Maintaining healthy corn crops requires good pest management. Corn fields are prone to a variety of pests throughout the growing season. Here is a list of common pests that can damage your corn, the time they appear, and the recommended insecticides to control them.

Pest	Recommended Insecticides	Application Stage
Aphids	Imidacloprid, Thiamethoxam, Acetamiprid	Early spring (seedling stage), throughout the growing season
Fall Armyworm	Lambda-Cyhalothrin, Chlorantraniliprole, Cypermethrin	Summer (June – August), during silking and ear formation
European Corn Borer	Bacillus thuringiensis (Bt), Carbaryl, Permethrin	June – July, during stalk and ear development
Corn Leafhopper	Imidacloprid, Thiamethoxam, Malathion	Early spring, early summer (vegetative stage)
Corn Leaf Miner	Lambda-Cyhalothrin, Pyrethroids (Permethrin, Cypermethrin)	Early growing season (March – May), during leaf expansion
Cucumber Beetles	Imidacloprid, Carbaryl, Permethrin	Early spring to mid-summer (vegetative stage)
Cutworms	Carbaryl, Chlorpyrifos, Lambda-Cyhalothrin	Early spring, immediately after planting (seedling stage)
Flea Beetles	Imidacloprid, Permethrin, Thiamethoxam	Spring to early summer (vegetative stage)
Grasshoppers	Malathion, Lambda-Cyhalothrin, Permethrin	Summer (June – September), during reproductive stage
Seedcorn Maggots	Carbaryl, Diazinon, Thiamethoxam	Early spring (before or during seedling emergence)
Spider Mites	Abamectin, Spirodiclofen, Dicofol	Hot, dry conditions (summer), during vegetative stage
Thrips	Imidacloprid, Spinosad, Azinphos-methyl	Spring and early summer (vegetative stage)
Wireworms	Chlorpyrifos, Carbaryl, Thiamethoxam	Early spring, during seedling establishment

1. Aphids (Aphidoidea)

• Damage: Aphids suck sap from corn leaves, causing yellowing, stunted growth, and reducing the plant’s ability to produce energy. They can also spread viruses, further harming the crop.
• When They Appear: Aphids usually show up in early spring.
• Recommended Insecticides:
  • Imidacloprid (Systemic, controls aphids)
  • Thiamethoxam (Broad-spectrum control)
  • Acetamiprid (Good for aphids)

2. Fall Armyworm (Spodoptera frugiperda)

• Damage: These larvae eat corn leaves, silks, and kernels, causing severe damage. They weaken plants and reduce yields, especially during silking and ear formation.
• When They Appear: Common in summer, between June and August.
• Recommended Insecticides:
  • Lambda-Cyhalothrin (Quickly kills larvae)
  • Chlorantraniliprole (Long-lasting protection)
  • Cypermethrin (Effective for armyworm control)

3. European Corn Borer (Ostrinia nubilalis)

• Damage: European corn borers tunnel into the stalks and ears of corn, causing structural damage and making the plant more vulnerable to diseases.
• When They Appear: Typically from June to July.
• Recommended Insecticides:
  • Bacillus thuringiensis (Bt) (Biological control)
  • Carbaryl (Broad-spectrum)
  • Permethrin (Effective for borers)

4. Corn Leafhopper (Dalbulus maidis)

• Damage: This pest spreads diseases like corn stunt and weakens the plants by feeding on sap.
• When They Appear: Most common in early spring and early summer.
• Recommended Insecticides:
  • Imidacloprid (Systemic, controls leafhoppers)
  • Thiamethoxam (Broad-spectrum)
  • Malathion (Quick kill)

5. Corn Leaf Miner (Argyrotaenia spp.)

• Damage: The larvae of corn leaf miners create tunnels in the leaves, reducing the plant’s ability to photosynthesize, which weakens the corn.
• When They Appear: Early in the growing season, usually from March to May.
• Recommended Insecticides:
  • Lambda-Cyhalothrin (Effective against leaf miners)
  • Pyrethroids (Such as Permethrin or Cypermethrin)

6. Cucumber Beetles (Diabrotica spp.)

• Damage: These beetles feed on corn leaves, stems, and roots, and they can also spread bacterial wilt.
• When They Appear: Active from early spring to mid-summer.
• Recommended Insecticides:
  • Imidacloprid (Systemic action)
  • Carbaryl (Effective for wide-ranging insects)
  • Permethrin (Quick knockdown)

7. Cutworms (Agrotis spp.)

• Damage: Cutworms attack young seedlings by cutting them off at the base, often leading to plant death.
• When They Appear: Usually in early spring, right after planting.
• Recommended Insecticides:
  • Carbaryl (Effective for soil pests)
  • Chlorpyrifos (Controls soil-borne pests)
  • Lambda-Cyhalothrin (Good for foliar and soil pests)

8. Flea Beetles (Chaetocnema spp.)

• Damage: These tiny beetles chew holes in corn leaves, which weakens the plant and reduces its energy production.
• When They Appear: Most active in spring to early summer.
• Recommended Insecticides:
  • Imidacloprid (Systemic control)
  • Permethrin (Effective for quick knockdown)
  • Thiamethoxam (A broad-spectrum insecticide)

9. Grasshoppers (Caelifera spp.)

• Damage: Grasshoppers feed on corn leaves, causing defoliation and lowering the plant’s ability to produce energy.
• When They Appear: They are most common in summer (June to September).
• Recommended Insecticides:
  • Malathion (Effective for grasshoppers)
  • Lambda-Cyhalothrin (Works well for grasshoppers and other pests)
  • Permethrin (Good for fast knockdown)

10. Seedcorn Maggots (Delia platura)

• Damage: Seedcorn maggots feed on corn seeds and roots, which delays plant emergence and weakens the corn.
• When They Appear: Common in early spring, especially during wet conditions.
• Recommended Insecticides:
  • Carbaryl (Controls larvae)
  • Diazinon (Effective for early pests)
  • Thiamethoxam (Systemic action)

11. Spider Mites (Tetranychus spp.)

• Damage: Spider mites suck sap from corn leaves, causing a stippling effect that weakens the plant and reduces yields.
• When They Appear: Most active during hot, dry conditions in summer.
• Recommended Insecticides:
  • Abamectin (Effective for mites)
  • Spirodiclofen (Controls mites systemically)
  • Dicofol (Effective for spider mites)

12. Thrips (Frankliniella spp.)

• Damage: Thrips feed on plant cells, causing silver streaks on the leaves. They can also transmit plant diseases.
• When They Appear: Most common in spring and early summer.
• Recommended Insecticides:
  • Imidacloprid (Systemic)
  • Spinosad (Biological control)
  • Azinphos-methyl (Broad-spectrum)

13. Wireworms (Agriotes spp.)

• Damage: Wireworms attack the corn seed and roots, weakening or killing young plants.
• When They Appear: Most active in early spring through summer.
• Recommended Insecticides:
  • Chlorpyrifos (Effective for wireworm control)
  • Carbaryl (Broad-spectrum)
  • Thiamethoxam (Systemic control)

Conclusion:

Effective pest management is key to growing healthy corn. By applying the right insecticides at the right time, you can protect your crops from damaging pests and ensure high yields.