Covers best protection against carrot rust flies

QAre floating row covers or insect netting over carrot plantings as protection from the carrot rust fly?

I grow perfect carrots using coffee grounds in the furrow and over the ground to mask the carrot odour that attracts the flies. A neighbour covers the scent of carrots by sowing green onions in between closely spaced rows of seeded carrots. This also gives him a crop of green onions.

AThe flies, drawn to the aroma of carrot foliage, lay eggs at the plant bases. Emerging larvae eat into the roots, disfiguring them with dark, rusty looking tunnelling.

Using coffee grounds and seeding green onions between the carrot rows may work to deter the flies where their populations are typically sparse. Where they are numerous, only a barrier like insect netting or floating row cover will ensure a crop of clean carrots.

Populations of the pest are typically spotty. People gardening in areas not far from me have never had a rust fly problem in their unprotected carrots. Other gardeners have stopped growing carrots because rust flies. They feel it’s too much trouble to place an insect barrier cover over their plantings. Actually, it’s quite simple. The cover makes for close to trouble-free growing of clean carrots.

Be aware too that vulnerable crops can grow without pest visitations for years before being “discovered” and damaged. I grew bulb onions uncovered for over 20 years in my current garden with no problem. Then one year, the planting started off fine and then the tops all fell over. There were onion fly maggots in every bulb. Now I cover the onions too.