Blacurrant leaves curled up

[Saraheliz]

Hi

a few of my blackcurrant bushes have new leaves emerging and they come out alll curled up or maybe they come out normal and curl up afterwards. Checked for greenfly, aphids or whitefly and not found any. Does anyone have any idea what is causing this?

thanks!

[Maddie106]

My fruit book from Ken Muir mentions "Blackcurrant Leaf Curling Midge" and suggests cultivating the soil around the bushes in dry weather in the summer to kill the pupae.
The midges are apparently minute, so you wouldn't see them.