I've been out-of-town for a few weeks only to come home and discover a major infestation of whiteflies in my tomato plants. I've tried garlic and soap spray, which sees to knock 'em down for a couple days but then they are right back.

I've read somewhere that you can place yellow cups around coated in oil to attract them....anyone tried that? Just looking for a suggestion for those that might have faced this in the past.

Thanks for you help!