So far this year I have not had a problem with many pests, including the slimy ones. They seem to have reduced with the increase in biodiversity as I am trying to be as organic as possible.
I do not use any pesticides or herbicides or additional feed other than lots and lots of manure. Hopefully my own compost will be ready soon to add to the plots in autumn.
So far the broad beans which are usually worst for aphids/blackfly have not been attacked either.
But then I did inter-plant with wildflowers, marigolds and nasturtiums on most beds. The latter go really well with broad beans as aphids love them, no problem with lettuce either inter-planted with onions, shallots, nothing likes them.