The purpose of this guide is to help you as an orchid owner protect your orchids and keep them alive for the seasons to come to enjoy their beautiful blooms and shapes. This post will focus on identifying if your orchid is suffering from common orchid diseases:

• Disease
• Fungus
• Issues related to the care given to your plants

In this busy day and age, it is important to be able to get answers you can trust in a quick manner so that you can resolve any issues that may arise promptly and intelligently.

Sympodial Orchids

Cattleya, Oncidium, and Dendrobium are the more common examples of sympodial orchids that you would find. Sympodial orchids have a rhizome, pseudobulbs, leaves, and flowers.

The rhizome is the stem of sympodial orchids and it produces roots as well as new growth that emerges above the potting mixture upon which pseudobulbs, leaves, and flowers grow.

The pseudobulbs are the storage system of sympodial orchids, they contain the nutrients and water that the orchids can draw upon in times of drought to sustain themselves.

The addition of pseudobulbs makes it not as necessary to water as often as you would need to with a monopodial orchid. There are two different types of pseudobulbs, a front bulb, and a back bulb. The plant also has a sheath to protect new leaves and an eye at the pseudobulb where new growth forms.

Monopodial Orchids

Most of the orchids that are sold in local grocery stores or other stores which you would most likely pick up as your indoor orchid of choice are phalaenopsis aka “Moth” orchids.

These orchids fall into the category of monopodial orchids. Monopodial orchids have a central main stem and don’t have a rhizome.

They grow vertically, leaves and flowers come from nodes that are on the stem. Vanda, another monopodial orchid, sometimes has fresh baby growth called “Keiki” which will sometimes grow at the base of the stem. These Keiki can be removed and grown on their own to create a whole new orchid. Unlike sympodial orchids, monopodial orchids don’t have any storage system for water and nutrients and therefore require more frequent watering.

Monopodial orchids have aerial roots with a gray-colored shelling that can absorb moisture and protect the root beneath. The inside of the aerial root is coated with a substance called velamen, which allows the aerial roots to absorb moisture and help keep the orchid hydrated.

Many orchids use their aerial roots for photosynthesis, along with their leaves. The aerial roots are above ground which leaves them exposed to sunlight and this gives orchids an extra opportunity to get energy. As the orchid grows, it will lose leaves towards the bottom and may have aerial roots.

Vocabulary Lesson

These are a list of terms used in regards to orchids and are here to use as a reference when continuing on in this guide to caring for an ailing orchid. When I was first learning about orchid care, I found that I needed to remind myself of care guidelines based on these words.

Foot Candle

Measurement of light used when referring to how much light a plant needs. The amount of light put off by a candle a foot away is what a foot-candle is talking about. Low light is 100-300, medium 300-600, and high 700-1200 foot candles. It isn’t necessary to calculate the exact foot candle when trying to get enough lighting for your plant. You can also use shadows to tell how strong the lighting is, the crisper the shadow, the higher the foot-candle.

Mixture

Sphagnum moss, Redwood bark, lava rock, gravel, cocoa husk, fur fiber and more are forms of mixture solutions for orchids. You need to place orchids in a mixture that will allow for air room for the roots as well as material that won’t allow water to sit for long periods while still allowing for the orchid to retain moisture.

A Few More Words To Learn

Reverse-osmosis Water

Water that has nearly all of the minerals removed from it.

Water softener

There are two basic solutions that soften the water for your plant and one uses salt and the other uses potassium chloride. The salt one is okay to use if you plan on doing reverse osmosis on it afterward because then any harmful salt will be removed. The softener that uses potassium chloride is fine because there won’t be any long-term damage to your plant in the long term from the potassium chloride.

Basic Problems You May Encounter

Depending on the type of orchid you have, you will have different symptoms that you can use to diagnose whatever it
is that’s ailing your orchid. Let’s take a look at possible problems that your orchid make be exhibit and how to diagnose it.

Orchid Getting Too Much Water?

Common problems with under watering your orchids:

Signs of an overwatered orchid:

• Wrinkled leaves.
• Shriveled up pseudobulbs.
• Yellowed and droopy leaves and wrinkled.
• Bud blast: the bud on your orchid will fall off instead of blooming. The appearance of wilting and yellowed bottom leaves.

Thirsty?

Common problems with under watering your orchids:

• An orchid that is under-watered will generally have the same appearance as an orchid that is over-watered. The reason for this is that in either case the roots have become damaged and are no longer getting the water that they require.
• You can water orchids every seven to ten days or longer depending on if the soil is dry in the pot. We don’t want to have wet soil left in the pot because then root tot will happen and this can kill the orchid.
• You should water orchids in the earlier part of the day so they will have time to absorb the water and dry.
• If you feel the need to mist your plants in order to create the type of humidity they would encounter in their natural environment, be wary. It isn’t in the best interest of your orchid to have water left sitting in the crevasses of the leaves because as is the case with the roots, there can be an incidence of rot and the possibility of fungal growth.

A Couple Of More Problems

Air Flow

Having nice airflow is important because it will allow the orchid to dry out and the leaves won’t be left with still water sitting on them that can lead to the aforementioned possibility of fungus or rot.

Pot Size

Choosing the correct pot size for your orchid is important in ensuring that your orchid won’t become overwhelmed when it comes to watering. Orchids don’t like to have a whole lot of room in their pot and the roots should be proportionate to the amount of mixture you are using.

If there is too much extra space and mixture in the pot, then the roots won’t be able to absorb all of the water. The mixture will hold the water and the roots will stay wet, leading to root rot.

Keeping the orchid in a tighter fitting pot will ensure that the roots are able to absorb the water and that in a week to ten days, you will see a dry mixture in the pot and will know it is time to re-water.

Common Orchid Diseases and Maladies

The following are common orchid diseases that your plants may be susceptible to, as well as their distinguishing features.

Crown Rot

The Phalaenopsis and Vanda orchids are the most susceptible to Crown Rot. Rotten brown soft spot forms where the leaves are growing from the stem for monopodial or from the Rhizome on sympodial orchids. This is a fungal infection that is caused by water left standing in the crown of the orchid.

Brown Rot

This is a bacterial infection that causes a brown and soggy water spot to form on the leaves of your orchid. If left unchecked, the rot can spread to the roots or pseudo-bulb and cause even more extensive damage. The amount of time it takes to spread and do serious damage you the orchid depends on what kind of orchid you have. For phalaenopsis, there are only two to three days worth of time before the whole plant could be lost to rot.

Botrytis petal blight

Aka “Gray Mold” prefers damp, cool conditions with limited lighting and poor airflow. This is a spore-borne mold that get aggressive during damp times such as spring and can lay dormant near your plant until the opportune time arrives. The mold will show itself to you in the way of small black or brown spots on the leaves of your orchid and made spread to cover more than just the petals of the bloom if the conditions are good.

Black Rot

This infectious disease prefers high temperature and humidity to thrive and will originate in the leaves, roots, or any new leads on the plant. The disease appears in the form of a black to purplish discoloration at the center of the plant or on the pseudobulb or rhizome. When the disease spreads to the pseudo-bulb or leaf of the plant, the leaf will fall off.

Brown Scale

An insect that can appear on any surface of the orchid, including the Rhizome or roots in some cases. Males have a cotton appearance and females are light yellow to dark brown in color, they are oval in shape. The scale insect will first be an egg that is protected by its mother’s hard shell and then hatches into a larva that will move to find a place to feed on your orchid.

Once the larva finds a suitable place to feed, it will again form a protective shell that will harden making it more difficult to eradicate. The scale moves easily from orchid to orchid when they are in close proximity and can cause a serious infestation. When your orchids infected with Scale you will see the hard small-shaped ovals dotted on your orchid and the plant may have cotton web-looking material.

Black Rot

Due to the highly infectious nature of black rot, it may be best to avoid attempts at saving the orchid and discard it before any of your other plants are infected. In the future, you can take care to avoid black rot by spraying your orchid with a fungicide before the humid times when this fungus will flourish.

Bacterial Brown Spot

Affects Phalaenopsis and Cattleya and appears as a small water blister at first and then as it progresses it becomes dried out and turns from a green color to a dark brown or black. In Phalaenopsis, this is a quick-spreading disease that will kill the orchid if allowed to reach the crown. In Cattleyas, the disease is slower spreading and is not as likely to be fatal as is with Phalaenopsis orchids.

Fusarium Wilt

The leaves of orchids infected with this disease are thin, yellow, and shriveled and may fall off. The Rhizome of the orchid will have a pink band around it, or in severe cases, the Rhizome will be completely purple. The disease will starve the plant by blocking off its vascular system and stopping the ability for water flow.

Solutions to Orchid Diseases

Crown Rot

First off, you can avoid crown rot from starting by not allowing water to gather and sit in the crown of your orchid, and also by watering early in the morning to ensure that your orchid has time to dry out before nightfall. If you do get crown rot, you can treat it with an application of hydrogen peroxide until the peroxide no longer fizzles when you apply it to the crown.

Brown Rot

Remove the infected area of the plant and treat it as well as any orchids that may be near a bactericide. A bactericide will kill any of the bacteria and help protect your plant as well, phyton 27 or physan 20 should work well.

Botrytis Petal Blight

Remove the infected bloom from the orchid to eliminate Botrytis. It may also be helpful to try increasing the night temperature slightly as well as reducing the humidity and increasing the airflow.

Scale

Separate the infected orchid from other plants to control the infestation and either spray the plant or apply hydrogen peroxide directly to the plant with a soft brush. If the infestation is severe, you may want to consider sacrificing the orchid for the safety of other orchids, if you want to try to save it you can use pesticides and make sure the roots aren’t infected.

Bacterial Brown Spot

As with Brown Rot, the solution is the same approach of removing any infected tissue and applying a fungicide. You will also need to spray any plants that are near as well as spray the infected orchid several times to ensure the bacteria is eradicated.

Fusarium Wilt

In order not to carry over the Fusarium Wilt, ensure that you remove all parts of the pseudobulb and rhizomes that show any signs of purple. Be careful that the part of the orchid that you are trying to salvage has no purple showing, also be sure to clean any tools you are using to cut in between each cut and sterilize the orchid you are saving in thiophanate methyl.

Keeping an Eye Out for Common Orchid Diseases

Armed with the proper knowledge of common orchid diseasse and care-related issues, you as the caregiver will now be better able to save the orchid that you are tending to from certain or slow demise.

This guide was intended to provide a basic care guide and how to in regards to when you start to notice that things are going south for your orchid and you want to try to nip the problem in the bud. Remember that under-watering and over-watering can have similar-looking effects and that you need to take a look at how often you have been watering and the moisture condition of the potting mixture to determine which is probably the cause.

Also, remember to be vigilant if your orchid is infected with a fungus or a bacteria because these problems can transcend to other orchids you may be caring for as well as possibly other household plants.

I wish you the best in your journey as an orchid caregiver! Orchids are a resilient plant and with the right atmosphere and attention to care, they will thrive in your home.