Whiteflies

I hate to admit it, but I have an insect problem. Well, not me, specifically, but my Morning Glory vines. They are infested with Whiteflies. But like all gardeners, you have to take the good with the bad and dealing with insect pests is just part of the job. 

Whiteflies are tiny, sap-sucking insects that can be found on the undersides of the leaves of many vegetable and ornamental plants. They excrete sticky honeydew and cause yellowing or death of leaves. When a heavily infested plant is disturbed, white clouds of the insects fly into the air. Whiteflies are most active during the daytime when the temperature is warm.

Here is a photo of some on my plants: 

The Morning Glory plants became infested through the introduction of another infested plant (Lantana) that I purchased from a greenhouse. Lantana has a known issue with Whiteflies in the greenhouse and although I kept the plant in isolation for a few days and treated it for insects before planting it among the other plants, I guess I didn't get them all. I will know better next year. 

Whiteflies are difficult to control because they multiply so quickly. I have tried insecticidal soap and it seems to work - but only for about a day. I have also tried manual control by squishing them with my hands or wiping them with a damp cloth. I don't get them all, but enough to feel like I'm doing something. I read somewhere that Ladybugs are a natural predator to Whiteflies and so I might try some of them next. Have any of you tried these? Or have you tried something else that works? I'd love to hear your suggestions.