They are on 2 of my Rose bushes. And on my Coreopsis/Salvia. The trees (and vines) were trimmed back to the fence on Wednesday and the debris sat all over this area for quite some time before the landscapers cleaned it up. I noticed the nasty white little buggers this morning and immediately did a G search because I didn't know what they were. They tend to infest trees, but also infest bushes and flowers. If they begin to eat what they are infesting, the plant will become distressed and die.
Some ways to get rid of Mealy bugs (also known as Woolly Aphids):
Use a mixture of warm water and dish soap and warm water. Mix approximately 1 tablespoon of soap per one pint of water. Use a spray bottle to apply the mixture while the water is still warm. The soap will help penetrate the waxy coating and will kill the mealy bugs. Some mealy bugs may be underground when you treat and kill the first batch of bugs, so it's important to retreat about one week after the first treatment.
Use jalapeno juice, Tabasco sauce, or a mixture of hot water and cayenne pepper. Parasites that infest plants in your garden can often be eradicated with simple pepper juices from your home. Woolly aphids can often be killed with garlic as well, so if you have any garlic extract in your home, put it in a spray bottle to use on the mealy bugs.
Rubbing alcohol and soap. Mix straight rubbing alcohol (no water), and 1/2 a teaspoon of dish soap. The dish soap, again, works to break down the waxy coating, and the rubbing alcohol will dehydrate the mealy bugs, killing them. (*I've used this and it seems to be working. I've seperated the veggies containers from the ones with the Aphids because they don't seem to have them and I don't want to use rubbing alcohol on my herbs & veggies. I hope the flowers survive*).
Other soaps, diluted 1 tablespoon to 1 pint water. Besides dish soap, you could mix water with the Murphy's Oil Soap or Dr. Bronner's organic peppermint soap. Not only will this kill mealy bugs, but it will keep other pests away, because parasitic insects don't like the strong scent of peppermint.
ICK, ICK, ICK double ICK!