Orchid Diseases, Bugs and Pests: Identifying and Tackling

Orchid diseases, bugs, and pests is an important topic to know about before or even after you have begun growing this plant in your garden. Knowing in advance will help you manage these problems, benefiting the orchids.

Orchid Diseases Bugs and Pests

Since there is no detailed article on these three things, we wrote one for you. Now, continue reading this article as we will guide you to learn about the diseases, bugs, and pests an orchid may face.

The Main Attacks and Orchid Diseases, Bugs and Pests

The main diseases that attack orchids are root rot, powdery mildew, downy mildew, botrytis, blight, and leaf spot. Each disease causes spots to emerge on the leaves, leading to curling and wilting. If you don’t stop the spread, orchids can even die.

– Root Rot

One of the most common orchid diseases that gardeners face is root rot. It is fungal that occurs when the potting medium stays wet for a long time. To elaborate further, it is caused by pythium spp and phytophthora spp fungi that have the reputation of thriving in the wet environment or the excessive moisture that would be around the roots.

In root rot, fungus first attacks the roots, as you can guess from its name. The infected roots discolor and start giving a foul smell, in the long run, they may also weaken and die.

The fungus attack then spreads to the base of the stem. With time, you can see spores on the stem and even on the leaves too. When the root rot worsens, big yellow and black spots can also be seen on the orchid, and the flowers would look quite lacking in strength.

– Powdery Mildew

Powdery mildew is one of the most lethal fungal infections that can cause the death of orchid plants. When it attacks, gray to white spots emerge on the leaves. The white powdery texture of a substance can also be seen on the infected plants, so this disease is called “powdery” mildew.

This is also a disease that attacks every part of the plant and not only the roots or the leaves on their own. You can see its damage on the roots, stems, leaves, buds, and flowers. After its attack, the orchid shows stunted growth with a fragile look.

In short, for all gardeners, this disease is a nightmare for orchid owners because people choose to grow these plants to increase the garden’s aesthetic value. But a mildew-infected orchid is neither beautiful nor healthy.

– Downy Mildew

Another fungal disease that harms orchids is downy mildew. It is caused by oomycetes- fungi that love the humid environment. That is why this disease is common in those areas where the humidity level stays high for most of the year.

In addition, the chances of a downy mildew attack also increase when you don’t care about plants’ hygiene. Since fungi love the dirt, you may also see other fungal diseases attacking the orchid in an unclean garden.

So, how can you confirm the Oomycetes attack the orchid? You should check for the keen signs, and when this organism attacks, the leaves first turn pale yellow. With time, gray to purple spore growth can also be seen on different parts of the orchids.

Moreover, when this attack gets severe, it leaves curls up and falls off. A time will come when there won’t be any healthy leaves left on the orchid. When this happens, the infected orchid will die.

– Botrytis

Botrytis can waste all of the efforts that you spend on growing a healthy orchid. The scientific name of this issue is Botrytis cinerea, and it is behind this problem, and it also likes wet and unhygienic environments; of course, just like any other fungi, it will weaken the plant and thrive in the unhealthy medium.

When Botrytis attack orchids, you will initially see small grayish spots. If you don’t do anything to stop the spread, these spots will grow and cover the whole area. The margins will turn pale pink, a big identifying factor of this disease.

– Blight

Petal blight disease is a big problem for flowering orchids like Cattleya orchids, to be specific. It attacks when the air circulation is poor in your garden. Furthermore, unhygienic growing practices also encourage the bacteria to spread to the entire garden or if indoors, the plants that are very near to it.

In blight, roots take a lot of damage, and if you dig up the soil, you will also see discoloration on them. Furthermore, spots emerge on the whole orchid with time as well. In severe cases, wilting is also possible.

– Leaf Spot

Bacterial leaf spot is one of the deadliest phalaenopsis orchid diseases. In this, scattered brown spots emerge on almost every orchid leaf. Sometimes, you will also see yellow and black patches on the vegetative parts.

Although, you may also notice that the leaf margins sometimes turn brown when the leaf spot invades. Another way to identify this disease is to look for irregular tan spots on the backside of the leaves.

– Black Rot

It is one of the common dendrobium orchid diseases. It occurs due to bacteria and fungi; however, this is one that is called the “Xanthomonas campestris pv. Campestris” scientifically, and it is the main reason behind the disease and the damage to the plant as a whole.

In this disease, V-shaped lesions can be seen on the orchid leaves. The black or dark spots emerge on the whole body, especially the stem. If this disease worsens, the orchid is also at risk of stunted growth and death.

Ways of Dealing with Orchid Diseases

To deal with orchid diseases, you should first make sure the soil is not excessively wet. Dry it by removing the top layer, providing proper care, and adding compost or sphagnum moss.

Ways of Dealing with Orchid Diseases

Then, clean your garden, manage the humidity, and apply appropriate fungicides or bactericides to control the disease spread.

– Focus on Potting Medium

The leading reason behind the attack of diseases is the soggy and poorly drained potting medium. Therefore, you should keep it dry and good at drainage. In this case, you can remove the top layer of wet soil and add compost, sphagnum moss, or bark. Doing this will also reduce fungi growth. Then, only water the orchid if the soil becomes dry.

– Follow Proper Care Measures

Following orchid care measures can also stop the spread of the diseases. The most important one is plucking out the infected leaves and flowers; of course, you can do this with your bare hands or with a pruning scissor. But overall, you should also carefully dig the soil and cut off the diseased roots.

It is also crucial you keep the garden free from any dirt. You should also habitually sterilize the gardening tools with hydrogen peroxide before you use them. In addition, you should maintain the humidity by pruning off extra orchid parts and watering sensibly.

– Try Fungicides and Bactericides

When nothing stops the disease from spreading, you should apply fungicide or bactericide, but be careful because this matter would be one that depends on which disease has attacked the orchid, and you should apply it accordingly. After their application, you should stay extra careful about watering, and hopefully, the disease will get treated, and the orchids will come back to life.

The Most Common Orchid Bugs and Pests

The most common orchid bugs and pests are ones like aphids, mites, thrips, mealybugs, gnats, whiteflies, snails, and slugs. These insects can be found on leaves, flowers, stems, and even under the soil.

Most Common Orchid Bugs and Pests

Most of them suck the cell sap, while snails and slugs chew the orchid’s parts.

– Aphids

Aphids are a common insect of lots of orchids, and they are the ones with green-black in color and tiny in size. You can find them on the backside of the leaves with their mouths inserted there and eat up the plant.

They love to suck the juice or sap from the leaves, which leads to spots so that they would be on the green parts of the orchid. However, this is not the only way this insect hurts the orchids. After leaving, aphids also release sooty mold- a black honeydew substance that you would see on the plant.

However, few aphids don’t do much damage, but if their population increases, you will see many yellow, brown, and black spots on the leaves. Furthermore, their continuous feeding also leads to curling and wilting as well.

The thing about aphids is that they are super lazy, and for those, getting rid of them is easy. However, since they are tiny, you must carefully observe the leaves to ensure they are free from these insects.

– Spider Mites

Spider mites are, namely, one of the most common orchid pests. They are oval in shape but small in size, so it is not easy to spot them with the naked eye. That is why we suggest you look for webbing.

If you see webs on the orchids, it means spider mites have attacked the plant. However, when many of them are in one spot, you can easily see their silvery bodies. Notw that mites’ mode of attack is also similar to aphids. They insert their extremities into the leaves and stems to suck the chlorophyll of the green parts.

During the early days of the mites’ infestation, only a few orchids are damaged by their mouth. The problem can go out of hand quickly because this insect can travel from one plant to another, causing harm to each of them.

– Mealybugs

Orchid pests mealybugs are the white bugs you will most likely see on the stems and leaves. They like to stay in groups, which will make you find them quite easier as there will be a dozen of them together. Looking at them from some distance, they will appear like white powder, and from close, you can easily see their shiny bodies.

Since they attack in “hoards,” it is hard for orchids to resist their damage—these bugs attack buds and flowers too. As a result, the orchid starts looking sick after some days of infestation.

Mealybugs usually enter your garden when you buy an infested plant from a nursery. Therefore, it is better to get plants from a reputable source and quickly sterilize them before putting them next to other plants.

– Whiteflies

You may also see whiteflies in your orchid plant as these flies are not ordinary ones. Note that they damage the plants in different ways. They would start off by clinging to the leaves and absorbing the sap with their mouth.

After this, they release sooty mold on the leaves, and this sooty mold invites other insects, like ants, to come to the infected orchid. Then, the spot where they drank the juice turns yellow. Due to this discoloration, the photosynthesis rate declines, which leads to a loss of vigor.

But the worst part about whiteflies is that they carry viral diseases. When they attack the orchids, they may also transmit deadly viruses to them, which can cause death in a few days. So, don’t wait a day if you see whiteflies in your garden.

– Fungus Gnats

Gnats are one of the most annoying insects. The adults have black bodies with gray wings. These adults don’t harm the orchids; they only want to deal with the fungi in the soil. It is their larvae that cause the devastation.

You must be quick to detect them, because a female gnat can lay up to 200 eggs in the soil. When the larvae come out of them, their main target is the roots. They feed them voraciously, impacting the orchid’s water and nutrient uptake capacity.

After some time, these larvae become adults, and the female ones then lay eggs again, and in short, they will be growing and developing as they take over. Therefore, it is very important you start the treatments immediately as soon as you see gnats roaming around the orchid.

Note that seeing gnats in your garden indicates that there is something wrong going on. They usually infest a garden if you keep the soil wet and don’t clean it properly. Therefore, you should immediately check the soil condition and take some measures to clean up the surroundings.

– Thrips

If you see tiny black bugs in orchid soil, chances are they are thrips. They are darker in appearance and have elongated bodies with fringed wings, although they are not attractive to look at, because surely the harm is great, as they would stab the orchid and drink all of its sap. They don’t even leave flowers; you can find some of them in the buds too.

Thrips love to roam on every orchid part, which is why you can find them everywhere. They are small, so observing them can become hard for you, unless they are in group form. However, these pests will also leave discoloration whenever they attack because of sucking the cell contents.

– Scale Insects

Scale insect is another orchid pest that has the power to deform plants. Just like different pests, these too are also sucking pest that loves to drink the cell contents or the sap. You will find two scale insects on the orchids: the armored one and the soft one. The armored insect has a tough body, whereas the soft-scale insect has a waxy coating.

No matter which type attacks the orchids, the result is yellowing; if you let them feast, they will leave a prolonged issue. It is because the sap contains chlorophyll- a compound that is the reason behind the green color of plants.

In short, when it gets depleted, orchid leaves will lose their color and become yellow. If these insects don’t face any resistance, they will continue drawing the juice, which will lead to wilting. A wilted orchid is dead, as it is nearly impossible to revive it.

– Leaf Miners

If you see little tunnel-like structures on the leaves, the leaf miners have started feeding on them. They are usually yellow-green and very hard to be seen through the naked eye.

Leaf miners rarely cause orchid death, but you should still not take them lightly as they greatly impact the plant’s capacity to do photosynthesis. When the photosynthesis rate slows, orchids cannot keep growing and will show stunted growth. Such plants are prone to disease infections too, and they will leave a long-term issue

– Cockroaches

Almost every human hates cockroaches, but if you also love to grow orchids, you have one more reason to dislike them. The cockroaches can feed on the new growths and buds of orchids.

They also eat the organic matter in the soil, which makes the potting medium unsuitable. The good news is that orchids cannot die from the feasting of these bugs. Still, they can significantly impact their health in the ways we discussed.

– Snails and Slugs

Looking at orchids and seeing half-chewed leaves means snails and slugs have infested your garden. They are mollusks and are known to eat every plant’s parts. The chewing is first visible on the tops. You may also see holes in between the leaves.

If you don’t get rid of snails and slugs, every leaf will be affected. It is hard to spot them during the day as they hide. Don’t worry; you can still control their and all other insects’ attacks, and it’s time to find out how.

How To Get Rid of Orchid Bugs and Pests?

To get rid of orchids’ bugs, and pests, you must first try organic repellents like horticultural oil, sticky traps, beneficial insects, etc. If the insect population keeps on growing, then spray chemical pesticides. Their fumes will kill the bugs and pests in no time.

– Try Organic Repellents

If the insect infestation is not severe, organic repellents should be your first choice. You may also try using horticultural oil like neem oil to eliminate garden insects. You can also go for cayenne pepper spray, baking soda solution, and vinegar to shoo away these unwanted creatures, if you don’t want to use chemicals.

Furthermore, sticky traps are very effective in trapping thrips and gnats, as both would be larvae and then become adults. Place them on the soil or in the garden where you think the insects hide, after a while wait for them to fall into our trap.

Try Organic Repellents

You can also get help from other insects to control the population of orchid insects. Releasing more insects can also free your garden from insects. But it’s the predatory ones that do this.

To elaborate further, the predatory insects eat most of your garden’s harmful insects, which reduces their numbers. The ones that you can use are our ladybird beetle, wasp, and lacewing. You can get these beneficial insects online and in big gardening stores.

– Spray Commercially Made Chemical Pesticides

If the insect population is not under control after following organic measures, you will have to give the pests a big blow by spraying chemical pesticides. Although expensive, they are super effective in killing all the annoying pests as soon as the fumes get in touch with their bodies.

It would be best to be careful while applying a pesticide because the fumes can also harm your eyes. Furthermore, breathing them can also cause lung problems. This means that you should be wearing a mask and goggles for protection. Also, don’t go in your garden for four to five hours as the chemical residues stay in the air for some time.


Knowing about orchid pests and diseases is important if you have plans to grow this plant or have already bought one. Let’s now have a look at the main points of the article to refresh the key information:

  • Both fungal and bacterial diseases attack if you water the soil excessively, don’t manage the humidity, and keep the garden unclean.
  • Diseases can kill the orchids if they get severe, so treatments are necessary.
  • Pests and bugs enter your garden when you bring an infested plant from outside, like a nursery.
  • If you don’t control pest and bug infestation, orchids can wilt and die.

That’s everything about the orchid’s diseases, bugs, and pests. You now know what they are and how to handle them easily, so make sure to keep observing plants daily so that you detect them early and get rid of them in their initial stages.

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