Neem Oil Insecticide: Natural Pesticide For Plants

Neem Oil Insecticide: Natural Pesticide For Plants

Here's the deal. There are three all-natural pesticide control products we recommend and reach for when pests in the garden become an issue. Those three are:

Plant pests are one of my least favorite subjects to discuss. Using neem oil a natural pesticide for plants makes the pests subject at least bearable.

It's not because plant bugs bother me. That is part of growing plants. However, every "grower" handles pests control differently.

  • In application method
  • "Chemical insecticides" used
  • Timing of control

It's a matter of preference from my experience in spraying crops with synthetic chemical pesticides for years.

I choose to use the best product for the job (organic pesticide if possible) with the least amount of damage to the environment and people.

In this article, we will share information on the versatile natural insecticide Neem Oil, the benefits, uses on plants and controlling garden pests.

If you like to use natural insecticides in your pest control program, you are sure to love Neem oil sprays, an all-natural pesticide made from the oil of the neem seed found on the Azadirachta indica tree.

The oil, itself is a yellowish/brown color, tastes bitter and smells a bit like garlic and/or sulfur. This natural substance has been used for centuries to treat diseases and control home and garden pests.

Today it is used in a wide variety of home, personal care and garden products. Look carefully, and you may find neem as an ingredient in your shampoo, soap, toothpaste or even cosmetic products.

Why Does Neem Oil Work As A Pesticide?

Some aspects of the efficacy of pure Neem oil remain a mystery. There are a number of effective components in this natural oil, but the most active ingredient is Azadirachtin.

This ingredient is responsible for repelling and/or killing insect pests. Sometimes this component is extracted to make a highly concentrated product. The leftover ingredients are then clarified to create a product known as clarified hydrophobic Neem oil. [source]

The many different components of the Neem pesticide work in multiple ways. Azadirachtin works as an insect repellant and reducing insect feeding.

Furthermore, it interferes with the hormone systems of insects, so they do not mature correctly. This prevents reproduction.

In addition to negatively impacting insect pests, Azadirachtin also reduces feeding activity in nematodes. There are also other components in Neem oil that interfere with pests' ability to feed. [source]

Where Does Neem Oil Come From?

Neem trees grow wild and are cultivated in Southeast Asia. Efforts are also being made to cultivate the tree in other parts of the world, such as Australia, California, and Florida.

Indian farmers have taken advantage of the powerful insecticidal properties of all of the parts of the Neem tree for many centuries.

In addition to distilling the oil, they have also used the neem leaves and branches to repel pests.

Branches can be hung in barns and grain storage facilities to prevent insect attack.

Why Is Neem Oil Beneficial In The Garden?

In the 1970s, Neem oil became available in the western world and scientists began exploring its properties and uses.

They found that the oil, while a powerful deterrent to unwanted insects, has very low toxicity for humans and animals.

Although Neem oil is most useful as a natural insecticide against soft-bodied larval pests, it can also interfere with feeding activities of bigger, tougher pests such as beetles.

It also works by reducing the levels of Ecdysone (an insect hormone). This disrupts the pest's molting process and prevents larvae from developing into adult insects. For this reason, you will sometimes see deformed and crippled insect pest limping about after Neem treatment. Alternately, immature insects may merely fail to mature and die as nymphs or larvae. Soft skinned larvae (e.g. aphids) are killed on contact with Neem oil spray. While many adult insects can survive direct contact with the spray, it may interfere with mating activities.

When used as a garden spray or soil drench, Neem oil does not have long-lasting residual effects. The neem extract degrades reasonably quickly when exposed to both rainfall and sunlight. Its insect repelling and killing effects are fast acting for soft-bodied pest insects. The fact it dissipates quickly means it poses little or no risk to beneficial insects, birds, reptiles, and mammals.

Research has determined that Neem oil does not negatively impact beneficial predators such as earwigs, ants, and spiders, but it does quickly decimate unwanted insects in the larval stage (e.g., flower fly larvae).

Does Neem Oil Work Alone For Pest Control In Gardening?

Neem oil has limited effect when used alone in the garden for pest management. It is best to use it in combination with multiple other natural pesticides and control methods. It is very effective as the centerpiece of an integrated pest management (IPM) plan.

Read More About Using Food Scraps to Control Pests

In IPM, you would combine careful vigilance (watch for the presence of larval pests) with judicious use of:

Remember it is always better to use natural remedies in a preventative way than to try to use them to treat raging infections. As a treatment, they can work; however, they are far more effective when used as preventative measures. Don't expect instant results with Neem oil, especially when using it as a drench. Because the oil will need to travel through the plant and effect its vascular system, it could take two or three weeks for results to be apparent. This is why it is better to use the oil as a preventative than as a treatment.

If you are treating a problem, begin the moment you notice the problem, be patient and continue treating in a preventative way even after your plants have recovered.

How To Use Neem Oil For Plants In The Garden?

There are many ways to use Neem organic pesticide oil to achieve the most significant effect. Because the oil works in several different ways, pests are very unlikely to build up a resistance to it. This is especially true when using neem as part of a comprehensive IPM program. [source]

There are several different ways Neem oil can work to control your insect pest population. Because it is an oil, it can form a coating on an insect's body and block its breathing. It also repels a number of insects. In addition to hampering pest insect activity, it also prevents some types of fungus from becoming established by stopping spores from being able to take hold, and it inhibits germination.

A very mild, 1% foliar spray of a Neem oil solution has been found effective in keeping powdery mildew under control on phlox, lilacs, and hydrangeas. [source] As an insecticide, Neem oil is effective against a wide variety of pests as well as fungal, viral and bacterial infections when used as a spray or as a soil drench. No matter what sort of problem you are battling, it's important to understand the challenge and mix up your organic Neem oil solution accordingly. You will need a stronger solution for bigger, tougher bugs and/or for more established pests or mold, viral or bacterial infection.

What Problems Can Neem Oil Help With?

Using neem oil as a pesticide helps control nearly 200 species of insects, 15 of fungi and allegedly some bacteria and viruses. Generally speaking, if you are having a pest, fungus or bacterial infection problem in your garden, try spraying some Neem oil on it!

It will probably help, and it won't hurt. Here is a complete list of the garden pests Neem oil is known to help control:

Black-headed caterpillars

Moths and moth larvae

Colorado potato beetles

Various boring insects

Mexican bean beetles

Fruit sucking moths

Root weevil adults

Red palm weevil

Corn earworms

Eriophyid mites

Cabbage worms

Mushroom flies

Japanese beetles

Spotted beetles

Blister beetles

Cotton stainers

Spindle bugs

Tomato hornworm

Squash bugs

Gypsy moths

Spider mites

Fungus gnats

Tea mosquito

Leaf webbers

Pulse beetle

Semi loopers

Leaf hoppers


Leaf miners

Flea beetles


White grubs

Boll worms




Sand flies





Lawn and root grubs

Lace bugs

Fruit flies

Bed bugs

Pod bug










Scale insects


Anecdotal evidence also indicates limited success with garden slug and snail control. The only study done on the effects of Neem on gastropods involved edible, tropical snails and indicated the product is not effective against them. [source]

What Are The Guidelines For Mixing Neem Oil Spray?

When it comes to mixing Neem oil solutions, you may feel a bit daunted because there are not any precise and exacting rules. You will need to gauge your situation and consider the type of plant you are treating, as well as the type of pest or infection you are attacking. You'll need a stronger solution for tougher and more persistent problems. As with most natural remedies and organic pest control, it is better to set prevention as your goal than eradication.

Establishing diligent habits of inspection and regular spraying with a mild Neem solution is much more effective than attempting to get rid of a massive infestation or infection after the fact. Generally speaking, if you want to mix up a good, mild, general purpose preventative garden spray, go with a half percent or one-percent solution. If you are dealing with tough or established pests, you may want to mix a stronger two-percent solution. If you are starting out, begin with the half-percent solution. If it is not effective, you can always add more Neem. Observe the results of your spraying and adjust your measurements accordingly. Keep in mind that Neem does not kill insects immediately, on contact. You will probably need to spray daily for a week or so to observe the spray's effect on your plants and your pests.

General Purpose Organic Garden Spray

Here's a basic recipe for a good, general purpose .5% garden spray.

1 quart of warm water

1 teaspoon of pure, cold-pressed Neem oil

1/3 teaspoon of dish soap or insecticidal soap

Spray bottle or spray applicator

If you want a 1% solution, double the amount of Neem oil and insecticidal soap. If you want a 2% solution, quadruple the amounts. You can do the math to make a big batch of any strength, but keep in mind that Neem oil degrades quickly when mixed with water. Do not mix up more than you can use within a couple of hours of combining the ingredients.

12 Tips For Using Neem Oil Successfully In Your Garden

  1. Always use a high quality of cold-pressed organic Neem oil.
  2. Don't try to mix Neem oil with cold water. Always use warm water with the dish soap or insecticidal soap already mixed in.
  3. If making a big batch, mix up the Neem oil in a small container of warm water and soap first, then add it to the larger container of water.
  4. You can mix up your spray in a separate container and then pour it into the sprayer, or mix it in the sprayer.
  5. Shake your mixture periodically as you work to prevent the oil and water from separating.
  6. Use all of your spray solutions within eight hours of mixing.
  7. If you have solution left over after you finish spraying, use it as a soil drench to get root-knot nematodes and other soil-dwelling pests under control and improve the condition of your soil.
  8. Neem oil can become semi-solid at cool temperatures, so be sure to create your mixture indoors or on a warm day. If you are doing all this and your Neem oil remains semi-solid, try adding a little more dish soap or insecticidal soap to help dissolve the oil.
  9. When applying a Neem oil spray, be sure to coat all surfaces of the plant thoroughly. Get the topsides and undersides of leaves and all stem, stalk and trunk surfaces. Apply extra in bends and crooks as pests like to hide in these natural crevices.
  10. If it is very sunny, windy or if it rains, you will need to reapply your Neem oil solution.
  11. If you are concerned the spray may injure some plants, do a test before spraying the entire plant. Put a small amount of the solution on a small part of the plant and check back in 24 hours to see if there have been any adverse effects. If not, go ahead and treat the whole plant.
  12. Pure Neem retains its potency much longer if stored at about 40 degrees F in low light and in a dark container.

How Often Can You Spray With Neem Oil Solution?

The frequency of spraying varies depending on your intentions, the type of plants you are treating, the kind of pests you are dealing with and the weather. Because of all these variables, your powers of observation are critical. Keep a close eye on your plants, so you notice pest and fungal invasions early on. Begin treatment immediately, using the mildest solution and then observe to determine the results. It's generally a good idea to spray again in two or three days as insurance and keep a close eye on your plants for further signs of problems.

If you are starting out with Neem oil sprays and already have a burgeoning population of pests or heavy mold, bacterial or viral infection, you'll need to use a 2% concentration. Be sure to thoroughly drench every part of the plant and the soil all around it. Repeat this treatment weekly (or sooner in case of rain) until the problem clears up. Continue to monitor closely, apply preventative half percent solution and treat more aggressively with a stronger solution as needed.

If you want to use a half percent solution as an ongoing preventative spray, plan on spraying every couple of weeks. This should help prevent pest and mold problems. When plants are very young, apply a half percent solution as a foliar spray weekly and as a soil drench every couple of weeks to keep them safe. The oil will stay effective in the soil for about three weeks. On the leaves, it is only effective for about an hour, but it will kill pests present when you spray.

How And Why You Should Use Neem Oil As A Soil Drench?

When you use Neem oil as a soil drench, it works as a systemic insecticide. The plant roots draw the neem oil up into plant's vascular system. [source] This means the oil is present throughout the plant structure and insects dining on your plant will consume a dose of Neem oil. To use the product as a drench, just mix it up exactly as you would a spray and saturate the soil around the affected plant. This is also an excellent use for any leftover spray mixture. It's best to water first, then treat with a Neem oil drench. Neem oil is a superb soil drench, and this is the healthiest and most effective way to use it. When you drench the soil around a plant with your Neem oil solution, it spreads throughout the plant, and any pest feeding on the plant (thrips and scale) is affected. Furthermore, when you deliver Neem oil systemically to your plant, it has added defense against fungal and bacterial infection.

Neem extracts show incredible success with not only battling fungus disease problems but also many forms of root rot. Soil drench helps the plant both above and below ground. It helps eliminate nematode worms and other pathogenic soil organisms, but it does not harm beneficial earthworms. Using Neem oil as a soil drench for your tomato plants is an excellent idea because they are especially likely to have nematode problems.

Although the possibility of people, pets, and wildlife being negatively impacted by aerial spraying of Neem solution is quite small, delivering the product to your plants through a soil drench eliminates this tiny possibility.

Using Neem Oil For Insect Control on Houseplants

One of the problems houseplant homeowners face comes with their indoor pest control options. They are limited!

This is why we use 100% Pure Neem Oil to naturally control indoor pests such as:

  • Aphids
  • Scale insects
  • Mealybugs
  • Spider Mites
  • Thrips
  • Powdery mildew

Neem oil is an excellent SAFE, NATURAL insecticide/pesticide solution for homeowners with pest problems. We DO NOT recommend spraying any type of insecticide indoors. If you cannot take your plant(s) outdoors to thoroughly spray them, clean the plant and wipe it down with a mixed neem oil solution.

Read about Indoor Plants and Air Quality

How Safe Is Neem Oil?

Neem oil is remarkably benign, but you must use it as directed. According to the Environmental Protection Agency (EPA) Neem oil is generally recognized as safe (GRAS). If you are using it on your veggie garden, be sure to wash your produce thoroughly (as you would anyway) before eating it. [source] I would always recommend wearing protective pest control spray clothing and a pesticide respirator when spraying plants. The EPA has no restrictions in place.

Improper use could cause problems. Naturally, you should never drink garden Neem oil (but there are some Neem teas and supplements made for specifically for ingestion).

Remember that Neem oil interferes with reproduction in insects, so even though it may seem a bit overly cautious, if you are pregnant or trying to conceive, take care when handling Neem oil.

Generally speaking, Neem oil is not dangerous for beneficial insects such as ladybugs, butterflies, and bees because they don't chew on plant leaves. Nonetheless, excessive use of Neem oil may be harmful to bees. Avoid spraying it onto blossoms that bees frequent. Avoid having Neem oil spray come in direct contact with bees.

NOTE: The United Kingdom, has banned pesticides containing azadirachtin the active ingredient in neem oil. [source]

Neem oil is our #1 go-to product for natural pest control and an excellent solution for homeowners.

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Lisa Roth Collins is a Registered Holistic Nutritionist (RHN) and is the Marketing Manager at She is passionate about health and wellness and tries her best to make healthier choices every day for herself and her family. Her journey to natural health was driven by her own struggles with digestive discomfort, depression, and anxiety. Lisa returned to school in 2014 to study nutrition at the Canadian School for Natural Nutrition. She threw herself into her studies so she could learn as much as she could to help herself feel better and thrive. Upon completing the program and being certified as an RHN, Lisa began her work at Naturally Savvy where she has been able to help so many people learn to make healthier choices for themselves. Through her work, she has connected with so many incredible people in the industry whether other authors, influencers, or brands. Plus, she is affectionately known as "Techie Spice" because of her ability to wrap her head around technology. Every day she gets up with a renewed sense of energy and ready to make a difference. You can read all of Lisa's content here. In her spare time, Lisa loves to try new recipes, make delicious and nourishing meals, and she is an avid reader. For more information about Lisa, check out her profile on here.