Marianne's Response

Currant worms on gooseberries

I’m somewhere between a beginner and expert gardener who has moved with the military too much to risk trying to establish perennials until now that I am retired in one place.
I planted several gooseberries bushes 3 seasons ago (North Lakewood) and they seem to be doing well enough — I do get some tasty fruit — but the battle with currant worms is intense enough that I’m considering digging them up and offering them at the local plant swap. The first year, the currant worms skeletonized the one plant before I knew what I was dealing with, which I assume is currant worms. The past two years I’ve used B.T. spray and, when the worms are very heavy, done some hand-squishing and picking as well; there can be hundreds of the tiny green guys on one fairly small plant. The problem with the B.T. is that I have to coat the plants almost weekly, still lose a lot of leaves if I forget it for a couple weeks, they get partially skeletonized by the end of the year and the plants look horrible.
Before I give up and get rid of them, is there something nastier and a little more persistent that I can use less often? If I gave them to someone who could plant them in full sun, would it be much less of an issue?
I’m not sure if the fact that my yard is “partial sun” favors the worms but that’s something I can’t fix and the plants do quite well otherwise.
Your rose link/list, a few years back, yielded a great choice by the way. I scoured that list for hours and went with a variety called “Fragrant Cloud”. It’s done very well. THank you!

Posted by John Eastlake on January 4, 2023

Marianne's Response

Welcome to gardening and so glad you had success with the Fragrant Cloud Rose. Controlling the gooseberry maggot begins with controlling the moth that lays the eggs of the larvae on the plant. Two things you can try are to cover the shrubs in early spring with fine netting or Agricultural fleece (trade name Remay) to keep the moths from landing on the plants and to cover the soil under the plant with black plastic to prevent the larvae from dropping eggs in the soil. Both have problems however. The fine mesh blocks sun and in your partially shaded garden this is not ideal. The black plastic mulch keeps out rain and heats up and so must be removed on very hot or very wet days. There is also a natural barrier control using Kaolin clay which is sprayed onto the plants. This clay repels the moth but you must cover all parts of the leaf. In conclusion, if you have nearby woods or large trees, I would give up on the gooseberry. The moths hang out on the trees and seem to always win the battle of the berry. Try blueberries instead. Keep growing, Marianne Binetti