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Do aphids harm milkweed plants?

Posted by caterwallin 6 (My Page) on
Sat, Sep 19, 09 at 14:48

I was under the impression that the oleander aphids aren't good for milkweed plants, that they suck the juices out of them. Is that true? Could they kill a plant? Or is it okay to leave them on the plant, and maybe the only harm they do to the plant is to make it unsightly due to the honeydew?

I learned some time back on here that ladybugs eat the aphids. I haven't seen many ladybugs this year. Has anyone else? Despite my not seeing many now, I'm sure before too long we'll have tons of the Asian ones here at our place. I used to like ladybugs when all that we had were native ladybugs, but after someone dragged the Asian ones over here, we've been getting swarms of them here in the fall and we can barely stand to walk outside (they bite). For probably about the past ten years the ladybugs have become a real nuisance in the house here in the winter (they get in by the thousands). It might not be a problem for someone who owns a fairly new house, but our house is very old.

From what I see on my milkweed plants, it would appear that the ladybugs aren't doing their job. I have tons of aphids. Do you think a person shouldn't kill the aphids because of the supposedly lower ladybug population (if we kill them, it could be detrimental to the ladybugs)? Just what would be the cause of the lower ladybug population this year? Maybe I shouldn't have killed so many oleander aphids last year, but there were thousands and thousands of them.


Follow-Up Postings:

RE: Do aphids harm milkweed plants?

Cathy ~ for what it's worth (since I'm fairly new at butterfly raisin',) I used to have about 10 large milkweed plants (A. curassavica) which were infested with the yellow aphids most of the time. This was when I lived in S. California. I found that when I let the aphids go wild and do their thing, that invariably, lacewings would come and lay multitudes of their eggs in bunches of long stalks on the leaves of the milkweeds. Then their larvae would wander around and eat up most of the aphids, and so make alot more lacewings, which would control the aphids in my entire yard. In short, I was raising lacewings in abundance! Yes, there were more ladybugs there too, enjoying the feast. Now, maybe the cheese done fell outa my sandwich, but I think that if you want the beneficial insects around, you have to have some plants that support large populations of aphids as food for them. After all, the "oleander" aphids didn't infest any other plants in my yard, so the milkweed/aphid combination turned out to be a great thing for me and my butterfly nursery.

RE: Do aphids harm milkweed plants?

Cathy, I do think that eventually they affect the overall vitality of the plant, but I am kind of inclined to agree Mlle. Buttefnly in that if you have food for the beneficials they will come, e.g. ladybugs and their larva, lacewings, and others I'm sure. T kind of take a "wait and see" approach. If the infestation gets so bad that the aphids are creating that black sooty mold on the foliage, particularly the new growth, I wash them down good with the hose, not really getting rid of all of them, but a good number.

If I can see a number of beneficials and their eggs around the yard, I will do nothing because they will have a meal ready for them when they hatch. So, it's kind of like using my own judgment about what, when, and how, or even if. I got so tired of squishing milkweed beetles this year - gross! They were my worst enemy on my milkweeds.

Aphids on Butterfly Week

I suddenly have a huge number of red aphids on my otherwise-fluorishing butterfly plant (weed). What's the best way to control them since we don't have any ladybugs either?

RE: Do aphids harm milkweed plants?

Those aren't 'red aphids' but are 'baby' Milkweed Bugs. ;P

I hose down the Oleander Aphids. The Lacewings are everywhere in my garden and their larvae have plenty to munch on even after I've hosed off the Aphids. I have Aphids I leave on my other plants so there is never any problems with the 'extra' food. Ladybugs are also reproducing in my garden as well so I don't think that my efforts in trying to control the Oleander Aphid population by my human methods has caused any harm in the insect world. In fact, for my school bug club I simply go out and wander around in my garden on any given day and can find the necessary life-cycle step of a ladybug which is quite cool! The kids have been able to watch ladybugs grow from egg and have seen each step all in one fell swoop.

I have seen what the aphids have done to MY Milkweed and am NOT fond of these little things. Period.

As for the little red MW bugs? Squish. I'm certain the bug police will be on me soon...

RE: Do aphids harm milkweed plants?

My milkweed becomes infested with these little yellow bugs. It is
the milkweed bug, but they do look like aphids. I do not spray
or hose them off because I have baby monarch cats on them. I
was almost going to give up and get rid of my butterfly weed
because of this infestation. What I do now is I inspect my plants,
usually when it starts blooming, every day to see if any of the
adult milkweed bugs are there. They don't come all at once. They
are very easy to spot, being bright orange and black. I get a plastic
cup, add water with a little dishwashing soap. Put the cup under the
bug and throw them in the cup with a stick. A few may get away
but you can get them the next day. This works for me and you
get way less aphids. My goal this summer is to get every adult I
see. My sister saw me doing this last summer and she wished she
had done it because her milkweed was so infested you could hardly
see the stem.

Are these the little bugs your talking about?


RE: Do aphids harm milkweed plants?

First of all, everyone answering on this page apparently does not know that the little yellow specks on the Milkweed pods are Oleander Aphids and not baby Milkweed Bugs. Baby Milkweed Bugs are bright orange and never yellow. Second, the Ladybugs from Asia are called Asian Lady Beetles and are mistaken for the American Ladybugs all the time. So, what is in someone's house that they are calling Ladybugs may in fact be Asian Lady Beetles, which are very similar and the same size. The Asian Lady Beetle has an M right behind the head. They can also be red, orange or even yellow.
As for the Oleander Aphids, they feed on the pods at the end of the season and are not a problem unless you have an extreme amount of them and they become a nuisance. Typically, other insects like the Green Lacewing, American Ladybugs, Ambush Bugs, Harvestmen (Daddy long-legs) and other species keep down the aphid population. I have many Milkweed plants and see the aphids every year with the Milkweed Bugs and other insects. My plants bloom every year and new plants come up every Spring. I have no problem. Also, Milkweed Bugs only feed on the seeds of the pods. They don't feed on the rest of the plant and don't feed on other plants at all. Milkweed Bugs are harmless. Don't worry about them. Never use pesticides for any reason. These chemicals kill many insects and other species. If you think you have too many aphids and they are not being eaten then blast the pods they are on with the jet setting on the hose. If you are not using the seeds or dried pods then you can also remove the pods with the aphids to get rid of them. None of the common insects seen on Milkweed plants will kill the plant or effect other plants in the yard.

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