IPM – 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