Witch's Broom

Witch's Broom is not a specific genetic clone, but rather a pathological condition or symptom characterized by abnormal, hyper-clustered growth. In *Trichocereus* and other cacti (such as *Lophophora*), it manifests as extreme, dense clustering of growth points, stacking pups, and abnormal white areolar fluff.

Because it is a disease state or symptom rather than a cultivar, there is no standard rib count, spine length, spine color, or epidermis color. Instead, the physical presentation is defined by: * Hyper-clustering: Growth points stack rapidly. True Witch's Broom presents growth that is at least “3X” more clustered than a typical active growth point. * Abnormal Fluff: Excessive white areolar wool or fluff often accumulates around the stacking pups. * Aborted Meristems: Pest damage or infection can cause the main growing tip to terminate, leading to a massive flush of lateral pups.

It is easily confused with benign genetic mutations (such as crested or monstrose growth forms, particularly in cultivars like “Olivia” which are prone to funky growth in crosses like Olivia x Jess), natural caespitose growth habits (e.g., *Lophophora williamsii f. caespitosa*), or localized pest damage from mealybugs, mites, or caterpillars. Early-stage monstrose growth or hormonal changes in reverting plants can also mimic these symptoms.

The term “Witch's Broom” historically refers to a deformity in woody plants, but in cactus cultivation, it describes a highly feared, infectious condition. The primary pathogen associated with the infectious form of the disease is a Mycoplasma-Like Organism (MLO), also known as a phytoplasma. Scientific literature, such as *Advances in Tissue Culture and Eliminating of the Pathogeny of Witch-Broom Disease (MLO)*, documents the pathology of this condition.

While the exact origin of the pathogen in *Trichocereus* collections is undocumented, it is widely recognized as a highly contagious systemic threat. However, the term is also used colloquially by growers to describe non-infectious, look-alike growth anomalies caused by environmental stress, hormonal imbalances in reverting monstrose plants, or severe pest damage.

Managing suspected cases of Witch's Broom requires immediate action to protect the rest of the collection: * Quarantine: Immediately isolate any suspect plant. Suspect plants should be kept at a significant distance (e.g., 200 yards) from the main collection. * Culling (Infectious Phytoplasma): If true infectious Witch's Broom (MLO) is suspected, the consensus recommendation is to destroy the plant entirely. Burning the plant, pot and all, is advised to prevent it from spreading. * Surgical Therapy: For valuable specimens or cases suspected to be pest-induced, growers have attempted surgical removal. This involves cutting off all affected parts with an isopropyl alcohol-sterilized knife, dusting the wounds with sulfur, removing all feeder roots, dipping the main root in a diluted hydrogen peroxide solution, and repotting in fresh soil. * Pest Control: If the clustering is caused by pests (such as mealybugs or caterpillars terminating the meristem), treat the infestation immediately. Once the pests are eliminated, the plant may resume normal growth. * Environmental Evaluation: Before culling, assess if the growth is a reaction to nutrients or lighting, as certain genetic lines (like “Olivia” crosses) display similar funky growth under specific environmental conditions.

Analysis of the discussion.

The community is divided on whether “Witch's Broom” should be defined strictly as the infectious phytoplasmic disease (MLO) or as a general symptom of meristem damage.

Kelly Beth Costello provides scientific backing linking the disease to MLOs, emphasizing its rapid spread and recommending immediate destruction of infected plants. Sam Payne clarifies this distinction, noting that while pest-induced damage can mimic the symptoms and clear up after treatment, the phytoplasmic bacterial form is highly contagious and fatal.

Conversely, Cody Hinds and ScrapGoat Benjamin view it as a symptom that can be triggered by stress, pests, or pathogens. Topic authority Gee Bee warns that genetic mutations, particularly in “Olivia” crosses, are frequently misidentified as Witch's Broom when they are actually showing systemic environmental responses to lighting and nutrients. Thomas Lauritzen provides a diagnostic rule of thumb, stating that true Witch's Broom will be at least three times more clustered than a normal active growth point.

* Gee Bee is recognized as a topic authority (10/10) whose expertise overrides general speculation, particularly regarding environmental and genetic factors in specific cultivars like “Olivia”. * Kelly Beth Costello (8/10) and Sam Payne (8/10) provided highly detailed, scientifically grounded explanations distinguishing infectious phytoplasmic pathogens (MLOs) from pest-induced symptoms. * Thomas Lauritzen (7/10) and Matt Olson (7/10) offered clear, actionable diagnostic criteria regarding clustering density and genetic mutations. * Johnathon Siwiec (7/10) provided a detailed, step-by-step treatment protocol based on direct cultivation experience. * ScrapGoat Benjamin (6/10) and Cody Hinds (6/10) provided helpful general advice and conceptual framing, though they noted their limitations in expert-level experience.