Cystotheca lanestris, the live oak witch's broom fungus, is a species of mildew that infects buds and induces stem galls called witch's brooms on oak trees in California, Arizona, and Mexico in North America.[2][3] Witch's brooms are "abnormal clusters of shoots that are thickened, elongated, and highly branched."[4] This fungus infects coast live oaks, interior live oaks, canyon live oaks, valley oaks, and tanoaks, and is most commonly found along the coast.[2] Research published in 2023 newly describes this fungus as also growing in association with Quercus laceyi and Q. toumeyi.[5]
| Cystotheca lanestris | |
|---|---|
| |
| Cystotheca lanestris witch's broom symptom on coast live oak, Los Angeles County, California, 2024 | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Leotiomycetes |
| Order: | Erysiphales |
| Family: | Erysiphaceae |
| Genus: | Cystotheca |
| Species: | C. lanestris
|
| Binomial name | |
| Cystotheca lanestris (Harkn.) Miyabe (1909)
| |
| Synonyms[1] | |
| |
According to the U.S. Forest Service Treesearch Department:
C. lanestris mycelium primarily grows on the lower leaf surface...The white mycelium turns tan to brown with age. The fungus can cause systemic infections that induce the formation of witches' brooms...Leaves on witches' brooms are small and senesce early...The entire broom becomes white when the fungus sporulates, and may either die out over the winter or produce either more brooms or normal shoots the following season.
While this fungus is technically considered a plant disease, most infections are harmless "except possibly in small seedlings".[4] Cystotheca lanestris is considered widespread in California.[4]
References
edit- ^ "GSD Species Synonymy. Current Name: Cystotheca lanestris (Harkn.) Miyabe, in Ideta, Handb. Pflanzenkrankh. Japans (Tokyo)(1): 226 (1909)". Species Fungorum. Retrieved 8 February 2024.
- ^ a b Russo, Ronald A. (2021). Plant Galls of the Western United States. Princeton University Press. pp. 91–92. doi:10.1515/9780691213408. ISBN 978-0-691-21340-8. LCCN 2020949502.
- ^ "Live Oak Witches' Broom Fungus (Cystotheca lanestris)". iNaturalist. Retrieved 2023-10-23.
- ^ a b c Swiecki, Tedmund J.; Bernhardt, Elizabeth A. (2006). A Field Guide to Insects and Diseases of California Oaks. Pacific Southwest Research Station (Report). Gen. Tech Rep. PSW-GTR-197. Albany, California: U.S. Forest Service Treesearch Department. pp. 82 (widespread), 83 (description), 87 (impact on tree health). doi:10.2737/PSW-GTR-197.
- ^ Bradshaw, Michael; Braun, Uwe; Quijada, Luis; Coombes, Allen J.; Contreras-Paredes, Carlos; Pfister, Donald H. (2023-05-04). "Phylogeny and taxonomy of the genera of Erysiphaceae, part 3: Cystotheca". Mycologia. 115 (3): 427–436. doi:10.1080/00275514.2023.2194172. ISSN 0027-5514. PMID 37159342.
External links
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