Transcript Unit 9: Alfalfa Insects

Unit 9: Alfalfa Insects
Unit 9: Alfalfa Insects

Alfalfa Weevil





Found throughout the U.S.
Damage done by larvae feeding on plant tips, new
leaves, flowers
Can strip the entire plant
Damaged fields can appear whitish in color
Insecticides can control effectively

Be cautious of withdrawal and cutting times
Unit 9: Alfalfa Insects

Ideal conditions

Early first harvest




Weevil feed on new growth coming for 2nd cutting
Crown buds
Can severely limit growth
Late harvest



Feeds on regrowth
Can damage crop before going into dormancy
Can make crop more susceptible to winterkill
Unit 9: Alfalfa Insects

Potato Leafhopper

Feeds by puncturing the leaves



Usually not a problem w/ 1st cut alfalfa due to life
cycle
Can break cycle by cutting



Causes yellowing of the plant
Leafhopper must have supply of succulent food to
survive
Can be very damaging to new seedings
Very susceptible to insecticides, some resistant
varieties
Unit 9: Alfalfa Insects

Alfalfa Seed Chalcid

Can cause extensive damage to the seedling





Adult deposits an egg on a developing seedling
Hatched larvae can devour the entire seedling
Several generations/season
Late fall larvae overwinter in seeds and can
reinfest the next crop
Mow/treat road ditches and perimeter for help w/
control
Unit 9: Alfalfa Insects

Heavy cleaning of seed alfalfa eliminates most
problems


Bug harbors inside seed
Lighter weight seeds are removed