These look like aphids, but they are the color of mustard. Every year these show up on the very new growth of the Hosta (here in photo) and this year a few are showing up on the really new growth of the Mandevilla. I've never seen them on other plants. They seem only to be on the newest growth and never hiding down in the foliage. They are easy to wipe off with my fingers. I've never seen any with wings or any other stage of growth. Even though they look to be a sucking organism, there is no detectable damage to the growth on either the Hosta or the Mandevilla. Anyone else have experience with them and know what they are?

There seem to be several colors of aphid, Donald. I get the yellow ones all over my Asclepias. Spraying with soapy water every week or 10 days keeps them in check for the most part.

Thanks Debra. I've seen brown ones, green ones and sort of white ones, but never these bright colored ones. It seems an odd trait to me because they are really visible and most aphids get down in tight leaf growth where they hide. These are way out in the open. They eventually disappear as the growth ages. Unless I see damage, I think I won't bother with spraying. With the other aphids, the foliage shows damage, but the Hosta never has. There aren't very many on the Mandevilla, but it also isn't showing damage. They must be doing something, but I can't detect it. Maybe they are some sort of tropical aphid and I'm overwintering them when I bring the plants inside.

Yup, those are aphids. That type attacks my tropical milkweed all the time when it is in bloom. My geraniums act as barrier so it does not move to the other plants. I just try to hose them down or use alcohol/diswashing liquid solution swab or spray it directly while the sun is not yet hitting the plants.

Just editing to add: if you have ladybugs around..they would love those aphids big time!

The ones on the Asclepias are, too. All up and down the stalk. Show up real good against that green, too.

The aphids are Oleander aphids. I teach organic vegetable gardening and I've always encouraged people to tolerate these aphids as a way to bring in beneficial predators. I was, however under the impression that they only had 3 host plants. (Oleander, Milk weed and Mandevillea) Now I know better. FUN FACT: I once fed some of these aphids to a hover fly larvae and got to watch him change color from Green to Mustard as he consumed them all! Too fun.

Aren't Asclepias a type of milkweed? Mandevillas have white sap, but the Hoya doesn't. At least not visually. I can't remember what Oleander sap looks like, but know it's poisonous. These aphids must be adapted to consume some harsh chemicals. Makes me wonder if the Hoya doesn't have plant properties that I'm unaware it has. I have Euphorbia tirucalli growing. I'll have to watch and see if the aphids are willing to tackle that one! But their taste for those plants may be why they don't hide like ordinary aphids. They may be a bit toxic themselves to some would be predators.

Tarev, I have lots of ladybugs here, but I've never seen them on the Hoya. Nor any ants. That doesn't mean either one doesn't get involved with the aphids, just that I haven't noticed it. I had regular sap-sucking green aphids get in the daylilies and the ladybugs have worked diligently on those aphids.

Yes, milkweed.

lovemyhouse said:Yes, milkweed.

It won't grow at my house . It grows beautifully as a native plant in the deep sand about 4 miles away, but just can't manage the hard red clay here.

It struggled with the black clay, here. Took four years to really take hold.

needrain said:Tarev, I have lots of ladybugs here, but I've never seen them on the Hoya. Nor any ants. That doesn't mean either one doesn't get involved with the aphids, just that I haven't noticed it. I had regular sap-sucking green aphids get in the daylilies and the ladybugs have worked diligently on those aphids.

When I used to have Hostas, they don't get attacked by aphids, my real problem with them are snails/slugs. The two hoyas I have outdoors, don't get attacked either by aphids thankfully.

Only my tropical milkweed-Asclepsias currasavica seems to be a magnet for these nasty aphids always. But I just do what I said earlier, alcohol/dishwashing liquid application to manage them, just have to do it, those aphids are persistent. And at times, I do see the ladybugs make a meal of those attackers. Oh, and I have mantids around here too, so they help in aphids control as well.
Got this photo in Sept 2013 - love the ladybugs!


Just editing to add, took a photo this morning of my tropical milkweed..no aphids yet thankfully..but a mantid is already there, guarding his lair: