The carrot fly not only affects carrots but parsnips and even celery as well. The fly’s maggots cause the damage, killing seedlings and burrowing under the skin of mature plants, leaving brown tunnels behind. The fly’s produce two generations in a year and are active in April/May & July/August which almost ensures they can get at our crops. You can try sowing outside of these time frames in February,March,June,September, and October but its not an absolute guarantee that your crop will not suffer from carrot fly.
The fly is attracted by the smell of carrots & is most active during the day, so thinning, which bruises foliage and releases the scent, is best carried out later in the day. Inter-planting with stronger smelling onions is suppose to confuse the fly but evidence is mixed. Growing your carrots high in containers like half barrels in the ground could keep your crops out of reach. The best barrier to protect from carrot fly is to grow them under fleece, especially in the danger months. There are no chemicals available to amateur gardeners, but there are now more carrot fly resistant seeds being sold like ” Systan Flyaway” & “Resistafly” which could be your best option.
Blog & research by Mark Burton (Allotment Secretary) – Pictures Mick Cooper
