what is the best protection against ‘Saw Fly’?

Question

I have two gooseberry bushes which were badly affected last year.

Answer 1

Since the larvae that do the damage emerge from the soil, using a row cover is preventative only if you had no sawflies last year. Closely inspecting the underside of the lowest leaves weekly allows you catch an infestation early where manual control may be possible. The Royal Horticultural Society gives this advice: https://www.rhs.org.uk/advice/profile?pid=517