I’ve had the same exactly bugs on my lupin Gladiator. The plant was literally covered with them and pretty much eaten alive.
They were absolutely disgusting. I sprayed it heavily with a pesticide spray, literally from top to bottom and keep checking it every day. The plant is doing better, even trying to flower (with what ever buds were left). Hopefully this was a permanent solution.
Janie, I've got them on my lupins too. Have been spraying them with a mixture of white vinegar and water - seems to be doing the trick. Need to keep doing it as more appear but flowerheads are doing well and look healthy.
They are a type of aphid, all of which seem to be flourishing this year. You can, of course, use a pesticide but a more environmentally friendly way to do it is to brush them off with your fingers or blast them with water from a hose - though not such a blast that you damage the plant. Sadly, birds don't seem to eat them but they can be managed unless your have huge numbers of lupins.
When I had a lupin and it was a big bugger and I never noticed the aphids but I did notice a lot of broken leaves. I watched and it was sparrows going after the aphids. The sparrows pretty much ruined the plant but at least the chicks got fed
Hmmm ... I have been spraying them with the hose, but it is relentless! Loathe to go down the insecticide route ... maybe I'll try with vinegar and water (this is ok for wildlife, isn't it?) ...
When we moved into our current house, there were some lovely lupins. One or two summers later, they started being devoured by aphids. They do self-seed however, and my understanding now is that they are short-lived perennials; I enjoy the seedlings randomly popping up. Perhaps with named varieties it is a bit of a lottery whether they self-seed or not (and whether they come true).
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Lupin aphids, methinks...
https://www.rhs.org.uk/advice/profile?pid=653
I just brush them off with my hands every few days.
Deals with the problem and doesn’t harm the plants or other invertebrates 😊
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.