Choanephora cucurbitarum

Choanephora cucurbitarum
Scientific classification
Kingdom:	Fungi
Order:	Mucorales
Family:	Choanephoraceae
Genus:	Choanephora
Species:	C. cucurbitarum
Binomial name
Choanephora cucurbitarum (Berk. & Ravenel) Thaxt., (1903)
Synonyms
Choanephora americana A. Møller, (1901) Choanephora heterospora B.S. Mehrotra & M.D. Mehrotra, (1962) [1961] Choanephora infundibulifera f. cucurbitarum (Berk. & Ravenel) Schipper Choanephora mandshurica (Saito & H. Nagan.) F.L. Tai, (1934) Choanephora simsonii D.D. Cunn. [as 'simsoni'], (1895) Choanephorella cucurbitarum (Berk. & Ravenel) Vuill., (1904) Cunninghamella mandshurica Saito & H. Nagan., (1915) Mucor cucurbitarum Berk. & Ravenel, (1875) Mucor curtus Berk. & M.A. Curtis, (1875) Rhopalomyces cucurbitarum Berk. & Ravenel, (1875) Rhopalomyces elegans var. cucurbitarum (Berk. & Ravenel) Marchal, (1893)

The fungus Choanephora cucurbitarum is a plant pathogen that causes fruit and blossom rot of various cucurbits. It can also affect okra, snap bean, and southern pea, and may cause a stem and leaf rot of Withania somnifera. Wet weather, high temperature and high humidity favor disease development from inoculum that is typically soil-borne. Signs of infection on fruits or leaves include water-soaked, necrotic lesions, which progress rapidly under ideal conditions. As the fungus begins to produce spores, affected tissues become dark grey-brown and hairy as a result of the superficial sporangia.

Description

Sporangiophores bearing sporangiola are erect, hyaline, unbranched, and apically dilated to form a clavate vesicle, from which arise dichotomously branched, distally clavate secondary vesicles. The sporangioles are indehiscent, ellipsoid, brown to dark brown with distinct longitudinal striations and measure 12-20μm x 6-12μm. Sporangia are multispored, spherical, initially white to yellow, pale brown to dark brown at maturity and measure 40-160μm. Sporangiospores from sporangia are ellipsoid to broadly ellipsoid, brown to dark brown, indistinctly striate with fine hyaline polar appendages, and measure 16-20 µm x 8-12 µm (Saroj et al. 2012).

External links

• APS: Choanephora fruit rot on squash. APS publication number IW00007.
• Index Fungorum
• USDA ARS Fungal Database

References

• P. M. Kirk. Mycol. Pap. 152:1, 1984.
• A. Saroj, A. Kumar, N. Qamar, M. Alam, H.N. Singh and A. Khaliq. 2012. First report of wet rot of Withania somnifera caused by Choanephora cucurbitarum in India. Plant Disease 96(2): 293.2. doi:10.1094/PDIS-09-11-0801