How to prevent pests on balcony vegetables?

How to prevent pests on balcony vegetables?

The most common pests on balcony vegetables are cabbage worms (caterpillars), primarily the larvae of the cabbage white butterfly (*Pieris rapae*). Control requires both prevention and treatment:

Source prevention

• Insect netting — cover vegetable pots with fine-mesh netting (mesh ≤1 mm) to prevent butterflies from flying in and laying eggs. This is the most effective physical control method.
• Clean seedlings — inspect the undersides of leaves of purchased seedlings for eggs before planting; plant only after confirming they are pest-free.
• Clean soil — use reputable potting soil; avoid soil of unknown origin.
• Seed source — purchase seeds from reliable sources to avoid introducing pests.

Daily inspection

• Check leaf undersides daily — butterflies lay eggs on the undersides.
• Look for small pale yellow granules (eggs).
• Look for small green caterpillars eating leaves.
• Remove any caterpillars found as early as possible.

Chemical control

• If caterpillars are too numerous to remove manually, spray dinotefuran-containing household insecticide.
• Spray evenly on both sides of leaves, especially where pests are concentrated.
• After spraying, wait the recommended pre-harvest interval before harvesting (usually 7-14 days for dinotefuran; check the product label).
• Rinse thoroughly with water before eating.

Crop rotation

• Do not plant vegetables from the same family (e.g., Brassicaceae like cabbage, bok choy) in the same soil consecutively.
• Rotation reduces the buildup of cabbage worm populations.