Corn Pests

Question 1

Seed Corn Maggot

Answer 1

• Feed on seed
• Found in large seeded crops in soils with large amounts of debris
• See flies buzzing around surface when corn is 4in tall
• Conditions that slow emergence increase risk

Question 2

Wireworm

Answer 2

• Commonly found when
  
  • plowing out long-term sod and rotating into corn
• Seed treatment available

Question 3

White Grubs

Answer 3

• Emergence and seedling pest
• Some soil insecticides
• Not good control

Question 4

Black-Cut Worm

Answer 4

• Migrate in as a moth in spring, Mid-April
  
  • can be seen on radar
• Lay eggs on grass weeds (cover crops)
• Larvae live on decaying CC until corn planting
  
  • Big enough to cut when corn is V2/V3

Question 5

Slugs

Answer 5

• Snails without shells
• Commonly found in No-till
• Holes in leaves, slimy trails
• Seedling and Emergence pest

Question 6

True Armyworm

Answer 6

• Early Whorl to Tassle pest
• Sping migrant from South April-June
• Only larvae from early spring migration are an economic problem
  
  • bc moths move long distances
• Primarily in grasses

Question 7

European Corn Borer

Answer 7

• Early Whorl to Tassle pest
• Typically 2 generations per year
  
  • 1st gen = pre-tassle corn
  • 2nd gen= ear
• Bore into stem
  
  • drag in stalk rots
  • takes 1 borer/stem for economic damage
• Leaf feeding shows up as dots in a line
• Sporatic Pest
• Bt Corn has taken care of this pest
  
  • All have refuge population
  • “refuge in a bag”

Question 8

Western Corn Root Worm

Answer 8

• Loding/Goosenecking in JULY
• larvae feed on corn
  
  • hatch late May
  • Feed on roots through June/July
• Adults emerge and feed on pollen
  
  • Beetle seen around pollination
• Over-winter as eggs in existing corn feilds
• First year corn has no risk
• More continuous corn = higher risk
• Management
  
  • Crop rotation
  • Bt resistant varieties
  • Soil insecticides
    
    • granular
    • seed treatments
    • less common bc farmers prefer ease of Bt