Whiteflies have attacked my containers in my atrium. I have grow boxes with veggies and containers with flowers and succulents. I have pulled the most infested plants trying to capture the whiteflies along with plant in a plastic bag. While I have cut things down, they are still there. How do I get rid of these pests.

First i wouldn't recommend chemicals for obvious reasons, chemicals are usually applied as a pesticide witch should be used as a last resort for any pest problem. There are many non-chemical pesticides available but be sure to buy one that works for your problem (whiteflies).Try Insecticides like soaps (safer soap,) and oils (like neem) both work well with whitefly's but worry when using any pesticide because white flies are known to become tolerant when applying repeatedly, ther for insecticides are effective but only to keep at bay. The best way to rid of whitefly infestation is an integrated program that relies on prevention, maintanence and biological control. Prevention and maintenance are as one, to prevent is pretty much covered when you practice proper garden maintenance. Most disease and pest prefer prolonged moist soil, making sure your soil has accurate drainage and adding top mulch (such as plastics, and or wood chips/bark) or pebbles helps. Also proper irrigation, check and make sure you have no leaks and as rule of thumb water less in cold weather. Practice proper fertilizing methods, most pest attack weak or diseased plants. Under fed plants and mostly over fertilized plants are common targets for pest and disease. Keep your grow area clean. Removing infested plant was a smart thing but be sure to also remove any infested leaves as well, either on a savable plant or non infested leafs on the ground! Yellow sticky traps  (white flys like yellow?)and simply using a strong stream of water to wash leaves/stems affected by the fly's work just as well as spraying with insecticide soap or oils. Foil top mulches are too very affective. These are all prevention and maintenance methods, when it comes to biological,  predator insects are number one. Just think for a sec the only reason whiteflies are able to infest a plant is most likely because ther natural enemies aren't around. This is why insecticides especially chemical are not recommended, most pesticides kill soil life, beneficial and predator insects as well.... so if using.. be careful were you apply and try to get the least harmful (ones labeled caution, not warning or worst danger). Predator insects may be a bit slightly difficult to come across but many are readily available in your own garden, you just got to know who is who. Many garden stores and especially garden websites sell predator insect, lady bugs being the most common. But other predators like green lacewings, encarsia formosa, pirate bugs, clitostethus arcuatus, prey mantisand few others; feed on whiteflies and  can be found at your local garden store or shipped to your door step threw the web, with direction on how and when to apply. Adding companion plants like marigold, nasturtiums, some mints and Basil's repel whiteflies and are other biological methods. In the end know your enemy for he is your best friend when it comes to dealing with them, and if all else fails use a store brand pesticide labeled (RTUready to use) not commercial concentrates. oh and wear proper clothing (gloves,long sleeves,garden boots) when applying .......Hope this helps

here are some links to help you out

whitefly info (id,biology,methods of conrtol)

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7401.html

ordering beneficial insect online (be sure to get the ones that prey on your pest)

http://www.wormsway.com/catalog.asp?cat=pestb