The most noteworthy thing about gardeners is that they are always optimistic, always enterprising, and never satisfied. They always look forward to doing something better than they have ever done before. ~ Vita Sackville-West.

Crop Pests - Carrot Root Fly

When planting carrots it is worth taking steps to protect them from their main pest, the carrot root fly (Psila rosae). These small black flies (8mm in length) lay eggs in the soil near carrots. About a week later larvae emerge and begin feeding. First symptoms are a reddening of the carrot leaves which begin to wilt. If you lift the root you will see tunnels eaten by the larvae and may see the creamy coloured larvae which are about 1cm in length.

There are usually two generations of flies with eggs first laid by over-wintering adults in April/May and a second generation laid in July/August. Carrots growing in the ground at these times are vulnerable to attack and more damage is caused by the second generation.

Preventing damage from carrot root fly

Cover the crop with a barrier to prevent the flies from laying eggs near carrots. Fleece works well but remember to bury the edges of the fleece to prevent the flies from getting in. Mulching the ground with a layer of grass clippings will also make it more difficult for the flies to lay eggs.
When in flight the carrot root fly stays low so surrounding the carrot bed with a barrier of polythene extending at least 60cm high can deter them.
It is thought that carrot root flies detect carrots by their smell which is particularly strong during thinning. Various strategies may minimise this smell
Planting several rows of onions or garlic between each row of carrots. Rosemary, sage or wormwood plantings may also work.
Sow sparsely to avoid having to thin seedlings.
Dust with calcified seaweed to disguise the smell.
Remove thinnings and other waste from the area.
Time plantings so roots are not in the ground during egg laying periods.
Sow a resistant variety. 'Carrot F1 Fly Away' and 'T&M Fly Away' have resistance to larval attack. 'Sytan' is also less susceptible to larval attack.
Avoid particularly susceptible varieties such as 'Autumn King'.
Carrot root flies are not strong fliers so planting in an exposed, windy site can prevent their attack.

This troublesome pest can affect related crops (in the apiaceae family) such as parsnips, celery, celeriac, parsley, coriander.

Beware Low Fliers!

It's a well known fact that the Carrot Root Fly (or Rust Fly) Psila rosae is not a strong flier and they rarely fly above 50cm. Although using garden fleece, upturned plastic bottles or whatever other method you choose, the best way to combat these pests is to grow your carrots above the height that Psila rosae can fly!

Try growing your carrots in raised beds or even in an old water butt filled with soil - anywhere out of reach of the destructive but low flying carrot root fly.

Root Fly Damage

Carrot Root Fly Larvae

The creamy-yellow larval stage of the Carrot Fly is very destructive to carrots, first burrowing around the outside, eventually tunnelling throughout the root. They are slender, without legs, and up to 1cm long. Parsnips, celery, dill, angelica and fennel can also be attacked.

Worth a Read!

Banish Slugs: Green Essentials - Organic Guide

Banish Slugs

This books provides really quick and easy ways of dealing with slugs and snails without harming the rest of the wildlife that comes into to my garden.

Slugs and snails are a curse for nearly every gardener &45; there can be nothing more disappointing than discovering that precious plants have been ravaged. And there’s no simple way of dealing with them. In this book we look at how to keep the slimy population under control without using poisons that could affect pets or other wildlife.

Take a look at Banish Slugs: Green Essentials