The other day we received this message on our e-mail:
The dragon fruit plant is turning brown and it’s not looking good. The leaves are starting to droop and the stem is starting to wilt. It seems like the plant is dying. I’m not sure what to do. I’ve been watering it regularly and I’ve been fertilizing it, but it doesn’t seem to be helping. I’m not sure if I’m doing something wrong or if there’s something wrong with the plant. Has anyone else had this problem?
So, let’s do a little research to see what’s going on.
Why does dragon fruit turn brown?
Dragon fruit turns brown when it gets too much water, not enough sun, or pests. Pitaya doesn’t need much water, and too much water can make the roots lack oxygen and cause them to rot. It doesn’t usually need to be watered very often. You should only water it when the soil is totally dry.
Don’t forget to let the water in the flowerpot tray drain out. Sunlight can be made brighter, but blazing sunlight should be avoided to keep from getting a sunburn. A small number of bugs can be killed with alcohol. When there are a lot of bugs, spray pesticide.
We’ll talk more about the reasons why the plant may have turned brown next.
Anthracnose
Most of the time, anthracnose (colletotrichum gloesporiodes) happens in places that are hot and damp. In the early stages of the disease, the stem has brown or water-stained spots that are hard to see. The part that is sick is sunk in, and small black spots in a spiral pattern show up on the healthy parts. Plants that are sick should be put in a separate area, their sick leaves should be cut off and burned, and the right pesticides should be used.
Stem rot
Pitahaya often gets a disease called “stem rot”. Over time, the diseased part will become soft and rot. Later on, the stem tissues start to rot and lose water until only the dried skins and the core are left.
There are two ways to stop stem rot.
- To clean the soil and make sure it is clean, loose, and able to let water through, put it in the sun or buy culture soil that has already been cleaned.
- Keep the plant base dry and avoid giving it too much water. If you see stem rot, cut off the diseased part right away and use sulfur powder or charcoal powder to clean the cut. Cut back on watering, repot the plant, and clean the soil.
At the beginning, a mixture of 1:100 bordeaux Mixture can be sprayed on the base of the plant once every 15 days for two or three times.
Bacterial stem rot
Stem rot is a disease that affects dragon fruit. It is caused by a type of the Xanthomonas campestris bacteria. This type of bacteria comes in a lot of different forms that attack a wide range of plants, from vegetables to trees. This stem rot is also called “black rot” because the infected tissue turns dark brown or black.
The spread of this disease needs to be stopped, and one way to do that is to get rid of bugs that spread it. Aphids and mites are common plant pests that can give healthy plants viruses and bacteria.
Fungal stem rot
The stems of dragon fruit plants can be hurt by several types of fungi. The Fusarium oxysporium fungus is a troublesome pathogen that causes diseases on trees, shrubs, and herbaceous plants.
The Fusarium fungus changes the color of infected tissue and makes stems lose their shape. As the decay eats away at the plant’s stems, the damaged shoots eventually break off. Stem disease in pitahaya is also caused by other fungi, such as those in the genus Pantoea.
Nematode that eats roots
The root-knot nematode is a soft bug with two sharp ends and a white thread. When root-knot nematodes attack a plant, the stem and leaves become dark on the outside, and the plant wilts, gets brown spots, and dies over time. Before planting, heat the soil and flowerpot to a high temperature to kill root-knot nematodes.
Root-knot nematodes don’t like high temperatures and can be killed at 55 °C, so using high-temperature disinfected culture soil is a good way to get rid of them.
Virus disease
There are different kinds of viruses that can infect dragon fruit, but the main signs are mosaic leaves and local necrosis. On the stem, you can often see green spots and spots with rings around them. When it’s hot and dry, the plant is more likely to get a virus. Another diseased plant is the main source of infection. So, once this disease is found, the sick plant should be put in a separate area or thrown away. Don’t forget to clean the tools you use to graft and care for plants.
Botryosphaeria dothidea
Botryosphaeria dothidea is the scientific name for the fungus that makes red or brown spots on the stems of pitaya cacti. Most of the time, these spots are flat but slightly raised compared to the normal areas around them. Sometimes one of these spots looks like a bulls-eye. Sometimes, this infection can cause a number of splotches that may join together.
This disease doesn’t seem to be fatal, but it can make plants weaker and cut fruit production by up to 44%. It is quite common in many parts of the world because of the way trees are pruned.
It looks like this disease can also hurt a lot of other plants. For example, this same fungus has been reported to cause panicle and shoot blight and canker diseases of pistachio, peach, apple, forest trees, chaparral bushes, and many other plant species. When it comes to rhododendron plants, heat stress and drought will make the disease worse. We don’t have much information about dragon fruit, so we could look at how this type of fungal infection is treated in other plants.
Other ways to treat Botryosphaeria dothidea plants
For walnuts, the UC California Agricultural Research Center says that if a tree is infected with Botryosphaeria dothidea, you should cut off any dead or diseased branches and avoid watering the canopy with sprinklers.
The fungicides that are approved to treat Botryosphaeria blight in pistachio trees are also listed in the same document about walnut trees. Antifungals like pyraclostrobin and trifloxystrobin are two of the more effective chemicals that can be used to treat pistachio trees.
Spread of Botryosphaeria dothidea
This fungus and other plant diseases can be passed from plant to plant by using the same tools to trim or prune from one plant to the next. Plant diseases can also be spread when plants touch each other.
There are also bugs that feed on sap and can spread disease. In particular, the Botryosphaeria dothidea fungus can be spread to other plants by bugs in the genus Leptoglossus. These bugs are also called leaffooted bugs.
Cactus virus X
“Cactus Virus X” makes the stems of dragon fruit cacti have blotchy spots, mottling, necrosis, and yellowing. Some people call the pattern of light and dark green spots on a branch a “mosaic pattern.” As far as I know, there isn’t much you can do right now for this kind of viral infection.
Bipolaris cactivora
Bipolaris cactivora is the scientific name for another dangerous mold. Pitahaya flowers and fruit can get black-brown spots from this disease. Branch or stem rot can also be caused by this infection.
Spider mites
Spider mites
If your plant has spider mites (there are 6 mm insects on the back of the leaves) the leaves will turn red and then yellow, and there are web-like structures. Wash the backs of the leaves with water, and then spray them over and over with a mite pesticide. Make sure there is enough airflow, so it doesn’t get too hot and dry.
Aphids
Aphids cause dragon fruit to turn yellow or change shape. At the soft parts, you can see small bugs. Get rid of them with water. If there are a lot of aphids, you can spray aphid killer.
Sunburn
Sunburn can look like some of the other diseases above. When a plant is moved quickly from a place with shade to a place with full sun, it can get burned. Sunburns can also happen when plants grow in places with more intense sunlight, like the desert.
This injury can cause areas to turn yellow, harden, scab, and peel. You can expect to see this damage on the South and top sides of the plant, which get the most sun. Also, sunburn can sometimes look a lot like an infection caused by Botryospaheria dothidea.
Pitaya stems can get sunburned from too much heat, especially in the summer. This causes the stems to change color, first turning yellow and then brown. Professional growers put up a 50 percent shade cloth to protect the DF on days when temperatures are expected to be high, like in the high 30s and above. When the temperature is back to normal, you can take off the cover. If your pitahaya is in a pot, you can protect it from the weather by putting it under a tree on a veranda or pergola.
Phototoxicity
Problems with sunburn that are similar to the ones above can also be caused by chemicals that are put on the skin. Most of the time, chemicals like horticulture oils, fungicides, insecticides, etc. that are sprayed on plants can make them more sensitive to the sun. This kind of increased sensitivity to the sun can also happen to us when we put oils and juice from citrus fruits on our skin (esp limes).
The sun and a chemical put on this cactus wound for a short time made a scar on a branch. Once the cause is taken away, the problem shouldn’t get worse. Another way to tell the difference between sunburn and an infection is that the damage doesn’t spread after the chemicals are gone.
Corking
Corking is a normal part of a cactus’s life cycle. During this process, the lower parts of the plant often change into something that looks like hard, dry, grey bark. This should start at the bottom of a plant and move slowly up from there. If a process doesn’t happen slowly from the bottom up, it’s probably not corking.
How diseases spread
Pruning and trimming tools can and will spread all diseases from one plant to another. There is also a good chance that these diseases can be spread when the roots and stems of two plants touch. Some insects, like Leptoglossus sp, can also move infectious diseases from one plant to another.
For some hard-to-treat diseases, many people have said that infected plants should be thrown away and the process should begin again in a different place. Your best bet is to avoid problems in the first place. Check plants before you buy them and keep your tools clean.
Also, make sure your pruners are clean!
It’s very important to clean your pruners and trimmers between plants. There are a lot of diseases that can be spread from one plant to another by cutting and trimming tools. This is true for all plants, but it is especially true for Dragon Fruit cacti, many of which have been infected with systemic diseases because they were not cleaned properly.
There are many ways to clean, such as with alcohol, hydrogen peroxide, and household cleaning products. The chemicals only need to be put on the blade that does the cutting. Before these liquids are properly sterilized, many of them need to be used for a while.
Quick care guides & condition requirement
Many problems can be avoided if you properly monitor and care for the plant. Here is some brief information on proper care. Hopefully, they will keep your plant safe from disease, and you will only see brown spots on dragonfruit in pictures on the internet and not on your favorite plants in the garden.
Planting
Sow, plant, or move plants when the temperature is between 15 and 20 °C in the spring or fall. When seeding, keep the humidity of the air high. Cover the soil with plastic wrap, and then take it off when the seeds start to grow.
Use flowerpots made of porous clay to grow plants. Too big of a flowerpot makes it easy for water to collect, while too small of a flowerpot makes it hard for roots to grow. Before you plant, make sure the soil is in direct sunlight and clean it to kill any pathogens.
Water
Pitaya grows in tropical, subtropical, and semi-desert areas where there is little rain, a lot of sun, and hot temperatures.
The best temperature range for growth is between 20 and 35 °C. If the temperature is below 10 °C or above 35 °C, growth slows and dormancy starts.
The humidity in the air shouldn’t be too high, and the room should have good air flow. Avoid places with a lot of water or humidity.
Dragon fruit is a plant that can survive in dry conditions and doesn’t need to be watered very often. When the soil is completely dry, water it well. When the plant is in a pot, water it slowly, wait for the water to flow out of the bottom, and then pour the extra water out of the tray so that water doesn’t build up.
It grows best in the spring, summer, and fall. Water the soil once or twice a week to keep it moist. In the winter, you should water less. Just make sure the soil doesn’t dry out too much, which is usually once a week. Also, use rainwater or distilled water instead of water from the tap.
There are a lot of calcium, magnesium, and other kinds of mineral salts in tap water. When used for a long time, soil tends to get packed down. When you water it, don’t splash water on the stem so it doesn’t rot.
Sunlight
Pitahaya is a heliophilic plant, which means it grows and blooms best in the sun. It can be put on a balcony or in the garden where there is no shade. But in the hot summer, it shouldn’t be left out in the sun for too long. Instead, it should be kept in the shade or cooled down a bit to protect it from the high temperatures.
Soil
Dragon fruit grows best in soil that is rich in gravel, well-drained, and has a pH of 6-7.
A common recipe for potting soil is 60% vermiculite, 20% coco coir or peat moss, and 20% sandy soil. You can also add a small amount of organic potting soil.
To make the soil better at letting air through, lightweight media like vermiculite can be added. You can also add eggshell powder or worm compost to the soil to make it more fertile.
When there isn’t enough oxygen, dragon fruit roots get very sick. Root rot can happen if the soil doesn’t let enough air and water through. It’s easy to tell if a medium is permeable: when you water it, water should move quickly through it, not pool on the surface and slowly seep down. Every year, repot the plant and break up the soil to make sure it can get air.
Fertilizer
During the growing seasons (spring, summer, and fall), use liquid fertilizer once a month to feed pitaya. In the winter, there is no need for fertilizer. When repotting in the spring or fall, a small amount of slow-release fertilizer can be well mixed into the soil.
Use nitrogen fertilizer when the plants are just starting to grow, and phosphate-potassium fertilizer before and after they bloom. The amount of fertilizer should be as low as it can be. If the base is yellow and grows slowly, it may be because there is too much fertilizer. Stop fertilizing right away.
Pruning
There isn’t much pruning that needs to be done on Dragon fruit. Take off any flowers or branches that have died so the plant can use the nutrients for healthy growth.
Harvest
Most of the pitahaya fruits can be eaten. When the fruit turns red, pick it. When you harvest, use gloves or tools like scissors and other tools.
Propagation
The main ways to spread the plant are by seeding, dividing the plant, and grafting. To divide, cut off the stem’s tip or side branches with a knife and plant them in the ground. After a while, many small shoots will grow near where the tree was cut. When a shoot is big enough, it can be cut off and moved to a new spot to make a new plant.
Seasonal safety measures
In the spring, summer, and fall, when plants grow the most, give them more water and fertilizer. In the summer, stay out of direct sunlight. When it’s too hot, spray water around the plant to cool it down, but don’t let any water stay on the stem. Don’t let water sit in the soil. Stop giving it fertilizer and water as little as possible or not at all in the winter.
Conclusion
In conclusion, it is important to take care of your dragon fruit plant in order to keep it healthy and looking its best. By following the simple tips mentioned in this article, you can help ensure that your plant stays green and vibrant. Keep up the good work, and enjoy the delicious fruit that your pitaya plant will produce!
References / sources
https://link.springer.com/article/10.1007/s00705-005-0617-7
https://link.springer.com/article/10.1007/s12600-011-0143-y
https://hyg.ipm.illinois.edu/article.php?id=407
https://ucanr.edu/sites/sdsmallfarms/files/172477.pdf
https://cetehama.ucanr.edu/files/183227.pdf
https://www.ndrs.org.uk/article.php?id=007025
https://www2.ipm.ucanr.edu/agriculture/pistachio/leaffooted-bugs/
https://www.fabinet.up.ac.za/publication/pdfs/146-2004_denman_crous_sadie_wingfield_austr_pl_path.pdf
