Including fungus gnats, neem oil is an all-natural, non-toxic insecticide that kills various pests on contact.
Neem soil soaks or neem cakes may be the most effective treatments for this specific hazard.
What Is Neem Oil?
The MacGyver of plant care, neem oil comes in three different forms: cake, clarified hydrophobic, and crude (or raw). Azadirachta indica tree seeds are crushed to make it.
What can I use as a spray to get rid of gnats on houseplants?
Some gnat species favor infesting indoor plants. Gnat-eliminating pest management techniques can be used without endangering your collection of indoor plants.
- Two liters of water and one tablespoon of dish soap with a lemon scent. Into a spray bottle, pour.
- Apply the soap mixture liberally to the infected indoor plant. Make sure to properly cover the dirt, stem, and leaves. Any adult gnats on the plant or in the pot will be eliminated as a result.
- One to two hours after applying the mixture, spray the plant with plain water to remove the soap.
- Let the dirt around the plants dry out. Wait until the top two inches of soil have dried completely before watering the affected plant again. Any larvae or eggs that the adult gnat has laid will perish under these circumstances. The plant could falter a little, but if you start watering it again, it should recover.
- Gently repot the afflicted plant in a new planter and fresh soil if the gnats are persistent. Place the old soil and planter in an outdoor garbage can for disposal.
How quickly does neem oil kill gnats?
In most cases, only one plant is seriously affected, therefore Jason always tries to isolate it by placing it in a protected area outside.
It’s preferable to keep it separate from any other plants you may have outside, especially those in pots.
Invest in sticky traps or plants
Adult flying insects will be captured (and killed) by sticky traps or plants. Population growth may be slowed by the fact that one adult can produce up to 200 eggs.
For those who like plants, sundews (Drosera sp.) are a species of carnivorous plant that use their sticky leaves to entice tiny insects like fungus gnats.
Use neem oil spray
You can get a bottle of neem oil almost anywhere that sells plants. It is an organic insecticide manufactured from the seeds of neem trees.
It can be purchased as a pre-diluted spray bottle that is ready to use or as a concentrate that must be diluted in a spray container.
To get rid of the larvae, Jason advises misting the soil with diluted neem oil.
Spray your neem oil over the top 5 to 10 cm of the soil once a week for at least two months (or for one month after you stop seeing the flying adults). Remember to wait a day or two in between waterings when using neem oil outside of that.
It won’t harm your pets or eradicate helpful insects like earthworms, unlike many other insecticides.
Consider creating a soil barrier
Some people have also found success by topping their potting mix with small pebbles or horticultural sand (not the beach variety). This may hinder female fungus gnats from laying eggs in the ground.
Jason says he doesn’t like it because it can be challenging to see what’s happening in the soil, but to each his own!
Neem oil — does it kill gnat eggs?
So your African violets have been invaded by fungus gnats? Let’s now discuss methods for managing both adult flies and fly larvae. Here, we advise using an integrated pest management strategy to cover all your bases and permanently safeguard the inhabitants of your greenhouse and houseplants.
Organic Fungus Gnat Control
Surprisingly, one of my top suggestions for getting rid of these pests is a common household item. You can saturate soil in hydrogen peroxide (the standard topical variety, 3 percent).
Pour a solution of one part hydrogen peroxide to four parts water through the soil in the root zone of the pot until it starts to emerge from the bottom. On contact, fungus gnat larvae are killed by the peroxide.
Neem oil works well as a soil soak to get rid of fungus gnat larvae. Follow the manufacturer’s instructions to dilute the oil with water, then immerse the plant’s roots in the solution. To deter adult gnats, you can additionally spray the plant’s uppermost part.
Neem oil contains concentrated azadirachtin in its natural state. It is safe to use indoors, in greenhouses, gardens, and hydroponically. Use it as directed by the manufacturer, much like you would neem oil.
Sprays containing pyrethrin are also effective at killing fungus gnat larvae. Use pyrethrins by misting the soil’s surface and all plant surfaces with a light mist. A light mist will do; you don’t want the plants to get drenched. Spray the soil exactly where adults usually rest to completely hydrate the top if there are fungus gnat larvae present, then prevent overwatering. Let the soil dry to a depth of at least two. When the issue has passed and the insects are no longer a concern, reapply these after three to four weeks.
Adults and larvae are the targets of a predatory Hypoaspis miles mite. Additionally, it preys on other insects like thrips and springtails, which can be a pest in a greenhouse or garden. Since solitary specimens are more difficult to treat, these are best used outside or in greenhouses.
As you can see, there are numerous biological control treatments available for the removal of fungus gnats. Apply pesticides along with wise cultural habits and effective preventative measures, and you’re good to go!
Cultural Control of Fungus Gnats
Avoid flooding your growing media. These insects thrive in the moist growing medium found in houseplants. Do not leave standing water in saucers next to growing medium or below houseplants for an extended period of time. Keep your growth medium away from your potted greenhouse residents and fix any irrigation system leaks that develop. To get rid of any larvae that may be feasting on the organic elements in your compost, pasteurize the growing medium. If you don’t like the notion of doing it yourself, use heated commercial growing medium mixtures. While you take care of the issue, keep any sick plant material and growth medium away from other people.
Biological Removal of Fungus Gnats
Fungus gnat larvae can be killed by a specific strain of bacteria called Bacillus thuringiensis var. israelensis. Most commercial BT sprays do not contain these bacteria, although they are also present as active components in some commercial products. You should see a reduction in your fungus gnat issues if you use them to fertilize your growth media.
By scattering Mosquito Bits or Mosquito Dunks over the soil’s surface and soaking them in, you can also introduce this bacterium. These are suitable for usage both inside and outside. They aren’t just used to kill mosquitoes! As they decompose, Bacillus thuringiensis var. israelensis is released into your soil, where it can begin to kill larvae. Mosquito dunks are more substantial and take longer to work.
The eradication of the fungus gnat larvae might also be greatly aided by the species of beneficial nematodes. The fungus gnat larvae and many other soil-dwelling pests will be eliminated by these microscopic soil dwellers, which you cannot see. Use a pot popper to incorporate these nematodes into the soil when treating an indoor plant. Commercial formulations can cover a larger garden or the entire yard since they uniformly distribute the nematodes with water.
Be warned that using a hydrogen peroxide soil drench and helpful nematodes at the same time will kill the nematodes! Nematodes should not be added back into the soil for at least a few weeks following the infestation. Nematodes should be used in cooler weather if you’re working outside because heat will kill them before they can perform their job. Keep in mind that you must apply more than once, twice a year.
Can neem oil be used on any indoor plant?
The majority of indoor plants can be used safely with neem oil, a multipurpose natural pest control treatment. This 100% cold-pressed neem oil, which is made from the seeds of the Indian neem tree, has a wide range of applications in the maintenance of indoor plants and is OMRI-listed for organic gardening. Our go-to natural remedy for controlling houseplant pests like mealybugs, thrips, aphids, and whiteflies is azadireachtin, which disrupts the hormones of insects, preventing them from maturing and eating.
Neem oil has natural anti-fungal qualities in addition to insecticide ones, therefore it can be used to successfully stop the spread of fungus, fungus, and powdery mildew. Because it leaves a lovely sheen on foliage, it is frequently sold as “leaf shine” – an extra bonus!
Simply mix 1.5 teaspoons with a quart of warm water to make a spray, then apply to both sides of foliage. During treatment, keep plants out of direct sunlight.
Although most plants can tolerate neem oil, certain plants might not. Before spraying an entire plant, test on a single leaf. Visit our blog to learn more about pest control.
What occurs if neem oil is applied to plants excessively?
Numerous organic chemical components have been found in neem oil, as demonstrated by studies, however azadirachtin is by far its most significant component.
This naturally occurring substance doesn’t kill pests right away, but after ingesting it, it will interfere with their capacity to feed, molt, and breed, ultimately killing them within a week.
Bugs are also covered in a thin coating of oil by neem oil. If you spray adult, hard-bodied bugs with neem oil, such as leaf-footed bugs, squash bugs, and stink bugs, they will get irritated but usually not die. Aphids and spider mites, which have smaller, softer bodies, are more vulnerable to anything that covers them in oil, especially if they are in the nymph stage. The azadirachtin will kill them if the oil itself doesn’t.
Fortunately, the oil won’t harm helpful pollinators, and once it’s diluted, sprayed on plants, and exposed to sunlight and the environment, it will start breaking down swiftly.
Neem oil can be applied more than once every 4–7 days, although generally speaking, you shouldn’t do so to maximize its effectiveness.
In other words, if you apply neem oil every 1, 2, or 3 days, you’re using it excessively and risk causing your plants slow-moving, long-lasting harm.
Neem oil will cover the leaves, branches, and blossoms of your plants in a thin film of oil, which is why it is true.
As I mentioned above, this oily layer will begin to disappear within a few hours, but if you keep reapplying neem oil without timing your applications properly or separating them so that the oil completely degrades in between, you risk seriously harming your plant in two ways.
Foliage Burns
The most obvious approach to harm your plants with neem oil is in this manner. Neem oil will heat up if it is exposed to direct sunshine before it has had a chance to properly dry, just like the oil in your frying pan does when it is exposed to higher temperatures.
Neem oil will likely harm whatever leaves it comes in contact with once it has heated up, resulting in burns that appear as streaks, splotches, or even spots, as well as eventual leaf rot. If your plant has too much neem oil on it, you risk completely killing it by damaging too much of its foliage.
Neem oil spray applications should always be made in the early evening for the simplest way to prevent these issues. While the light is still bright enough for me to see clearly, I do this as it is setting. As a result, there is no doubt that the neem oil will have at least 10 hours to dry before the sun rises the next day.
I once neglected to apply neem oil in the evening and, against better judgment, chose to do so the following morning. I believed that by doing it early, it would dry before the sun could do any harm, preventing any scorching.
Fortunately, I had only lightly sprayed a few plants with neem oil, so they quickly recovered. However, I learned from the experience not to try to make up for missed neem oil applications the following morning. Simply wait until the suitable time the following day, then spray your plants.
Neem oil treatments frequently can result in unwanted side effects on three critical biological processes that all plants carry out in addition to the potential for foliage burns:
Photosynthesis
The process through which plants convert carbon dioxide, sunshine, and water into oxygen and carbohydrates is known as photosynthesis. However, the precise mechanism by which this happens is less well understood.
Simply put, stomata (or stoma if you’re referring to a single pore) are epidermal pores found in plants. By absorbing carbon dioxide from the environment, these tiny apertures are crucial to photosynthesis. The cells that surround each stoma serve as gatekeepers. When there is sufficient carbon dioxide in the plant, the cells close the stoma to momentarily slow or stop the flow; when there is insufficient carbon dioxide in the plant, the cells open the stoma to let more CO2 in.
Therefore, stomata are essential for photosynthesis. They don’t participate in the actual chemical reactions occurring inside the plant, but they do manage how much and how frequently carbon dioxide enters the plant, so regulating a crucial aspect of photosynthesis.
Transpiration
To take in carbon dioxide, stomata open, but in the process of doing so, they also lose something: water. Also in plenty. According to the U.S. Geological Survey, a single huge oak tree can transpire up to 40,000 gallons of water annually, compared to up to 4,000 gallons for an acre of maize.
The stomata control when and how much each plant transpires at any one time. Transpiration fluctuates depending on a wide range of conditions, including heat, humidity, wind speeds, and soil moisture, to mention a few.
Oxygen Release
When plants engage in photosynthesis, they draw carbon dioxide from the atmosphere and combine it with water to produce oxygen and carbohydrates using energy from sunshine. As an unneeded consequence of the photosynthetic process, they then expel the extra oxygen.
It should come as no surprise that these exchanges also happen through the plant’s stomatal openings, especially during the day. As a result, the open stomata serve two purposes: they let CO2 in while also enabling oxygen to escape.
Studies have demonstrated that anything that interferes with these stomatal routes would have a negative effect on plants, obstructing their biological functions and retarding their growth.
And this brings me to my concern with neem oil: if you spray neem oil too much and too often, you run the risk of coating and re-coating your plant’s leaves in oil, which could clog the stomata and impair the plant’s capacity to absorb carbon dioxide and release both water and oxygen.