Has anyone else experienced this pest? After several years of growing milkweed (the common variety and swamp milkweed), this year all of my milkweed had an infestation of thousands of these golden colored aphids. The stems of my plants were solidly covered. It took many weeks but the plants finally succumbed to these pests. They did not spread to other plants in my yard except for Butterfly weed. Does anyone know anything about them? An organic way to get rid of them? Do they come back once they have been in my garden? How could I try to prevent that from happening? Thanks.