Neem Oil vs. Horticultural Oil: Which Natural Insecticide Should You Use?

Dec 28, 2023

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As an agriculture and gardening enthusiast, you know how pests can be destructive. You also probably know that, sometimes, pest control can also lead to crop destruction.

Many gardeners want to steer clear of artificial pesticides and try a natural alternative. Afterall, natural solutions have minimal human and environmental health concerns.

Neem oil and horticultural oils are popular alternatives. These two are friendly to the environment and effective. Each has its benefits, characteristics, usage instructions, and ingredients. We will explore their properties, pest targets, and their effectiveness. You will also learn how to use them well to avoid plant damage and gain the greatest benefits. Here is a detailed review of neem oil vs. horticultural oil.

In a way, neem oils and horticultural oils are the same. Horticultural oils are all-natural oils made from minerals, plants, and animals. At the same time, neem is also horticultural oil since it comes from a neem tree.

©iStock.com/Ninetechno

However, neem oil is very different from other agricultural oils. While horticultural oils prevent plant pests and disease invasion, neem oils repel and inhibit pests’ growth. Hence, these oils use different methods to achieve the same goal.

Neem oils control insects at all development stages: eggs, larvae, and adults. This oil has 140 active compounds, with azadirachtin as the active chemical. This explains its effectiveness in insect control.

Horticultural oils help to manage insect infestation on plants. These oils contain:

The properties of this oil include the following:

Hence, the oil works through repelling or smothering. Also, some of these oils have mild fungicides to act upon rust, powdery mildew, and sooty mold diseases.

Lastly, you must check the oil's effects on different types of plants because some plants are not oil tolerant.

Also, it would be best not to substitute non-gardening or cooking oils on plants. This is because these oils may contain impurities and risk plant health.

Both neem and horticultural oils work best on specific pests. These include:

You can use neem oils for both outdoor and indoor plants to regulate pests.

Neem extract can help to control:

Besides controlling these pests, neem oil can also control fungal diseases. It can help with black spot, scab, blight, anthracnose, and powdery mildew. Note that you cannot use neem oil to control all pests. So, identify the pests and look for the right product.

©kale kkm/Shutterstock.com

You can use horticultural oils to control:

On top of the above pests, horticultural oils also help to control some fungal diseases. You can use it for sooty mold, rust, and powdery mildew.

Neem and horticultural oils are easy to use and effective. You only need to spray them on your plants in need. But their effectiveness depends on the type of formula and different application methods. Here are the top factors to consider:

Neem oil uses several modes to control pests. It disrupts the growth and development of pests, inhibits feeding, and repels them. In contrast, horticultural oils suffocate insects and disrupt their breathing.

This means that neem oil is mostly effective against pests that don't succumb to suffocation.

Neem oil does not remain on the plant for long. So, you will need to apply neem oil in intervals for it to be effective. In contrast, horticultural oils can remain on the plant for some time.

Plants can absorb neem oil through their leaves and roots and supply it to the rest of the parts for systemic protection. In comparison, horticultural oils affect pests through contact. Pests must come into contact with the oil for it to work.

You can use both oils for various pests.

These oils are environmentally friendly. However, horticultural oils may affect aquatic invertebrates and fish. In contrast, neem oil is not harmful to aquatic life.

From the above explanation, each oil is effective depending on the pest and how you apply it. Use neem oil to deal with soft-body pests, since suffocation might not work. And use horticultural oil to deal with pests that will succumb to suffocation.

When using horticultural oils as insecticide, here are some safety usage guidelines:

Before you open the package, read all the labels and directions. You will learn timing, application, and precautions.

Apply horticultural oils on the leaf's upper and lower sides or back. If you use it as a fungicide, you must completely cover the plant leaves on the upper side.

Apply horticultural oils at the right temperatures to avoid plant damage. Please note that these oils may damage plant tissue, especially leaves. This may happen if you apply the oils with high heat or low evaporation.

It is advisable to apply when the temperatures are below 85 degrees Fahrenheit, such as in the morning or in the evening during summer.

Always apply horticultural oils with temperatures between 50-60 degrees Fahrenheit and above. Then repeat the application for several days. This temperature helps keep the oils at their optimum viscosity.

Always test the plant oil sensitivity by spraying on a small part. This is important when you need clarification on the plant oil tolerance level. Then wait for about two days for the reaction. Also, do not use these oils on plants with gray or blue foliage because the oils may interfere with their coloring wax.

Re-application helps deal with pests that didn't die in the first application. But check the instructions to know how long to wait between your spraying sessions.

This refers to the time you must wait before going to the treated areas or the wait time before eating vegetables. You must read the oil's label for these instructions and wait until the time lapses.

Horticultural oils may lead to aquatic life intoxication. Refrain from spraying near rivers, ponds, lakes, or other water bodies. If you must do so, consider using buffers to avoid overflows.

In addition:

You can use neem oil to protect crops from pests and insects without harsh insecticides. You must use it well to avoid crop damage and also achieve good results. For efficiency, use the tips below when using neem oil on your plants:

Read the label well to get instructions on using the product to achieve results. Also, this will help you with proper timing, safety precautions, and quantities.

If you use neem oil for indoor plants, move them away from kids and pets.

If you are unsure whether your plants are oil tolerant, try using some oil on a small part. This helps to avoid damaging the whole plant or large portions of the plant.

Apply the oil for about 24 hours to see the possible effects on the plant. Then proceed if there is no discoloration or burns.

To get good results, apply your neem oil on the plant's leaves, top and bottom. Pay special attention to the bottom side since many pests hide there.

Apply a light coat on the leaves and repeat after seven to 10 days, depending on the manufacturers’ guide.

Neem oil may take some time to take effect. So, repeating the application process is good until you get the results. If you want to use neem oil for bacteria and fungi, use it in pure form. This will help to eradicate the diseases in your fruits and vegetables.

Use neem insecticides when the plants are out of flowering season. You can spray them in two-week intervals until their buds open. Stop, then proceed when the flowers drop. This helps to reduce the oil's effects on pollinators and other useful animals.

Plants can absorb neem oil through their leaves. Prepare an insecticide solution and pour two to three cups around the tree base. Repeat the process every two to three weeks until the pests die, and the plant is disease free.

Finally, avoid applying neem insecticides on poor-quality plants. Instead, revive the plant and then proceed with the insecticides. Meanwhile, you may use root soak to curb the insecticides as the tree recovers.

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