Variegation, Petal

the mottled coloring of the petals of various plants. Petal variegation may be viral or genetic. Viral variegation is observed in many ornamentals, including tulips, gladioli, and phlox, that are infected with viruses that cause mosaic diseases. It is characterized by the appearance of light and dark spots and stripes, irregularly distributed over the surface of the petal. The pattern formed by the spots is not repeated. The causative agents of viral variegation are transmitted through bulbs, corms, and tubers, as well as by sucking insects. Plants with viral petal variegation lose their value as a variety and finally die. Control measures include disinfection of planting material and destruction of diseased plants and insects.

Genetic petal variegation is a varietal characteristic that is transmitted in ornamental plants to succeeding generations by seeds, bulbs, corms, and tubers. As with viral variegation, the petals are variegated, but the light and dark spots are usually distributed in a definite order, most often along the margin of the petal. The pattern, as a rule, is repeated.