By Vmparry
United Kingdom 
I have three lovely lupin plants in my garden. However, for the past couple of years they have become covered with a horrible mass of tiny white creatures that look like miniature grubs. The cause the leaves etc to go brown and curl up and die. I have sprayed with a number of bug killers but it kills them for a few days when they reappear again all up and down the stalks. They are horrid, Despite repeatedly spraying the plants as I say they reappear and I do not know what they are or how to get rid of them permanently. I do not even know what insect lays them in the first place. None other of my plants is affected. I should be most grateful for any advice please.
21 Sep, 2010
Answers
Soap spraying should be very thorough and fairly frequent, though, Vmparry. Any of the little critters you miss can repopulate the plant in a week or so. Pyrethrins are the same way. If you get desperate, you can use Provado, which will kill off the ones you miss, and last for a month, but it's rather more harmful to the environment. Neem oil is organic and long lasting, and makes a good preventative, but it works very slowly once the bugs are started.
21 Sep, 2010
Previous question
I think these are lupin aphids. They are huge fat pale green greenflies. They lay eggs and then they are able to give birth to live young very readily throughout the summer. I find spraying with soapy solution is effective and it doesnt harm the birds and other beneficial insects.
21 Sep, 2010