Common Napa Cabbage Pests and Diseases and How to Control Them Naturally

ByStephen Albert

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Napa cabbage is a cool-season favorite, but like all brassicas, it can attract pests and diseases. Using natural, hands-on methods keeps your crop healthy and chemical-free. Drawing on decades of gardening experience, here’s how to identify, prevent, and control the most common problems.

Common Napa Cabbage Pests

1. Aphids

  • Tiny green or black insects feeding on new leaves
  • Cause leaf curling and stunt growth

Natural Control:

  • Blast off with a hose
  • Introduce ladybugs or lacewings
  • Spray with insecticidal soap

2. Cabbage Loopers and Worms

  • Caterpillars that chew large holes in leaves

Natural Control:

  • Handpick daily
  • Use row covers to protect young plants
  • Encourage parasitic wasps

3. Flea Beetles

  • Small jumping beetles creating tiny pits in leaves

Natural Control:

  • Apply diatomaceous earth around plants
  • Use floating row covers early in the season

Common Napa Cabbage Diseases

1. Black Rot

  • Yellow V-shaped lesions on leaf edges
  • Caused by bacteria spreading in water

Natural Control:

  • Rotate crops every 3 years
  • Avoid overhead watering
  • Remove infected plants

2. Clubroot

  • Swollen, distorted roots causing stunted growth

Natural Control:

  • Maintain soil pH above 7.2 with lime
  • Rotate brassicas
  • Remove infected plants

3. Downy Mildew

  • White, fuzzy growth on leaf undersides

Natural Control:

  • Improve air circulation
  • Space plants properly
  • Water at soil level

My Experience

In my Sonoma Valley garden, rotating Napa cabbage with legumes, using row covers, and encouraging beneficial insects consistently reduces pest and disease problems without chemicals, producing tender, healthy heads.

Napa Cabbage Learning Hub

Start here: The Ultimate Guide to Growing Napa Cabbage

Napa Cabbage Planting & Timing

Napa Cabbage Starting & Transplanting

Napa Cabbage Care

Pests & Diseases

Harvest & Storage

Containers & Small Spaces

Varieties

Companion Planting

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. Harvesttotable.com has more than 10 million visitors each year.

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