Imported Cabbageworm
Pieris rapae
moderate risk
insect
Overview
Caterpillar of the cabbage white butterfly. One of the most common garden pests of brassica crops worldwide.
Adult butterfly white with black spots, 45-50mm wingspan. Caterpillars velvety green, 25-35mm with pale yellow-green stripe.
Prevention Strategies
- •Row covers exclude egg-laying butterflies
- •Inspect for eggs on leaf undersides weekly
- •Companion plant with strong-scented herbs (dill, thyme)
- •Attract parasitic wasps
Control Methods
- •Hand-pick caterpillars
- •Bacillus thuringiensis (Bt) spray highly effective
- •Spinosad insecticide
- •Pyrethrin spray
- •Encourage parasitic wasp Cotesia glomerata
Interesting Facts
- •Adult cabbage white butterfly introduced to North America from Europe in 1860
- •Nearly impossible to grow brassicas without managing this pest
- •Bt spray is completely safe and very effective - no insecticide residue concerns
- •The white butterfly you see in garden is laying eggs on your brassicas