Pest identification
What's eating my purple milkweed?
Oleander aphids (Aphis nerii)
Signs: Colonies of yellow insects clustered on tender new growth and flower stalks; sticky honeydew and black sooty mold
Control: Dislodge with a strong water jet; apply insecticidal soap when caterpillars are not active; avoid systemic insecticides
Monarch caterpillars (Danaus plexippus)
Signs: Rapid, complete defoliation — small clumps of purple milkweed can be stripped before seed set
Control: Plant in larger masses; no chemical control appropriate. Move a caterpillar to another milkweed species if plants are critically depleted
Milkweed seed bugs (Lygaeus kalmii)
Signs: Black and red bugs feed on seeds within pods; reduce seed bank for natural spread
Control: Collect seed pods early before full bug infestation; hand-pick bugs; low-priority in most gardens
Keep purple milkweed pest-free
Healthy plants resist pests best. Get the basics right:
Purple Milkweed pests — FAQ
What is eating my purple milkweed?
Purple milkweed (Asclepias purpurascens) faces the same pest community as other native milkweeds: oleander aphids are the persistent nuisance while monarch caterpillars are welcome defoliators. Milkweed bugs target developing seed pods. This species is less common so caterpillar pressure can feel intense — planting several together distributes the feeding load.
How do I get rid of oleander aphids (aphis nerii) on purple milkweed?
Colonies of yellow insects clustered on tender new growth and flower stalks; sticky honeydew and black sooty mold Dislodge with a strong water jet; apply insecticidal soap when caterpillars are not active; avoid systemic insecticides
How do I get rid of monarch caterpillars (danaus plexippus) on purple milkweed?
Rapid, complete defoliation — small clumps of purple milkweed can be stripped before seed set Plant in larger masses; no chemical control appropriate. Move a caterpillar to another milkweed species if plants are critically depleted
How do I get rid of milkweed seed bugs (lygaeus kalmii) on purple milkweed?
Black and red bugs feed on seeds within pods; reduce seed bank for natural spread Collect seed pods early before full bug infestation; hand-pick bugs; low-priority in most gardens