A Comprehensive Guide to Corn Pest and Disease Management

Corn (maize) is a vital crop globally, but its yield can be significantly affected by pests and diseases. Two notable pests, the tobacco caterpillar (Spodoptera litura) and the pod borer (Helicoverpa armigera), along with various diseases, pose challenges to corn farmers. Though not primary pests of corn, their occasional attacks can damage leaves, cobs, and young stems. This article explores these pests, associated diseases, and effective control measures to ensure a healthy corn harvest.

Tobacco Caterpillar (Spodoptera litura) and Pod Borer (Helicoverpa armigera)

Though not the primary enemies of corn, the tobacco caterpillar and pod borer can occasionally wreak havoc. Their larvae feed on leaves, cobs, and tender stems, leading to reduced crop quality and yield.

Control Measures for Tobacco Caterpillar and Pod Borer

Effective pest management involves both preventive and curative strategies. Here are proven methods to control these pests:

1. Pheromone Traps: Use traps like Heli or Spodo Lure to monitor and reduce adult pest populations.
2. NPV Spray: Apply Heli NPV or Spodo NPV to target larvae biologically.
3. Trichogramma Cards: Deploy 3-4 cards per acre to release parasitic wasps that attack pest eggs.
4. Azadirachtin Spray: Mix 3 ml of Azadirachtin (10,000 PPM) per liter of water and spray.
5. BT Formulation: Use 2 ml of Bacillus thuringiensis (BT) per liter of water for spraying.
6. Poison Bait for Mature Larvae: Prepare a mixture of 5 kg rice bran + 500 g jaggery + 500 ml Monocrotophos/Quinalphos with sufficient water per acre. Spread this bait across the field in the evening.
7. Chemical Spray for Young Larvae:

• Thiodicarb 75% WP @ 1.5 g/liter of water.
• Monocrotophos 36% SL @ 1.6 ml/liter of water.
• Spinosad 45% SC @ 1 ml per 3 liters of water (during cob formation).

Corn Diseases and Their Management at a Glance

Corn is susceptible to various diseases that can compromise its growth. Below are key diseases, their symptoms, and control measures presented in tabular form for easy reference.

1: Leaf Blight

Symptoms: Pale, elongated, or oval spots on leaves that dry up progressively.

2: Downy Mildew

Symptoms: Yellow, wet spots on leaves turning brown, stunting plant growth.

3: Rust

Symptoms: Similar to Downy Mildew but with rust-like spots.

4: Post-Flowering Stalk Rot & Bacterial Diseases

Symptoms: Stalk rot after flowering; bacterial infections causing wilting and decay.

Recommended Herbicides for Weed Control in Corn

Weeds compete with corn for nutrients, water, and sunlight. Here are recommended herbicides:

1. Atrazine 50% WP: 400 g active ingredient (a.i.) per acre, applied 0-2 days after sowing.
2. Topramezone 33.6% SC: 10 g a.i. per acre, applied 20-30 days after sowing.
3. Tembotrione 34.4% SC: 48 g a.i. per acre, applied 20-30 days after sowing.

Conclusion and Next Steps

Effective pest and disease management is crucial for a successful corn harvest. By combining cultural practices with targeted chemical controls, farmers can protect their crops and maximize yields. Stay tuned for our next article, where we’ll discuss the use of machinery in corn farming. Click here to learn more!