Tony O’Neill, gardener and author of the popular “Composting Masterclass” and “Your First Vegetable Garden,” combines lifelong passion and expert knowledge to simplify the art of gardening. His mission? Helping you cultivate a thriving garden. More on Tony O’Neill
While preparing my garden and growing my vegetables, I often notice some white mass on the plants and fluttering amongst the leaves of many. Upon further examination, I realized they are living insects. But just what are those little white flying bugs on your plants? They are called whiteflies, a menace in the garden. These tiny pale pests suck the sap from plants and spread disease.
How to kill whiteflies on plants? There are many applications a gardener can use to get rid of whiteflies. These include neem oil, SB Plant Invigorator, and even Castile soap. However, none of the methods will work on a one-off application to ensure they get rid of them for good. Applying regularly is the answer.
The best method(s) to use may also depend on the size of the garden, the type of plants you may want to grow, as well as the location of the garden. In this post, I hope to open you to more options for controlling and removing whiteflies, highlighting the benefits and possible hindrances to using some.
How do whiteflies damage plants?
Whiteflies are considered a significant pest for crops, not only because they cause considerable damage and loss of production but also because they feed on many different plants, causing damage to a wide array of plants.
Whiteflies can cause two types of damage to a plant:
- Direct Damage
- Indirect Damage
Direct damage and indirect damage. Whiteflies can seriously injure plants for direct damage by sucking the sap from the host plant, causing leaves to weaken, fade, and drop prematurely.
Additionally, as they suck out the sap, they release toxic substances into the phloem, which then spread throughout the plant, causing metabolic imbalances, which can, in turn, also cause discoloration on the parts of a leaf that have been feeding on.
Regarding indirect damage, whiteflies excrete molasses, or “honeydew,” a sweet substance that forms a sticky coating on leaves. The honeydew enables fungi, such as sooty mold, to form on the leaves, making them look dirty. Sooty mold may not necessarily be dangerous to plants.
Still, when it exits excessively, it may indirectly damage plants by preventing sunlight from reaching leaf surfaces, acting as a screen and reducing the plant’s photosynthetic capacity.
In severe cases of infestation, the damage caused by whiteflies can be devastating. Large numbers of whitefly can stunt plant growth, reduce fruit yield, and cause premature death of plants. Preventing an infestation is, therefore, crucial to protect your garden.
How to identify whiteflies
- Possibly the easiest way to detect whiteflies would be to give the plants a soft shakeup. This is the first thing I do. It helps for easy and essential detection. A gentle rustle will make the whiteflies leave the plant briefly, flying into the air before falling back to the plant.
- Whiteflies secrete a sticky substance known as honeydew. If you happen to notice these honeydew drops on the leaves of your plants, then you should probably check for whiteflies/
- You’re most likely to find Whiteflies feeding on the underside of leaves, so you should check the bottom of leaves for especially adults (which look like tiny, white moths).
- If you see white clusters on the undersides of the leaves instead of adult whiteflies, these may be whiteflies’ eggs. So start taking all the steps to control whiteflies because these clusters are the eggs that will give birth to a swarm of these whiteflies.
- Whitefly feeding also causes visible signs of damage. When whiteflies attack, the plants start turning weak, which can be a symptom to suspect whiteflies. They can give leaves a withered appearance and cause discoloration and yellowing, wilting and stunting of plants, premature leaf dropping and even death of the plant.
Plants are usually affected by whiteflies.
- Tomatoes (Read my blog on tomatoes here)
- Bell Peppers (Read my blog on peppers here)
- Sweet Potatoes
Ways to get rid of Whiteflies
- Yellow sticky traps: Available on Amazon. I found these helpful in trapping all sorts of plant-damaging insects. They should be kept close to or around plants or within gardens affected by whiteflies.
The whiteflies are attracted to yellow, making this trap effective are helpful for monitoring and suppressing adult populations.
They are beneficial as they are easy to implement, require low maintenance, are inexpensive, and are non-toxic. They may also disrupt the breeding cycle, producing fewer eggs and creating an effective monitoring method.
- Hosing: one straightforward method of removing whiteflies is physically removing them with a strong blast of water from a high-pressure hose. It’s best to get to the undersides of the plats, as this is where whiteflies usually stay.
It’s also best to use the hose that works for high-pressure sprays because while adult whiteflies are easily displaced, the nymphs (tiny, scale-like creatures) are more difficult to remove as they cling tightly to leaves will be able to hold on if the jet is not strong enough.
This should be done regularly (at least once weekly) for the best results and used with other control methods. Among the benefits of this method, it is easy to do and inexpensive; however, as far as negatives, this method may not remove all whitefly from the plant, ad it must be repeated regularly for best results, which may make it time-consuming.
- Natural predators: insects such as ladybug beetles, parasitic wasps, and predatory mites are all predators of whiteflies. They feed on whitefly eggs, and whitefly parasites can destroy nymphs and pupae. A female wasp can kill up to 95 whiteflies over her 12-day lifespan, making them a highly effective means of reducing whitefly numbers.
- Among the benefits, it is a sustainable, natural, non-toxic means of biocontrol. Using natural predators is easy to implement, cost-effective, and effective in killing large numbers of whiteflies. The major disadvantage of this method is that if the natural predators are not released at an optimal level, it may lead to another infestation with another set of issues.
- Companion Planting: Flowering plants such as Mexican marigolds can harm these whiteflies. These flowers produce a scent that cannot be digested by the whiteflies and chase them from the plants they have infested.
- Organic Neem Oil: Available on Amazon. Neem oil is an effective DIY method to control whitefly in the garden. It can be sprayed on plants to kill eggs, larvae and adults.
- Mixing about 1 oz/ gallon of water and spraying all leaf surfaces (including the undersides of leaves) until completely wet may prove effective against immature nymphs, stifling their development and killing them before adulthood.
- Also, it may act as a repellent, preventing adult whitefly from landing on plants or laying their eggs on the leaves. Because of the nature of this oil being natural, they are non-toxic, Biodegradable and environmentally friendly. They can also e used on edible plants and house plants.
- They are cost-effective and easy to use. However, they only kill when applied directly, must be reapplied regularly, and are time-consuming. Neem oil can be created by mixing: 1/2 tsp of organic neem oil concentrate.
Making a Neem Oil Mix
- 1/2 tsp of organic neem oil concentrate
- 1 tsp of mild liquid soap
- 1 liter of tepid water
- Horticultural oils or hot pepper wax spray can also be very effective when used directly on whiteflies. Horticultural oils work by smothering insects.
- SB Plant Invigorator: Available on Amazon. This product is organic and is used to boost plant immune systems. A side effect of this is that it is perfect for killing whiteflies. It can be used around ponds without damaging the wildlife living within the pond. It will also help to remove aphids, powdery mildew and sooty mold.
- Castile Soap Solution: Available on Amazon. Otherwise known as baby soap, Castile soap is excellent for making a soap solution to help kill whiteflies. It does this by coating the whiteflies and knocking them off the plant to the floor.
- They cannot climb back onto the plant and suffocate on the floor. Castile soap is pure soap and is not dishwashing detergent. This later product is a surfactant and can damage your plants and garden. Dishwashing detergents should not be used to spray on your plants.
- Vacuuming: this may be an effective way to remove whiteflies quickly. You can use the high-pressure air from the vacuum cleaner nozzles to blow flies away. Alternatively, you can suck them.
- Insecticides: these should be used as a last resort. I would not recommend insecticides against whiteflies, as many species resist the chemicals. Chemicals can also have adverse effects on the environment.
- They might not kill whiteflies but may affect other, more valuable insects, which may help reduce their populations. However, a short-lived natural pesticide may be helpful by damaging the outer layer of soft-bodied insect pests, causing dehydration and death within hours.
Whiteflies are an especially pesky group of creatures. They might seem harmless individually, but that’s where the gardener gets caught out. These pests multiply very quickly, and before you know it, you have an infestation. You want to do all you can to remove them from your plants and out of your garden, but like with most things, it requires some effort.
The options I have laid out can provide the most effective results. I believe that to control whiteflies more effectively, combining these options will give the best possible outcome. Mixing these options will enable you to see a reduction in the pests in your garden.
Each garden is different and has its own set of growing conditions. Some of this may make it easier for this pest species to multiply. It may be worth looking at your husbandry or even how you water, which may help tackle this pest.
I trust you found this post helpful and are ready to get those bugs off your plants. Subscribe to the blog for more helpful posts like this.
Remember, folks, You Reap What You Sow!