Post category: Carrot root fly
Tiny white or yellowish maggots tunnel into carrots. If the attack takes place early on, the plants will be completely stunted. Later, the roots can be made useless if the attack is severe. After feeding in the roots, the maggots pupate in the soil, emerging as adults after a few weeks, or the following spring.
Carrot root fly mines in carrots
Parsnips are often attacked in the southern part of the country, and occasionally elsewhere. Parsley and celery are sometimes attacked too. The symptoms are the same as carrots – stunting and reddening of foliage, and small, rusty mines in the roots.
Control is quite difficult. The adult flies rarely fly above 60 centimetres; a barrier fence of polythene 60 to 75 centimetres high will keep most of them out and few roots will be affected. The barrier must have no gaps, especially at ground level. Make sure to tuck the polythene into the soil. Erect this as soon as the carrots germinate.
Growing onions or garlic with carrots to confuse the fly has given mixed results. Spent coffee grounds scattered along the row, over the root tops has given good results, but must be replaced as it is washed away by rain. Delaying sowing until May does not work in the garden because there is considerable overlap in the emergence of generations of the flies.