Orchid White Spots on Leaves: Reasons and Their Solutions 

Orchid white spots on leaves are an issue that can happen for many reasons like over-watering, exposure to low humidity levels and sun, various fungal diseases, etc. If you need to know which reasons apply to your orchid plant, our plant experts are here to help you!

Read on as we thoroughly inspect each one of these reasons and help you find the solution once and for all.

Reasons That Cause an Orchid White Spots on Leaves

The reasons that cause white spots on orchid leaves is because of watering beyond the plant’s needs, exposure to direct sunlight, low humidity levels, different pest infestations, and fungal infestation, like powdery mildew, or Pythium Ultimum that the leaves have been exposed to.

– Overwatering

Orchid leaves have white-colored spots, probably because you have over-watered the plant. You must keep a close on your plants’ watering needs to prevent them from falling prey to deadly fungal diseases.

Constant exposure to water can cause white and oval spots on the orchid leaves. This is because you have been getting out of the regular schedule of the plant and watering it too many times.

– Low-humidity Level

Your plants are more prone to drying out in low humidity. It has often been thought there is little to no need to water the plants if the humidity levels are not high, but that is when they are wrong.

As this matter keeps on going, issues will start to rise, because the plant has the humidity level at an insufficient pace. As a result, you will see tiny spots appear on the leaves with a white outline and can outgrow as huge white patches, spreading to the stem.

– Powdery Mildew

One of the many reasons that can cause spots on the leaves of your beautiful orchid plants is the fungal disease, commonly known as powdery mildew. It forms a layer of spots on mostly the upper surface of the leaves and even white spots on orchid stems.

Another way to be sure that this certain kind of fungus infects your plant is through the shape of the leaves and the way that they have been exposed to a color change. You will mostly find them twisted or disfigured; the buds and growing tips are also disfigured, especially in the growing season, and you will see this on the leaves.

These spores are dispersed easily by wind, so keeping your healthy plants away from the infected plants is better. The disease is not only responsible for the appearance of white-colored spots but also restricts your plant’s growth, and in worse conditions, it reduces the yield and quality of fruit.

– Mealybug Infestation

Mealybugs are tiny insects, barely 0.2 inches long. They mostly have pink to purple bodies but turn to gray or white when covered with a cotton-like wax. If the leaves of your orchids have a white, slime-like secretion on them, the plant may be under attack by the mealy bugs.

Unlike the rest of the pests, like spider mites and aphids that attack the axil and the lower surface of the leaves, mealybugs invade the entire plant. Therefore, white spots on orchid roots are also caused by the crawling mealybugs, and they will be apparent on the leaves specifically, as they also are responsible for the white spots on orchid flowers.

Furthermore, if you live somewhere with a low humidity level or a cold climate, mealybugs are something that you will have to deal with sooner or later. Also, excessive use of nitrogen fertilizers creates favorable growth conditions for the mealybugs.

– Phytophthora Cactorum

The phytophthora cactorum is a fungal disease that spreads up to the root crown area of plants. This black rot fungus affects many species of orchids, and it will cause small white patches on the leaves, often appearing as spots, that progress to black or brown spots in worse conditions.

The fungus produces zoospores that spread by water, which means that it would go to the roots through irrigation. After the matter, you will see the leaf changing colors, at first they will be white little dots, but then as this fungus spreads, it will show black dots.

– Pythium Ultimum

It is another fungal disease exhibiting a cotton candy-like growth. Plants infected by such a fungus go through root rot diseases. Most of its species are found in sand, ponds, field soils, and even through stream water, just about every damp area.

The orchid fungus loves to over-winter in the soil or the plant’s debris. It spreads with water and equipment exposed to the wet, affected grass. It thrives in dense, evergreen grass and prefers lawns that do not have a well-drainage system.

– Sunburned

A small scorched spot is not a major concern as long it does not happen frequently. Most plants and their leaves recover when you place them in a sunny, ventilated spot indoors; however, the spots cover a large surface area, and they will spread as quickly when left as such.

In that case, observing the plant’s behavior is necessary as it can lead to catastrophic consequences of the complete removal of the plant. The top leaves are more affected by sunburn than the lower ones, meaning the dry spots on orchid leaves are more likely to progress to yellow spots and then ultimately to brown or black spots on the upper leaves.

Solutions to Overcome Orchid White Spots on Leaves

The solution to overcome orchid white spots on leaves is to have a fixed watering schedule and make sure to adjust the humidity in the right way.

Tackle the mildew, and control the mealy buys. Use home remedies to tackle fungal infestations, and recover the sunburn.

– Having a Fixed Watering Schedule

If your plant is damaged from over-watering, pull the entire plant out carefully and remove the seeds in the soil. Prune the damaged parts, gently place them in a new container, and start fresh with a new watering schedule.

Having a strictly-followed watering schedule is a guaranteed way of keeping the water intake of your plants in check. You can pot your plants in containers with drainage holes to eliminate any excess water. Insert your finger about an inch deep into the soil, and if it feels dry, it is time to water your plants; so if you are worried about how to get rid of white spots on orchid leaves, you now know what to do with the right watering schedule.

– Adjust the Humidity

A dry plant can cause many other orchid leaf problems, so as we mentioned, it is important to check how frequently you need to water your plant. Keeping the water needs of the plant in check prevents it from wilting.

Therefore, ensure you water your plant according to the surrounding temperature. Always remember that the humidity level would have to be between 40 and 70 percent, and you can check it through a hydrometer or mist around it when the humidity is low.

– Tackling the Mildew

The fungus can also be prevented using herbicides, but you must check with your local nursery to know the kind allowed in your area; however, a homemade fungicide also does the job equally well. All you need to do is mix a teaspoon of baking soda in four cups of water and spray the mixture thoroughly on your plants, as it only kills the fungus with which it comes in direct contact.

You must be wondering how to get rid of white fungus on orchid. An effective solution to prevent mildew from recurring is placing your plants in sunny spots, as the fungus thrives in shaded areas. On another note, you may also prune the neighboring, overcrowding plants to promote air circulation.

– Mealybug Control

If you are sure that mealybugs infest your orchid, cutting off dead or damaged leaves or stem is the first step towards a mealybug-free plant. You must begin by cleaning off any visible mealybugs with the help of a cotton bud. To remove the clingy insects, spray the leaves with soapy water and rinse your plant under warm running water.

You can also apply a homemade garlic tincture on the infested leaves; you must simply boil five garlic cloves and mash them with the same ratio of water. Rub the prepared mixture evenly and thoroughly on the affected areas.

Another effective remedy is using onion-infused water. You should begin by pouring approximately 250 ml of water on a medium-sized onion and let it soak for five to six hours. Spray the infused water on the leaves every week.

– Using Home Remedies for Phytophthora

An easy way to cure Phytophthora is using hydrogen peroxide; note that most households already have it because of its various medicinal uses. You need a three percent solution of hydrogen peroxide for your common orchid.

Begin by mixing one part hydrogen peroxide and three parts water and then apply them to the soil. Do not resume your regular watering sessions until the mixture enters the soil well so that it cleans the roots deeply.

– Clean the Infestation

Most plants recover from the disease, and orchids are one of them. You only need a few things to clean your plants infected from the Pythium, like an old toothbrush, protective gloves, preferably surgical gloves, and seventy percent rubbing alcohol.

Firstly, pour a small amount of the rubbing alcohol into a dish and dip your toothbrush into it. Gently scrub the leaves, especially the infected areas. Repeat it a couple of times a week or until you have clean and healthy leaves like before. To be safe, trim the shriveled flowers to avoid spreading the disease.

– Recovering the Sunburned Leaves

To help the orchid recover from the extreme damage caused by the sun, place your plant in the middle of the room and surround it with shields of fine paper, or curtains. You know your plant is in a controlled environment when the leaves are not too hot to touch because the sunlight has to be indirect for this plant. Furthermore, you can keep your protected plant near the windowsill that receives filtered sunlight to help it bloom better.

Conclusion

Understanding why your orchid leaves have white spots is simple now that you have read our article and even learned how to solve this issue! Let’s summarize the key points we mentioned, so you are fully prepared to help out your orchids:

• Do not water them beyond their need, make sure you stick to your schedule instead.
• Filtered sunlight is more suitable to help the plant grow and bloom and reduce the risks of the feared leaf spots.
• Keep a look-out for the early signs of pest infestation and fungal diseases to avoid the risk of losing your healthy plant.

After reading our recommendations here, you can now take the steps necessary to prevent your orchids from falling prey to fungal diseases and other issues leading to the formation of spots. All solutions related to the mentioned reasons require you to amend your orchid care practices, so happy gardening.