Milkweed, aphids, and monarch caterpillars

4 years ago

I have a small patch of milkweed of varying varieties on the side of my garden. I can honestly say that I have neglected these plans with any attention over the last few weeks except for weeding and mowing around.

The other day however I happened to notice that a majority of the plants were covered in clusters of aphids. I began a very targeted extermination attempt using Dr. Earths insect spray that very night. Now a few days later I inspected the plants expecting a boneyard of dead aphids, only to find many of the clusters still very active. On top of that, while inspecting my plants, I happened to find my very first monarch cat on what believe is Common Milkweed.

My questions are this: Should I stop using the spray and admit defeat for this year vowing to be more alert next year? Or should I continue my targeted extermination process being careful not to spray to much but the infested parts of the plants? Or is there some other advice someone could offer me.

I removed the cater from the plants and now have it housed in a butterfly tent on a potted milkweed.

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Comments (4)

MissSherry
4 years ago
I can only tell you what I did to, hopefully, solve my MW aphid problem. Mine had gotten so bad, the leaves were turning yellowish.

I cut the plants back severely (I didn't have caterpillars at the time), put the debris in the garbage, and sprayed insecticidal soap all over the leaves and aphids that were left. It killed the aphids, but I noticed that some of the leaves withered, like maybe the insecticidal soap was too much for them, too. So, I cut the MW back some more and began just killing the few aphids left by squishing the leaves they were on with two fingers. I check again, and if I miss one I squish that one, too. The MW/Asclepias curassavica grew back rapidly with lots of pretty new leaves, and, since that time, I inspect the leaves every day, and, if I find aphids I squish them. This doesn't hurt the leaves, just turns my fingers yellow. I don't miss a day, because it's amazing how so many can come back so quickly!

I also quit using insecticidal soap, because there's no use depending on something that might kill the monarchs in order to kill the aphids. I was lucky to have monarch cats in spring this year, and I might get some in the late summer or fall, the usual time for me to get monarchs.

'Hope this helps!

Sherry
annabananaflzone9b
4 years ago
I also just squish and spray aphids off with a water hose. Squishing is really the best method, especially for milkweed bugs. If you use the water hose, know it's got to be on high and you have to hold the effected leaves in your hand for support. It takes a lot of water pressure to dislodge aphids. Here in FL, I go on an Aphid, Milkweed Bug and now Milkweed Assassin Bug Hunt every 3 days. I've got about 50 milkweed plants total (Swamp, Tuberosa, Curassavica) and it takes a couple of hours. But, even with that, I'm getting ready to cut most of mine back to about 12-15". The Milkweed Bugs have been especially bad this year and our season was in full swing in March. So, 4-5 months later it's time.

I just hope bug guts make fingernails harder. :)

Anna
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dbobul
Original Author
4 years ago
Thank you both for your input on this.

MissSherry- about how far down do you usually cut the plants down? Just the flowering crown or down to the root?

i think I may have to go the cutting route and remain vigilant to squish and more that pop up.
terrene
4 years ago
I do regular patrols on my milkweed too, for earwigs, milkweed beetles, spider nests, milkweed weevils, etc. The earwigs and beetles get drowned in a little soapy water or smushed, the spiders and lady beetles get transferred to another part of the garden, and the milkweed weevils are smushed.

I don't get many aphids, maybe the insect predators are eating them? Anyway, they seem to show up first in the growth tips, so one option is to brush off the aphids at the first sign with fingers or a small paint brush to prevent them from getting established.

Or do as MissSherry did, clip off the tips and discard. The plant will send up new shoots and the Monarchs love the fresh shoots.