I don't know but the only problems I've come across with gooseberries are sawfly and American blight. Sawfly can be controlled by vigilance - at the first sign just remove the affected leaves. The caterpillars hatch in groups on the undersides of the leaves and are easy to remove if you get them before they have dispersed. Mildew: there are blight resistant varieties, which solve the problem and you can find a list on the RHS site. I have been growing Invicta for years with no problems. Keep the bushes open for a good air flow and burn all your prunings as it overwinters on the plant. Sprays are not very effective. Most sprays have been found to be ineffective against it.