Witch's Broom [San Pedro Cactus Wiki]

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====== Witch's Broom ======
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===== Description =====
Witch's Broom is a pathological condition and growth symptom in cacti, characterized by highly abnormal, hyper-clustered growth. It affects various species, including //Trichocereus// and //Lophophora//.  This pathogen is highly contagious and spreads rapidly through collections. It is not curable, and left to run its course eventually ends in plant death.
  * **Rib Count:** In affected areas, distinct ribs are typically absent or highly reduced due to the extreme density of the stacking growth points.
  * **Spines:** Spines on the clustered pups are often miniature, dense, and can range from light yellow to brown, though they are frequently obscured by excessive areolar wool.
  * **Epidermis:** The epidermis remains light to dark green in early onset but turns yellow to red as the disease progresses and growth outpaces nutrient availability. In heavily afflicted areas the epidermis is heavily crowded by the rapid proliferation of new shoots.
  * **Areoles:** Areoles in the affected zones often produce an abundance of dense white fluff or wool.
  * **Foolproof tell:** Pups on pups on pups. Pups coming out of every areole of other recent pups.

=====Origin =====
  * **Pathological Origin:** True Witches Broom is caused by a Mycoplasma-Like Organism (MLO), a type of phytoplasma.
  * **Pest Induced spread:** The phytoplasma infection can spread from insects feeding on afflicted plant areas, then feeding on other healthy plants.

===== Commonly confused with =====
  * **Monstrose growth:** This condition is easily confused with natural monstrose, crested, or caespitose growth forms (such as //Lophophora williamsii f. caespitosa//). Certain monstrose genetic lines, such as crosses involving the cultivar "Olivia", are highly prone to throwing funky, clustered growth that can be confused with Witch's Broom.
  * ** Pest damage:** Non-infectious broom-like growth can be triggered by physical damage to the meristem. Sucking pests like mealybugs, mites, or caterpillars can damage the growing tip, causing it to terminate and throw a dense cluster of lateral pups. If pests are treated growth will eventually return to normal.

===== Cultivation Notes =====
Proper management of suspected Witch's Broom is critical to protecting a collection:
  * **Quarantine:** Immediately isolate any suspect plant. Keeping it quarantined at a significant distance (e.g., 200 yards) from the main collection is highly recommended while monitoring the growth.
  * **Culling:** If infectious phytoplasmic (MLO) Witch's Broom is suspected, the safest course of action is to burn or trash the plant, pot and all, to prevent rapid spread.
  * **Surgery:** For valuable specimens showing localized or pest-induced damage, growers have successfully excised the affected parts. Use a knife sterilized with isopropyl alcohol to cut away the clustered growth. Dust the wounds with sulfur. Keep quarantined for an extended time period to ensure broom type growth does not reappear.
  * **Pest Management:** Closely inspect the grow area for pests. Treat for whatever pests are present. This should help prevent spread and reintroduction.

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===== Community Discussion & Citations =====
//Analysis of the discussion.//
The community discussion centers on distinguishing true infectious Witch's Broom from benign look-alikes. Experienced growers emphasize that "Witch's Broom" is often used as a catch-all term for a set of symptoms rather than a single disease. While the phytoplasmic (MLO) variant is highly contagious and destructive, many cases of "brooming" are actually caused by localized pest damage (such as mealybugs or caterpillars terminating the meristem) or genetic mutations.

In particular, crosses involving the cultivar "Olivia" are noted for naturally producing funky, highly clustered growth points that can easily be mistaken for the disease. Topic experts advise adjusting environmental factors like nutrients and lighting before panicking, as these genetic lines frequently exhibit systemic responses to cultivation inputs.

^ Date ^ Speaker ^ Key Insight/Quote ^
| 2026 (approx) | Gee Bee | "No, Olivia is known for funky growth in crosses. This is systemic environmental; nutes, lighting etc." |
| 2026 (approx) | Kelly Beth Costello | "I would burn it, pot and all or it spreads fast." |
| 2026 (approx) | Sam Payne | "Witches broom is the name for a set of symptoms not a specific disease. So this looks like witches broom caused by pest insects, once treated it hopefully will clear up. Phytoplasmic bacterial witches broom is the nasty contagious hard to treat one that people burn plants about." |
| 2026 (approx) | Thomas Lauritzen | "Does not look like WB to me. Looks like a active grow point. WB will be 3X this "clustered". You are good" |
| 2026 (approx) | Matt Olson | "I'm not an expert on the broom, but I don't think it's brooming. If this was just a regular non monstrose cactus, I would be more suspicious. Which is broom, does affect the hormone levels But this just could be the mutation." |
| 2026 (approx) | ScrapGoat Benjamin | "Oh yeah. My opinion id say quarantine. cut it off. Dust with sulfur. Let it heal. Or you could let it go but if it actually is broom and you let it go you might regret it" |
| 2026 (approx) | Cody Hinds | "witch's broom isn't a disease, it is a symptom. Sometimes it is caused by viral, fungal, bacterial, or insect infestations, sometimes it is caused by heat or sun stress." |

===== Contributor Confidence =====
//Visible to trusted reviewers only.//

^ Contributor ^ Confidence ^
| Gee Bee | 10/10 |
| Kelly Beth Costello | 8/10 |
| Sam Payne | 8/10 |
| Thomas Lauritzen | 7/10 |
| Matt Olson | 7/10 |
| ScrapGoat Benjamin | 6/10 |
| Cody Hinds | 6/10 |


===== Credibility Notes =====
* **Gee Bee:** Recognized as a premier topic authority on Trichocereus genetics. Their expertise on "Olivia" crosses and environmental growth triggers overrides general community speculation.
* **Kelly Beth Costello:** Provided direct scientific literature citations regarding Mycoplasma-Like Organisms (MLO) and offered clear, actionable biosecurity advice.
* **Sam Payne:** Provided a highly detailed, accurate botanical breakdown distinguishing between pest-induced meristem termination and contagious phytoplasmic infections.
* **Thomas Lauritzen & Matt Olson:** Offered consistent, detailed diagnostic criteria regarding clustering density, hormonal shifts, and genetic mutations.
* **ScrapGoat Benjamin & Cody Hinds:** Provided solid, practical cultivation advice and accurate conceptual definitions of the symptom, backed by years of observation.
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