Recently Emerged Buddleja Pest

Last year was the first time I'd seen significant aphid damage to Buddlejas, even to some B. davidii cultivars. It's been so bad so far this year (undercover), the aphids have even killed some immature plants. This seems to be nationwide problem, with people telling me about distorted foliage from all over England. My impression is that this is a new problem.

I don't know which species is responsible, whether it's a new, recently introduced aphid species, or whether an existing native species has mutated to exploit Buddleja. In any case, aphids are now a serious pest on immature plants.

I'm using horticultural soap (1% solution) to both spray and physically wash off the worst infestations. Seems pretty effective so far. Pesticides are a no-no as the residues will find their way into the nectar in July. Later in spring, I will search out hoverfly and lacewing larvae to put on affected plants as these are voracious predators.