Witch's Broom

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.

• 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.

• 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.

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.