| Scientific Name | Basidiophora entospora Roze & Cornu, Annls Sci. Nat., Bot., sér. 5 11: 89 (1869) |
|---|---|
| Synonyms | 6 synonyms= Peronospora entospora (Roze & Cornu) Berk. & Broome, Ann. Mag. Nat. Hist., Ser. 4, 7: 432 (1871)
= Peronospora basidiophora Roze & Cornu, Bull. Soc. Bot. France 25: 294 (1878) = Peronospora simplex Peck, (Annual) Rep. New York State Mus. Nat. Hist. 31: 45 (1879) = Gilletia spinuligera Sacc. & Therry, Michelia 2: 587 (1882) = Plasmopara entospora (Roze & Cornu) J. Schröt., Kryptog.-Fl. Schles. 3(1), Pilze 1: 237 (1886) = Basidiophora montana R.W. Barreto, Bot. J. Linn. Soc. 107: 323 (1991) |
| Disease | Downy mildew |
| Taxonomic Rank | |||
|---|---|---|---|
| Order | Peronosporales | Family | Peronosporaceae |
| Host Plant | |||
|---|---|---|---|
| Common Name | Horseweed (망초) | Scientific Name | Erigeron canadensis (=Conyza canadensis) |
| Distribution | Circumglobal where the host plant is growing |
|---|---|
| Characteristics | Lesions commonly causing slight discoloration of the tissues, rarely defined, and vein-limited; spots sometimes coalesce and cover larger areas. Down hypophyllous, white to greyish, consisting of scattered sporangiophores. Sporangiophores arising singly or in small numbers through stomata, hyaline, clavate, unbranched, slender, straight, gradually enlarging toward the distal end, (200.0–)237.1–271.5–305.8(–330.0) μm long; basal end usually bulbous; callose plugs absent. Apical vesicles (18.0–)20.5–23.5–26.4(–28.0) μm diam., ending in swollen tips. Sporangia hyaline, ovoid to subglobose, (19.2–)21.0–22.6–24.3(–25.1) μm long, (17.1–)19.9–21.6–23.3(–24.3) μm wide, l/w ratio (0.84–)0.96–1.05–1.14(–1.38) (n = 30). |
| Notes | Basidiophora entospora was traditionally considered a morphologically distinctive downy mildew with a broad host range among members of the Asteraceae. Constantinescu (1998) restricted Basidiophora to a single species, B. entospora, by treating B. montana as its synonym and transferring B. kellermanii to the genus Benua. However, molecular phylogenetic analyses subsequently revealed several distinct, apparently host-associated lineages within Basidiophora, indicating that the formerly broad concept of B. entospora probably included several cryptic species (Sökücü and Thines 2014). In the same study, Peronospora simplex on Symphyotrichum novae-angliae was recognized as a distinct species and transferred to Basidiophora as B. simplex. The subsequent description of B. delawarensis from Solidago sphacelata further demonstrated previously underestimated species diversity within the genus (Wallace et al. 2018). Basidiophora entospora sensu stricto is closely associated with Erigeron canadensis (= Conyza canadensis), the host on which the species was originally described. Therefore, older records of B. entospora from other asteraceous hosts should be interpreted cautiously unless supported by molecular evidence. In Korea, B. entospora on E. canadensis was first reported by Shin and Choi (2003), and the Korean material was morphologically consistent with previously described specimens of this species. |
| Economic importance | Erigeron canadensis is a widespread and economically important weed in agricultural and disturbed habitats. Basidiophora entospora causes downy mildew on this host, producing chlorosis, leaf distortion, and whitish to greyish sporulation on the lower leaf surface. However, direct economic losses attributable to the disease have not been documented. Because E. canadensis is a troublesome agricultural weed, B. entospora has also attracted interest as a naturally occurring pathogen potentially affecting weed populations, although its practical value as a biological control agent has not been established. In Korea, downy mildew caused by B. entospora on E. canadensis has been recorded since 2003 (Shin and Choi 2003). |
| References | Constantinescu, O. 1998. Nova Hedwigia 66:251–265. Shin, H. D., and Choi, Y. J. 2003. Mycotaxon 86:249–267. Sökücü, A., and Thines, M. 2014. Mycol. Prog. 13:1137–1143. Wallace, E. C., et al. 2018. Mycol. Prog. 17:1283–1291. |
