Greg at Ashland Greenhouses has kindly responded with a remedy to an AGC member’s white fly problem in her new greenhouse!
White flies are extremely challenging especially if you are trying to be organic. There are some pesticides that are very ‘soft’ that work pretty well. We use an IGR (insect growth regulator) which disrupts their molting. It is called Enstar II and it does not kill the adults, so you must spray a couple, three times to stop. The advantage is that is very specific to the white fly family so it does not kill beneficals, and it is not very harsh.
We have also used imidacloprid with good results and it is registered for use on tomatoes.
Finally there is beauveria bassina which is a naturally occuring fungus that does a fairly good job, but is slow reacting.