Whiteflies are not only a nuisance but a clear danger to your garden. They feed on host plants weakening them until the plant deteriorates so badly. Additionally, they increase the risk of disease. So, if you find yourself dealing with these pests or want to prepare in advance, here’s how to get rid of whiteflies on plants in the garden.
I’ll go through everything you need to know about whiteflies so you know where to find them and how to identify them. Then, show you the different ways to treat whitefly problems and how to prevent them.
What are Whiteflies?
Whiteflies look like white colored flies. This is how they got their name. But, the name is actually quite misleading as whiteflies are not flies at all.
Instead, they’re more closely related to aphids. And, like aphids, they suck on the sap of plants which make them dangerous. This is especially true as they grow in number where they’re able to overwhelm the plant by weakening it as they take more and more of the plant’s juices.
This is why it is important to quickly treat them when you notice their presence or damage they cause.
If not, the adult whiteflies will lay eggs and hide them on the bottom sides of the leaves. In warm weather, these eggs can grow quickly becoming adults in 16 days or so.
Given that adult females can lay hundreds of eggs, this makes them quickly multiply to become infestations.
How to Identify Whiteflies
Whiteflies are quite small. But, you can easily spot them with the naked eye since they look like white specks against the green foliage. That’s because each whitefly is about 1/12 of an inch in size.
As they grow in number, they’ll look like dandruff on leaves or a light layer of snow on top of the foliage.
If you disturb them, them will scatter like into a sparse cloud.
In addition to their white speck-like appearance, another symptom of whiteflies is honeydew. This is a dark brown, gooey substance. It actually looks like very thick but a bit translucent coffee.
This is something they produce when they suck out the sap from the plants. As such, you’ll see the plant have these brown molasses looking stuff in places there shouldn’t be any.
If you see honeydew, it means the whiteflies have been feeding on the plant for at least a few days now. Ants will likewise appear as they’ll come after the honeydew.
And as these pests keep taking more and more sap as they increase in number, you’ll later see leaves turn pale color then yellow. Growth will slow and then stunt. Finally, foliage will drop off.
Life Cycle of Whiteflies
Whiteflies thrive during warm weather. Around the end of spring, adult whiteflies will lay about 200 to 400 eggs and hide them on the bottom side of leaves.
These are very easy to spot if you check the underside of the leaves as you’ll see concentric patterns in some cases looking like strange circular drawings with designs in the middle. Their white color make them stand out against the green foliage background.
In about 5 to 10 days, these eggs hatch and will quickly grow into crawlers and then shed their skin to transform into adults. The process is fairly quick between the time they are nymphs until they are ready to lay their own eggs.
It goes through this quickly because it will only live for about 2 months or so before dying.
However, their sheer number and continuous egg laying process allow whiteflies to become infestations if you don’t treat them as soon as you spot them.
Where Do Whiteflies Come From?
Whiteflies are primary warm weather pests. And, they live on host plants, especially those with smooth, soft leaves.
This makes houseplants and greenhouse environments their go-to places. They’ll also be around in warmer climate areas (USDA Zones 8 and above). Due to the cold, freezing winters of USDA Zones 7 and below, you’re less likely to see these pests there as they can’t survive through the winters.
This makes whiteflies seasonal garden pests. For the most part appearing around late spring and summer.
They don’t live in soil nor are they harmful to humans. Instead, their main interest is to feed on the juices of plants.
Adult whiteflies can fly. This allows them to go from one plant to another and lay eggs. The young whiteflies, called nymphs, tend to say where the food is. This means you’ll often find them hiding on the underside of leaves. They also do so during winter to stay warm.
Since whiteflies like to feed on new growth, their usually targets are those that are starting to grow new leaves come springtime.
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Which Plants are Susceptible to Whiteflies?
Whiteflies are not too discriminant about which plants they attack. This makes it harder to isolate them since they’ll go for ornamentals as much as vegetables.
This makes your tomatoes, cabbage, and peppers unsafe. Similarly, they’ll also strike some fruits like citrus as well as ornamental plants.
So, you do have to inspect for them in most of your plants since they go for a wide variety of species.
Symptoms to Look Out For & Diagnosis
There are a few signs that you’ve got whiteflies in your plants.
- A cloud of white flies appears when you disturb the plant. They’ll suddenly puff up and you’ll see tiny white particles disperse in the air when you move or touch the leaves.
- If they lay eggs, you’ll easily see white circular patterns on the underside of leaves.
- Honeydew is another sign of whiteflies. These brown colored thick ooze is a byproduct produced when they suck on the sap of plants.
- Weak plants with damaged leaves that are turning yellow or dropping are results of a weakened plant due to the loss of nutrients and fluids.
How to Get Rid of Whiteflies
Whiteflies suck on the sap plant. in a way, the plant’s juices are the life source of the plant since these transport fluids and nutrients to different parts of the plant through the stems.
When there are many whiteflies on a plant, they’ll weaken it making it prone to diseases that the whiteflies themselves carry.
Another bad thing that whiteflies do to plants is they turn the plant’s juices into honeydew, which is a thick, dark colored gooey substance. The honeydew attracts more problems like fungus and sooty mold.
If there’s enough honeydew to cover the plant, it will struggle with its photosynthesis process as it cannot absorb enough sunlight.
Thus, it is very important to get rid of whiteflies as soon as you spot them as well as areas where they have caused the damages. Cutting off any damaged leaves will help prevent further problems.
When it comes to dealing with whiteflies avoid chemical insecticides are they are mostly resistant to these. Over the years, they’ve developed a tolerance to the toxins in these products.
What you’ll end up doing is blasting the beneficial insects instead making the whiteflies go unopposed since their predators are now gone.
Thus, the best way is to prevent them from growing into an infestation to begin with.
This takes regular inspection and vigilance.
Once a week is a good frequency to check on the plants. You can likewise make your inspections when you water the plant.
Now that you know what to look for and whiteflies are harmful to your houseplants, it is time to talk about treatment.
The most important thing here is to spot them early and treat them immediately upon discovery. The earlier you notice them, the easier they are to eradicate.
Spray Them Off Using a Garden Hose
This is the easiest one to do. But, you do need to consider some logistics.
That’s because hoses work best outdoors. And, you don’t want to spray them off one plant only to blow them over to other plants.
You can try to be stealthy and move like a ninja to carry to plant outside before spraying. But this can also cause the adults to disperse into the air.
So, many gardeners use spray bottles instead and move other plants away from the infected one before spraying the whiteflies off.
The younger whiteflies don’t fly. So, they’re easier to get rid off via this method.
Use Sticky Yellow Traps
This is the old fashion way of catching some insects. You use small sticky traps that will cause any whitefly that comes into contact with the paper strips to stick to them.
You can get these yellow sticky traps in packs or make them yourself.
A DIY alternative would be to use small index cards and place petroleum jelly on them.
Clean Them Off with a Vacuum
This method requires some sneakiness. The goal is to catch them off guard so they get sucked into the vacuum before they can fly away.
If you have s a strong vacuum, use the low suction mode as you don’t want the entire plant or its stems and foliage to get sucked or damaged in the process.
As always, you want to not only target adults but also the nymphs.
Keep in mind that the whiteflies are still alive in the vacuum. So you want to dump them outside your home away from the garden or any plants.
Use Soap and Water
While they’re large in number, whiteflies are not overly resilient or strong pests. As such, simple methods work very well on them.
A combination of dish soap and water in a spray bottle works really well according to the National Gardening Association. And, this mixture applied to the leaves is enough to get rid of them.
Note that you won’t get them all in one spraying.
But, you also don’t want to use an overly intense mix as this cam damage the plant’s leaves. if you notice any leaf burn, that means the concentration of dish soil is too high. Thus, dilute it before using again.
Keep spraying every 2 days until there are no more whiteflies.
Neem oil is another very effective way to get rid of whiteflies. You can use this as an alternative to the soap solution spray to kill the pests.
Neem oil is an essential oil that not only works in treating whiteflies but also to prevent them from happening.
But, like other mixtures, always test before using and dilute as you go since too much concentration will cause leaf burn.
Another option if you don’t have neem oil on hand is to use vinegar. You can dilute the vinegar with water and apply it to the leaves just like soap spray and neem oil.
Use a Natural Repellant
One interesting thing about whiteflies is that they don’t like strong smelling plants. Thus, placing these kinds of plants near the infested plants will help rid it of the pests.
You can use mint, bee balm, zinnia, nasturtium, parley or cilantro just to name a few.
Prune Leaves and Treat the Pests
In addition to using the different solutions, it is a good idea to prune damage leaves. Since many of these whiteflies hide under the leaves, doing so lets you limit their growth to prevent potential infestation.
How to Prevent Whiteflies from Attacking Your Plants
When it comes to pests, prevention is much more important than treatment. That’s because it takes a while for the treatment to take effect. And, pests have the ability to keep spreading.
Adult whiteflies in particular can fly which makes them more potent in laying more eggs in other nearby plants.
So, if you can prevent them from happening, it would save you a lot of time, effort and stress later on.
Regularly Inspect Your Plants
The most effective way in preventing whiteflies from growing in number is to inspect your plants regularly.
Since they love to hide under the leaves, you want to thoroughly check those areas as well.
The same is true when you bring new plants from the shop.
I like to quarantine the plant for a week or so on its own. I usually check it as soon as I get home and look for any damages and pests. Then care for it in isolation before incorporating it with the others.
Be Wary of High Nitrogen Levels
High nitrogen levels help with new growth. Unfortunately, it also attracts these pests because they love the taste of young leaves, which are more flavorful to them compared to older ones.
Take Care of Your Plants
While regular inspections help deter whiteflies from increasing, the only real way to prevent them from coming around the first place is to keep your plants healthy.
Healthy plants are not attractive to pests.
So, giving them the right amount of sunlight, humidity, water and fertilizer helps keep these critters away.
Also, removing wilted leaves and avoid causing stress to plants helps.
Deploy Natural Predators
All plants and animals have natural predators. That’s just how the world works.
Whiteflies are afraid of insects like ladybugs, spiders, lacewings and dragonflies. As such, having them around keeps the these pests away.
Reflective mulch works in two ways to deter whiteflies.
- The extra layer of mulch helps keep the whiteflies from actually getting to the plant
- The reflective aluminum causes light to bounce back which blinds the whiteflies.
In doing so, it helps protect your plants from these sap suckers.
I’ve never met a gardener who enjoyed dealing with pests. Whiteflies are not only harmful to plants but also can spread really quickly.
Hopefully, the tips above have helped you learn a few ways on how to get rid of whiteflies on plants without having to resort to chemical pesticides.