Are you noticing white, flying insects around your houseplants when you water them in the morning or during the day? Your plants looking a little more lackluster than you remember? Or, are you getting some stickiness on leaves with no apparent cause? It’s time to look a little more closely - you may have yourself a whitefly problem. But don’t worry, we’re here to help you identify, treat, and prevent whitefly infestations in your precious indoor plant babes.
So, how do you know if you’ve got a whitefly problem? Since these pests are active during the day, they’re actually pretty easy to find while feeding - just disturb the leaves of your plant, and if a cloud of tiny white flies springs up, bingo - you’ve got whiteflies. You may not notice them at first glance because they hide from the sun and predators by clinging to the underside of leaves, where they also lay their eggs (tiny, pale specks that dot the undersides, sometimes in circular patterns). You should look around areas of new growth especially, and you may also feel stickiness on the leaves from their honeydew secretions. Signs of whitefly damage include leaves turning yellow and falling off the stem, and overall stunted growth.
Left: whiteflies and their eggs; right: whiteflies and their larvae
Whiteflies are tiny (about 1/12th of an inch) triangular-shaped flying insects with a pale yellow or white body and white wings. Some varieties may look a bit different, like the bandedwinged whitefly, that has subtle stripes on its wings. These soft-bodied pests are related to aphids and mealybugs, and are actually not a type of fly. When they lay eggs, they can lay over 400 at a time, and they hatch within a week to a month; the eggs will be pale until they are about to hatch, when they turn brown. When hatched, the larvae will stay in place, feeding, until they mature into winged adults.
Note: If there are a lot of larvae, eggs, and honeydew covering a leaf’s underside, they may resemble mealybugs, but the presence of flying adults is a giveaway for identifying these pests.
Where do they come from? Whiteflies are outdoor and indoor pests that thrive on most common houseplants, especially ones with soft, smooth leaves; they don’t live in soil, and won’t harm humans. You may notice whiteflies more often in mid to late summer when it gets warm and humid, but there’s always a risk of bringing them home on a plant from an infested greenhouse. Though they don’t like the cold, they can overwinter on their host plants and come out in the spring.
Whiteflies and their larvae feed by sucking plant juices out from the underside of leaves, weakening the plant. When they feed, they also leave behind a sticky substance known as honeydew, which can attract other pests like ants, as well as encourage mold and other fungal diseases. Larger, heartier plants can survive their parasitic feeding longer, but smaller plants can be more quickly overcome by an infestation; in either case, whiteflies are no good and should be eradicated. The good news is that these pests are relatively easy to find and, given time, patience, and consistency, whiteflies can absolutely be dealt with.
1. CHECK PLANTS FIRST (AND ROUTINELY)
Before bringing a new plant home from a nursery or plant shop, give it a once-over, looking in every nook and cranny for any sign of pests. It’s a good idea to keep new additions to your collection in isolation until you can be sure they’re in good health (keeping new soil in isolation for a few days before use isn’t a bad idea, either). If you see anything on your plant, hose it off gently outside and treat it in isolation until it’s ready to join your plant family. In general, we recommend periodically looking under leaves and in crevices as you go about your watering routine, so you can catch any sign of an infestation early.
2. AVOID HIGH-NITROGEN FERTILIZERS
To avoid attracting pests with particularly tasty new growth, try to stay away from fertilizers that are too rich in nitrogen. Try our Wally Nutrients blends, which are specially formulated for general houseplant growth and for trailing plant length, for an effective alternative.
3. REGULAR TLC
Keeping on top of basic maintenance such as pruning, removing wilted leaves, and ensuring the right climate and humidity for your plants to encourage them to thrive can help reduce the risk of all sorts of pests and diseases, and should never be overlooked.
For the greatest success treating your whitefly problem, approach them in the early morning or evening, when they will be the most sluggish. You’ll want to use a combination of the below methods to make sure the whiteflies won’t come back, and you may need to repeat treatments every few days until it’s under control.
1. HOSE IT OFF
Bring your plant outside and hose it off to scatter adults and help dislodge eggs and larvae. Pay special attention to the underside of leaves and new growth. Then, keep it away from your other plants so the insects don’t hop to another plant while you’re treating it.
2. YELLOW STICKY TRAPS
To whiteflies, the color yellow looks like a bunch of delicious new foliage. For an easy time attracting them, check out our yellow sticky trap packs (they’re labeled for gnats, but will absolutely work for whiteflies and other flying pests, too). For a DIY alternative, try coating a yellow index card with petroleum jelly. In either case, they will be attracted to the yellow, get stuck, and die. Remember - if you use this method, you’ll still have to deal with any eggs left on the underside of leaves, so make sure to use another method listed here in addition to the sticky traps, or they’ll just keep coming back. Once you take care of the whiteflies, it’s not a bad idea to keep new sticky traps installed as a preventative measure, too. There are many options for sticky traps (like tape and stakes), so find which ones work best for you.
3. USE A VACUUM
Carefully use a handheld attachment on your vacuum cleaner with a low suction setting to vacuum the underside of leaves every few days, collecting eggs, larvae and adults alike. Make sure not to empty your vacuum inside your home afterwards! Remember, a single female whitefly can lay over 400 eggs, so be thorough, and avoid damaging your plant.
4. INSECTICIDAL SPRAYS (DIY AND OTHERWISE)
Spraying the underside of your plant’s leaves with Neem oil or a soap spray can kill these pests. For best results, spray in the mornings or evenings when it’s cooler. To avoid blocking photosynthesis, don’t spray the top surfaces of your plant’s leaves (the whiteflies don’t hang out there, anyway). Here are a few options:
To make your own soap spray, try using 8 drops of dish soap and 1 liter of warm water, pour into a spray bottle, and apply directly to leaves. Try it out first on an out-of-the-way leaf to make sure the mixture won’t damage your plant’s leaves - all you have to do is saturate the leaf with the soap spray and return 2 days later; if you notice leaf burn, dilute the mixture a bit with more water or less soap. Spray the underside of each leaf with the soap spray and, after a while, rinse the plant to dislodge the dead bugs (as they can attract other pests) then repeat every other day until the problem is under control. This process might take a few weeks to completely eradicate the pests.
A mixture of equal parts vinegar and water will also do the trick; make sure to test on a single leaf first and dilute the mixture accordingly. Repeat as needed.
Neem oil is a natural essential oil that works wonders with both treating and preventing pests, and has lasting effects due to its scent. To help it stick to the leaves of your plant, you can make an optional mixture of 1 teaspoon Neem oil, 1 tablespoon dish soap, and 1 liter of water and apply that using a spray bottle to the underside of leaves. Make sure to test for leaf burn on a single leaf first, as with the other mixtures, and dilute as needed. Reapply every few days until the whiteflies are completely gone, and make sure to rinse the dead bugs off after the oil has done its work. To defend against future infestations, you can also use Neem oil every so often as a preventative measure. Note: Do not use Neem oil on plants in direct sunlight - the oil can trap heat, and may dehydrate the plant.
5. PRUNE AND TREAT
Keeping your leaves pruned can be a good way to control a smaller whitefly population. Any leaves with visible eggs or larvae can be trimmed and dunked in a bowl of rubbing alcohol or a mixture of dish soap or water to kill the pests, then you’ll just have to deal with the fliers before they lay any more eggs; use in combination with sticky traps for an effective treatment (but keep an eye out for a resurgence of eggs). This works best when you identify the problem early on.
6. USE A NATURAL REPELLANT
A safe, easy way to help repel whiteflies is to add a naturally repelling plant near your infested plants (after isolating it for a few days to ensure its health first!). Strong-smelling plants like mints, parsley, cilantro, onion, or any other aromatic plant can make whiteflies shy away; other options include nasturtiums, zinnias, pineapple sage, hummingbird brush, or bee balm. If used in combination with a good hose-down and a soap spray, it can help keep whiteflies away after dislodging and killing eggs and larvae.
We hope these tips help you eradicate your pest problem!