I am with Goodlife on this.
Until this year I persisted in growing carrots without insect mesh. Almost gave up on carrots, but this year I discovered Gardening-Naturally and Harrod Horticultural meshes.
I would use mesh that is 2.5 or 3 metres wide, as it allows it to be well tucked into the earth or weighed down with heavy timber. The 2m wide one had gaps - and guess what happened...