Civil Rights Information

Search this web site Cooperative Extension Directory Cooperative Extension Calendar Research and Education Center  College of Agriculture & Natural Resources UD Home

 
Agriculture & Natural Resources
  Find information about:
  • Field Crops
  • Vegetables
  • In-Season Pest Reports
  • Traps
  • Publications
  • Training
  • Links
 
  Other Resources:
  • Northeastern IPM
  • UD Department of ENWC
 
  Fact Sheet Search
 


Search in:
Search all Subjects

 
 
  << IPM home
  << Agriculture & Natural Resources home
  << Cooperative Extension home
IPM - Alfalfa Insect Thresholds
Pest
March - April
May - early June
mid June - mid Sept.
Alfalfa weevil 0-11 in. - 0.7 per stem

12 in. - 1.0 per stem

13-15 in. - 1.5 per stem

16 in. - 2.0 per stem

17-18 in. - 2.5 per stem

0-11 in. - 0.7 per stem

12 in. - 1.0 per stem

13-15 in. - 1.5 per stem

16 in. - 2.0 per stem

17-18 in. - 2.5 per stem

after 1st cutting - 2 per crown

 

Pea aphid <10 in. - 50 per stem

>10 in. - 100 per stem

1 or more beneficials per 50 aphids should provide control

<10 in. - 50 per stem

>10 in. - 100 per stem

1 or more beneficials per 50 aphids should provide control

 

Potato leafhopper

 

3 in. or less - 20 per 100 sweeps

4-6 in. - 50 per 100 sweeps

7-11 in. - 100 per 100 sweeps

12 in. or more - 150 per 100 sweeps

3 in. or less - 20 per 100 sweeps

4-6 in. - 50 per 100 sweeps

7-11 in. - 100 per 100 sweeps

12 in. or more - 150 per 100 sweeps

Garden webworm / general defoliators

 

 

25-30% of tips damaged
Blister beetles

 

 

1 per sweep
University of Delaware Cooperative Extension