Whitefly

Whiteflies feeding on a cucumber leaf.

We recently discovered whitefly infestation in the 248x52 greenhouse.  Whitefly is considered as one of the most disastrous pests that had caused hundreds of millions of dollars loss in agriculture worldwide.  Houwelings also underwent whitefly attack that led to the clean-up of entire facility.  Very useful information on whiteflies can be found in Wikipedia: http://en.wikipedia.org/wiki/Whitefly

In short, whitefly produces toxic saliva to feed on phloem of a plant, which makes the plant lose turgor pressure.  Whitefly also carries variety of diseases that gets transferred upon feeding on the plants.  Not only that, whitefly excrete honeydew (much like Aphid does) that promote mold growth on the plants.

Whitefly control is difficult as whiteflies rapidly gain resistance to chemical pesticides.  So the use of same chemical over long period of time is not recommended.  In our greenhouse, we spray chemical to take care of whiteflies (need to ask Carl what he sprays).  But there are many biopesticides available such as green lacewings and ladybugs.  At Merom, Carl uses ladybugs to counter whiteflies.