Black stem rust reduces big sagebrush seed production.

Abstract

We conducted an experiment to determine the effects of a rust disease on big sagebrush (Artemisia tridentata Nutt.) seed production. We ranked 760 plants as to disease intensily in an established 'Hobble Creek' mountain big sagebrush (Artemisia tridentata ssp. vaseyana Rydb. Beetle) seed-increase garden. These rankings were divided into 4 classes: I. very light intensity; II. light intensity; III. medium intensity; and IV. heavy intensity. Three years after planting all plants in the test showed signs of infection. The heavier the infection the fewer seeds produced. Cost of the rust disease was estimated at about $3,862 ha(-1).