Neem oil has long been used as a means of preventing and treating plant diseases, and is also a fungicide and insecticide. Neem oil is safe for humans to handle, but should not be applied when the plants are flowering or about to produce fruit.
Neem oil can be used to control a wide range of insects, such as aphids and whiteflies. As mentioned above, it has a repellent effect on mites. It is also an effective larval control for root-knot nematodes in soil.
The majority of neem oil is used in agriculture. It is applied to plants as a foliar spray to protect them from disease and insects. It is typically applied only when conditions are optimal for the plant (typically when the plant has just emerged from the ground or flowers have just emerged). It is also added to feed supplements for cattle to control insect vectors of diseases.
Neem oil can also be used as a spray or as a dip by dipping cotton and/or tissue paper into a neem oil solution. Neem oil is also available in a ready-to-use form in spray cans.
Using neem oil on houseplants is not recommended. It can be used as a foliar treatment, but is toxic to humans or pets while in contact with the plant. It can be inhaled or ingested by pets. Application to plants, dead or alive, is not recommended unless the plant is infested with anthracnose and has been treated with all other available chemicals to no avail.
Neem oil is a source of azadirachtin (also known as N-vinyl-2-azabicyclo-[2.2.1]heptan-2-one), a naturally occurring flavonoid that exhibits insecticidal properties against insects and mites [See: article]. Azadirachtin (azA) has shown to have significant fungicidal activity against Cladosporium spp., Patina spp., and Trichoderma spp.
Azadirachtin-containing neem products are used to treat many fungal infections in humans and animals. Azadirachtin (azA) is also marketed as an insect control agent for the control of whitefly, spider mites and aphids.
The major route of metabolism for azA in insects is hydrolysis of the n-acetyl group by cytochrome P450 enzymes. The n-acetyltransferase activity results in the formation described as azA 2 . AzA 2 has a similar effect on insect physiology as azA 1. The enzyme that catalyzes this reaction is known as tryptophan hydroxylase (TPH). In the insects, this enzyme is expressed in the haemolympic tissue (haemolymph) as compared to the insect’s brain. It is also produced in the haemolymph of insects that do not have haemolymphic tissue but do have a central nervous system (i.e., mosquitoes).
Insects that produce significant amounts of azA 2 either synthesize it within their cells or readily degrade it. Insects can be identified by examining their corneas with a microscope; they will be injected with 1% azA 2 and then examined under light microscopy, which will reveal clear, open spaces between cells.
AzA 2 is also known as azadirachtin, azadirachysin, and cycloheptan-2-one. Neem oil is a mixture of various esters of azA 2 . The major component (the most abundant) is called dehydrated azadirachtin (DEAD). Other components are terpinen-4-ol and azadirachtins A and B.
Besides being an effective insecticide against mites, nematodes, and whiteflies, one of the other uses for neem oil is to prevent nematodes from eating roots of tomato plants.
Applying nematodes to plants is a way to control the numbers of nematodes that will attack tomato plants in their first year of life. When an adult female, or gravid female, finds a suitable host plant, she lays eggs in the soil. She only lays 200-300 eggs, resulting in two or three generations per year. The presence of the nematode larvae will interfere with regular watering and other routine soil care activities performed by gardeners. The use of neem oil as a soil treatment will reduce the numbers of these pests on plants and prevent other pests from invading tomato plants.
After applying oil to the plant roots, it is important to wait a week before planting tomatoes again. It is preferable to use applications on a warm, sunny day in the late afternoon for best results.
Insecticidal properties of neem oil against pests include:
- Whiteflies, aphids, thrip and spider mites.
- Root knot nematodes, fungus gnats, root knot nematode larvae, tomato thrips and leafhoppers.
Neem oil may be used as a foliar spray on fruit trees and ornamentals such as roses to control scale insects. The oil is also effective against Japanese beetle.
The main toxicities of the oil are:
- Ingestion: nausea, vomiting, diarrhea.
- Dermal and eye contact: burning or irritation of skin, redness.
- Inhalation: coughing and dyspnea (difficulty in breathing).
Neem oil has been shown to have weak mutagenic properties. The European Union banned its use in cosmetic products based on a study demonstrating mutagenic potential of azadirachtin in human lymphocytes.
An Indian study found that the anti-nymphal properties of azadirachtin were due to concentration-dependent toxicity combined with the inability of insects to break it down before it reached their nervous systems. The study concluded that azadirachtin could be used as a neuro- and/or cardiotoxic agent to control pest insects.
Quick Note About Neem Oil for Plants
Known as the “tree of the 21st century”, neem is a widely used and medicinal plant. It is said that there is no part of neem that is not useful. From leaves, fruits, seeds to bark, roots, etc., people get some or the other benefit from almost all parts. Neem oil is one of the many beneficial uses of neem. So let’s know the details of neem oil –
What Is Neem Oil?
Among the products commercially produced from neem, neem oil is the most important. Neem oil is made from the extract of the seeds and fruit of the neem plant. As a bio-pesticide, it is equally effective. Generally pure neem oil can be golden yellow, yellowish brown, dark brown, reddish brown etc. depending on the production process. Pure neem oil has a pungent smell mixed with the smell of peanuts and garlic. It has a bitter taste due to the presence of triterpenoid compounds.
Neem oil can be applied directly on plants either in the form of spray or diluted with water and the result is effective. It is better to mix neem oil with a base oil like castor, olive, or jojoba etc. before applying on plants. The reason for this is that pure neem oil may be too bitter and drying for plants. On the other hand, if you mix it with a base oil then neem oil can effectively protect against aphids, whiteflies and many other harmful insects.
Azadirachtin, triterpenoids, antioxidants, calcium, fatty acids, vitamin E etc.
How Neem Oil Works
Polyacrylic acids are the most important bioactive ingredients of neem oil. In the presence of calcium and magnesium ions, polyacrylic acid molecules assume a shape that is similar to that observed in bacterial cell walls. This is known as polysaccharide-reinforced bacteria cell walls and it is known to kill bacteria instantly. On top of that, neem oil contains triterpenoid compounds such as azadirachtin and emodin. These two compounds can now be found in a variety of commercial extracts including saw palmetto extract and American ginseng extracts etc.
The role of triterpenoid compounds in neem oil is to kill pests directly at the cellular level. Neem oil has a silencing effect on pests. It can also be used to treat fungal infections, parasitic diseases and many other diseases of plants. It kills insects directly by destroying their metabolic functions and by interfering the neurological function of the insects. From this point of view, neem oil can be used as an insecticidal, fungicidal, and microbial agent all at once.
Neem Oil Dosage
The received wisdom today is that pure neem oil should not be applied onto plants to achieve effective control because it contains too much calcium and magnesium ions. The ratio of concentration of neem oil should be 6:3. That is, 6 parts of base oil and 3 parts neem oil. Neem oil should never be used directly on plants because it has a very high viscosity.
A better way to use neem oil is to develop a customized spray that contains some other vegetable oils that can dilute pure neem oil such as castor or olive oils. This customized spray can then be applied onto plants. The process involves mixing up to 4 oz (115 ml) pure neem oil with 2 gallons (8 liters) water and filling the sprayer tank with it and spraying it onto the plant leaves thoroughly.
The most effective concentration for neem oil is between 1%-5% for soil treatments and 0.5% for foliar sprays.
How Often to Spray Neem Oil?
The answer to this question depends on a number of factors including the type of pest, the size and the severity of infestation etc. Therefore, it is best if you first contact a local expert and then proceed with application. In addition to spraying neem oil onto plants, you can also apply it directly into the soil to get rid of insects that are living in the soil. The concentration here should be based on one’s own experience rather than any fixed formula as this will depend upon the type of soil and plant etc.
If you are using pure neem oil without any dilution, then you should spray it lightly at least twice in a week. In the presence of base oils, the interval should be between 3-4 days.
As a soil drench (addition directly into soil of plants), neem oil should be added every 3-4 weeks until two weeks after harvest and every two months during dry periods in warmer climates. If your goal is to kill pests living inside the plant tissue, it can be applied every 7-10 days for several weeks until pests are eliminated. For plant diseases, spraying is required from time to time when symptoms appear. It is best to read labels carefully for each situation and follow directions carefully.
Neem oil can be used against pests and diseases in every growing stage of plants. It is best to use it as soon as signs of pest infestation begin to appear.
Neem Oil Fungicidal Action Against Molds & Fungi
Fungicidal action of neem oil was first reported by a Japanese scientist by the name of Suzuki. He had observed that neem oil was effective against many kinds of fungal infections like mold and mildew in addition to insect pests and viruses. Neem oil has been used successfully against nematodes, leaf spots, rusts and other fungal diseases especially in warmer climates like India where most commercial products are still produced from neem seeds.
Neem oil is similar to an antibiotic in that it works by interfering with the synthesis of proteins at the ribosomal level. This is a mechanism which every cell has in common, from bacteria to plants and animals including humans. It also inhibits photosynthesis by destroying chlorophyll. Neem oil acts like a neurotoxin in that it interferes with neural transmission at the synapses. Neem oil also counteracts the growth of fungi by preventing the fungus from producing energy. In other words, neem oil interrupts every possible route of energy production and this results in fungal death.
Neem Oil & Fungus Diseases of Roots
Root diseases are caused by various kinds of soil borne fungi that attack roots. These fungi penetrate into root tissue and block it resulting in localized or systemic plant disease. A sample application of neem oil can be used to force some kind of systemic response to get rid of the infection before it spreads further and the damage becomes irreversible. Use 0.5% neem oil at the rate of 1 tsp per gallon of water. A sprayer can be used for this application.
Neem Oil & Fungus Diseases of Stems
A similar situation applies to stem diseases. Neem oil can be easily applied to stems of trees and shrubs without causing much harm to the foliage. The fungus is still likely to spread onto the leaves and even flower buds depending on the severity of infection but this can be counteracted by using a very low amount of neem oil, such as 0.25-0.5% at the rate of 1 tsp per gallon of water. A wetting agent like liquid fertilizer can be added simultaneously with neem oil and a 0.5% sprayer can also be used for this application.
Neem Oil & Fungus Diseases of Flowers
Neem oil is very effective against many fungal diseases of roses and other flowers as it is effective against molds and mildews. Spray neem oil onto the flowers, stems and foliage thoroughly. Apply the same amount of neem oil at the rate of 1 tsp per gallon of water onto branches, leaves etc. The results will vary according to growth timing, weather conditions etc but for a large number of plants applications seem to be helpful in getting immediate results within 2-3 weeks. If necessary repeat applications can also be done periodically to make sure that fungus does not start growing again in the future.
Neem Oil & Fungus Diseases of Fruits & Vegetables
Neem oil is effective against various types of soil borne fungi like molds, mildews and powdery mildew. As with other diseases and pests, the best way to treat them with neem oil is to use a very dilution for the application. That’s why it is best to mix up a customized spray and then apply it directly onto plant foliage, buds or fruit. There are studies that suggest that neem oil can be used as a foliar spray at the rate of 0.5%-1% on vegetables but this depends on crop type and other factors as well.
Neem oil can be directly applied to fruits, vegetables and other plant parts during the growing season. Thorough coverage of all plant parts is essential for effective results. Neem oil should be used in the form of a water dispersible concentrate at a rate of 0.5%-1% in water volumes ranging from 0.25-1 oz per gallon of water depending on the target organism, type and size of leaf surface etc. Seedling can also benefit from neem oil applications by mixing it with their soil media before transplanting them into containers or direct transplanting them into the field or garden.
Neem Oil as Fungicide for Wood Decks
Because of its natural ability to kill pests and diseases, neem oil is an ideal material for use against termites, termite-infested wood and other soil borne pests that attack wooden structures. Neem oil combined with the proper sealant will act as a protection against water damage, humidity and other factors that contribute to decay and rotting of wooden structures. During dry summer seasons, it is already advisable to periodically apply neem oil in order to keep pests away from the wood. In case of termites and other pests, the following can be done:
Apply neem oil on all wooden components and surfaces of the structure. Once dry, thoroughly wash off with water. Apply a sealant that has been mixed with neem oil in order to combine the antifungal properties of both. If applying neem oil is not possible, use a specialized termite treatment that has been mixed with neem oil for maximum protection against wood eating pests like termites, beetles etc.
Neem Oil & Fungal Diseases of Trees
Because a large number of trees worldwide are constantly under attack by various kinds of fungal diseases, it is important to know how to properly use neem oil. Neem oil can be applied directly to trees in order to boost their natural immunity against diseases and pests. Again, the best way is to use very dilute applications so that the oil does not harm leaves, flowers or fruits. Always be sure to thoroughly cover all parts of plants in order for neem oil to be effective against the target organism. If any adverse effects are observed make sure they subside before reapplying neem oil.
Neem Oil as Fungicide for Shrubs
Even though shrubs are commonly affected by fungus diseases, they do not need to be treated with neem oil that often in comparison to other plants. The best way to keep shrubs healthy and free of any fungal diseases is to regularly apply neem oil during each growing season at the rate of 0.5%-1% in order to boost their natural immunity. Wherever possible use organic fertilizers, herbicides, insecticides and other vegetable or plant extracts for a better result.
Keeping shrubs free from any fungal diseases is important for both the health and appearance of plants. In case of diseases it is possible that individual shrubs will not respond completely to neem oil applications but it will surely increase their immunity levels and well being. When choosing neem oil, always go for a dilution as high as 1% in water volumes ranging from 0.5-1 oz per gallon if necessary.
What You Need to Make Neem Oil Spray for Plants
Neem oil spray is a solution that has been used for generations as an effective pest defense in the garden. The plant dwellers like bees and flies are an annoyance any time they try to rob you of your little cucumber seedlings, but neem oil spray turns them into pests against themselves. It makes them go blind and actually die from the fumes of this conditioner. This topic will teach how to make it at home so that you can use it on your plants without having to run out for a bottle of Neem Oil Spray every few days.
Beyond pest defense, neem oil is also very beneficial for your health that you spray it in your face or on your clothes. I use it as a personal moisturizer that I put on my skin just before I go to bed. The goodness of neem oil is so wonderful that it can be used for everyday skin care, hair care and even as an insect repellent if you use mosquito coils in your backyard.
- First thing you will need to make neem oil spray is either a 4 liter container or a bottle of gallon and a half size of water. If you are going to make the garden spray, then ensure that you get two bottles since they will give an extra protection against weeds and insects. Do not get a bottle that is less that one gallon and a half, as you will have to dilute it with water. You can dilute it with water, but the diluted solution will work, but the results are not as good.
- Next, while at home you should make sure that you have neem oil in your spice cupboard or in your kitchen. It is not necessary that you have to buy neem oil; you can make your own. This can be carried out by crushing seeds of this herb and mixing it with hot water. Make sure that you stir well so as to break all the plant parts into small bits so it will release its oils.
- Finally, you need to remove the seeds that have been released into your water, but if you do not want to discard it, then use a strainer and transfer it to your container. Fill the remaining space with hot water so that it is at least half a gallon.
- The next thing you need to do is mix the neem oil solution with either water and lime or just water. I personally prefer using lime since it reduces the odors from this solution. The mixing ratio can be as much as 2 parts of neem oil in 4 parts of water, but for spray purposes, two parts of neem oil in one part of water is sufficient. The result is an odorless spray that can be used for up to two weeks if stored in a cool place.
- If you want to make more than one bottle, all you need to do is repeat the steps listed above. If you still have some neem oil left in your container, then all you need to do is dilute it with hot water and pour it into a bottle of gallon and a half. You may also decide to mix it with lime and water as well.
Important note: Use your neem oil spray only on healthy plants since its toxic effects are likely to affect the leaves as well.
If you want to use it on your skin, then you will need to dilute it with hot water and mix it with your favorite moisturizer. Two teaspoons is enough for a daily use. You can also mix it with other oils like almond oil or jojoba oil to make your own blend that is healthy and tasteless.
Important note: Never use this spray directly on your skin, it may also sting you. You may instead choose to wear gloves while diluting the solution, then shake the bottle for 30 seconds and pour its contents into a spray bottle.
A good tip is not to use this spray on birds and pets as they may be affected by its fumes as well. Moreover, do not use it every day or else you will have an allergic reaction as well as environmental contamination of neem oil that can harm the environment.
Important note: To ensure that you have used the neem oil spray correctly and effectively, simply check the plants every day after their application. You will notice very few pests on them and even the ones you find will be in greater numbers than before. The symptoms of an effective neem oil spray are no live insects, no decaying leaves and a better tasting food.
If you have not used this spray on your plants ever, then it is time to make up your mind. This method is cheap, simple, effective and has excellent results with little cost as well. When you use it as a mosquito repellent, make sure that you do so early in the morning since mosquitoes are not present at this time of day.
Benefits of Using Neem Oil for Plants
- Other insecticides have many side effects but neem oil is completely natural and has no side effects.
- It disrupts the hormonal balance of harmful insects thereby ensuring proper crop yield.
- Organic pesticides do not cause any damage to plants or the environment even if the amount of application is slightly less or more.
- Neem oil mixed with water and applied at the base of the plant kills insects, fungi, spiders etc.
- It has medicinal properties.
- It can be safely used on fruit trees, there is no damage to the fruit.
- Does not harm beneficial insects and bees.
- Ripe fruits can also be used on trees. Flowers, fruits, vegetables etc. can be used up to the day of collection.
Neem oil is commonly used as a spray on plants. In this case, mix 2 ml of any liquid soap/ handwasher/ dishwasher and 5 ml of neem oil in 1 liter of warm water. When the mixture cools down, fill it in a spray bottle and spray it on the plants. This mixture can be used once a week on affected plants and once every 15 days on healthy plants. This mixture can also be used on soil. However it is used, try to use it in the afternoon.
Neem oil can usually be used up to two years from the date of manufacture. However, it is important to store it properly. Should be stored in a cool and dry place. Dark storage is best. Can also be stored in the refrigerator but may freeze. Take it out of the fridge and soak it in lukewarm water to make it usable again.
Where Do You Get It?
While buying neem oil for plants, make sure that it is 100% pure and organic. For pure neem oil contact Greeniculture Agrotech Ltd website or facebook page. Because oil obtained from green culture –
- Neem fruit, made from seeds under expert supervision is therefore completely safe.
- 100% pure and healthy.
What Bugs Does Neem Oil Kill?
Many people want to know what bugs does neem oil kill. Neem Oil is derived from the neem tree which can grow in places where other plants cannot live, such as dry hillsides and disturbed areas. Neem oil has been found to be effective against certain pests like bedbugs, lice and ticks. The result is a product that not only repels a variety of insects, but destroys them on contact.
Can neem oil kill bed bugs?
There are plenty of products available for killing and removing bed bugs, but none of them work as well as neem oil. Using neem oil against bed bugs is safe, especially when it is used in conjunction with a bed bug spray.
Bed bug sprays generally have harsh chemicals in them, and they are typically only effective if they are applied while the bugs are still alive. Any residual spray will not kill the eggs, however, so additional treatments will be necessary to eliminate that problem.
A mixture of neem oil and water makes a lethal combination against these tiny pests.
The most effective and safest way to kill bed bugs and other insects is to use a steam cleaner with a powerful fan. After the bugs are dead and the debris has been vacuumed out of the hotel room, there can be no possibility of further infestation.
Bed Bug Sprays: An Important Step in Managing Bed Bugs
Bed bug sprays provide an immediate solution to your bed bug problem. They are also extremely efficient at killing bed bugs as well as eggs. The four or five chemicals commonly found in bed bug products may provide some immediate relief, but they will not kill all of the eggs during one treatment. These sprays are also not able to prevent new infestations from happening since the eggs can be spread by movement and contact.
The essential component of any bed bug spray is the insecticide. You will want to look for an ingredient that includes pyrethrin and/or permethrin. These ingredients are very effective at killing bed bugs, but they can also be risky if used frequently or in homes with small children or pets. Pyrethrin is known to cause skin irritation, reddening of the eyes and coughing. Permethrin is toxic when ingested although it has no effect on mammals as it only affects insects by repelling them as well as killing them on contact.
The best way to use a bed bug spray is to spray the pesticide directly on the infested areas. It is important that you cover all of the areas where you have seen the pest or think you might see it. Bed bug sprays are not effective if they are sprayed over your whole home and do not stay in contact with the bugs. The spray should be applied thoroughly, but it need not be dripping wet for it to be effective.
It is recommended that you test any bed bug spray in an inconspicuous area before use in order to make sure that a reaction does not occur. Most bed bug products will have instructions included with them that tell you what parts of your body should be covered. There are also some types of bed bug sprays that can be applied to use on pets, where the little critters will not be able to lick the insecticide off of their fur.
Insecticidal Soap vs Neem Oil
Insecticidal soap, like many other topical pesticides, is actually a combination of surfactants (emulsifiers, like lecithin) and a carrier agent, such as sodium or potassium salts of fatty acids. These ingredients are mixed together with an insecticide to create a thin film that will kill insects and protect plants from insects for up to one month. Insecticidal soaps can be used on any plant directly (without diluting with water or soil) and can be washed off with plain water. However, they must be applied within 30 minutes of being exposed to the insect, or they lose their effectiveness. Insecticidal soaps do not work on insects that are airborne, such as mosquitoes and flies. Insecticidal soaps can also be used to remove old or dead outer layers of leaves before applying new neem oil.
Neem oil is a unique non-chemical pesticide that is made from the tree neem in India. Neem influences the development of microorganisms in plants, affecting the microbiome (a community of microorganisms living on a living organism) that can affect defenses against insects and pathogens present in the plant tissues. The active ingredient found in neem oil prevents insect development by interfering with cuticle formation and inhibiting gut function and reproduction, as well as blocking calcium metabolism, resulting in abnormal organ morphology and abnormal cell death.
Neem oil enters a plant through wounds or injuries inflicted by insects. It is absorbed into the plant and travels to all parts of its tissues. Although neem oil is very toxic to insects, it does not cause any long-term damage to the plant tissues. Thus, neem oil has no lasting effects on the insects.
Neem oil can be safely applied to various types of fruits, vegetables, ornamentals and other greenhouse crops if the soil is loose enough for easy absorption and the plants are not too tall or close together. Avoid using neem oil near flowers or fruit while they are in bloom, as it may adversely affect their appearance.
Frequently Asked Questions for Neem Oil
What is neem oil?
How do I use neem oil?
Should I use neem oil in my greenhouse or garden?
How do I dispose of neem oil?
Do I need to worry about repelling beneficial bugs?
Is neem oil safe to use on my food crops?
Is neem oil organic?
Does neem oil kill bees?
How do I use neem oil on my pets?
What is the shelf life of neem oil?
Sum It Up
To sum it up, you now know the steps needed to make neem oil spray for plants. With the information above, you will be able to save a number of dollars by making your own spray. This article has only shown you how to make neem oil spray for plants and not ones that are used as insecticides and sprays. The best thing is that it can be used any time because you will always have some around whenever you need them.
If you have any questions or concerns pertaining to this article, please let me know by using the comment box below so that I can address each of your concerns individually. Your thoughts are important in determining how I enhance this work in order to better serve everyone.