Alcea "Alcea" species are used as food plants by the larvae of some Lepidoptera species including "Bucculatrix quadrigemina" and "Vanessa cardui", the painted lady. The mallow flea beetle ("Podagrica fuscicornis") is a pest that makes tiny holes in the leaves. Cutworms, aphids, and capsid bugs use the plant as a food source in hotter and drier conditions. A number of weevils use "A. rosea" as their host plant, including "Rhopalapion longirostre", "Alocentron curvirostre", and "Aspidapion validum". The plants are also susceptible to the pathogenic fungus "Puccinia malvacearum", the hollyhock rust. A hollyhock flower, known in Japan as , was incorporated into
Pityriasis rosea which cause roseola in infants. Experienced practitioners may make the diagnosis clinically. If the diagnosis is in doubt, tests may be performed to rule out similar conditions such as Lyme disease, ringworm, guttate psoriasis, nummular or discoid eczema, drug eruptions, other viral exanthems. The clinical appearance of pityriasis rosea is similar to that of secondary syphilis, and rapid plasma reagin testing should be performed if there is any clinical concern for syphilis. A biopsy of the lesions will show extravasated erythrocytes within dermal papillae and dyskeratotic cells within the dermis. A set of validated diagnostic criteria for pityriasis rosea is