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How to Check Oregano for Bugs

A collage of oregano infested with bugs.

An aromatic herb that is commonly featured in Italian and Greek cooking, oregano is a lovely herb for your indoor herb garden. It has a sprawling growth habit that dangles over the edges of your herb pots and has beautiful deep green oval-shaped leaves. When you grow oregano in your kitchen, you will simply need to reach over and snip a few stems from the plant to season many of your favorite dishes.

Pests on Oregano

A bee collecting nectar on oregano flower.

Oregano, in general, is a very low maintenance plant. Most of the time, you will simply need to water the plant when the soil is dry and give it plenty of sunshine. For those who do not want a plant that is fussy, oregano is a wonderful choice.

However, oregano does have a few pests that you have to look out for. Many times, you will not encounter these pests when you grow your oregano indoors. Even though it is unlikely that you will end up with these pests, it is always a good idea to know what to look for. When you are aware of potential problems, you can know exactly what to do if your plants begin to struggle.

The most common pests on oregano plants are aphids, spider mites, and leaf miners. Take action as soon as you notice that something is wrong to avoid having the pests spreading to other healthy plants.


Watering oregano plant on a pot.

Aphids are small green insects that pierce plants with their sharp mouths and suck the juices from the plants. One or two aphids is no big deal, but en masse, these pests can do major damage to the plants in your indoor herb garden. However, even if you only notice a few aphids on your plants, you should act fast.

They can multiply rapidly and before you know it your plants will start looking sickly. An infestation of aphids can rob your plants of so much sap that the oregano plant will start to look stunted and misshapen.  Aphids can also transmit plant diseases, compounding your plant woes. If you notice a handful of aphids on your oregano plants, work quickly to resolve it before you end up with a major issue. 

When you notice that something is wrong with your oregano plant and you think you might have aphids, you should examine the undersides of the leaves and the stems of the plant. If it is aphids, you will see a row of green, brown, or black oblong critters on the plant.

Another tip-off that you have an aphid problem is a sticky substance present on the leaves and stems of your oregano plants. Aphids leave behind a goo called honeydew when they feed. Sometimes ants are drawn to this substance, so even if you don’t actually see the aphids, the honeydew and the ants are a pretty good indicator that they are present. 

To get rid of a mild aphid infestation, you should set the plants in a sink and blast them with a strong stream of water. Be sure to pay attention to the undersides of the leaves, because aphids are sneaky and you don’t want any of them to escape.

If spraying with water doesn’t work, the next course of action is to try to use an organic pesticide. It’s best to try organics first since your plant is in your house and you are hopefully going to be consuming it when it recovers from its aphid infestation. 

To spray for aphids, combine 3 teaspoons of dishwashing liquid with a quart of water and spray it all over the plants. For a stubborn infestation, add a teaspoon of cayenne pepper to the mixture. Apply these sprays to your plants every day for up to two weeks. 

For very stubborn infestations, you can make your own insecticidal soap by combining one cup of any kind of cooking oil and one tablespoon of dishwashing liquid. Then, to mix this combination, take 2 teaspoons of this concoction and add it to a cup of warm water. Spray this on your plants every day until the aphids are gone. 

Spider Mites

Spider Mites making a nest on a leaves.

Spider mites are tiny eight-legged pests that can damage your oregano plants by piercing the plants and sucking the juices from them. These pests are super small, generally only one-fiftieth of an inch, so unless you have incredibly keen eyesight, you may not actually be able to see the pests themselves. To get a good look at the mites themselves, you may need to use a magnifying glass.

However, if you end up with an extensive enough infestation, you will definitely be able to see the effects of the infestation.

When you have a spider mite infestation, the first sign that you may notice is webs on the underside of the leaves of your oregano plants. However, you will also notice the effects of the mites’ eating habits on your plant’s leaves. There will be tiny dots on the leaves, and the leaves may turn yellow and start to die.

The plants will have a dull appearance since their life blood is slowly being sucked away by these pesky mites. Spider mites like dry, warm conditions and you may not have problems with them until the winter months.

If you suspect that you have a spider mite problem, gently shake your plant over a plain sheet of paper. If you have mites, they will fall onto the paper. To the naked eye, the mites will look like nothing more than specks of dust. However, if you watch carefully, the specks may start crawling around on the paper.

To get rid of spider mites, you have several options. First, you can set the plant in your kitchen sink. Using your sprayer on the sink faucet, blast the leaves with a strong stream of water. This will dislodge the mites and get rid of them.

Second, if you have a very stubborn infection, you can use an insecticide called neem oil. Neem oil is a natural pesticide and has been used for hundreds of years in places like India. Use caution when spraying it because some people are allergic to neem oil, and read the label carefully, following all directions for mixing and spraying your plants.

While neem oil is safe and organic, you probably should wait about five days after spraying your oregano with neem oil before you harvest any oregano for kitchen use, just to be on the safe side. After five days, neem oil breaks down on plants, but you should still wash your oregano before you use it. The full effects of neem oil will not be seen until about 72 hours after its use.

Be sure, as you use neem oil, that you spray the undersides of all of the leaves of your oregano to make sure that you kill all of the spider mites.

Garden safe insecticide and an oregano plant.

Rosemary oil and eucalyptus oil are also natural essential oils that will kill spider mites. To use rosemary oil to kill spider mites, mix 3 teaspoons of rosemary oil with a liter of water and one teaspoon of liquid dishwashing soap. Shake these together in a bottle and spray them on your plants every two or three days.

To use eucalyptus oil, combine 2 teaspoons of the oil with a liter of water and a teaspoon of dishwashing liquid. Shake the bottle together to combine and spray your plants with this solution every three days.

Leaf Miners

A Leaf Miners larvae tunneling on a leaf.

Have you noticed thin white trails on the leaves of your oregano plants? If so, these are the signs of leaf miners. When you have leaf miners, you will probably never see the insects that cause these trails. Leaf miners are the larval stage of certain beetles, moths, and flies.

The insects themselves are tiny, only 1/5 to 1/8 of an inch in size and they live inside the leaves of the plant, feeding on the tissues inside your oregano plant. That is what makes the trails on the surface of your plant’s leaves.

The adult insects lay eggs on the leaves of your plants, and when they hatch, the tiny larva bore into the plants. The only way to tell that your oregano plant has leaf miners is when you notice the tell-tale trails in your leaves.

To get rid of leaf miners, you will want to act fast. They can quickly decimate your plants. Pick off the leaves with the trails in them if you can do so without eliminating so many leaves that your plant will suffer. Throw these away immediately. 

You can also spray your plants with neem oil or Castile soap. Both of these will need to be applied daily to effectively kill the bugs inside the leaves of your oregano plants.

In general, oregano is a fairly trouble-free plant that has very few insect pests, particularly if you are growing it indoors. However, if you know which insects are likely to be a problem, you can act quickly when you notice that something is a problem.