Spermogonia and aecia are unknown.
Related invasive species
- Phakopsora meibomiae
Related Farm Practice
- Hosts
P. meibomiae is a rust native to the tropical and subtropical regions of the Americas that has a broad host range among legume species. It infects soyabean (Glycine max), but is less aggressive on that host than the Asian soyabean rust species, Phakopsora pachyrhizi, which has invaded and spread widely throughout the Americas. Due to the fact that the American species has not caused epidemics on soyabean in South America or invaded North America, it can be considered to be much less invasive than the Asian species. Given its broad host range, the possibility exists that strains of P. meibomiae could be a threat to other legumes cultivated in warm parts of the world.
Infections occur mostly on leaves, often on petioles, and less frequently on stems. On susceptible species/cultivars, infections result in small yellowish-brown or greyish-brown spots or lesions (TAN-type), which, on soyabean [ Glycine max ], are delimited by the vascular bundles. On some hosts, spots are round rather than angular (Vakili and Bromfield, 1976). Pustules of urediniospores are formed on both the adaxial and abaxial surfaces of lesions, but are more frequent on the abaxial surface. The angular lesions coalesce, turn dark-brown and are covered by buff or pale-brown spore masses as sporulation progresses. When resistant species/cultivars are infected, minute angular reddish-brown spots (RB-type) appear, on which no or only a few uredinial pustules are formed. Sporulation on the RB-type lesions is much less than on the TAN-type lesions (Vakili and Bromfield, 1976;Bromfield et al., 1980;Bonde et al., 2006). Later in the season, lesions may become dark reddish-brown and crust-like;these contain subepidemal telial clusters. The telial stage has been found only occasionally on a few species and not on cultivated soyabeans in the field (Ono et al., 1992).
In the field, P. meibomiae infects and sporulates on 51 species in 20 genera of the subfamily Papilionoideae of the Fabaceae (Ono et al., 1992), with Aeschynomene americana, Canavalia villosa, Crotalaria anagyroides, Lablab purpureus, Phaseolus coccineus, Phaseolus lunatus and Phaseolus vulgaris being the principal hosts.
Neonotonia wightii is one of several alternate hosts of P. meibomiae in Brazil (Carvalho and Figueiredo, 2000).
In addition to these naturally-infected hosts, the following legume species have been shown to be susceptible to this rust species by artificial inoculations: Alysicarpus vaginalis;Cajanus cajan;Cassia occidentalis;Clitoria ternatea;Coronilla varia;Crotalaria spectabilis;Kummerowia stipulacea;Kummerowia striata;Lupinus albus;Lupinus luteus;Melilotus officinalis;Pisum sativum;Pueraria phaseoloides;Sesbania exaltata;Sesbania sericea;Trifolium incarnatum;Trifolium repens (Rytter et al., 1984);Calopogonium mucunoides;Crotalaria grantiana;Crotalaria juncea;Macroptilium atropurpureum;Macroptilium lathyroides;Vigna mungo;and Vigna aff. wilmanii (Ribeiro do Vale et al., 1985);Vigna unguiculata;and Phaseolus aff. longepedunculatus (Vakili and Bromfield, 1976). Although the level of susceptibility observed was low for some species, other isolates of the fungus or other test conditions might have produced more disease.
See Ono et al. (1992) for additional hosts, based on reports and specimens in collections.