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Dragon Fruit Diseases

Dragon Spots:

Many dragon fruit cacti have spots on their stems and these spots may be sign of an infection. However, other non-infections injuries such as a scaring from physical trauma or sunburn may result in a similar appearance. This article will outline the key characteristics of the most common Dragon Fruit diseases.

Most importantly, having this knowledge will help you to avoid buying infected plants.  In addition, many of these same pitaya problems listed here can also infect other plants in addition to cacti.  Therefore, the information provided below may be transferable to your other garden loved-ones.  The best option is prevention which includes keeping your Dragon Fruit cacti healthy and using sterile pruning techniques.  For a complete guide to growing healthy Dragon Fruit, check out my article on How To Get Your Dragon Fruit Cactus To Fruit.

Botryosphaeria dothidea:

The fungal infection known by the scientific name Botryosphaeria dothidea causes blotchy red/brown spots on the stems of Dragon Fruit cacti.  These spots are typically flat but slightly raised compared to adjacent normal areas.  Sometimes these spots have an appearance of a bulls eye (see first picture below).  Other times, this infection can result in multiple irregular spots that may coalesce together (see second picture below).  This disease may first present as yellow areas on a branch that then develop the darker spots mentioned above. This disease does not seem to be deadly but has been reported to decrease plant vigor and fruit production by up to 44%.  Because of unsterile pruning practices, this disease has become rather common in many parts of the world.

Other plants with this Botryosphaeria dothidea infection:

Apparently, this infection can impact a lot of other plants too. For example, the first article to describe this disease in Dragon Fruit also states that, “This same fungus has been previously reported to cause panicle and shoot blight and canker diseases of pistachio, peach, apple, forest trees, chaparral bushes, and many other plant species.”  In rhododendron plants, heat stress and drought will increase the severity of the disease.  Since we don’t have a lot of data for dragon fruit, we could look to how this fungal infection is treated in other plants for insight.

Other plant treatments for Botryosphaeria dothidea:

For walnuts, the UC California Agricultural Research Center, says that for Botryosphaeria dothidea infected walnut trees, you should prune dead branches or blighted shoots and avoid sprinkler irrigation that wets the canopy.   That same walnut reference document lists the fungicides registered for treating Botryosphaeria blight in pistachio trees.  Some of the more effective chemical treatments for pistachio trees listed are the antifungals pyraclostrobin and trifloxystrobin.  As reference, the product Armada 50 WDG Fungicide contains trifloxystrobin and Bonide Chemical Fruit Tree and Plant Guard contains pyraclostrobin.

In addition, according to the USDA Agricultural Research Center, for apples and pears, copper fungicides have proved effective for Botryosphaeria dothidea in Japan.  I am somewhat skeptical that a topical spray could cure this infection.  However, a topical spray is rather appealing and this would be my personal first attempt at treatment.   As another potential option, a systemic antifungal such as thiophanate-methyl might also work.  The problem with systemics is that they will kill a lot of other good fungi in the soil.  Overall, studies are still underway for Dragon Fruit and (to my knowledge) there is nothing definite for them yet.

Botryosphaeria dothidea spread:

This fungi, (and other plant infections) can be spread by trimming/pruning tools that have not been sterilized between plants. Direct contact between plants can also be a way to spread disease.

There are also sap sucking bugs can also spread disease. Specifically, bugs in the Leptoglossus genus (aka leaffooted bugs) have been known to be a vector that can spread the Botryosphaeria dothidea fungus to other plants. I caught a pic of a Leptoglossus sucking on a flower-bud of one of my Cereus Cacti. The one in the pic below looks a lot like Leptoglossus occidentalis. However, That particular one is said to feed on pine, so it must be some other close relative. Regardless, this genus is a bunch of destructive sapsuckers that can spread disease and are not welcomed. The University of California has a nice short article about what to do about the leaffooted bugs (if you are a pistachio farmer)… but same ideas apply.

For additional reading:

For additional reading on this topic, I have listed some scientific journal references on this Botryosphaeria dothidea fungal infection.

Brown lesions on dragon fruit Dragon Fruit Diseases

‘Fish eye’ lesion caused by Botryospaheria dothidea. Photo from the journal article titled, “A brief overview on pitahaya (Hylocereus spp.) diseases.” (July 2013, Volume 42, Issue 4, pp 437-440)

 

Brown spots on dragon fruit stems. Dragon Fruit Diseases

Dragon Fruit symptoms of stem spots caused by Botryosphaeria dothidea. Image from the journal article titled “Conidial germination of Botryosphaeria dothidea and histological alterations on stems of pitahaya (Hylocereus undatus H.) (Haworth) Britton & Rose.” (Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo vol.45 no.1 Mendoza ene. jun. 2013)

 

Bug spreads dragon fruit, Hylocereus, and Cereus cactus disease

The sap sucking Leptoglossus sp have been known to be a vector that can spread the Botryosphaeria dothidea fungus to other plants.  In this pic above, I believe this insect-parasite which is drinking from my Cereus Cacti might be the specific bug known as Leptoglossus occidentalis). Bastard!

 

Spot disease of Ric Rac Orchid Cactus, Fishbone Cactus, St. Anthony's Rick-Rack (Selenicereus anthonyanus)

This spot disease (Botryosphaeria dothidea) can also infect many other plants/cacti including the ‘Ric Rac cactus’ (Selenicereus anthonyanus). This cactus was happy and healthy inside the house until it was placed outside near an infected Dragon Fruit Cactus. Bummer.

 

Colletotrichum gloesporiodes:

Colletotrichum gloesporiodes (aka Anthracnose) is the name of another fungi that can infect dragon fruit cacti.  The lesions from this fungal infection look like concentric haloes on stems and fruit (see picture below).

  • The journal article, A brief overview on pitahaya (Hylocereus spp.) diseases discusses this disease briefly.
Yellow brown spots on dragon fruit. Dragon Fruit Diseases

Concentric haloes from Colletotrichum gloesporiodes. Photo from the journal article titled, “A brief overview on pitahaya (Hylocereus spp.) diseases.” (July 2013, Volume 42, Issue 4, pp 437-440).

 

Bipolaris cactivora:

Yet another fungal pathogen has the scientific name Bipolaris cactivora.  This disease can cause black-brown spots on dragon fruit flowers and fruit.  This infection can also cause branch/stem rot.

Spots on dragon fruit. Dragon Fruit Diseases

Brown, depressed lesions which may expand to form large areas of rot on flowers and fruits caused by Bipolaris cactivora. Photo from the journal article titled, “A brief overview on pitahaya (Hylocereus spp.) diseases.” (July 2013, Volume 42, Issue 4, pp 437-440)

 

Dragon fruit branch rot. Dragon Fruit Diseases

Dragon Fruit branches with ‘dry stem rot’ caused by Bipolaris cactivora. Image from the article titled, “First report of Bipolaris cactivora causing fruit blotch and stem rot of dragon fruit pitaya in Israel.” (Phytoparasitica; April 2011, Volume 39, Issue 2, pp 195-197)

 

Cactus virus X:

‘Cactus Virus X’ causes blotchy chlorotic spots, mottling, necrosis and yellowing on dragon fruit cactus stems (see picture below).  The pattern of of light and dark green areas on a branch is sometimes referred to as a mosaic pattern.  As far as I know, there is not much you can currently do for a viral infection such as this.

Cactus Virus X on Dragon fruit stem. Dragon Fruit Diseases.

‘Cactus Virus X’ on Dragon fruit stem. Image sourced via an online ppt from Deborah Mathews, Ph.D at UC Riverside

 

Stem soft rot caused by Enterobacteria:

This wet rotting disease typically infects the ends of dragon fruit branches.  This infection is caused by the gram negative bacteria called Enterobacteria.  I have seen this type of thing burn itself out and I have also seen it take over a plant.  To be safe, I would cut off the diseased branch(es) at a point where there was no visible sign of disease.  Then carefully dispose of the sick branch and sterilize your cutting tools when done.  Studies have shown that the rotting appears 15 days after inoculation with the bacteria.  Apparently, plants deficient in calcium and nitrogen may develop more severe symptoms.  On that note, keeping your Dragon Fruit cacti healthy may help you to avoid this disease.

  • Additional info about this rotting infection can also be found on the article titled, A brief overview on pitahaya (Hylocereus spp.) diseases.
We rot on dragon fruit stems. Dragon Fruit Diseases

Symptoms of ‘soft rot’ from Enterobacteria infection. Images from the journal article titled, “A brief overview on pitahaya (Hylocereus spp.) diseases.” (July 2013, Volume 42, Issue 4, pp 437-440)

 

Disease transmission:

All infectious diseases can-and-will be transmitted from plant to plant by pruning/trimming tools.   There is also a strong possibility that these diseases can also be spread by direct contact of roots and stems that touch each other.  Some insects (such as Leptoglossus sp mentioned above), can also spread infectious disease from plant to plant.

For some difficult diseases, many have advocated destroying infected plants and starting over in a different location.  Your best bet is prevention; inspect plants before you buy and keep your tools clean. On that note….

Sterilize your pruners!

  • It is really important to sterilize your trimmers/pruners between plants.  There are many infectious plant diseases that are unknowingly spread from plant to plant by cutting/trimming instruments.   This is true for any plant, but particularly so for Dragon Fruit cacti… many of which have been infected with systemic diseases because of sub-optimal sanitizing techniques.
  • There are a many sanitizing options including household cleaning solutions, alcohol, and hydrogen peroxide. These chemicals only need to be applied to the cutting blade. Many of these liquids require some application time before they are adequately sterilized.
  • Another faster option is heat sterilization of your cutting blade with something such as a small hand held torch. The torch technique, is convenient and fast, but obviously results in the tips of your trimmers being hot… Which are then a potential burn hazard to you and to your plants… as well as being a general fire hazard.   Definitely don’t try burning things in your garden/yard if you are in a fire danger area (which is most of California).  And my favorite disclaimer of all,  “don’t try this at home.”
  • Interestingly, I just found this other tool that actually spritzes your hand pruners with sterilizing fluid with each cut. I have no idea how well this product works, but it is an interesting take on addressing the problem. For reference, here is a link to that product Hand Pruners with Spray Applicator.
  • While I was getting my hair cut today another thought came to mind.  I wonder if that Barbicide chemical they put hair cutting scissors in would also kill unwanted plant microbes.  Seems like it should do the job, and apparently it is fully biodegradable.  All of that said, I have never heard of anyone else using a barbers/hair salon disinfectant such as Barbicide for this purpose.

Noninfectious injury:

Sunburn:

Sunburn can have an appearance similar to some of the other diseases listed below. Sunburn can be a problem when a plant is moved quickly from a shady area to a full sun location. Growing in areas of more intense sunlight such as the desert can also lead to sunburn injury.

This injury may present as areas of yellowing, corking, scabbing and pealing.  You can expect this injury to be seen on the most sun exposed sides of the plant (South/top of the plant).  On that note, sunburn can also sometimes look very similar to Botryospaheria dothidea infection. However, the distribution of the stem lesions should be different. Specifically, if something looks questionable but is on the under-surface of a plant, then it is not sunburn.  In this situation, you should consider one of the infectious diseases listed above as the cause.

Cacti disease Hylocereus

Sunburn on a Cereus Cactus branch.  This branch turned and is now lying on the ground resulting in a sudden increase in sun exposure to just one part of the branch.  The same thing can happen to Dragon Fruit cacti. Note, only the most sun exposed side of the branch got sunburn.

 

Cactus pealing disease

Close up of the same sunburn seen above on a Cereus cactus branch.

Phototoxicity:

Sunburn problems similar to the above can also be the result of increased sensitivity to sunlight from topical chemicals. This phototoxixcity is classically the result of spray chemicals such as horticulture oils, fungicides, insecticides, etc which can increase sensitivity to the sun.  By example, this type of increased sensitivity to the sun can also happen to us people as a result of topical exposure to oils and juice from citrus (esp limes).

This topical cactus injury results in a scar on a branch from a short term chemical exposure + sun. Once the offending agent is removed, the problem should not spread.  This lack of spreading after removing the chemicals is another way to help differentiate between sun injury and infection.

 

Corking:

Corking is a normal part of cacti aging. In this process, lower parts of the plant often mature-change to a hard, dry, grey bark-like appearance.  This should first occur from the bottom of a plant and slowly work its way up from there.  If a process does not follow this slow ‘bottom-up’ progression, then it is probably not corking.

About Thomas Osborne, MD

Dr. Osborne is a Harvard trained Radiologist and Neuroradiologist who loves to share his insight about medicine and gardening.

16 comments

  1. Hi Dr.,

    I wish you would leave a reply box within each blog you write. This reply does not concern Dragon Fruit, instead I’m adding some information on Mosquitos. Please insert this into your blog on them. I use crumbled Neem leaves in my rain barrels and any other standing water. Also if you distill Neem leaves in water for a day or so you can use it as a pesticide spray on yourself (is does smell pretty bad, but it works).

    • Thomas Osborne, MD

      Hey Steve
      Thanks for the great comment and awesome idea.
      Genius really… I wasnt aware that the chemicals in the leaves was strong enough to kill the insects when diluted in water like that
      Do you grow Neem trees?
      If not, where do you get your Neem leaves?

      Sorry you were not able to add a comment to the bottom of the mosquito article. I am looking at that article now on another browser and I see there are several other comments on that mosquito article. Must be some strange glitch. If you could try looking at the end of that article again to see if it is working now, that would be great. Thanks.

      Thanks!

  2. Capt. Michael Buzzard

    Dr.,
    I am located on the central coast of California about 3 miles from the beach with marine layer prevalent most of the year. My Pink Dragon Fruit are planted in full sun. The plant is approximately 6 years old and was started from a cutting. I fertilize only with well composted Chicken manure, and have been fertilizing 3 times a year fall, spring and mid-summer. The plant at 3 years developed 1 fruit, at 4 years 3 fruits, at 5 years 5 fruits. Now in the 6th year I counted 10 blossoms. My questions are would you advise: (1) I thin the blossoms? (2) should I prune some of the “wild branches” at this time? (3) should I apply fertilizer during the blossoming stage? (4) I have some Botryosphaeria dothidea spots and thought to apply Neem Oil during the blossoming stage. I am opposed to using a systemic due to contamination of the soil and ultimately the fruit ….. your thoughts?
    Thanks in advance for you reply.
    Buzz

    • Thomas Osborne, MD

      Buzz

      Thanks for the great questions.
      Overall, my approach is more of a treat well and let it be ‘laissez faire‘ attitude.

      Per your questions:
      (1) I dont thin out the blossoms. I figure the more cross pollination material floating around out there the better.

      (2) I do sometimes prune the wild branches, but more for propagating others and for general practical navigation/aesthetics. There are some who say that cutting back branches just before flowering and/or fruiting will help with production. However, I have not found that to be the case myself.

      (3) I have some organic fertilizer brewing just about all year long. I tend to amp up in the spring and early summer to match nitrogen needs of growth. I know fertilizing can help/hurt some other plants fruit production at flowering time. However, I dont have any direct observational experience to know either way. In the wild, these plants are often growing in the tops of jungle trees and likely get bird pooped-on all year. So, I would be surprised if it would impact fruiting. But I really dont know. Please let us know if you happen to find any info on the subject.

      (4) Yea, I would also like to get to the bottom of the Botryosphaeria diothidea treatment plan. Here is what I know so far.
      I have no idea if neem would work. However, I suspect that the disease is at least somewhat present deep in the tissue and the superficial neem may not make it that deep into the plant.

      Last year, I took some new growth cuttings from otherwise infected plants. These cuttings did not have any external signs of the disease when I took the cuttings. They have been growing in isolation in the other side of the property and so fat only 2 out of 10 have a few spots on them. This suggests to me that the disease is not completely systemic.

      I also suspect (just my guess) that the spots represent the site where sap sucking bugs take a bite and deposit the infection. That would explain the spots in areas where parasitic bugs are likely to be feeding.

      Finally, I have been in contact with a plant pathologist with the California agriculture department about this disease to get some concrete data because there is all kinds of unsupported info out there about how to deal with it. Anyways, I submitted some infected plant samples last week so I am just waiting for a reply. Ill let you know what I discover.

      Best,
      Tom

  3. Hamid reza Alidadi

    hi.
    I plant pitaya behind my window and its about 3 month old the height is 14 centimeter and .5 centimeter wide .its very soft I make a grow area with lamp with more than 35 centigrade degree and 7000 lumen ful spectrum light with air freshner but when the lamp is off pitaya get too soft and fall down plant on the edge of the pot and I must to belt it I water it every time saw the soil is dry the soil is peatmoss .is it a disease or water problem or light problem or?

    • Thomas Osborne, MD

      Hi Hamid
      Good question.
      It is hard for me to tell for sure based on just a written description.
      However, it sounds like your plant might be dehydrated.
      A well watered dragon fruit cactus will be firm.

      Although these plants are cacti, they need much more water than your typical desert cactus.
      However, you can also over water them if not careful.
      They do best with frequent deep watering. The frequency of watering will depend on the environment, however, you dont want the soil to get bone dry. The soil should also be rich and well draining.

      Best of luck,
      Tom

    • hi hamid

      You’re living in Iran?

  4. Hi Tom,

    Our dragon fruit cactus fruit season was over by November. But infections are all over cactus strands. Friend suggested treatment with water soaked with Neem leaves. Effect is random, some cactus branch have been cleared of infections but others still have spots or soft brown segments.

    I look forward to more effective remedial measures, and will appreciate your advise.

    Ernest Leung, Angeles, Philippines.

    • Thomas Osborne, MD

      Hi Ernest
      Thanks for the note.
      What type of disease do you have?
      You mentioned spots and soft areas; spots makes me think possible Botryosphaeria dothidea infection, and the soft areas could potentially be Enterobacteria infection.
      (Since they are caused by different types of infections, there are different treatment options for each).
      Best,
      Tom

  5. This is great information. I live in St. Lucie County, Florida and am working on raising a few. Some are doing better then others, I wish I knew someone close to me with experience that could help, lol. Please keep this information highway open!!! Thank you

    • Thomas Osborne, MD

      Thanks for the great feedback Michele
      Your also fortunate; Florida provides a great climate for dragon fruit.
      Best,
      Tom

  6. Hi Thomas
    I am Situated in the Northern Part of South Africa in the sub-tropical town of Tzaneen. We have extremely favorable climate for growing dragonfruit.
    I have noticed one of my plants to develop a soft rot in the middle of the base like an insect caused injury. the whole base rot I scratched it open and covered it with antiseptic pruning liquid and it seemed to stop the infection. although the whole one side of the plant rot away. I do have pictures. Please I am just concerned about it being the beginning of an epidemic. It is very hard for us to get cuttings and I would really like to keep them safe.
    Please reply with email address to send pictures.
    Best Regards
    Bennie

    • Thomas Osborne, MD

      Hey Bennie
      Thanks for the note,
      Sorry about your soft-rot problem.
      I have noticed this happening to physically damaged branches (from insects, rubbing, and even cold).
      Sounds like you are doing exactly what I would have done.
      Best,
      Tom

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