A dragon fruit plant turning yellow is often due to an environmental factor that is stressing the plant. Being able to identify the cause is the first step in finding a remedy for the situation.
The common causes of yellowing dragon fruit plants are too much sun, stem rot, overwatering, disease and pests.
In this article, we will discuss the different causes of yellowing dragon fruit plants and how to remedy each one.
Why is my dragon fruit plant turning yellow?
Too much sun
Dragon fruit is a type of cactus which means it tends to do well in places with little rain and plenty of sun, but there is such a thing as too much sun for this plant. Dragon fruits do best when in a semi-tropical climate, where they can get just the right balance of sun and cold.
When the outside temperature is over 100 degrees Fahrenheit, the plant can get sunburnt and experience summer stress.
You can check if the plant has been getting too much sun by squeezing its branch. If the branch feels firm, it likely still has moisture inside. If the branch feels dry and snaps, it may be in need of moisture and is getting more sun than it needs.
You can try to protect the plant from the sun by covering it with burlap or a shade cloth. A shade cloth can block out 75% of the sunlight and might affect the fruit’s sweetness, or fruit production in general. You can also use plant guard or sunscreen for the dragon fruit plant. This sunscreen is made of organic paint powder and plant oils which, when applied to the plant, protect it from the extreme heat. If the plant is in a pot or container, you can move it to a cooler spot in your home while also giving it water to help it recover.
There are varieties of dragon fruit, like the Tricia, that naturally produce a white powder that helps protect them from both extreme heat and cold. One downside of this variety, though, is the thorns.
You can also plant the dragon fruit in an area that has plenty of large trees that provide enough shade to protect it from the sun. Younger plants also tend to be more affected than mature plants. The older the dragon fruit plant, the more resistant and heat-tolerant it becomes, so it does not turn yellow as easily from too much sunlight.
Stem rot
Another common cause of yellowing dragon fruit plants is stem rot. Symptoms of dragon fruit plants that have stem rot include susceptibility to various diseases, smaller fruit, stunted growth, easily sunburnt, and a lower drought tolerance.
The fungi that usually cause stem rot are prevalent in tropical countries because they thrive in heat and humidity. It is possible that the spores are already present in a healthy plant, where they may have been transferred by contaminated tools or insects.
These spores are waiting for the perfect opportunity to attack. They do so when the plant’s immune defences are weak. It is tricky to pinpoint infected plants, especially if they are reasonably healthy. The best way to prevent stem rot is to prevent any opportunity for infection from happening in the first place. Make sure your plant is well-nourished and healthy.
The most common causes of stem rot that turn the dragon fruit yellow are the Erwinia carotovora and Xamthomonas campestris bacteria.
It has also been observed that plants with nitrogen and calcium deficiencies are more susceptible to severe soft stem rot. These infections usually start from injured areas on the plant and spread from there. It can start from a sunburn or a spot caused by a fungus.
You can treat stem rot by pruning the dying stems. Remember that these diseases are spread through infected tools, so make sure you sterilize all the tools you use after each cut so you do not spread the disease to other plants. You can sterilize the tool by soaking it in an alcohol solution, a 10% bleach solution, or by running the blade over a flame in order to kill any pathogens on it.
You can use any form of copper fungicide, such as copper sulfate, to spray on the affected areas to help control the stem rot in its early stages. The copper fungicide will not treat the stem rot, but it can prevent the disease from developing further.
Another way to prevent stem rot is to whitewash the plant. This is when you paint the plant’s susceptible areas with a solution containing a fixing agent, insecticide, fungicide and lime. This solution prevents disease from developing in the first place.
Overwatering
When your dragon fruit plant is overwatered, it can lead to root rot. The roots of your plant turn brown or black and become weakened, and the nutrient transport system in the roots becomes ineffective, adding to the possible reasons for your dragon fruit plant turning yellow.
Do not overwater your dragon fruit plant, as this can also cause the little particles in the green branches of your plant to burst and become yellow. All of the excess water also makes the plant more vulnerable to bacteria and fungi.
The roots can be further weakened if you use too much fertilizer. In order for the soil to be ideal for your plant, you need well-draining soil, just enough fertilizer, and just enough water.
Pests
Dragon fruit plants also deal with their fair share of pests. Pests that suck the sap from the plant, such as the leaf-footed Leptoglossus, are believed to be the vector of the fungus Botryosphaeria dothidea. Other insects that might infest your dragon fruit plant include fruit flies, beetles and ants.
Conclusion
Dragon fruit plants can turn yellow as an indication of stress due to environmental factors, which need to be identified and remedied as soon as possible.
The most common causes of yellowing dragon fruit plants are too much sun, stem rot, overwatering, disease and pests.
It is essential to be able to quickly and correctly identify the problems that affect your dragon fruit, because this can dictate the potential outcome of your fruit yield.
Image: istockphoto.com / HuyThoai