Gooseberry bushes being eaten

I've noticed that my gooseberries are being munched by this destructive caterpillar - or a hundred!!

 

Gooseberry sawfly, pick them off and squash, they will defoliate the whole bush, two lots a year and they spend the winter as pupa in the soil.

 

Yes they have started on ours early this year. Nightmare. One suggestion is to put something under the bush (easier said than done!) and then shake the bush rapidly and the caterpillars will fall off. Not tried it as our bushes are in an area than is difficult to get something under the whole bush. We do try and squash them but will always miss loads.

 

I have this battle every year...except this one!?

 

We get them later in the year where they always strip the bushes clean. It doesn't seem to do any harm then but I wouldn't want them earlier. I think we don't have a problem with the first flush because the fruit cage is open for pollination and the birds do a good job, we reward them later on with plenty of fruit. For us it's near impossible to pick them off or put anything under the bushes because they are so old, big and crowded (but fruit wonderfully with benign neglect).

 

Maybe a solid mulch would help as theyll struggle to dig through the soil. youd do that in winter to stop the last generation digging up.
slate would look nice but not sure if they could get through it, maybe thick newspaper would work

 

I did go out with the best intentions of finding the caterpillars yesterday. I looked at all the stems eaten or not and couldn't find one. I know they are there but hopefully not too many. The fruits though don't look as good as usual.

 

6oz 137cm Natural Hessian Jute

this company sells jute which you could try for mulch. not sure if the grubs could eat into it, doubt they could eat through two layers.

 

Nope I take that back