White flies have two main species which are active in the United States. The Citrus and the Greenhouse are most commonly found but others exist. Citrus white flies are found on just about any plant – not just fruit. Citrus white flies are hardy and will be active year round.
White flies are a problem because they have piercing mouth parts which allow them to such plant sap. This behavior is what they do to feed and host plants are prone to many problems during such feeding. There are many problems that feeding white flies cause including:
Leaf damage. Feeding white flies will cause leaves to turn up and brown, disabling them to perform their responsibilities. Damaged leaves look bad and promote decay fungus and bacteria to form.
Sap drainage. White flies have an insatiable hunger for plant sap and will suck as much of it as they can from the host plant. Young host plants will not be able to meet these demands and don’t stand much of a chance to survive; adult plants which loose vital sap are more prone to disease, heat stress and less likely to rebound from any environmental shock.
White flies excrete honeydew which lures other nuisance insects onto the host plant. These secondary insects will feed off the honeydew and effectively farm it for it’s nutritional value but invariably they will become established on the property or in nearby structures. This secondary insect infestation is usually some type of ant, wasp or beetle. Regardless, feeding white flies allow such populations to thrive. Furthermore, the honeydew goes bad and grows a mold known as Black Sooty. This mold damages host plants preventing them from processing food properly further contributing to the host plants demise.
White flies are unsightly when they populate any plant and if prized landscaping gets infested it really looks bad. Active white flies will buzz around host plants throughout the day and are very noticeable. They are annoying when active on fruit or flower producing stock and can easily be brought into the home with anything harvested off infested plants.
Lastly, white flies are extremely prolific. Once they get established on any plant around the home or garden they will readily migrate and look to infest any other nearby vegetation. White flies don’t discriminate; they will move onto any plant that has healthy and abundant sap.