Uromyces ciceris-arietini, the Cause of Chickpea Rust: New Hosts in the Trifolieae, Fabaceae.

Uromyces ciceris-arietini has been reported on Cicer arietinum (chickpea) and Medicago polyceratia. Plants of Medicago polymorpha in Riverside and San Diego, CA were collected with severe rust caused by U. ciceris-arietini.

First Report of Uromyces striatus on White Sweetclover in Kansas.

Rust was observed on leaves and stems of Melilotus alba Medik. plants in Riley County, Kansas, in November 1999. Rust reoccurred during the summers of 2000 and 2001.

Reactions of Accessions in the Annual Medicago Core Germ Plasm Collection to Erysiphe pisi.

Reaction to Erysiphe pisi was evaluated in the annual Medicago core germ plasm collection of 199 USDA Plant Introduction accessions from 33 species. Seedlings at the first trifoliolate leaf stage were inoculated with conidia and maintained in growth chambers for 21 days at 20°C, 70 to 90% relative humidity, and a 12-h photoperiod. Beginning 4 days after inoculation, plants with the first sign of powdery mildew were recorded and removed daily.

Reactions in the Annual Medicago Core Germ Plasm Collection to Two Isolates of Peronospora trifoliorum from Alfalfa.

Peronospora trifoliorum causes downy mildew of alfalfa throughout the temperate regions of the world, but little is known about its host range within the annual Medicago species (medics). Several medics have characteristics potentially beneficial to sustainable agriculture programs and to the genetic improvement of alfalfa. Therefore, we evaluated resistance in 199 accessions representing 33 species of the annual Medicago core germ plasm collection to P.

Powdery Mildew Caused by an Oidium sp. on Twenty-One Annual Medicago spp. in California.

Powdery mildew was observed in plots of USDA Plant Introduction accessions of medic plants grown for seed increase at Riverside, CA, from 1995 to 1998. White, diffuse to dense, amphigenous mycelia bearing Oidium conidia appeared on shoots in April each year and remained active until the last plants matured in June. Invaded leaflets became necrotic and dropped prematurely, sometimes leaving a green petiole.