Whiteflies are closely related to aphids, and can be similarly pesky! They’re also especially small, so are even able to crawl through mesh coverings, and can be responsible for spreading a number of different plant viruses. But don’t worry - Planta can help you to manage and recover from an infestation.
SYMPTOMS & IDENTIFICATION
Whiteflies are often found in clusters on the undersides of leaves, so make sure to check your plant thoroughly. They are active during daytime, and are mostly seen during mid- to late summer, when it gets warmer. They often lay their eggs in concentric (circular) patterns, which is another sign to look out for if you’re unsure if your plant has whiteflies.
There are also symptoms that you can check for on your plant. These include:
Leaves turn yellow and fall off prematurely
Sticky liquid, or honeydew, can be found on the leaves
Treatment: It’s a good idea to try and treat a Whitefly infestation as early as possible, before they cause your plant to become irreparably weakened.
1. Isolate the infected plant - move your plant to a separate, closed-off room if possible to prevent Whiteflies from spreading and infecting your other plants
2. Catch them with yellow sticky traps
You can buy these from your local garden center, home improvement store, or online
Place them close by your plant, but out of reach of the plant’s canopy.
If necessary, replace the traps when they become full with pests
This is a good way to monitor how severe the infestation is, as you will see how many Whiteflies gather and how quickly
3. Spray the leaves with short bursts of water from a hose
This will physically remove the pests from the plant
Additionally, water will help to remove the sticky honeydew residue that is left behind by Whiteflies
4. Spray with soapy water / neem oil spray
Spray the leaves until completely wet - this will kill all flies, eggs, and larvae
Neem oil will also deter whiteflies from laying more eggs
5. Consider using recommended pest control for Whiteflies
Whiteflies respond well to biological pest control, so try to expose them to natural predators. These predators include lacewings and ladybugs
Avoid using chemical insecticides unless it’s completely necessary, as whiteflies are largely resistant to these anyway
HOW CAN I AVOID THIS HAPPENING AGAIN?
It’s always a good idea to do regular checks of your plants for pests, as early detection is a great way to prevent a full infestation from taking hold. Give your plants a quick once-over every now and then to check for any signs of pests. Whiteflies also dislike reflective materials, so you can try positioning your plants near a reflective surface, such as an old CD.
QUESTIONS ABOUT WHITEFLIES
WHAT DO THEY LOOK LIKE? Adults Whiteflies are moth-like in appearance, with white wings that vary in shape depending on the type of Whitefly, but are often triangular. They are small, (usually around 1/16 inch or 1.5 mm long), with short antennae.
DO WHITEFLIES BITE HUMANS? Whiteflies are harmless to humans, and are only drawn to plants, so shouldn’t be a problem for people or pets.
WHERE DID THEY COME FROM? These pests typically come from outdoors, and can also be introduced by new plants purchased from elsewhere, so always make sure to check new plants for pests and quarantine them if possible before adding them to your collection.
HOW DO THEY SPREAD? Because adult whiteflies can fly, it is possible that they will fly to new plants to lay eggs. However, they mostly choose to stay near their host plant. However, as nymphs can’t fly, they attach to the plant to feed and do not move.
HOW LONG DO THEY LIVE? A whitefly’s whole life cycle takes around 3 weeks in total. Adults can then live for up to 2 months. Around 200-400 eggs are laid which then hatch within 5-10 days. During the pupal stage is when they are the easiest to identify, whereas the nymphal stage can be tricky as they can be mistaken for scale insects.
WHAT DO THEY EAT? Both adults and nymphs feed on plant sap, which can quickly leave the plant weakened and unable to photosynthesize effectively. The honeydew that they produce and deposit on leaves can also lead to the development of black mold.
WHERE DO THEY USUALLY LIVE? Whiteflies are found worldwide, but prefer warmer climates and cannot survive freezing conditions (although nymphs can overwinter as long as it doesn’t get too cold). This means that in southern regions, they are found all year round outdoors, but in colder northern regions, there is only a risk of indoor infestations. As such, they are also a common greenhouse pest.