Insect

Root Maggot

Small white legless fly larvae 6 - 8 mm long found tunnelling through roots and bulbs; adults resemble small grey houseflies and lay eggs at plant bases.

Symptoms to Look For

Plants wilting and yellowing despite adequate moisture
Roots and bulbs tunnelled with dark slimy channels
Plants lifting out of the soil with no root system remaining

Affected Plants

BrassicaRadishTurnipOnionLeekCarrotBeetroot

Organic Solutions

Brassica collars

Place a 12 cm square of carpet underlay or felt flat on the soil around each brassica stem to prevent adults laying eggs at the soil surface.

Beneficial nematodes

Apply Steinernema feltiae nematodes to moist soil at transplanting time and again 3 weeks later to control larvae in the root zone.

Row covers

Drape fine mesh insect-proof netting over crops from sowing to exclude egg-laying adults completely.

Prevention

Rotate brassica and allium crops to a fresh bed each year to break the soil-based lifecycle
Avoid planting brassicas during the peak adult fly period in spring - wait until late May in most regions
Cultivate soil deeply after harvest to expose overwintering pupae to frost and predatory birds

Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.