Alfalfa Pests

Question 1

Alfalfa Weevil

Answer 1

• Complete metamorphosis
• Chewing mouthparts
• Adults overwinter, larvae feed on leaves
• Adults leave the field for remainder of summer
• Damage gives the stand a Frosted look
• Management
  
  • Early detection
  • Treat with insecticide if more than 10days to harvest and 40% stand showing feeding

Question 2

Potato Leafhopper

Answer 2

• Arrives in Spring on Thunderstorms
  
  • Memorial Day
• 2nd/3rd cutting pest
• Overwinter in south on pine trees
• Damage is characteristic V
• Management
  
  • PLH resistant variety
  • early harvest if stand is over 15inches
  • treatment

Question 3

Clover Root Curculio

Answer 3

• Stand loss from direct root feeding
• Adults overwinter outside field
  
  • Move into field in spring and lay eggs
• Eggs hatch and larvae feed for 30 days
• Rotation is only management

Question 4

Alfalfa Snout Beetle

Answer 4

• All flightless females
• Two year life cycle
  
  • Adults emerge, lay eggs in crown, larvae emerge (legless)
  • Larvae in year 1 and 2, then pupaete and emerge in fall as adult
  • Damage mimics winter kill bc of this
• Feeding
  
  • Take off taproot first
  • Stays below ground
• Management
  
  • NO insecticides are effective
  • Short alfalfa rotation (3yr)
    
    • seeding year, 2 production years
  • Biological control with nematodes
  • moderately resistant varieties