Gardenias, Crepe Myrtles, and Azaleas. Favorites of Georgia landscape designers and homeowners alike. They are also favorite targets for a pesky little ornamental pest called white flies. If your plants are otherwise healthy, but you start to notice the leaves yellowing, wilting, and prematurely dropping between the middle of July through the middle of October, it may well be white flies.
Here is a quick breakdown of white flies, the damage they cause, and how to control them from the pest control experts at Nature’s Turf, serving homeowners in the greater Atlanta, Georgia area.
What Are White Flies
Before we talk about controlling white flies, let’s dig in and understand them a little more deeply. When considering a pest and how to control it, knowing the focus of your energy and attention are key. While the name ‘white fly’ suggests that these little flying foes are related to house flies, they are in a different taxonomic order of insects altogether. House flies are order diptera (often referred to as true bugs). White flies are order hemiptera which is the same order as aphids, another familiar ornamental pest that creates similar damage.
While there are many species of white fly, there are only a few that are significant pests in our landscapes, the most significant of which is the silverleaf white fly. Where some species have very small host ranges, the silverleaf is polyphagous which is a fancy word that means it isn’t super picky about what it eats.
White flies have a hybridized metamorphosis, meaning their juveniles don’t look like the adults. Silverleaf white flies lay their eggs on the bottom side of young leaves in no particular pattern. As they hatch, their first instar is called a crawler. They make their way to an appropriate feeding location, and this is where they will stay until they become an adult. Instars 2 and 4 look an awful lot like scale making for a unique set of challenges before becoming adults.
In general, white flies are easy to identify. They are teeny tiny little flying insects that are white. Adults are small, roughly a millimeter long, with a waxy white secretion on their bodies and wings. While most of the species hold their wings flat, silverleaf white flies hold theirs at a 45 degree angle, making them look like they have a little roof on their back.
What Kind of Damage do White Flies Cause?
Whether freshly hatched or full fledged adult, all phases of white fly feed in the same way: with piercing sucking mouthparts. They use tiny, needle-like structures to pierce the leaf tissue and suck the contents out as they flow through. The result is interveinal chlorosis which simply means that the leaves turn yellow between the branch like veins. Initial damage may present itself as stippling, or tiny yellow dots that coalesce and grow.
A secondary damage created by white flies is the development of sooty mold on their excretions. Just like their relatives, the aphid, white flies excrete honeydew as their digestional byproduct. Since it is high in sugar, sooty mold will use it to grow in warm/wet conditions. While not immediately detrimental to the plant, it certainly detracts from a plants aesthetic appeal, and can be an indicator of a larger problem like a white fly infestation.
Injury can happen quickly. In warm weather, broods can be quite large, and since their entire life cycle takes place in 2.5-5 weeks, many overlapping generations in a single season can be expected. If uncontrolled, exponential population growth is likely, and damage can be extreme. Young plants in high white fly pressure can succumb to their injuries.
How Do You Control White Flies?
All good pest control strategies find their roots in understanding the pest itself. Since we can’t eliminate the host (your plants) and the environment is full of variables, removing the pest itself is key. This can be a little difficult if you don’t understand the habit of white flies, however.
Since the juveniles are on the bottom of leaves, immobile, and encased during portions of their development stages, contact insect control products aren’t as effective as we’d like them to be. Adults also generally find their way under leaves during the day to shelter their tiny bodies from sunlight, and simply fly away when provoked.
The most effective method of control for white flies is to meet them where they eat, and we aren’t talking about a dinner date where we hash out our differences. Instead, applying a systemic weed control product that spreads throughout the plant tissues and exists in their food as they consume it is the most effective method of control. Each stage of their lives is susceptible to this control method, meaning we don’t only control the ones we see, but also the ones we can’t, all while preventing future generations from forming. A small aside, Nature’s Turf offers this protection with our tree and shrub program.
Important Takeaways:
- Gardenias, Crepe Myrtles, and Azaleas. Favorites of southern landscape designers and homeowners alike. They are also favorites targets for a pesky little ornamental pest called white flies.
- While there are many species of white fly, there are only a few that are significant pests in our landscapes, the most significant of which is the silverleaf white fly.
- In general, white flies are easy to identify. They are teeny tiny little flying insects that are white. Adults are small, roughly a millimeter long, with a waxy white secretion on their bodies and wings.
- Whether freshly hatched or full fledged adult, all phases of white fly feed in the same way: with piercing sucking mouthparts. They use tiny, needle-like structures to pierce the leaf tissue and suck the contents out as they flow through. The result is interveinal chlorosis which simply means that the leaves turn yellow between the branch like veins.
- Applying a systemic weed control product that spreads throughout the plant tissues and exists in their food as they consume it is the most effective method of control.
