Agriculture & Natural Resources

IPM – Soybean Insect Thresholds

Pest
Pre-Bloom
Bloom – Podfill
Full green bean – 50% yellow leaves
Bean leaf beetle Cracking-2nd trifoliate: 2/ft. row and 25% stand reduction After 2nd trifoliate: 2-3/plant and 30% defoliation 35% defoliation
Grasshoppers 1 per sweep and 30% defoliation 1 per sweep and 35% defoliation
Japanese beetles (and similar beetles) 7/ft. row and 15% defoliation
Mexican bean beetle Seedling: 2/plant and 30% defoliationPrebloom: 6/ft. row and 30% defoliation 5/ft. row and 15% defoliation0.5/sweep and 15% defoliation 6/ft. row and 35% defoliation0.5-1/sweep and 35% defoliation
Potato leafhopper Stressed plants: 4/sweepUnstressed plants: 8/sweep Stressed plants: 4/sweepUnstressed plants: 8/sweep Stressed plants: 4/sweepUnstressed plants: 8/sweep
Spider mites 20-30/leaflet and 10% of plants with 1/3 or more leaf area damaged 20-30/leaflet and 10% of plants with 1/3 or more leaf area damaged
Thrips 8/leaflet and leaf damage 8/leaflet and leaf damage 8/leaflet and leaf damage
Green cloverworm 15/ft. row and 30% defoliation 20/ft. row and 15% defoliation 35% defoliation
Podworms (corn earworm, fall armyworm) 1-2/ft. row3/25 sweeps (narrow rows)

5/25 sweeps (wide rows)

Silver spotted skipper 5/ft. row and 15% defoliation 35% defoliation
Soybean looper 35% defoliation
Woollybears 5/ft. row and 15% defoliation 35% defoliation
Yellow striped armyworm 5/ft. row and 15% defoliation 35% defoliation