Whiteflies are similar to aphids: they are tiny white flies (duh) that feed by sucking the sap from plants. In the north they die off during the cold weather (though greenhouses still can have this problem due to the warm temperatures), but here in the south they are a year round pest. They are found on the undersides of leaves and fly into the air in white clouds when disturbed.
Whiterflies attack the plant by sucking it's juice, causing leaves to turn yellow and fall, but they also secrete a sticky substance that attracts black, sooty mold which interferes with photosynthesis.
My problem is this: I would spray them with chemicals to save my citrus, but also in our greenhouse is a swimming pool filled with tilapia fish which are highly sensitive to pesticides.
Here's a solution that I hope will help - two homemade remedies that I plan to make and use this afternoon.
The first is Yellow Sticky Boards. Apparently whiteflies are attracted to the color yellow so I will paint pieces of cardboard yellow and coat them with a sticky substance. I have petroleum jelly on hand so I will use that - a homestead motto - USE WHATCHA GOT! Then I'll hang these from the infested trees. Hopefully this will trap the adults.
The second is a homemade, insecticidal soap:
*one gallon water
*2 t baking soda
*2 t dish detergent
*2 t white vinegar
Spray this solution under the leaves of your plants where the white fly eggs, scale and adults reside.
In order for it to be effective, each leaf must be sprayed.
Repeat every 3-5 days until pests are eradicated
I'll let you know how it works.
And I'm open for any and all advice - always. About everything!