What's eating my florence fennel 'romanesco'?

Florence fennel 'Romanesco' shares all fennel pest pressures: aphids — especially the fennel aphid (Hyadaphis foeniculi) — are the dominant threat, clustering on stems and in the bulb base. Slugs damage young plants, and aphid infestations on the swelling bulb render it sticky and unattractive at harvest.

Dense grey-green colonies on stems and leaf bases; honeydew and sooty mould accumulate on and inside the swelling bulb. Water-jet knockdown; encourage beneficial insects; apply neem oil or insecticidal soap targeting stem junctions and bulb base.

Seedlings cut at the base; irregular holes in young feathery shoots; bulb bases gnawed in wet conditions. Use iron phosphate pellets; protect seedlings with individual plastic bottle cloches; hand-pick at night during wet spells.

Larvae tunnel into the base of developing fennel bulbs, leaving rusty-brown channels; foliage yellows prematurely. Grow under fine mesh or fleece throughout; avoid thinning near dusk (scent attracts females); grow away from carrots and parsley.