Last year, my gooseberries were defoliated before I even figured out what was going on. I wasn’t totally miffed, however we got only a handful of gooseberries.
This year, I’ve found the culprits… Gooseberry Sawfly – Nematus ribesii.
These guys cleared this shrub in less than one day. I’ve got many flowers that are blooming in this garden bed and visit it daily.
The treatment for them is the same for rose sawfly – Endelomyia aethiops.
Larvae can be effectively controlled with a neem oil product or an insecticidal soap. Spray only the leaves (both sides), in the morning as neem oil can possibility hurt pollinators The strategy is to find larvae while they are still small and before damage becomes severe. You can also use a garden blower to launch them far away from the plant chemical free!!
There is no need for control after the larvae have finished eating and left the plants, give or take mid-July.
Just for the record, using dish soap is not acceptable for a cheap substitute for horticultural soap. Now-a-days, the dish soap is not soap anymore, detergent is the main ingredient and modern soap lacks the fatty acids that are helpful in killing the insect.