Gold Aphids and ;milkweed

Please, anyone that can share information about gold aphids that attacked both my milkweed species that I plant for Monarchs in my yard this year. They have never bothered them in past years. I've never even seen gold aphids before. My milkweeds were decimated by millions of these golden aphids. I try to go organic so didn't resort to toxic chemicals. I had to eventually cut them all down. Will these aphids come back next year? Is there an organic way to deal with them? Thanks.
Jan

I grew Asclepias one year (don't remember which species) and had the same thing, the little orangey aphids seemed to love them. I just kept hosing them off, they never seemed to move on to other plants and I never completely got rid of them, but by hosing them off every day or two I kept them from doing much damage to the plants. I don't know if they came back the next year because I moved and haven't planted Asclepias here yet.

Jan,

In all likelihood they are milkweed aphids (Aphis nerii) which are pretty common and cluster on the stalks and under the leaves. Usually later in the season a lot of them turn brown when they die - they are parasitized by a particular species of wasp. Do a Google search on milkweed aphid and you will find lots of info on them. They won't really hurt anything - I just leave them alone. They only bothersome thing about them is the sticky aphid "sap" they leave which may attract ants. They don't hurt the milkweed plants and I still have monarch caterpillars on my milkweeds even when I have the aphids, which I did this year. The organic way to deal with most aphids is to use strong jets of water from the hose to wash them off the plant (not so strong as to injure the plant). The other way is letting nature do it with the parasitic wasp that I mentioned. Mine (the aphids, not the plants) are pretty much gone now - all turned brown and died.

Claire
(edited to add that I posted another thought regarding "decimation" of your milkweeds below, since I forgot in this post)

This message was edited Sep 2, 2007 11:02 AM

This link has some good pictures and discusses the parasitic wasp.

http://edis.ifas.ufl.edu/in520

I forgot to say, if your milkweed plants were decimated, it was probably by something other than the aphids. The aphids suck the sap but generally not enough to damage the plants (mine, this year, were covered from top to bottom on the stem and under the leaves....no plant damage). Thousands of them were all over the plant. The monarch cats that were on the plant did decimate them though, after a time, by eating all the leaves! But, the tops are re-sprouting now.

Here is a pic of my swamp milkweed later in the season (late July) when a lot of the aphids had turned brown and died. Then there is a cat eating the leaves. Aphids can't eat leaves, they only have sucking parts in their mouths, not chewing parts.

The way I get rid of them is put a garden glove on and slide you fingers along the stems and leaves and just squish them, I know it's gross, but it works. Be sure and remove any cats that you can see first. You can then take a spray bottle with water and clean off the remains.

The Monarch cats have a lot of competition for those mw plants, so many bugs love them.