Hollies (especially Ilex crenata ), Boxwood, and Citrus. Crops: Tobacco, Cotton, Carrots, and Lettuce.
Pansy, Viola, Calibrachoa (Million Bells), Vinca, Petunia, Poinsettia, and Phlox. black root rot fungus
Black root rot thrives in cool, wet, and often alkaline (higher pH) soil conditions. It is a versatile pathogen, affecting a wide range of plants, including: Hollies (especially Ilex crenata ), Boxwood, and Citrus
In the quiet world of nursery production and home gardening, few pathogens are as persistent—or as devastating—as ( Berkeleyomyces basicola , formerly Thielaviopsis basicola ). This soil-borne fungus operates in the shadows, attacking the plant's foundation and turning healthy, white root systems into decayed, blackened messes, leading to stunted, wilted, or dead plants. The Anatomy of an Infestation Black root rot thrives in cool, wet, and
The Silent Killer: Understanding and Managing Black Root Rot
Above-ground symptoms often mimic nutrient deficiencies, such as yellowing (chlorosis) and stunted growth, causing gardeners to over-fertilize, which only increases stress on the plant. The most distinct sign is a dramatic, firm, blackening of the roots—specifically caused by the buildup of dark chlamydospores. How the Fungus Spreads Black Root Rot - UC IPM