Yellow nutsedge control with rust (Puccinia canaliculata (Schw.) Lagerh.) collected in Salisbury, MD., was evaluated alone or in combination with pebulate at 1.7 or 3.3 kg ai ha-1 in transplanted tomato. Foliar applications of urediniospores in mid-June did not affect the yellow nutsedge population; however, tuber biomass was reduced 32%. In July, yellow nutsedge infection was manifest as an increase of phytotoxicity from 2.3 to 4.1 (0 to 10) and of disease incidence increase from 3 to 37%. Pebulate, 3.3 kg ha-1 reduced the yellow nutsedge population and ground cover by 79 and 90%, respectively, in June, with a 48% reduction of both tuber population and biomass in September. Tomato yields were not increased by rust or pebulate treatments. Marketable tomato yield was increased 46% by handweeding. Yellow nutsedge control was not enhanced by the combination treatments of pebulate followed by rust inoculation.
