Three years ago I was in the same boat as you ... ended up with not a leaf on any bush. Since then I've made up a spray of neem oil and as soon as all the leaves are out in April I drench each bush. Any spare solution goes onto the soil below the plant as the earthworms are supposed to love it. I do a second drench at the end of May (just in case) and have had great crops since.
Neem is totally organic and although it stinks a bit is easy to mix up and apply (see link below). I got mine off ebay .... wasn't expensive for a big bottle which will last ages. At room temperature it is solid, but goes liquid again with a couple of hours in the airing cupboard.
Am using this year on the lilies as the dreaded beetle has now put an appearance in Scotland.
Just a shame it doesn't work on slugs ....
So, worth a try ... good luck.