Thanks, Jack. The trick toharvesting currents is to use 6 year old people with small fingers. i am thinking a girl and her brother for squashing the pests!

@Spinliesel Interesting use of children. Do they get paid in things made from the berries? I have a friend who planted several black currants and asked me to harvest them (this is usual for her - she plants and others do the rest of the work). The plants grow too tall for children and they require a lot of pruning. I remember Schwartze Johannisbeeren Saft from my years in Germany and actually found it at a wholesaler in Seattle. I made preserves from it (I no longer harvest it as it is toooo much work and I have a separate orchard which also requires time.
It would be best to put gloves on the kids when going after the flies as, as you know, the thorns can literally be a pain. One thing I noted is that if you get the flies early then there are far fewer of them the following year.

I think it is the black currant bush that put nematodes into the soil to eliminate all other "competitor" for nutrients, especially coniferous trees ( pines, firs, etc.) I sometimes find mrabelle plums at my local farmers' market. So delicious!

@Spinliesel I will have to watch-out. They are in isolation and do not have trees around them.

@AlexRam It is the same in my garden.

@Spinliesel Interesting to know.

Yes, and create an environment detrimental to evergreens.