Please enable JavaScript.
Coggle requires JavaScript to display documents.
Diagnostic Guide for Soybean Problems (Seedling to Flowering (Plants dead,…
Diagnostic Guide for Soybean Problems
Planting to Emergence
Poor Emergence
Seed normal, not swelled
Soil too dry, planted to shallow
Seed swelled
Soil too cold or wet
Seedlings twisted, misshapen, or hypocotyl thickened underground
• Dinitroaniline herbicide injury
• Soil crust or compaction
Hypocotyl elongated but not reaching the surface
Planted too deep
Seed eaten or sprout cut
• Insects:
-Seed corn beetle
-Seed corn maggot
-Wireworm
-Cutworm
• Bird or rodent feeding
Seed rotten
•Seed decay:
-Pythium
-Fusarium
-Rhizoctonia
-Phomopsis
-Etc.
No seed
-Soil disturbed
• Planter failure
• Bird or rodent feeding
Seedling to Flowering
Plants dead
In small areas of individual plants
Seedling blights and root rots:
-Phytophthora
-Pythium
-Rhizoctonia
-Fusarium
Round burnt areas in field
Lightning damage
Plants stunted
Symptoms
Leaves discolored, root injury
Soybean cyst nematode root insects:
-White grub
-Grape colaspis
-Garden symphylan
Imidazolinone or chloriumron herbicide injury.
Yellowing followed by necrosis
Glyphosate herbicide injury
Yellowing between veins
Magnesium or Iron deficiency
Leaves malformed,puckered, possibly discolored
•Soybean mosaic virus
•Nutrient deficiency
•Thrips
•Chloroacetamide herbicide injury
• Diphenyl ether herbicide injury
•ALS inhibitor herbicide injury
•Plant growth regulator herbicide injury
Stems bent or twisted
Plant growth regulator herbicide injury
Sandblasted appearance
Twospotted spider-mite
Plants normal in height but leaves damaged
Symptoms
Leaves Discolored or with lesions
Foliar disease:
-Bacterial blight
-Septoria brown spot
-Bacterial pustule
-Downy mildew
•Nutrient deficiency
Leaves torn
•Hail or hard rains and wind
•Bacterial blight or pustule
Small holes in leaves
Insect damage:
-Southern corn rootworm
-Bean leaf beetle
-Japanese beetle
Large holes in leaves
Insect damage:
-Grasshopper
-Blister beetle
Inter-veinal chlorosis or necrosis on lower leaves
Triazine herbicide injury
Contact burn or necrotic lesions
Contact herbicide:
-Diphenyl ether herbicides
-Paraquat
-Bentazon
Flowering to Maturity
Plants normal height
Symptoms
Interveinal chlorotic leaves or necrotic lesions
Leaf disease:
-Brown spot
-Bacterial pustule
-Downy mildew
•Twospotted spider mites
•Glyphosate herbicide injury
Insects feeding on leaves
Insect damage:
-Japanese beetle
-Grasshopper
-Cabbage or soybean looper
-Green cloverworm
-Bean leaf beetle
-Mexican bean beetle
-Webworm or leaf roller
-Soybean aphid
Improper maturation
Symptoms
Plants die prematurely, lesions on or discoloration of stems
Stem and root rots:
-Pod and stem blight
-Brown stem rot
-Charcoal rot
-Stem canker
-Anthracnose
-Phytophthora
Plants remain green
•Thiocarbamate herbicide injury
•Bud blight virus
Damage to pods or seeds
Symptoms
Insect feeding
Insects:
-Grasshopper
-Corn earnworm
-Fall armyworm
-European corn borer
Abnormal color or shriveled seeds
•Stink bug
•Pod and seed disease:
-Anthracnose
-Downy mildew
-Purple seed stain
-Pod and stem blight
-Stem canker
-Soybean mosaic virus
-Bacterial blight
