Tuberculina and the Life Cycle of Uromyces koae

Abstract

Koa rust (Uromyces koae Arthur ex Stevens) was reported on koa (Acacia koa Gray) in Hawaii in 1925 (Stevens, 1925). Two spore stages were described, uredia covering parts or usually all of the surface of hypertrophied shoots and telia in discrete spots on otherwise normal leaf tissues. The two stages were apparently considered to be related on the basis of association on the same host. Recently the occurrence, characteristics, and effects of koa rust in Hawaii Volcanoes National Park (HVNP) were discussed but attempts to infect with either spore stage failed (Gardner, 1978). Field observations led to the discovery of the frequent association of Tuberculina maxima Rostrup with the rust on hypertrophied shoots. Morphology of the hyperparasite was similar to T. maxima on Cronartium ribicola Fischer and C. quercuum (Berk.) Miyabe ex Shirai f. sp. fusiforme (C. fusiforme Cumm.) (Hubert, 1935; Kuhlman and Miller, 1976). This is the first report of a species of Tuberculina in Hawaii.