Insect
Cabbage Looper
Light green caterpillars up to 4 cm long that arch their body into a loop as they walk; they feed voraciously on brassica leaves, often leaving only the midribs.
Symptoms to Look For
- Large ragged holes in brassica leaves, often starting in the leaf centre
- Leaves skeletonised to the midrib on heavily infested plants
- Green frass pellets on leaves and in the soil below plants
Affected Plants
BrassicaLettuceSpinachPeaTomatoCelery
Organic Solutions
Bacillus thuringiensis spray
Spray Bt onto both leaf surfaces at first sign of young caterpillars, repeating every 5 - 7 days and after rain, for effective larval control.
Hand-picking
Inspect the undersides of leaves in the morning and remove caterpillars by hand, dropping them into soapy water.
Row covers
Drape lightweight insect mesh over brassica crops from transplanting to prevent adult moths from laying eggs on leaves.
Prevention
- Check under leaves regularly for pale green ribbed oval eggs and crush them before hatch
- Encourage wasps and ground beetles by maintaining diverse plantings near the vegetable garden
- Plant a succession of brassicas to stagger the risk period and avoid all crops being in a vulnerable stage simultaneously
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.