X-rays alter wave length, change color of gems

Abstract

Isolates of Fusaria of the Elegans section cause two major types of disease in Gladiolus. One, a rot of stored corms, has long been known in Britain. The other, probably the same as the North American Fusarium Yellows (McCulloch, 1944), has only recently been recorded here, but is widespread and occurs in nearly all commercial stocks of susceptible varieties.The two diseases have been regarded in America as etiologically distinct, corm rot being attributed to Fusarium oxysporum Fr. var. gladioli Massey, and yellows to F. orthoceras Woll. var. gladioli McCull. This seems not to be so in Britain. Fusaria isolated from rotting corms caused yellows in growing plants and isolates from yellowed plants rotted corms in storage. Whether different isolates caused yellows or corm rot, both or neither, depended on the Gladiolus cultivar to which they were inoculated. Corms that resisted invasion by some isolates formed cambial tissues and cork barriers.The pathogenic properties and taxonomie characters of the different isolates so overlap that it seems most reasonable to classify all of them as F. oxysporum Fr. f. sp. gladioli (Massey) Snyder & Hansen.