What's eating my 'january king' cabbage?

January King cabbage stands in the garden through autumn and winter, making it a long-season target. Cabbage white butterflies lay eggs throughout summer; aphids infiltrate the outer leaves from August onward; and wood pigeons are a serious UK pest all winter. Club root disease (though not an insect) devastates crops in acidic, wet soil — raise pH before planting.

Caterpillars penetrate between outer wrapper leaves into the developing heart, making the cabbage unwholesome and difficult to wash clean. Fine insect-proof netting from transplant stage prevents egg-laying entirely. Bt spray on outer leaves. Check between outer leaves for late caterpillars before harvest.

Colonies infiltrate between tightly packed outer leaves from late summer and remain through mild winters, causing yellowing and making heads unmarketable. Remove loose outer leaves early to expose and wash out colonies. Neem oil or insecticidal soap applied to outer leaves. Avoid dense planting that traps moisture and harbours pests.

Strips outer leaves and pecks into heads from autumn through early spring — standing winter brassicas are particularly targeted when other food is scarce. Bird netting on hoops over the entire bed. Check for and repair gaps after wind. No non-physical deterrent is reliably effective against persistent wood pigeons.

Diamondback moth larvae create 'windowpane' damage — eating leaf tissue from one side leaving a transparent membrane — from late spring through autumn. Bt sprays are effective against early-instar diamondback larvae. Insect-proof mesh prevents adult moths laying. Pheromone traps monitor adult flight periods.