The Gardener's Almanac

Yes, it is possible to organically control caterpillars.

If no attack has yet started, cover the crop with an agricultural fleece, the fine mesh will exclude the egg-laying butterflies.

If there are already caterpillars on the crop, spray with the biological control bacillus thuringiensis, this is a special bacterium

species that attacks and kills caterpillars.

It can be obtained biological control specialists.

The disease you describe could be white blister.

It can attack most plants in the cabbage family, including honesty.

The best control would be to remove the worst leaves and any fallen ones, then spray with a fungicide.

After cropping, dig out and burn all plant residues and follow a crop rotation to keep new seedlings and plants away from older

ones.

The small white maggots are the larvae of the 'Cabbage root fly' and they live in the soil and eat the roots of cabbages and

other brassicas.

Infested plants wilt, especially in dry weather, and young plants may be killed.

The adult flies are active in April and May when they lay their eggs on or near plant stems at soil level.

Three generations of adults develop during the summer and attacks may persist until mid-September.

This pest is now resistant to many of the insecticides available to the amateur, so it is best to alternate between different

pesticides at each treatment, thus reducing the chances of non resistance.

Jeyes fluid although a disinfectant can be applied as a soil drench prior to planting,

It is thought that the fly is deterred by the smell so it moves on and lays its eggs elsewhere.

Plant out in a different bed each year to ensure you are not affected by over wintering fly pupae in the soil.