SPORANGIA WITH SPORANGIOPHORES in conglomerations on all above-ground plant organs, under discoloured, protuberant epidermis when young, later, after its tearing, dusty. The conglomerations are 0.5-2 mm diam and frequently connect with one another. Infected plant organs frequently are deformed, curved, and have processes of a different shape.

SPORANGIOPHORES (sp) clavate, 22-41 x 7-17 µm, with a highly thickened wall at their base, occur in a compact layer.

SPORANGIA (s) globose or slightly angular, thin-walled, 11-22(-28) µm.

OOGONIA colourless, thin-walled, 45-60 µm diam.

OOSPORES with a brown, thick, episporium, ornamented with large, globose or irregular warts.

PLANT HOST AND DISTRIBUTION. Albugo candida affects numerous species of the family Brassicaceae. The fungus commonly occurs in Poland and the other regions of the world (Kochman and Majewski 1970).

NOTES. The specialization of isolates of A. candida has been reported (Smith et al. 1988).

Albugo candida grows biotrophically as intercellular mycelium forming small spherical haustoria.

Primary infections are by zoospores arising from oospores in the soil or plant debris. Then, spread is by airborne sporangia that release zoospores on the surface of the plant host which encyst and penetrate directly.

REFERENCES

Kochman J., Majewski T. 1970. Grzyby (Mycota) IV. Glonowce (Phycomycetes), Wroslikowce (Peronosporales). Warszawa, 308 pp.

Smith I. M., Dunez J., Lelliott R. A., Phillips D. H., Archer S. A. 1988. European handbook of plant diseases. Blackwell Scientific Publications.