That little pest that really bothers me is the Carrot fly: A creature that is a member of the family Psilidae, also called “Rust Flies.” In addition to eating carrots, they can also be found in: celery, parsnips, and parsley. It seems to me that they are out to get my crop, whatever I do.
To understand them, the place to start is to know what they do. The fly lays its eggs at the base of the plant, they hatch and begin to eat the closest food, that is, your crop. The fly attacks the seedlings because of their smell.
There are two ways to prevent this, both of which try to make the crop unpalatable to the fly.
One way to do this is to soak the sawdust in paraffin and spread it between the rows.
Another idea is to spread wood ash over the entire seedbed.
However, the carrot fly has a great disadvantage and that is that it cannot climb more than a meter from the ground. Using this debuff is a much better way to grow a good crop of carrots.
Again, there are two ways to do it:
One is to make a three and a half foot barrier around the seedbed with wool or horticultural netting. I tried this and found that it is not that easy to maintain the barrier due to wind and rain causing it to collapse.
The way I use, is to plant my carrots in tubs or troughs and put them on a bench. A friend of mine puts his on the roof of his garage. We both have good carrot crops every year.
the celery fly
The celery fly is a very different creature than the carrot fly; They can fly and have green eyes. The larva of this fly is 7mm long, while the larva of the carrot fly is 9mm long, so if you don’t see the two together in the larval stage, it’s hard to tell the difference.
Again, the best way to deal with this pest is to have the celery fly leave and feed elsewhere making the foliage unsightly. This is best done by dusting the crop frequently with equal parts lime and old soot. The lime should be finely pulverized and dusting should be done when the foliage is wet or damp with dew, so that the soot-lime mixture adheres to the foliage.
It really is worth doing something about this pest because the females of this very destructive fly are more prolific at laying eggs. The hatching larvae force their way into the celery foliage tissues and absolutely kill the crop.
The celery fly also attacks parsnips. the crop will show erratic lines on the leaves along with brown patches. You can save your harvest by taking the leaves and burning them.
If you wish, I’m sure you can buy some sort of chemical spray to treat the ‘fly problem’, however I prefer the chemical-free garden.