How do I prevent whiteflies in the greenhouse? i am a special education teacher that has taken over the horticulture program at our school. This is my 3rd year and we have had white fly problems the last 2 years. thank you for any suggestions!!!!

Hi, I've had the same problem with my greenhouse. I have sprayed the leaves top and bottom with Safer Soap, and I've also used Neem oil. It has helped, but they're not totally gone. Here is some info from the internet:
http://ipm.ucanr.edu/PMG/PESTN...

Whiteflies are tough to get rid of. You spray and they fly away just to settle someplace else. The best thing I have used its yellow sticky traps. Hang them from sticks near your plants and shake the plants. The flies will resettle on the sticky traps - yellow is their favorite color.

Good luck!

>> we have had white fly problems the last 2 years.

I think the above suggestions are right on: insecticidal soap spray, Neem and sticky traps will reduce their numbers. I think the soap spray can be repeated frequently.

Extreme cleanliness MAY reduce the problem a little. Removing damaged plants or leaves ASAP might reduce their numbers slightly. Since whitefly eggs hatch, dead leaves and soil should be cleaned up quickly.

I hope the students are old enough to appreciate how realistic the lesson is!

About three days after you figure out how to get seedlings to sprout, you start wondering how to get rid of the ##^#*##^### pests!

And how tempting it is to go in with the nuclear pesticide option and poison everything in sight.

And how non-toxic methods like "Integrated Pest Management" CAN be used ... with more effort and more smarts and constant vigilance ... and slower results. But less poison.

Kay, since this is in a greenhouse you could use a biological control, Encarsia, a parasitic wasp, that is available commercially to control greenhouse whitefly. That would be a good lesson for the kids too. I think they work best if introduced before the infestation becomes significant.

Rick, IPM does allow the use of pesticides, and not only "non-toxic ones". But they must be used judiciously and responsibly when they are necessary as part of a program that includes other methods of reducing pest problems. It is often said that in IPM programs pesticide use is only as a last resort but there's an interesting article discussing that statement here:

http://www.entsoc.org/press-re...

I had a horrible whitefly problem in my greenhouse last year. Gah! I had to use chemicals, my g'house is too big. Since I bring in plants from many people to overwinter, the pests come in with those, for the most part. This year I cut everything back pretty hard (as I usually do), and sprayed as I brought the plants in. We'll see how that goes. I need to put up some new yellow stickie papers. I've had some up, but I think they need to be replaced.

sooby said: ...
Rick, IPM does allow the use of pesticides, and not only "non-toxic ones". But they must be used judiciously and responsibly when they are necessary as part of a program that includes other methods of reducing pest problems. It is often said that in IPM programs pesticide use is only as a last resort but there's an interesting article discussing that statement here:

http://www.entsoc.org/press-re...

I liked the article's distinctions like "toxic to WHAT?" and "toxicity vs. risk" when used properly. (Quotes are only approximate.)

I also like points they made like: "Last Resort” vs. "carefully timed", e.g. it may be necessary to use pesticides before the problem becomes unmanageably severe.

Over-reliance on any one pesticide, or over-use, or misuse, can lead to significant weed resistance and other problems.

Maybe if IPM had been practiced more widely, starting decades earlier, pesticide use would not have as bad a reputation as it does. For decades, "use" often meant "over-use and mis-use".