Alfalfa Pest Management
- Health & Well-being
-
Agricultural Programs
- Agribusiness
- Animal Science
- Beginning Farmer Program
- Commercial Crops
- Commericial Horticulture
- Delaware Soil Testing Program
- Disease Management
- Farm Vitality and Health Project
- Irrigation
- Nutrient Management
-
Insect Pest Management
- Insect Trapping Program
- IPM Hot Topics
- Commercial Field Crop Insect Management
- Commercial Field Crop Disease Management
- Commercial Fruit & Vegetable Crop Pest Management
- EIPM Implementation Projects
- Pollinators
- Research and Extension Demonstration Results
- Brown Marmorated Stink Bug (BMSB) Management, Research, and Resources
- Publications
- Pesticide Safety Education Program
- UD Plant Diagnostic Clinic
- Variety Trials
- Weed Science
- Certified Crop Advisor Program
- 4-H
-
Horticulture
- Climate Variability and Change
- Delaware Soil Testing Program
- Forestry
- Lawn and Garden
- Master Gardeners
- Master Naturalist Program
-
Nutrient Management
- Nutrient Management Certification
- Continuing Education for Nutrient Management
- Nutrient Management Planning Resources
- Commercial Nutrient Handler Resources
- Poultry Litter and Manure Management
- Turf Management
- Agriculture Notebook
- Horticulture Handbook
- Agriculture & Horticulture Handbooks
- Crop Production
- Soil Fertility
- Delaware Climate Change Coordination Initiative (DECCCI)
- Salt Impacted Agricultural Lands
Alfalfa Pest Management
Alfalfa Insect Management Recommendations
Sampling Guidelines
Pest |
Sampling Method |
Growth Stage: Mid- March to First Cutting | |
Alfalfa weevil | Minimum of 30 stems per field collected in a W-pattern, place stems top first in bucket, measure stem height and count the number of larvae per stem |
Pea aphid | Collect a minimum of 30 stems per field and count the number of aphids and beneficial insects present per stem ( e.g. lady beetles and syrphid fly larvae ) |
Growth Stage: After First Cutting (mid-May) to September | |
Alfalfa weevil – only for 2 weeks after first cutting | Minimum of 30 stems/crowns per field in a W-pattern, place stems top first in bucket and count the number of larvae per stem/crown |
Potato leafhopper | Ten sweeps in ten locations – plants should be dry |
Blister Beetle | 10 sweeps in ten locations< |
Garden webworm and other defoliators | Estimate defoliation in 10 location |
Alfalfa Insect Thresholds
Pest | March – April | May – early June | mid June – mid Sept. |
Alfalfa weevil | 0-11 in. – 0.7 per stem12 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 stem12 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 sweeps4-6 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 sweeps4-6 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 |
The University of Delaware is an Equal Opportunity Institution and Provider. Visit UD’s Office of Equity & Inclusion to learn more.
Additional Links
531 South College Avenue Newark, DE 19716 (302) 831-2501