What are Whiteflies and What Do They Look Like?

Q. In a previous post you talked about whiteflies. 

https://xtremehorticulture.blogspot.com/2015/02/how-to-control-whiteflies-on-tomato.html

https://xtremehorticulture.blogspot.com/2015/06/the-whiteflies-are-coming-whiteflies.html

What do they look like and how do I know if my plants have them?

Whiteflies on pomegranate

A. Whiteflies are commonly found on many different vegetables during summer months, like tomatoes, squash and melons. But they are not as common to ornamental trees and shrubs. As far as ornamentals go, they can be a problem for ash trees, citrus, pomegranate, gardenia, hibiscus, iris, flowering annuals, gladiolus and some others. Whiteflies are small insects, brilliant white in color as winged adults, that suck plant juices from leaves and young stems much like aphids and leafhoppers.

            If you are observant and constantly tinkering around your plants, you will notice them during the heat of the summer swarming in the air when disturbed from plant leaves like white “dandruff”. This is an indicator to look at the undersides of leaves where you will find a massive number of unwinged young’uns sucking “juice” from the plants.

            If you are not as observant, you might notice sticky, sugary sap dropping on plant leaves from the feeding just above it. Or you might see columns of ants attracted to this sugary sap, going back and forth to their underground nest carrying this sugary food. Sometimes a black mold will grow on this sugary sap in more humid climates, just like it will with aphids. This black mold is called “sooty mold” which can cause lots of plant damage if left unchecked.

            The adults can fly while the young-uns can’t.  So that swarm of white adults you see flying are adults only and a sure sign that feeding damage is underway.

            It’s winter now so you will not see whiteflies on plants unless they are on plants in warm spots like greenhouses. They are tough to control because they are resistant to  many chemical controls. If you find them early enough, removing infested leaves might keep them in check. Repeated soap and water sprays will kill them. Winter applications of dormant oil to woody trees and shrubs in January will help suppress their numbers in the summer from overwintering adults.