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| ====== Witch's Broom ====== | ====== Witch's Broom ====== |
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| ===== Overview ===== | ===== Description ===== |
| Witch's Broom is a highly feared condition in cactus cultivation characterized by abnormal, hyper-clustered growth. While some growers view it as a symptom triggered by environmental stress or pests, it is widely associated with infectious pathogens that can rapidly spread through a collection. Proper identification is critical, as benign genetic mutations and environmental stress can easily be mistaken for the disease. | 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. |
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| ===== Symptoms & Identification ===== | =====Origin ===== |
| Witch's Broom causes extreme, dense clustering of growth points. According to Thomas Lauritzen, true Witch's Broom will present growth that is "3X" more clustered than a normal active growth point. | * **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. |
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| It is frequently confused with: | ===== Commonly confused with ===== |
| * **Genetic mutations:** Crested or monstrose growth forms. Matt Olson notes that hormonal changes in reverting plants can throw a bunch of pups that mimic the disease. | * **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. |
| * **Cultivar quirks:** Cultivars like "Olivia" are known for throwing funky growth in crosses. | * ** 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. |
| * **Pest damage:** Scarring or damage from insects can cause localized, abnormal growth clusters. | |
| * **Caespitose forms:** Naturally multi-headed growth habits. | |
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| ===== Cause & Spread ===== | ===== Cultivation Notes ===== |
| The underlying cause of Witch's Broom is a subject of discussion among growers: | Proper management of suspected Witch's Broom is critical to protecting a collection: |
| * **Pathogenic Cause:** Kelly Beth Costello cites scientific literature identifying Witch's Broom as a disease caused by Mycoplasma-Like Organisms (MLO). | * **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. |
| * **Environmental/Stress Cause:** Cody Hinds suggests that Witch's Broom is a symptom rather than a single disease, potentially triggered by viral, fungal, bacterial, or insect infestations, as well as heat or sun stress. | * **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. |
| * **Systemic Environmental Factors:** Topic authority Gee Bee states that abnormal growth in certain cultivars (such as Olivia crosses) is actually "systemic environmental," driven by factors like nutrients and lighting. | * **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. |
| * **Transmission:** The disease is highly contagious. Kelly Beth Costello warns that it "spreads via every means available" and spreads quickly. ScrapGoat Benjamin also notes that letting the disease go unchecked can result in it infecting an entire collection. | * **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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| ===== Treatment & Management ===== | <ifauth @trusted_grower,@admin> |
| * **Quarantine:** Suspected plants should be immediately isolated far away from the main collection. | ===== Community Discussion & Citations ===== |
| * **Culling (Recommended for true WB):** Due to the high risk of transmission, Kelly Beth Costello advises to "burn it, pot and all" rather than risking the collection. | //Analysis of the discussion.// |
| * **Surgical Removal & Disinfection:** For localized damage or valuable plants, some growers attempt to salvage the plant. Johnathon Siwiec reported success by cutting off all affected parts using an isopropyl alcohol-sterilized knife, dusting the wounds with sulfur, removing feeder roots, dipping the main root in a diluted hydrogen peroxide solution, and repotting in fresh soil. | 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. |
| * **Environmental Adjustment:** Before destroying a plant, evaluate if the growth is simply a reaction to lighting or nutrients, as advised by Gee Bee. | |
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| ===== Reported Cases ===== | 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. |
| //Community examples - the photos above belong to these reporters; credit them.// | |
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| ^ Date ^ Reporter ^ Diagnosed by ^ Confidence ^ Key note / quote ^ | ^ Date ^ Speaker ^ Key Insight/Quote ^ |
| | 2026-04-27 | Wes Byers | Gee Bee | 10 | "No, Olivia is known for funky growth in crosses. This is systemic environmental; nutes, lighting etc." | | | 2026 (approx) | Gee Bee | "No, Olivia is known for funky growth in crosses. This is systemic environmental; nutes, lighting etc." | |
| | 2026-06-01 | Johnathon Siwiec | Kelly Beth Costello | 7 | "It spreads via every means available, not worth it to me to threaten a collection." | | | 2026 (approx) | Kelly Beth Costello | "I would burn it, pot and all or it spreads fast." | |
| | 2026-06-22 | John Alan Steigenberger | Thomas Lauritzen / Matt Olson | 6 | "Does not look like WB to me. Looks like a active grow point." / "I don't think it's brooming... could just be the mutation." | | | 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." | |
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| ===== Notes & Contradictions ===== | ===== Contributor Confidence ===== |
| There is a ongoing division in the community regarding whether Witch's Broom is always an infectious disease or if it can be a general symptom of stress. While some contributors attribute the growth to pests or heat stress, Kelly Beth Costello provides scientific backing linking it to MLO (phytoplasmas). | //Visible to trusted reviewers only.// |
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| Importantly, Gee Bee clarifies that funky, clustered growth on certain cultivars (specifically "Olivia" crosses) is often not a pathogen at all, but rather a "systemic environmental" response to nutrients and lighting. Growers should rule out genetic mutations and environmental factors before assuming a plant has infectious Witch's Broom. | ^ 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 | |
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| | ===== 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. |
| | </ifauth> |
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| ===== References ===== | |
| * **Topic Authority:** Gee Bee | |
| * **Contributors:** Kelly Beth Costello, Thomas Lauritzen, Matt Olson, Cody Hinds, ScrapGoat Benjamin, Johnathon Siwiec | |
| * **Photo Credits:** Wes Byers, Gil Tsap, John Alan Steigenberger | |
