Brownish-red spots on tropical milkweed

[mickapoo]

Tropical Milkweed with reddish-brown spots.

Hello all! I live in Central Florida, and am hoping to have some help with what is afflicting my tropical milkweed. There are reddish-brown colored spots on the underside of the leaves. The milkweed is potted although I have seen this very same thing on my milkweeds that are in the ground.

I've attached a photo. I'm not sure if this could maybe be some sort of insect such as scale or maybe a fungus like rust? Thank you!

[Mona Miller]

viewtopic.php?f=7&t=2673&p=13114&hilit=problems%2C+milkweed#p13114

viewtopic.php?f=7&t=2350&p=11480&hilit=problems%2C+milkweed#p11480

The above topics deal with some of the problems with the milkweed. I used the search and searched on "problems, milkweed". It takes a while, but there's loads of info on the forum already.

[mickapoo]

Thanks for your response. I did review those postings, along with tons of other stuff on milkweed but I can't seem to figure out what it is. I was hoping if anyone did read this posting who has had the same problem might be able to identify it. I have seen it on tons of milkweeds here in Central Florida but even the nursery owner didn't know what it was. Whatever it is is destroying the health of the mllkweed and the cats won't go near the leaves.

[Mona Miller]

Have you look into thrips? Have you contacted your cooperative extension person?

[mickapoo]

Yes, I did contact my local extension office and they recommended I bring it in to their office for viewing under a microscope. Unfortunately they aren't that close to me and aren't open on the weekends so it's virtually impossible for me to get over there during business hours. I was hoping maybe if someone in the central FL area has had this same problem maybe they could more easily identify it. I've seen it on tons of milkweed in this area.

I finally found out how to take a macro shot on my camera, so this photo reveals it in much detail. I've sent it off to other forums and horticulturists and if I get to the root of the problem I"ll definitely post back here. Here is a much better photo (it's large, so please be patient when loading!)
http://www.hybriddesign.net/monarch/milkweed.jpg
http://www.hybriddesign.net/monarch/milkweed2.jpg

Thank you!

[Mona Miller]

Here's another website:
http://www.mobot.org/gardeninghelp/plan ... =Asclepias
Problems Associated with Asclepias

It looks like some type of scale insect.

I will also post this to the Monarch list serv (dplex-L). Hopefully, we'll get an answer soon.

[Mona Miller]

http://edis.ifas.ufl.edu/ch195
"Florida Red Scale - Chrysomphalus aonidum (L.)
Florida red scale has circular armor made up of three concentric rings. The color is dark reddish brown with a conspicuous light brown center (Fig. 6). The adult female is about 2.0 to 2.2 mm in diameter and produces bright yellow eggs which are deposited under the scale armor in groups of approximately 10 eggs. Eggs generally hatch in 24 to 48 hours. The adult male is small, gnat-like and free flying. Florida red scale infests only the leaves, green twigs, and fruit (Fig. 7).

Florida red scale is under biological control by the introduced parasite, Aphytis holoxanthus (DeBach). Some additional insect predators feed on Florida red scale."

[mickapoo]

You're going to chuckle at this but I just received an email from an extension office (next county over from mine) after they looked at the same photos (the larger ones I linked to in my last posting). They stated, "These are not scale insects. It looks like a fungal problem to me." Jeez! I'm so confused now!

[Mona Miller]

Did you ask the extension agent how to deal with the problem?

If it isn't fungus and is a scale problem, here's the info on that:
http://edis.ifas.ufl.edu/mg005

But, be careful of pyrethrims and products containing neem. Read the labels. Pyrethrims stay on plants way too long and will kill Monarch caterpillars.