigs by avoiding unnecessary pesticide sprays.
d) Chemical Control
When infestation is high, chemical sprays can help manage the pest.
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Apply Carbofuran 3G granules (10–12 kg/ha) or Phorate 10G granules (10 kg/ha) in the leaf whorl 20 days after sowing.
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Alternatively, spray Lambda-cyhalothrin 5 EC (0.5 ml/litre) or Chlorantraniliprole 18.5 SC (0.3 ml/litre) when the first signs of damage appear.
Repeat the spray after 15 days if needed. Always follow the recommended dose and safety precautions while spraying.
e) Resistant Varieties
Planting stem borer-resistant or tolerant maize hybrids developed by agricultural universities can significantly reduce pest incidence and minimize yield loss.
4. Integrated Pest Management (IPM)
The most effective and sustainable approach is Integrated Pest Management (IPM). This combines cultural, biological, and chemical control methods. Regular monitoring, maintaining field hygiene, releasing bio-control agents, and timely spraying ensure better pest control with less pesticide use.
Conclusion
Stem borer is a major pest in maize that can seriously affect yield if ignored. Farmers should focus on prevention by maintaining clean fields, using resistant varieties, and practicing crop rotation. If infestation starts, adopt integrated methods — combining light traps, bio-control, and need-based chemical sprays. Regular field monitoring and balanced crop management will keep stem borer under control and ensure a healthy, high-yielding maize crop.
