IPM- Alfalfa Insect Thresholds

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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